ANALYSIS OF CORROSION FATIGUE FOR

COMMERCIALLY PURE TITANIUM USING

NITROGEN ION IMPLANTATION

NURDIN ALI

A thesis submitted in

fulfillment of the requirement for the award of the

Doctor of Philosophy

Faculty of Mechanical and Manufacturing Engineering

Universiti Tun Hussein Onn Malaysia

APRIL 2014

v

ABSTRACT

The objective of this research is to determine the corrosion fatigue behaviours for

commercially pure titanium (CpTi) using nitrogen ion implantation. A series of

studies was conducted to obtain the mechanical properties, corrosion resistance and

fatigue and corrosion fatigue behaviours and to develop model prediction of

corrosion fatigue life of nitrogen ion implanted CpTi (Nii-Ti). Initially, nine

specimens of CpTi were implanted nitrogen ion with the energy of 80, 100 and 115

keV and dose of 0.5x1017

, 1.0x1017

and 2.0x1017

ions/cm2 to characterize its surface

properties and to obtain corrosion resistance. The result shows that energy of 100

keV and dose of 2.0x1017

ions/cm2 was the optimal implanted parameter. In the

second study, fatigue and corrosion fatigue test were performed to investigate the

fatigue and corrosion fatigue behaviours. The fatigue specimens were implanted with

the energy of 100 keV and dose of 2.0x1017

ions/cm2. The fatigue tests were carried

out for Nii-Ti specimens in saline solution and for CpTi and Nii-Ti specimens in

laboratory air by means of axial loading condition at stress level between 240 and

320 MPa. The results were nitrogen ion implantation improved slightly the fatigue

life of CpTi and Nii-Ti with the fatigue strength of 250 MPa and 260 MPa,

respectively. Finally, the prediction of corrosion fatigue life was developed based on

corrosion pit growth law. The stress amplitudes of 250, 260 and 280 MPa were

selected to measure penetration rate of specimens at various elapsed times using

electrochemical method in saline solution, then established the empirical model. The

result shows that the expression fits the experimental data well. In conclusion, the

effects of nitrogen ion implantation on surface properties and adhesion strength of

nitride layers improved the fatigue and corrosion fatigue life of Nii-Ti.

vi

ABSTRAK

Objektif kajian ini ialah untuk menentukan tingkah laku lesu kakisan untuk titanium

komersil murni (CpTi) menggunakan nitrogen ion implantasi. Satu siri kajian telah

dijalankan untuk menentukan sifat-sifat mekanikal, rintangan kakisan, kelesuan dan

tingkah laku lesu kakisan dan membangunkan pengiraan daripada model hayat lesu

kakisan CpTi setelah ditanamkan ion nitrogen (Nii-Ti) Dalam kajian awal, sembilan

spesimen CpTi yang telah ditanamkan ion nitrogen dengan tenaga 80, 100 dan 115

keV dan dose 0.5x1017

, 1.0x1017

dan 2.0x1017

ions/cm2 untuk ciri-ciri sifat

permukaan dan rintangan kakisan. Hasil kajian menunjukkan bahawa tenaga 100

keV dan dose 2.0x1017

ions/cm2 adalah parameter optimum penanaman itu. Dalam

kajian kedua , ujian lesu dan kakisan lesu telah dijalankan untuk melihat lesu dan

hayat lesu kakisan. Spesimen lesu telah pun ditanam ion nitrogen dengan tenaga 100

keV dan dose 2.0x1017

ions/cm2. Ujian lesu dengan dijalankan bagi spesimen CpTi

dan Nii-Ti dalam persekitaran makmal dan ujian lesu kikisan untuk spesimen Nii-Ti

dalam larutan masin dengan keadaan beban paksi dalam julat tegasan antara 240

MPa. dan 320 MPa. Berdasarkan kajian ini didapati bahawa penanaman ion nitrogen

meningkat sedikit hayat lesu CpTi dan Nii-Ti dengan kekuatan lesu masing-masing

iaitu pada 250 MPa dan 260 MPa. Dalam kajian akhir terhadap angaran hayat

kakisan lesu telah dibangunkan berdasarkan hukum pertumbuhan kakisan lubang.

Amplitud tegasan 250 MPa, 260 MPa dan 280 MPa telah dipilih untuk melihat kadar

penusukan yang terjadi terhadap specimen Nii-Ti pada pelbagai masa berlaku

mengunakan kaedah elektrkoimia dalam larutan masin; kemudian menubuhkan

model empirik bagi anggaran hayat kakisan lesu. Keputusan kajian menunjukkan,

pengiraan dan ujikaji boleh dibandingkan dan bersesuian juga. Sebagai kesimpulan,

kesan penanaman ion nitrogen pada sifat-sifat permukaan dan ketegasan lekatan

lapisan nitrida boleh meningkatkan hayat lesu dan hayat lesu kakisan Nii-Ti.

vii

TABLE OF CONTENTS

TITLE

DECLARATION

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

ABSTRAK

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

LIST OF SYMBOLS AND ABBREVIATIONS

LIST OF APPENDICES

iv

v

vi

vii

xii

xvi

xvii

xx

CHAPTER 1 INTRODUCTION

1.1. Background of research

1.2. Problem statements

1.3. Objective

1.4. Scope of research

1

1

2

3

3

viii

1.5. Contributions of research

1.6. Thesis organization

4

4

CHAPTER 2 LITERATURE REVIEW

2.1 Titanium in biomedical applications

2.2 Mechanical Loading imposed on an implant device

in human body

2.3 Ion implantation technique for surface modification

2.3.1 Review of ion implantation technique

2.3.2 Theoretical prediction of penetration depth

2.3.3 Surface modification of CpTi by nitrogen

ion implantation

2.4 Corrosion effects associated with biological

environment

2.4.1 Corrosion forms of pure titanium

2.4.2 Effect of nitrogen ion implantation on

corrosion resistance of titanium

2.5 Fatigue and corrosion fatigue of metals

2.5.1 Mechanism of corrosion-fatigue

2.5.2 Stress -life approach in corrosion fatigue

2.5.3 Crack initiation in corrosion fatigue

2.5.4 Crack propagation in corrosion fatigue

2.6 Trends in fatigue of titanium in various

environment

2.6.1 Fatigue of titanium in laboratory air

6

6

9

11

12

15

15

17

17

19

20

23

23

25

28

31

32

ix

2.6.2 Corrosion fatigue of titanium in SBF

environment

2.7 Trends in corrosion fatigue modeling

2.8 Fatigue life prediction under various environment

2.8.1 Prediction of fatigue life under laboratory air

environment

2.8.2 Prediction of crack initiation life under

corrosion fatigue

2.9 Summary of literature review

33

34

35

36

37

38

CHAPTER 3 METHODOLOGY OF RESEARCH

3.1 Materials

3.2 Experimental procedures

3.2.1 Preparation of specimen for ion implantation

3.2.2 Nitrogen ion implantation process

3.2.3 Nitride phase observation

3.2.4 Surface hardness evaluation

3.2.5 Electrochemical studies

3.3 Tensile properties test and wear resistance evaluation

3.4 Fatigue testing in laboratory air and in saline solution

3.5 Prediction of corrosion fatigue life

3.6 Development of corrosion fatigue testing method

3.6.1 Corrosion chamber

3.6.2 Justification of fatigue test specimen

dimension

3.7 Summary of research methodology

39

39

41

41

43

44

45

47

51

53

58

61

62

64

66

x

CHAPTER 4 RESULTS AND DISCUSSION

4.1 Analysis of surface properties

4.1.1 Formation of nitride phase

4.1.2 Surface hardness assessment

4.1.3 Corrosion behaviour of Nii-Ti

4.1.4 Assessment of Nii-Ti surface properties

4.1.5 Tensile properties and wear resistance

4.2 Fatigue and corrosion fatigue of CpTi and Nii-Ti

4.2.1 Fatigue of CpTi and Nii-Ti

4.2.2 S-N curve of Nii-Ti in laboratory air and in

saline solution

4.2.3 Formulation of stress-cycle relationship

4.2.4 Fracture surface analysis of failure specimen

4.2.5 Scheme of crack geometry at fracture

surface

4.3 Corrosion fatigue behaviour of Nii-Ti

4.3.1 Characteristics of corrosion rate during

corrosion fatigue

4.3.2 Corrosion behaviour of Nii-Ti during

corrosion fatigue

4.4 Fatigue life prediction

4.4.1 Fatigue life prediction of Nii-Ti

4.4.2 Prediction of corrosion fatigue life of Nii-Ti

4.5 Summary of results and discussion

67

67

67

74

77

85

87

92

92

93

95

96

99

100

100

105

108

108

109

112

xi

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

5.2 Recommendations

114

114

116

REFERENCES 117

APPENDICES 129

VITA 156

xii

LIST OF FIGURES

FIGURE TITLE PAGE

2.1 Examples of titanium application: (a) artificial hip joint

(b) bone plate implant and (c) hip replacement

8

2.2 Schematic illustration of a cross-section of a deformed

metallic biomaterial surface showing the complex interactions

between the material’s surface and the physiologic

environment

11

2.3 Schematic of an ion implantation system 13

2.4 Schematic of the ion implantation process 13

2.5

Schematic view of the path of an individual ion in process of

ion implantation

14

2.6 Cross-sectional illustration of thin film and surface-modified

layer formation

17

2.7

Theoretical conditions of corrosion, immunity and passivation of

titanium

18

2.8 Schematic illustration of cyclic loading parameters 21

2.9 Schematic description of total fatigue life and its relevant

factors

22

2.10 Schematic description of total corrosion fatigue life 26

2.11 Corrosion pit formation mechanism and fatigue crack

initiation of CpTi in saline solution

27

2.12 Typical fatigue crack growth rate behaviour 30

2.13 S-N curve of CpTi of untreated and sandblasted samples 33

3.1 Flow chart of research methodology 40

3.2 Grinding and polishing machine for sample preparation 42

3.3 Form and shape of the specimen prior to preparation process 43

xiii

3.4 Cockcroft-Walton accelerator Type 200 keV/200 μA 44

3.5 X-Ray diffraction-BRUKER D8 ADVANCE 45

3.6 Vickers hardness test procedure 46

3.7 Hardness testing repetitions 47

3.8 Shimadzu Hardness Micro Vickers tester 47

3.9 Shape and form of specimen for electrochemical study 48

3.10 Electrochemical test set up 49

3.11 Apparatus of corrosion test WPG 100, WonATech 50

3.12 Dimension of wear test specimen 52

3.13 Pin-on Disc wear tester 20LE 53

3.14 Shape and dimension of the fatigue specimen according

to ASTM 1801-97

54

3.15 Machining procedure of fatigue specimen 55

3.16 Flow chart of the machining process of fatigue specimen. 56

3.17 Shimadzu SERVOPULSER 100 kN fatigue machine 57

3.18 Set up of corrosion fatigue testing 58

3.19 Apparatus set up for corrosion test of corrosion fatigue

specimen

59

3.20 Flowchart of corrosion fatigue behaviour modeling 60

3.21 Scanning Electron Microscope (SEM) JSM-61180LA 61

3.22 Drawing of the corrosion chamber 62

3.23 Corrosion chamber for current test (a) before installed

position and (b) in loading condition

63

3.24 Specimen with the diameter gage of 7 mm failed at the grid

section

64

3.25 Specimen failure due to buckling for stress amplitude of 280

MPa and 300 MPa.

65

3.26 An example of the specimen used for current study 65

3.27 Specimen of fatigue failure 65

xiv

4.1 Spectrograph for Nii-Ti with (a) 0.5x1017

ions/cm2 dose and

(b) 2.0x1017

ions/cm2 dose

69

4.2 XRD patterns for the original and implanted CpTi (a) at

different energies, (b) at different doses and (c) the

verification of unit cell formation

71

4.3 The projected range (Ri) of nitrogen ion implantation with

different energy: (a) energy of 80 keV (b) energy of 100 keV,

and (c) energy of 115 keV

73

4.4 Effect of beam energy on penetration depth 73

4.5 Surface hardness of CpTi and Nii-Ti, (a) effect of dose; and

(b) effect of energy on surface micro-hardness

77

4.6 Tafel polarization curves of CpTi and Nii-Ti in 3.5% NaCl at

(a) different doses and (b) different energies

80

4.7 Potentiodynamic polarization curves of CpTi and Nii-Ti in

saline solution at different energies and doses

84

4.8 Curve of hardness vs corrosion rate (a) in 3.5% NaCl

(b) in SBF solution

86

4.9 Microstructure of CpTi in original condition 88

4.10 Stress-strain relationships of CpTi and Nii-Ti 90

4.11 Wear resistance surface of CpTi and Nii-Ti with energy of

100 keV and dose 2.0x1017

ions/cm2

91

4.12 S-N curves of CpTi and Nii-Ti in compare with the work of

Fleck & Eifler

93

4.13 S-N curve of CpTi and Nii-Ti in laboratory air and

in saline solution

94

4.14 Log-log plot of S-N curve for obtaining the Wöhler’s and

Basquin’s formula

96

4.15 SEM image of CpTi specimen tested at 260 MPa in laboratory

air showing (a) overview of the fracture surface, (b) specimen

surface crack initiation, (c) transgranular crack initiation and

propagation

97

xv

4.16 SEM image of Nii-Ti specimen tested at 280 MPa in

laboratory air showing (a) overview of the fracture surface (b)

fatigue-crack and propagation (c) transgranural crack

initiation and granular crack propagation

98

4.17 SEM image of Nii-Ti specimen tested at 280 MPa in saline

solution showing (a) overview of the fracture surface (b)

corrosion pit formation, fatigue-crack and propagation (c)

specimen surface corrosion

99

4.18 Scheme of the crack geometry at surface of Nii-Ti 100

4.19 Polarization curves of corrosion fatigue specimen tested at the

stress, (a) 250 MPa (b) 260 MPa and (c) 280 MPa.

102

4.20 Penetration rate as a function of time. 104

4.21 Variation of experimental constant as a function of stress

amplitude

105

4.22 Corrosion rate versus elapsed time in saline solution 106

4.23 Variation of Ecorr as a function of elapsed time 107

4.24 Variation of current density (icorr) as a function of elapsed

time

107

4.25 S-N curves of experimental and analytical data for Nii-Ti 108

4.26 S-N curves of corrosion fatigue initiation life of model and

corrosion fatigue life obtained by experimental work

111

4.27 S-N curves of predicted corrosion fatigue life (Nf) of model

and corrosion fatigue life (Nf) obtained by experimental work

112

xvi

LIST OF TABLES

TABLE TITLE PAGE

2.1 Physical properties of unalloyed titanium 9

3.1 Chemical composition of CpTi 41

3.2 Mechanical properties of CpTi 41

3.3 Experimental design of nitrogen ion implantation process 42

3.4 Simulated body fluid solution reagent 48

3.5 Comparison of mpy unit with equivalent metric-rate

expressions

51

3.6 Experimental design for fatigue and corrosion fatigue test 54

4.1 Width and peak of intensity XRD pattern for CpTi, TiN and

Ti2N

72

4.2 The projected range (Ri) and longitudinal straggle Ri at

different energies

74

4.3 Comparison of different method of hardness test 74

4.4 Micro-hardness distribution at different energies and doses 75

4.5 Corrosion behaviour of Nii-Ti in 3.5% NaCl 81

4.6 Corrosion behaviour of Nii-Ti in SBF solution 85

4.7 Material properties of CpTi and Nii-Ti 90

4.8 Fatigue life and corrosion fatigue life of CpTi and Nii-Ti in

the averaged number of cycles

95

4.9 The electrochemical properties of corrosion fatigue 103

4.10 Critical size of initiation crack 109

xvii

LIST OF SYMBOLS AND ABBREVIATIONS

A - Area

ASTM - American Society for Testing and Materials

Al - Aluminium

Al2O3 - Aluminium Oxide/ Alumina

At% - Atomic Percentage

a.u. - Auxiliary unit

BATAN - Badan Tenaga Nuklir Nasional (National Nuclear

Energy Agency of Indonesia)

bcc - Body centred cubic

cm - Centimetre

C - Paris’s material constant

CE - Counter Electrode

CpTi - Commercially pure titanium

,

- Fatigue crack growth rate

EW - Equivalent weight

Ecorr - Corrosion potential

f - Frequency

F - Corrosion degradation factor

fcc - Face-centred cubic

h - Hour

Hz - Hertz

HF - Hydrofluoric acid

HNO3 - Nitric acid

H2O - Water

Icorr - Total anodic current

xviii

icorr - Corrosion current density

K - Stress Intensity Factor

k - Strength coefficient

Kc - Critical stress intensity factor

KIC - Fracture toughness

Kpc - Stress intensity factor at instance of crack initiation

Kt - Stress concentration factor

keV - Kilo electro Volt

K - Stress intensity factor range

ΔΚth - Fatigue threshold stress intensity factor range

l - Liter

m - Paris’s material constant

mV/s - Milivolt per second

mg - Miligram

mm - Milimetre

MPa - Mega Pascal

mpy - Mil per year

mV - Milivolt

n - Number of element

N - Number of cycle

2Nf - Reversals to failure

nA - nanoampere

NaCl - Sodium chloride

N2 - Nitrogen

Nii-Ti - Nitrogen ion implanted Cp Ti

O2 - Oxygen / Air

R - Stress ratio, (

RE - Reference Electrode

Sa - Stress amplitude

Scf - Fatigue strength in corrosive medium

Sf - Fatigue strength in laboratory air

Sm - Mean stress

S’f - Fatigue strength coefficient

xix

SBF - Simulated Body Fluid

SEM/EDS Scanning Electron Microscopy/Energy Dispersion

Spectroscopic

- Stress range ( )

Ti - Titanium

TiO2 - Titanium Dioxide

TixN - Titanium Nitride

WE - Working Electrode

- Plastic strain

- Elastic strain

ɛ - Epsilon

- Fatigue strength

κ - Kappa

ϴ - Theta

α - Alpha

ρ - Rho (density)

γ - Gamma

- Chi

μA - Microampere

μm - Micrometer

W - Atomic weight of the element

XRD - X Ray Diffraction

- Geometry correction factor

xx

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Quality Certificate Sample 129

B Calculation of Wear Resistance 130

C Phase Diagram of Titanium (Ti) – Nitrogen (N) 133

D X-ray Diffraction Patterns of CpTi and TiN 134

E Calculation of Material Behaviour 140

F Calculation of Material Exponents 149

G Prediction of Corrosion Fatigue Life 151

H Certificate of Nitrogen Ion Implantation 152

I Nitrogen Ion Implantation of Fatigue Specimens 153

J List of Publications 154

CHAPTER 1

INTRODUCTION

This chapter begins with the background of the research and important elaboration,

followed by problem statements, objective, scope, contributions of the research and

organization of the thesis.

1.1 Background of research

Metallic biomaterials are the most appropriate implant materials to replace failed

hard tissue at present. Stainless steels, cobalt based alloys, titanium and its alloys are

the three most used metals for biomaterials in fabrication of medical devices.

Recently, titanium and titanium alloys are getting much more attention as

biomaterials because they have high specific strength, low density, good resistance

to corrosion, moderate elastic module of 100-110 GPa (Leyens & Peters, 2003;

Majumda et al., 2008), no allergic problems and good biocompatibility (non-toxic and

not rejected by the human body) among other metallic biomaterials. They exhibit a

high corrosion resistance due to the formation of a stable passive layer (TiO2) on its

surface.

Therefore, they have been extensively used in the last several decades as

materials for dental implants, and medical devices. Nowadays, they are also

considered by medical engineering as the material of choice for medical application

(Elias et al., 2008; Niinomi, 1998; Van Noort, 1987), i.e. the prosthetics, internal

fixation, inner body devices and instrumentation.

Since significant benefit of titanium for patients, surgeons and engineers, the

use of the titanium would steadily increase in the near future. Besides the increasing

2

of titanium used as implant materials are due to the increase in the olders generation

or aging population worldwide, the trend toward more active lifestyles, and the

ability to control health care cost.

The population ratio of the aged people has grown rapidly, so the number of

the elder demanding and replacing failed tissue with artificial devices from

biomaterials is also increasing, particularly, the amount of usage of instruments for

replacing failed hard tissues such as artificial hip joints, and dental implants.

Pure titanium and Ti–6Al–4V are still the most widely used among the

titanium alloys where they meet a demand almost the market of titanium

biomaterials. Basically, they are developed as structural materials particularly for

aerospace structures (Niinomi, 2003; Luetjering & Williams, 2003).

Therefore, the development of titanium targeted for biomedical applications

are highly required. Accordingly, the research and development on titanium

composed of non-toxic elements were started (Silvaa et al., 2004), and are under

development which increase continuously. Although commercially pure titanium

(CpTi) exhibit several advantages as biomaterial, but its resistance to wear is lower

than Ti alloy. It is therefore necessary of surface treatment of commercially pure

Titanium (CpTi) to enhance the resistance to wear by ensuring no decline in

corrosion resistance.

Some surface processing, such as sandblasting, induces rough and

contaminated surfaces and it might be an increasing in risk to failure due to this

surface condition results in higher corrosion susceptibility. Electrochemical

investigations of the corrosion behaviour of CpTi and Ti alloys have always

demonstrated very good passivity condition of the surface. However, the study about

ensuring reliability of medical implant is still insufficient. Therefore, the prediction

of the corrosion fatigue life of pure titanium with nitrogen ion implanted surface as

the implant material would be a valuable contribution on ensuring the sustainability

of the implant devices.

1.2 Problem statements

Nitrogen ion implantation was introduced onto CpTi to modify the surface condition

for more reliable performance and to increase its surface resistance to wear and

corrosion. However, the problem with ion implantation is crystallographic damage,

3

produces implantation damage on the surface (Rautray et al., 2011) and point defect

in target crystal on impact resulting imperfection in lattice crystal such as vacancies

and interstitials known as point defects. Ion implantation introduces both a chemical

change in the target surface and a structure change in the crystal structure that could

be surface defect in the form of a void or micro crack those can cause premature

failure of the implanted device.

Several research works studied on corrosion behaviour of CpTi and Titanium

alloys (Fukumoto et al., 1999; Sundararajan, & Praunseis, 2004; Raman et al., 2005),

however more work are necessary in the area of fatigue as well as corrosion fatigue

for the nitrogen ion implanted CpTi (Vardiman & Kant, 1982).

This study focuses more comprehensive on the analysis of corrosion fatigue for

commercially pure titanium using nitrogen ion implantation. The nitrogen ion

implantation might create surface damage and lattice disorder in the near surface of

the material. Therefore, the nitrogen ion implanted CpTi, with surface damage, when

it is applied a cyclic stress in body fluid or saline solution environment could be the

potential factors caused the corrosion fatigue failure for the proposed biomedical

material. Intensive research is needed to prove the fatigue behaviour of CpTi after

implantation with nitrogen ion.

1.3 Objective

The objective of this research is to analyze corrosion fatigue behaviours for

commercially pure Titanium using nitrogen ion implantation. A series of studies was

conducted to achieve specific objectives as follows:

1. To obtain the optimum parameter of CpTi after nitrogen ion implantation.

2. To investigate the influence of the nitrogen ions implantation on fatigue and

corrosion fatigue properties.

3. To develop an empirical model based on experimental data for corrosion

fatigue life prediction.

1.4 Scope of research

The scopes of this research are as follow:

4

1. Introducing the nitrogen ion onto surface of CpTi by ion implantation method

to modify the surface hardness that can improve the wear and corrosion

resistance. Beam energy of 80, 100 and 115 keV and dose of 0.5x1017

,

1.0x1017

and 2.0x1017

ions/cm2 are used as the variables proposed for

nitrogen ion implantation process.

2. Specimens that had been implanted with nitrogen ion were analyzed for the

formation of nitride phase. Surface hardness and corrosion rate of the Nii-Ti

specimens were tested to verify the optimal parameter of implantation

process. In addition, the tensile and wear resistance tests were also to be

carried out on the nitrogen ion implantation specimens.

3. The nitrogen ion implanted specimens were tested the fatigue in laboratory

air and in saline solution with the frequency of 10 or 20 Hertz and stress ratio,

R, of -1.

4. Based on the experimental results, the empirical model was developed for

estimation of corrosion fatigue life for CpTi using nitrogen ion implantation.

1.5 Contributions of research

Corresponding to the above objective, some important points could be expressed as

contribution to the knowledge and professional usage as well as industrial

application. There are three prominent contributions that can be provided from the

result of this research.

1. Improvements in corrosion resistance and mechanical properties for Ti used

biomedical applications have practical importance. Different energies at

different doses for implanting nitrogen ion are a good approach.

2. The use of nitrogen ion implantation is a good technique for the improvement

of fatigue strength of Ti base materials.

3. The penetration growth law for Nii-Ti was established for contribution to the

service life estimation of Ti base materials in acidic environments.

1.6 Thesis organization

The present thesis comprised of five chapters that were organized in order to address

the objectives referred to in section 1.3 which are:

5

• Chapter 1: The description of research overview was discussed and the

investigations performed in this area was briefly reviewed. The knowledge gap

for significant corrosion behaviour and mechanical properties of CpTi with

surface modification is extracted from the state-of-art to define the research

objectives. The problem statements, research objective, scope of the research and

the research contributions are described. The overall contents of the thesis are

also summarized in this chapter.

• Chapter 2: The basic theory to support the implementation of the whole research

is discussed in this chapter.

• Chapter 3: The details of the experimental investigations are presented. The

properties of the CpTi, the fabrication process and equipment used in the research

activities are described. The loading set-up, experimental conditions and

measuring systems employed to collect the experimental data are explained.

• Chapter 4: The achieved results of the research are presented and discussed

following the objective of the research. The most important findings are also

described.

• Chapter 5: The conclusions derived from experimental and theoretical

investigations are presented. The future works as recomendations are also stated

in this chapter.

6

CHAPTER 2

LITERATURE REVIEW

The current research on the effect associated with nitrogen ion implanted

commercially pure titanium (Nii-Ti) in body fluid environment are important to

understand and keep up to date as it changes with the latest technology and materials.

Establishing a framework for the present study, the basic concept involved in surface

modification, corrosion and corrosion-fatigue are reviewed. Later, specific examples

are outlined to show basic trends found in the literature. Finally, empirical model of

fatigue-life time prediction was briefly described.

2.1 Titanium in biomedical applications

Titanium is found in the earth‟s crust at the level of about 0.63% by mass and it is the

seventh-most abundant element metal (73.8%) (Barksdale, 1968; Barbalace, 2006). It

is recovered from TiO2 which is rich with deposits of rutile and ilmenite, FeTiO3,

that are found on every continent (Luetjering & Williams, 2003). Since its discovery

in 1791, and up until Kroll‟s innovative process development in 1932, there had been

no practical methods to recover titanium metal from these ores because of its

prominent affinity for oxygen. Since the modern ore extraction, beneficiation and

chemical processes are discovered, then it is enabled the large-volume manufacturing

of high-grade TiO2. This compound became an important pigment for paints and

commercial products, and of titanium metal for the production of the CpTi grades,

titanium-based alloys and other alloys systems. The Dupont Company was the first to

produce titanium commercially in 1948. Today, the primary consumer of titanium is

7

the aerospace field, whereas the other market such as medicine, automotive are

gaining increased acceptance (Leyens & Peters, 2003).

Commercially pure titanium is unalloyed titanium. At service temperatures it

consists of 100% -hcp phase. As a single-phase material, its properties are controlled

by chemical elements (iron, oxygen and interstitial impurity elements) and grain size.

It is classified into Grades 1 through 4 depending on strength and allowable levels of

the chemical elements i.e. iron, carbon, nitrogen, and oxygen. CpTi ASTM Grade 2

has the yield strength of 275 MPa. (Luetjering & Williams, 2003 and Niinomi,

1998).

In the galvanic series of metals, titanium has a standard reduction potential of

-1.63 Volts which is close to aluminum of -1.662 Volts. Therefore, titanium is very

active in Electro-motif force (Emf) series about 1.2 V more active than iron with

standard electro potential of -0.44 (Winston & Uhlig, 2008). The excellent resistance

of titanium to general corrosion in most environments is well-known. This is the

result of stable protective surface film, which basically consists of TiO2. This thin

oxide film makes the titanium passive as long as the integrity of film is continuously

formed and maintained, generally caused by which most oxidizing environment. On

the other hand, titanium is not corrosion resistant under reducing condition, where

the protective nature of oxide film breaks down such as in sulfuric, hydrochloric and

phosphoric acid is not good (Luetjering & Williams, 2003).

Titanium (Ti) and its alloy have been widely used for medical implants or

fixtures, owing to their superior specific strength, corrosion resistance, and

biocompatibility. The use of such materials can be proposed in response to a need for

artificial hard tissue, because they have characteristics that are advantageous to

biomedical engineering purposes (Balazic et al., 2007; Jagielski et al., 2006; Liu et

al., 2004; Fukumoto et al., 2000; Niinomi, 1998). Figure 2.1(a)-(c) show examples

on usage of Titanium for artificial hip joint bone plate implant and hip replacement,

respectively.

8

Figure 2.1 Examples of titanium application: (a) artificial hip joint (Liu et.al. 2004), (b)

bone plate implant and (c) hip replacement

(source: http://www.supraalloys.com/medical-titanium.php)

The material properties of Ti and its alloy have been proven to be well accepted by

human tissues, compared to other metallic biomaterials (Liu et al., 2004; Jagielski et

al., 2006). Table 2.1 shows the physical properties of unalloyed titanium (Liu et al.,

2004). The unalloyed titanium presented in Table 2.1 is classified as high grade

titanium. Its ultimate strength and yield strength are almost equal to the titanium

alloys with ultimate strength of 860-965 MPa (Sun et al., 2001; Geetha et al., 2009).

The performance of biomedical implants relies on the biocompatibility,

corrosion behaviour, mechanical properties, formability, and availability of the

materials (Liu et al., 2004; Balazic et al., 2007). CpTi is now widely used for hard

(a) (b)

9

tissue replacement due to the fact that its properties are suited for the needs of

medical applications, except wear resistance when used for artificial hip joints.

Table 2.1 Physical properties of unalloyed titanium

(Liu et al., 2004)

Properties Values

Atomic number

Number of electrons

Atomic weight (g/mol)

Equivalent Weight (EW)

Crystal structure

Alpha, hexagonal closely packed (hcp)

c(Ǻ)

a(Ǻ)

Beta, body centered cubic (bcc) a(Ǻ)

Density (g/cm3)

Coefficient of thermal expansion, α, at 20°C (K-1

)

Thermal conductivity (W/(mK))

Melting temperature (°C)

Boiling temperature (estimated) (°C)

Transformation temperature (°C)

Electrical resistivity

High purity (μΩCm)

Commercial purity (μΩCm)

22

2

47.90

23.95

4.6832±0.0004

2.9504±0.0004

3.28±0.003

4.54

8.4×10-6

19.2

1668

3260

882.5

42

55

The nature of CpTi is its inherent corrosion resistance, which is attributed to the

spontaneous formation of a strong passivation oxide layer. The extent of this

corrosion resistance dictates its biocompatibility and is suitable to be used in a

physiological saline solution (Pompe et al., 2004). The nature of CpTi is also

sufficient elasticity, which has become necessary for apt design of hip joint

replacements; elasticity is a decisive factor for hard tissue replacement. The

characteristics of Ti and its alloy are characterized by the inert nature within the

human body: immune from the attack of bodily fluids, compatible with bone growth,

strong, and flexible.

2.2 Mechanical loading imposed on an implant device in human body

An implant is often subjected to cyclic loading during daily activity of the human

body. It can also be chemically attacked by the body fluid medium, under certain

conditions. Among the mechanical and chemical parameters that can influence the

10

corrosion-fatigue behaviour of such material, cyclic stress's parameter in body fluid

(saline solution) is need to be highlighted and verified its effect on stress cycles

before the final failure of implant devices. Another factor that also assists the fatigue

failure is crack length of material implant. Therefore, fatigue and other mechanical

properties such as toughness and wear resistant of biomaterial structure in a living

environment need to be evaluated and improved in order to confidently use the

implants for a long period of time.

The complexity of the service conditions and loads encountered on devices

implanted in the human body is generally quite high. Depending on the activities of

the patient, implanted device experiences of both static loading in the form of body

weight and also dynamic in the form of cyclic stress during walking or running.

These stresses are actually far under fatigue limit of the material implanted, however,

the implanted device can fail before its life time due to the mechanical and chemical

loading of implanted device. Figure 2.2 shows a schematic picture of the cross-

section of a deformed metallic biomaterial surface, surrounded in a physiological

environment (Teoh, 2000). The Figure 2.2 illustrates three distinguishable layers,

namely (1) the molecular absorbed layer, (2) the passive oxide film, and (3) the

deformed layer. The molecular absorbed layer is an aqueous sandwich layer of biological

components to establish a good bond between the host tissue and the biomaterial. The

passive oxide film is protective passive film consist of either metal oxides or

hydroxides and act as a burrier protecting the metal surface from the corrosive

environment (Kim, J. J. & Young, Y. M., 2013), and deformed layer is surface and

subsurface damage arising from a spherical indentor.

The implant device is introduced into a patient must have sufficient strength to

sustain and transmit the load actions resulting from joint and muscular forces. The

actual stress working on the material implant in human body depends on the body

weight where a value of 2.5 BW (Body Weight) seems to be reasonable in hip

implants design. Peak forces are considered to be equal to 2.5 BW. While for loading

frequency is taken 0.5 Hz with an assumption that we could walk 2 h per day with a

pace of one step per second. (Cicero et al., 2007).

11

Figure 2.2 Schematic illustration of a cross-section of a deformed metallic

biomaterial surface showing the complex interactions between the material‟s surface

and the physiologic environment (Teoh, 2000)

Another researcher (Mudali et.al. 2003) argued that mechanical forces imposed on

the implant as follows: (1) the load varies with the position in the walking cycle and

reaches a peak of about four times of body weight at hip and three times the body

weight at the knee. The frequency of loading and load cycles encountered over a

specific time period are also important. A past rate of walking corresponds to one to

two million steps per year. For an active person, the number of steps taken may be

two or three times more taken by a normal person (2) the human body is a harsh

environment for metals and alloys having to be in an oxygenated saline solution with

salt content of about 0.9%, at pH 7.4 and temperature of 37+/-1 (Mudali et al., 2003)

2.3 Ion implantation technique for surface modification

Surface modification is a technique used to change the physical, chemical, electrical

or mechanical properties of metallic material surface such as wear resistant,

corrosion behaviour, fatigue properties and of enhancement of biocompatibility

particularly subjected to medical application. Several established methods of surface

modification are employed: shot peening, plasma nitriding, plasma immersion ion

implantation (PIII), magnetoelectopolishing, chemical etching, anodizing, ion

implantation etc. Ion implantation technique will be discussed in detail in this

section.

Molecular absorbed

Layers

Cyclic stress

Contact body Physiological environment

Cells

Passive oxide layer Damage zone

Deformed layer

Intrinsic microstruture

12

2.3.1 Review of ion implantation technique

Ion Implantation is a potential enhancement method for modifying the surface

properties of materials by insertion of accelerated atoms, within the first atomic

layers of the component using a high technology approach. It is similar to a coating

process, but it does not involve the addition of a layer on the surface. Originally, this

technique was developed to produce controlled doping of semiconductors, and still

used extensively in that capacity today and now it had being used to modify or

change the material‟s near-surface chemical composition or defect state.

Consequently, there can be a distinct modifications to the near-surface microstructure

and chemical, physical and mechanical properties which for example can appear as

changes in corrosion behaviour, electronic properties, stiffness, hardness, wear

resistance, friction response (Al Jabbari et al., 2012), or other surface-region-

sensitive mechanical properties such as fatigue and contact fracture toughness

(Tanaka et al., 1996; Nastasi & Mayer, 2006).

Using highly energetic beams of ions (positively charged atoms), this

technique is used to modify surface structure and chemistry of materials at low

temperature. The moderate heating associated with the process virtually eliminates

any risks of distortion or oxidation effects and mostly the operating process is

between 150oC and 200

oC which depend on the level of the ion beam flux (Woolley,

1997). The process does not adversely affect component dimensions or bulk material

properties. It has been used extensively and successfully for studying the mechanism

under-laying the so called reactive element effect. In general it is found that

influence of the implanted element is applied as a coating or present as an alloy or

oxide dispersed addition.

on implantation is also a powerful method for modifying the near surface

properties of material. To cater for diverse research and application, the implanting

facilities must be flexible. For example, ion beams of elements are desirable, dose

can cover the range from 109 ions cm

-2 to 10

18 ions cm

-2, In ion implantation, high

energy ions are generated in an ion accelerator and implanted into the alloy surface.

The penetration depths are typically in the order of 1-100 nm while the concentration

distribution has a maximum value of up to several tens of percent (Stroosnijder,

1998; Nastasi & Mayer, 2006). In addition, more recent investigations have reported

that ion implantation had improved fatigue and corrosion resistance in metallic

13

alloys, polymers and ceramics. Currently, the technique is most commonly

employed to treat the surface of cutting and machining tools, moulds, casting dies,

alloys for nuclear reactors containers, food packaging materials, medical implants,

biocompatible materials, etc (Agarwal & Sahoo, 2000). Figure 2.3 and Figure 2.4

show schematic of an ion implantation system and ion implantation process,

respectively.

Figure 2.3 Schematic of an ion implantation system (Nastasi & Mayer, 2006)

Figure 2.4 Schematic of the ion implantation process (Denison et al., 2004)

Improvement of the surface hardness as well as corrosion resistance that yielded by

ion implantation technique is influenced by the implantation parameters involve

14

energy, dose or time. The two key parameters defining the final-implantation profile

are dose D (in ions/cm2) and energy, E, (in kilo electro Volt, keV). The dose is

related to the beam current, I, expressed by the following formula (Equation 2.1):

(Spitzlsperger, 2003; Nastasi & Mayer, 2006; Wen & Lo, 2007).

)(106.1

)()()(

219 cmqAx

stnAIdoseD

(2.1)

where D denotes implantation dose, I represent the beam current (nA), t is beam time

(s), q is charge state of the ion, and A is defined as the striking area (cm2).

A significant advantage of ion implantation is that the treated surface is an

integral part of the work piece and does not suffer from possible adhesion problems

associated with coatings. The moderate heating associated with the process virtually

eliminates any risks of distortion or oxidation effects. The process does not adversely

affect component dimensions or bulk material properties. Ion implantation produces

no dimensional changes in the work piece (Woolley, 1997). Figure 2.5 illustrates the

path of an individual ion in ion implantation process.

Figure 2.5 Schematic view of the path of an individual ion in process

of ion implantation (Hirvonen & Sartwell, 1994).

Modified region

15

2.3.2 Theoretical prediction of penetration depth

The penetration depth of the implanted ions depends on the ion weight or mass,

energy and on material substrate (Hunsperger, 2009). As the ions penetrate into

substrate of the specimen, they lose their energy due to the interaction with the

electrons and the atoms of the specimen. Their energy continuously decreases when

the ion is traveling deeper into the substrate.

The energies of ion implantation range from several hundred to several

million kilo electrons volt (keV), yielding in ion distributions with average depths

from < 10 nm to 10 µm. Doses range from 1011

ions/cm2 for threshold adjustment to

1018

ions/cm2 for buried dielectric formation. Theoretical calculation was made using

the simulation program Transport of ions in matter (TRIM)-Stopping and Range of

Ions in Matter (SRIM) simulation software providing an approach of the penetration

depth penetration. SRIM is a computer program used to calculate interaction of ions

with matter and the core of SRIM is a program Transport of ions in matter (TRIM).

This open source computer programs were developed by Ziegler et al., 1985 and are

being continuously upgraded with the major changes occurring approximately every

five years. SRIM is based on a Monte Carlo simulation method, namely the binary

collision approximation with a random selection of the impact parameter of the next

colliding ion. It needs the ion type and energy (in the range 10 keV - 2 GeV) and the

material of one or several target layers as the input parameters.

The predictions of the implantation depth in the near surface of specimens

were provided from that software, and calculated the depth of implanted ions using

following equation:

𝑥𝑖 = 𝑅𝑖 + 𝛿𝑅𝑖 (2.2)

where, 𝑥𝑖 is penetration depth of implanted ions, Ri is ion range and 𝜹Ri is the

longitudinal straggling (Nastasi & Mayer, 2006; Saryanto et al., 2009; Suzuki, 2010).

2.3.3 Surface modification of CpTi by nitrogen ion implantation

Surface modification methods such as anodic oxidation treatment, (Song et al., 2007)

sandblasting, (Jiang et al., 2006) carbide coating, (Velten et al., 2002) plasma

16

nitriding, (Kapczinski et al., 2003) electrochemical treatment (Guilherme, 2005) and

nitrogen ion implantation (Jagielski et al., 2006; Fukumoto et al., 2000; Shikha et al.,

2008; Arenas et al., 2000) have been proposed to increase corrosion-resistant and

wear-resistant of material. CpTi with modified surface has good mechanical and

chemical properties as well as biocompatibility in human body environment.

The most common ion used for application in metallurgical surface treatment

is nitrogen. When the nitrogen ions penetrate and diffuse the surface of the specimen,

some of them wedge micro cracks, some occupy lattice spaces in crystalline

structures, and some form compounds through the chemical reaction (i.e.; titanium

nitride: TiN; Ti2N), resulting a new lattice properties as inherent of face center cubic

(fcc) and tretragonal space lattice. It has been established that nitrogen implantation

into metals can alter their surface properties such as hardness, friction, wear and

corrosion resistant, etc.

Among the treatment options, as mentioned previously, the nitrogen ion

implantation technique is a good method to enhance passivity and to reduce the

corrosion rate. This is due to the fact that the formation of TiN and Ti2N phases elude

the migration of ions and stabilize the TiO2 film growth on the surface of titanium

(Arenas et al., 2000; Mudali et al., 2003). Nitrogen ion implantation can modify the

Ti surface to produce wear-resistant species such as nitrides (TiN; Ti2N) other than

TiO2 from the surface. The surface of nitrogen ions implanted Cp Ti appeared to

consist of a mixture of TiO2 and TiN/Ti2N or a Ti oxynitride as shown in Figure 2.6

(Liu et al., 2004). Figure 2.6 illustrates the cross-sectional view of thin film and

surface-modified layer formation for surface modification of titanium by ion

implantation technique. Surface modification had been performed at specific energies

to assess the formation of the nitride phase, surface hardness, wear resistance, and

corrosion behaviour in various doses (Sundararajan, & Praunseis, 2004; Arenas et

al., 2000; Fukumoto et al., 1999). Still, the mechanical properties, chemical

composition, and corrosion resistance for CpTi surface implanted nitrogen ions in

various doses and energy need to be verified for achieving good result from

combining parameter between energy and dose as optimal parameter of the ion

implantation process.

17

2.4 Corrosion effects associated with biological environment

A multidisciplinary approach is necessary in studying corrosion-fatigue that involves

chemistry, electrochemistry, mechanics and metallurgy. In this section, the

chemistry, electrochemistry and mechanics that cause corrosion related failures are

described. First, it reviewed the various forms of corrosion that lead to failure in pure

titanium related with chemistry or electrochemistry that caused them. Then, the

mechanisms responsible for the effects of corrosion fatigue are discussed.

2.4.1 Corrosion forms of pure titanium

Pourbaix (1966; 1974) demonstrated that a metal could react in one of four ways

when exposed to a corrosive solution. He proposed the diagrams which are called

Pourbaix Diagram by varying the electrode potential and pH of the solution. The

diagrams demonstrate the corrosion activity that is thermodynamically favored in a

given system. A Pourbaix diagram for titanium in water at 25oC is shown in Figure

2.7. The diagram shows conditions of corrosion, immunity and passivation of

titanium in dependency of oxidizing potential and pH.

The diagram consists of four areas that represent the ways that a metal can

react to a corrosive solution. He demonstrated that a metal could be immune (passive

TiH2 region) from chemical reaction (passive TiH2 region), shown active corrosion

(Ti+2

region) displayed passivity due to formation of a protective oxide film (Ti02

Figure 2.6 Cross-sectional illustrations of thin film and surface-modified

layer formation (Liu et al., 2004)

18

region), or suffered from pitting corrosion due to localize breakdown of a passive

film. If the protective oxide film breaks down locally, then the surface metal is exposed to

the solution and released its ion forming the pit.

Figure 2.7 Theoretical conditions of corrosion, immunity and passivation of titanium

(Pourbaix (1966; 1974)

The above diagram shows the significant differences in corrosion behaviour resulting

from different properties of TiO2 film. This film is very chemically resistant and is

attacked by very few substances. The following reactions are the basic corrosion of

Titanium in aqueous environment (Equation 2.3 – 2.4):

eTT ii 22 VEo 63.1 (2.3)

222 HeH and

OHeOOH 4422 (2.4)

19

The basic reaction of Titanium in water is (Equation 2.5 – 2.6):

2

22 HTHT ii (2.5)

242 2)(4 HOHTOHT ii (2.6)

4)(OHTi is a passive film of Titanium by a direct electrochemical reaction.

Balakrishnan et al., (2008) observed the formation of passive film on titanium

surface in SBF solution with the presence of Ca, P, Ti and O elements. The surface

passive TiO2 layer reacts with SBF solution which can be illustrated in Equations 2.7

– 2.11 as follows (Liu et al., 2004):

32 HTiOOHTiO (2.7)

eOHTiOHTi 4)(3 (2.8)

2223 2/1.)( HOHTiOeOHTi (2.9)

43 )()( OHTiOHOHTi (2.10)

OnHHTiOOHOnHTiO 2322 .. (2.11)

The Ti–OH groups formed on the surface from the above reaction are negatively

charged and have a chemical affinity for Ca2+

and Na+ ions in the Simulated Body

Fluid (SBF) solution.

2.4.2 Effect of nitrogen ion implantation on corrosion resistance of titanium

Besides the design of the joint replacement, material selection plays an important

role. Materials for human body implants must be biocompatible, corrosion resistant,

and strong and have sufficient elasticity (Pompe et al., 2004).

Because it is absolutely inert in the human body, immune to attack from

bodily fluids, compatible with bone growth and strong, and flexible, titanium is most

biocompatible of all metallic implant, i.e. Stainless Steel 316L, cobalt alloys (Nasab

& Hassan, 2010; Niinomi, 2008) . Biocompatibility and corrosion resistance of the Ti

metal are the result of passive TiO2 film of 2 to 6 nm thickness formed on the surface

of Ti (Balakrisnan et.al., 2008; Tamilselvi & Rajendra, 2006; Raman et al., 2005;

Dearnley et al., 2004; Arenas et al., 2000). The corrosion behaviour of Ti and its

20

alloys has been studied using certain types of biological media (Tamilselvi &

Rajendra, 2006; Raman et al., 2005; Dearnley et al., 2004).

The implantation of nitrogen ion can enhance the passivability and reduce the

corrosion kinetics of the alloy surface with increasing tendency for repassivation and

with a significant decrease in ion release rates (Gordin et.al., 2013), and thus can

enhance corrosion resistance. This improvement arises from the formation of

precipitates of TiN and Ti2N, which screen underlying titanium atoms, avoiding their

migration and stabilizing the growth of the oxide film (Arenas et al., 2000).

Introducing to commercially pure titanium, Nitrogen-ion implantation

showed an improvement in the electrochemical behaviour of the passive film. Doses

between 4x1016

and 7x1016

ion/cm2 is recommended for orthopedic applications. A

detrimental effect is shown by implantation with higher doses due to the formation of

nitride phases (Sundararajan & Praunseis, 2004; Kapczinski et al., 2003) that can

accumulate surface damage, thus leading to increasing the corrosion resistance and

nanohardness (Shikha et al., 2008).

2.5 Fatigue and corrosion fatigue of metals

Fatigue is a process of progressive localized permanent structure change occurring in

a material subjected to condition that produce fluctuating stress and strain at point

that may culminate in crack or complete fracture after a sufficient number of

fluctuations.

The load histories for a real components, structures and vehicle are quite

diverse, at one extreme, they may be rather simple and repetitive, at the other

extreme, may be completely random. The constant amplitude loading is used to

obtain material fatigue behaviours/properties for used in fatigue design. Figure 2.8

illustrates schematically the basic fatigue loading for constant amplitude loading

pattern. The load ration (R-ratio) is defined as the ratio of minimum to maximum

stress amplitude as shown in Equation 2.12.

𝑅 = 𝑆𝑎𝑚𝑖𝑛/𝑆𝑎𝑚𝑎𝑥

(2.12)

Where: 𝑆𝑎 , 𝑆𝑚 𝑎𝑛𝑑 ∆𝑆 (𝑆𝑚𝑎𝑥 − 𝑆𝑚𝑖𝑛 ) denote stress amplitude, mean load and stress

range respectively and f denote the frequency of the cycle stress. The R-ratio value of

fully reversals is -1 (R=-1) which means that the mean stress, 𝑆𝑚 = 0 and 𝑆𝑎 = -𝑆𝑎 .

21

Figure 2.8 Schematic illustration of cyclic loading parameters

Most mechanical components and structures made of metal and alloy are subjected to

cyclic loading. Some those machine components such as super-heaters, propeller

shafts, turbines and pump elements, drilling equipment in petroleum industry

severely suffer from corrosion fatigue problem. Once cyclic loading occur in inert

environment, the structures or components suffer to fatigue failure. However, when

the components and structures subjected to cyclic loading and corrosive environment

even fresh water or atmospheric air, the Corrosion Fatigue “C-F” can occur (Ebara,

2007; Genel et al., 2000; Murtaza & Akid, 1996).

The first study of metal fatigue is believed to occur around 1829 by German

mining engineer Albert. The detailed research effort into metal fatigue was initiated

in 1842 following the railway accident in France. The cause of this accident was

traced to fatigue failure. A systematic investigation of fatigue failure was conducted

by Wöhler, during the period 1852-1869 in Berlin. His work led to characterization

of fatigue in term of Stress-life (S-N) curves and to the concept of fatigue „endurance

limit‟. Another well known fatigue researcher of this era was Fairbairn, (1864),

Geber, (1872), Goodman (1899), Ewing & Rosenhain (1900), Ewing and Humfrey

(1903). The development of metal fatigue research came in new era was begun by

Griffith (1921) and Paris et al., (1961). They applied the fracture mechanic concept

to solve fatigue problem of notch specimen. Later it will be described some detail

concepts of development in fatigue as well in corrosion fatigue.

In order to understand the fatigue mechanism, it is important to consider

various technical conditions that influence fatigue life and fatigue crack growth.

There are three technical conditions involved (a) material surface quality, (b) residual

+𝑆𝑎

−𝑆𝑎

𝑁

Cycle (2 reversals)

𝑆𝑚 = 0

𝑅 = 𝑆𝑎

−𝑆𝑎 =−1→Fully reversed

22

stress and (c) environment effect. This understanding is necessary to analyze fatigue

properties of engineering structure in term of fatigue as a crack initiation process

(crack initiation period) followed by a crack growth period as shown in Figure 2.9.

Corrosion fatigue is the metal cracking caused by combined action of a cyclic

loading and a corrosive environment. The severity of the action depends on the range

and frequency of the stress, the nature of the corroding condition and the time under

stress (Murtaza & Akid, 1996; Sivaprasad et al., 2006). So, corrosion fatigue is

influenced by various mechanical, chemical and structural parameters that interact

locally.

Corrosion fatigue is similar to stress corrosion cracking in many aspects. The

principal difference between these two types of environment enhanced cracking is in

the character of loading, which is static in stress corrosion cracking and repeated

loading in corrosion fatigue. Both fatigue life and fatigue limit are reduced in the

presence of corrosive environment as compared to the fatigue in neutral

environment. These are caused by interaction of electrochemical, metallurgical and

mechanical processes at the crack tip (Ramsamooj & Shugar, 2001a).

The aim of the above review is to describe some phenomenological

observation of corrosion fatigue failure of mechanical components and structures and

method of evaluation. In addition, some results proposed by previous researcher in

term of stress-life, strain-life and crack initiation and crack growth rate-stress

intensity range will be presented.

Figure 2.9 Schematic description of total fatigue life and its relevant factors

(Schijve, 2009)

23

2.5.1 Mechanism of corrosion-fatigue

Under cyclic loading conditions, the embrittling environment can accelerate the

initiation of a surface flaw in an initially crack-free material and propagate the flaw

to certain critical size. Corrosion fatigue is a term which is commonly used to denote

the damage and failure of material under the combination action of cyclic stress and

any embrittling medium, although most wide spread adaptation is in the context of

aqueous environments. The corrosive environment produces corrosion products.

Corrosion fatigue is associated with two different mechanisms: Anodic dissolution

mechanism of corrosion fatigue and hydrogen assisted corrosion fatigue (Ramsamooj

& Shugar, 2001a; Marcus, 2002).

The mechanism of anodic dissolution cracks initiate at the surface sites of

localized concentration of tensile strength. A crack progresses along a specific path

which is composed of specific crystal planes within the grains. The mechanism of

anodic dissolution is mainly referred to as corrosion fatigue of carbon steels and

Stainless steels (Makhlouf et al., 2003) in water and also corrosion fatigue of

Aluminum alloys (Chlistovsky et al., 2007) and Titanium alloys in aqueous chloride

solutions. Genel et al., (2000) reported that cathodic polarization suppressed the

metal dissolution and pit formation, resulting in a noticeable increase in corrosion

fatigue strength up to 2.6 times that of free corrosion fatigue. In contrast to anodic

dissolution mechanism, hydrogen assisted corrosion fatigue is enhanced by cathodic

reaction: 2H+ + 2e

- = H2 occurring on the crack tip surface. The atomic hydrogen

dissolves in the metal where its ions interact with the dislocations of the crystal

lattice causing decrease of the metal ductility (Suresh, 1998).

2.5.2 Stress -life approach in corrosion fatigue

Corrosion fatigue in aqueous media is an electrochemical behaviour. Cracks are

initiated either by pitting or at persistent slip bands “PSB” (Xie et al., 2002).

Corrosion fatigue can hence be reduced by alloy additions, inhibition, and cathodic

protection all of which reduce pitting (Congleton & Craig, 1982). Since corrosion

fatigue cracks initiate at the metal surface, surface treatments like plating, cladding,

nitriding (Genel et al., 2000) and shot-peening or sandblasting (Jiang et al., 2006)

were found to improve the materials' resistance to this phenomenon.

24

The important concept of stress-life was proposed by Wöhler. The method

characterizes the total fatigue life in terms of nominal stress amplitude and cyclic

number (S-N) curve (Stephens et al., 2001). The total fatigue is defined as

accumulation crack initiation, short crack, long crack and critical fracture or final

failure (Kaynak et al., 1996; De-Guang et al., 1998). The fatigue life equation is

written as follows (Equation 2.13):

fa NS log (2.13)

where Sa is stress amplitude, α and β are constants and Nf is number of cycle.

Basquin modified Wöhler‟s formula in term of correlation log-log scale, a linear and

power law relationship are commonly observed, as shown in Equation 2.14 and

Equation 2.15. The stress-life curve characterizes the contribution of crack initiation

and crack propagation processes to total fatigue life in nominally smooth specimen.

fa NS lnln (2.14)

or

b

ffaa NSS

S)2('

2

(2.15)

where 𝑆𝑎 is stress amplitude, 𝑁𝑓 is number of cycle and α and β are constants, 𝑆′𝑓 is

fatigue strength coefficient and 2𝑁𝑓 is reversals to failure and b is fatigue strength

exponent (Basquin‟s exponent).

A new approach on the study of early stages of corrosion fatigue cracking

was proposed by Acun‟a-Gonza‟lez et al., (2008). A visual recurrence analysis

applied to the electrochemical current oscillations registered during corrosion fatigue

tests allowed us to characterize the electrochemical dynamics on stainless steel

samples surface showing clearly the dynamics of localized corrosion, as well as the

formation and initial growth of short corrosion fatigue cracks.

Experimental study of corrosion fatigue behaviour welded steel structures has

found that the fatigue crack propagation in the corrosive medium is influenced

strongly by important weld-geometry parameter and accordingly, Paris‟s material

constant need to be determine experimentally to evaluate the corrosion fatigue life

(Wahab & Sakano, 2001). Ramsamooj & Shugar (2001b) proposed a new model for

117

REFERENCES

Acuña-González, N., García-Ochoa, E., & González-Sánchez, J. (2008). Assessment

of the dynamics of corrosion fatigue crack initiation applying recurrence plots

to the analysis of electrochemical noise data. International Journal of Fatigue

30 (7), pp. 1211-1219.

Agarwal, R., & Sahoo, L. (2000). VLSI Technology and Design: Ion Implantation

Chapter 5, 1st Edition. Technical Publications Pune, India (Google book

ISBN 9788184324069).

Agung, I., Syarif, J., Ghazali, M.J. & Sajuri, Z. (2011). Effect of Cu particels

precipitation on wear behaviour of Fe-3mass%Cu under dry sliding

condition. Key Engineering Materials, 462-463, pp. 1224-1229.

Al Jabbari, Y. S., Fehrman, J., Barnes, A. C., Zapf, A. M., Zinelis, S., & Berzins, D.

W. (2012). Titanium Nitride and Nitrogen Ion Implanted Coated Dental

Materials. Coatings, 2, pp. 160-178.

Arenas, M.A., Tate, T.J., Conde, A. & De Damborenea, J. (2000). Corrosion

behaviour of nitrogen implanted titanium in simulated body fluid. British

Corrosion Journal, 35(3) pp. 1-5.

ASTM Standard, ASTM. (2008). Standard practice for corrosion fatigue testing of

metallic implant materials. Annual Book of ASTM Standard. ASTM Standard

F1801-97, ASTM International.

ASTM Standard, ASTM. (2010). Standard practice for conducting force controlled

constant amplitude axial fatigue tests of metallic materials. Annual Book of ASTM

Standard. ASTM Standard E466-98, ASTM International, pp 471-477.

ASTM Standard, ASTM. (2010). Standard practice for verification of constant

amplitude dynamic forces in an axial fatigue testing. Annual Book of ASTM

Standard, ASTM Standard E468-97, ASTM International.

118

ASTM Standard, ASTM. (2008). Standard test methods for tension testing of

metallic materials. Annual Book of ASTM Standard. ASTM E8M-04, ASTM

International.

ASTM Standard, ASTM. (1999). Standard practice for calculation of corrosion Rates

and related information from electrochemical measurements. Annual Book of

ASTM Standard. ASTM G102, ASTM International.

Bahmanpour, H., Youssef, K. M., Scattergood, R. O., & Koch, C. C. (2011).

Mechanical behaviour of bulk nanocrystalline copper alloys produced by high

energy ball milling, Journal of Materials Science. doi:10.1007/s10853-011-

5312-3.

Balakrishnan A., Lee, B. C., Kim, T.N., & Panigrahi, B. B. (2008). Corrosion

behaviour of ultra fine grained titanium in simulated body fluid for implant

Application. Trends in Biomaterials and Artificial Organs, 22(1), pp. 58-64.

Balazic, M., Kopacpp, J., Jackson, M. J., & Ahmed, W. (2007). Review: titanium

and titanium alloy applications in medicine. International Journal of Nano

and Biomaterials, 1(1), pp. 3-34.

Bannantine, J.A. Comer, J.J. & Handrock, J.L. (1990). Fundamentals of Metal

Fatique Analysis. NJ: Prentice Hall, Englewood Cliffs.

Barbalace, K. L. (2006). Periodic Table of Elements: Ti – Titanium. Retrieved 12-26.

Barksdale, J. (1968). Titanium. in Clifford A., Hampel (editor). The Encyclopedia of

the Chemical Elements, New York: Reinhold Book Corporation. pp. 732–

738. LCCN 68-29938.

Brooks, C. L., Prost-Domasky, S. A., Honeycutt, K. T., & Mills, T. B. (2003).

Predictive modeling of structure service life. In ASM Handbook Volume

13A, Corrosion, Fundamental, Testing and Protection, pp. 946-958.

Carlson, R. L., & Cardomateas, G. A. (1996). An Introduction to Fatigue in Metals

and Composites. London: Chaman & Hall.

Carpinteri, A. & Paggi, M. (2007). Self-similarity and crack growth instability in the

correlation between the Paris‟ constants. Engineering Fracture Mechanics, 74,

pp. 1041–1053.

Cassar, G., Banfield, S., Avelar-Batista Wilson, J. C., Housden, J., Matthews, A., &

Leyland, A. (2012). Impact wear resistance of plasma diffusion treated and

duplex treated/PVD-coated Ti-6Al-4V alloy. Surface and Coating

Technology 206, pp. 2645–2654.

119

Chlistovsky, R.M, Heffernan, P.J. DuQuesnay, D.I. (2007). Corrosion fatigue

behavior of7075-T651 aluminum alloy subjected to periodic overloads,

International Journal of Fatigue 29, pp. 1941-1949.

Cicero, S., Gutierrez-Solana, F., Allvarez, J. A., & Sanchez, L.(2007). Failure

analysis of a hip implant by using the FITNET fitness for service procedure,

Engineering Fracture Mechanics 74, pp. 688-702.

Congleton, J. & Craig, I.H. (1982) in Corrosion Processes, Parkins, R.N (ed.).

Applied Science Publishers, London, pp. 209-269.

Dearnley, P. A., Dahm, K. L. & Cimenoglu, H. (2004). The corrosion–wear

behaviour of thermally oxidised CP-Ti and Ti–6Al–4V. Wear, 256, pp. 469-

479.

De-Guang, S., Wei-Xing, Y., & De-Jun, W. (1998). A new approach to the

determination of fatigue crack initiation size. International Journal of

Fatigue, 20 (9), pp. 683-687.

Denison, A. B., Hope-Weeks, L. J., Meulenberg, R. W., & Terminello, L. J. (2004).

Quantum Dots, in Introduction to Nanoscale Science and Technology. In Di

Ventra, M, Evoy, S, and Heflin, J.R (Eds.). Springer Science & Business

Media Inc.: pp. 183-198.

Ebara, R. (2007). Corrosion fatigue crack initiation in 12 % chromium

stainless steel. Materials Science & Engineering A 468-470, pp 109-113.

Ebara, R. (2010). Corrosion fatigue crack initiation behaviour of stainless steels.

Procedia Engineering 2, pp 1297–1306.

El Haddad, M. H., Topper, T. H., & Smith, K. N.(1979). Prediction of non

propagation crack. Engineering Fracture Mechanics 11(3), pp. 573-584.

Elias, C. N., Lima, J. H. C., Valiev, R., & Meyers, M. A. (2008). Biomedical

applications of titanium and its alloys. Biological Materials Science, JOM,

pp. 46-49.

Forman, R. G. Kearney, V. E., & Engle, R. M. (1967). Numerical analysis of crack

propagation in cyclic-loaded structure,. Transactions ASME. Journal of Basic

Engineering, 89(3), pp. 459-464.

Fukumoto, S., Tsubakino, H., Inoue, S., Liu, L. T., Erasawa, M., & Mitamura, T.

(1999). Surface modification of titanium by nitrogen ion implantation.

Materials Science and Engineering A, 263, pp. 205-209.

120

Fukumoto, S., Tsubakino, H., & Terasawa, M. (2000). Corrosion resistance of

nitrogen ion implanted titanium alloy for medical implants in physiological

saline solution. Paper presented at the IEEE Xplore.

Fleck, C., & Eifler, D. (2010). Corrosion, fatigue and corrosion fatigue behaviour of

metal implant materials, especially titanium alloys. International Journal of

Fatigue 32, pp. 929-935.

Geetha, M., Singh, A. K., Asokamani, R., & Gogia, A. K. (2009). Ti based

biomaterials, the ultimate choice for orthopaedic implants: a review. Progress

in Materials Science, 54(3), 397-425.

Genel, K., Demirkol, M., & Guemez, T. (2000). Corrosion fatigue behaviour of ion

nitrided AISI 4140 steel. Materials Science and Engineering A288, pp. 91-

100.

Gordin, D. M., Busardo, D., Cimpean, A., Vasilescu, C., Hӧ che, D., Drob, S. I.,

Mitran, V., Cornen, M., & Gloriant, T. (2013). Design of a nitrogen-

implanted titanium-based superelastic alloy with optimized properties for

biomedical applications. Materials Science and Engineering C, 33(7), pp.

4173-4182.

Guilherme, A. S. (2005). Surface roughness and fatigue performance of

commercially pure titanium and Ti-6Al-4V alloy after different polishing

protocols. The Journal of Prosthesis Dental 93, pp. 378-385.

Harlow, D. G. & Wei, R. P. (2001). Probability modelling and statistical analysis of

damage in the lower wing skins of two retired B-707 aircraft. Fatigue &

Fracture of Engineering Materials and Structures. 24, pp 523–535.

Hieda, J., Niinomi, M., Nakai, M., Cho, K., Gozawa, T., Katsui, H., Tu, R., Goto, T.

(2013). Enhancement of adhesive strength of hydroxyapatite films on Ti–

29Nb–13Ta–4.6Zr by surface morphology control. Journal of the Mechanical

Behaviour of Biomedical Materials 18, pp. 232–239.

Hirvonen, J. K., & Sartwell, B.D. (1994). Ion Implantation. ASM Handbook, Vol. 5

pp 1680-1690.

Hoeppner, D.W. (1978) Corrosion fatigue: chemistry, mechanics and microstructure.

NACE-2, National Association Corrosion Engineers, pp. 3-11.

http://www.supraalloys.com/medical-titanium.php February 25th

, 2013.

Hunsperger, R. G. (Ed) (2009). Integrated optics theory and technology (6th ed.).

New York, USA: Springer Science & Bussiness Media. LLC.

121

Ishihara, S., Saka, S., Nan, Z.Y., Goshima, T., & Sunada, S. (2006). Prediction of

corrosion fatigue lives of aluminum alloy on basis of corrosion pit growth

law. Fracture of Engineering Materials and Structures 29, pp. 472-480.

Jagielski, J., Piatkowska, A., Aubert, P., Thome, L., Turos, A., & Abdul Kader, A.

(2006). Ion implantation for surface modification of biomaterials. Surface &

Coatings Technology, 200(22-23), pp. 6355–6361.

Janssen, M., J., Zuidema, J., & Wanhillet. R.J . H. (2004). Fracture Mechanics (2nd

ed.), London: Spon Press.

Jiang, X. P., Wang, X. Y., Li, J.X., Man, C.-S., Shepard, M. J., & Zhai, T. (2006).

Enhancement of fatigue and corrosion properties of pure Ti by sandblasting.

Materials Science and Engineering A 429, pp. 30–35.

Jones, D. A. (1992). Principles and Prevention of Corrosion. New York: Macmillian

Publishing Company.

Kabadayi, Ö. (2004). The channeled stopping powers of boron ions and range

calculations in Si. Czechoslovak Journal of Physics, 54(4), pp. 461-468.

Kapczinski, M. P., Carlos Gil, C., Kinast, E.J ., & Alberto dos Santos, C. (2003).

Surface modification of titanium by plasma nitriding. Materials Research,

6(2), pp 265-271.

Kaynak, C., Ankara, A., & Baker, T. J. (1996). Effects of short cracks on fatigue life

calculations. International Journal of Fatigue 18(1), pp. 25-31.

Khan, Z., & Younas, M. (1996). Corrosion fatigue life prediction for notched elastic

fracture mechanics concepts. International Journal of Fatigue 18(7), pp.491-

498.

Kim, J. J. & Young, Y. M. (2013). Study on the passive film of type 316 stainless

steel, International Journal Electrochemcal Science 8, pp. 11847 – 11859.

Kim J. H., Semiatin S. L., Lee, Y. H. & Lee, C. S. (2011) A self-consistent approach

for modeling the flow behaviour of the alpha and beta phases in Ti-6Al-4V.

Metallurgical and Materials Transaction A. 42, pp 1805-1814.

Kitegava, H. (1972) in Corrosion fatigue, chemistry, mechanics and microstructure,

O. Devereux eds. NACE, Houston, p.521.

Kokubo, T. H., Kushitani, H., Sakka, S., Kitsugi. T., & Yamamuro, T. (1990),

Solutions able to reproduce in vivo surface-structure changes in bioactive

glass-ceramic A-W. Journal of Biomedical Materials Research, 24, pp.721-

734.

122

Krupp, W. E., & Hoeppner, D. W. (1973). Fracture mechanics application in

materials selection, fabrication sequencing and Inspection, Journal of

Aircraft, 10(11), pp. 682-688.

Leyens, C., & Peters, M. (2003). Titanium and titanium alloy: Fundamentals and

Applications. Weinheim, Jermany: Weley-VCH Verlag GmbH &Co KGaA

Lee, Y-L., Pan, J., Hathaway, R., & Barkey, M. (2005). Fatigue Testing and

Analaysis. Theory and Practice, New York: Elsevier.

Liu, Y., & Mahadevan, S. (2009). Probabilistics fatigue life prediction using an

equivalent initial flaw size distribution. International Journal of Fatigue (31),

pp. 476-487.

Liu, X., Chu, P. K., & Ding, C. (2004). Surface modification of titanium, titanium

alloys, and related materials for biomedical applications. Materials Science and

Engineering R, 47, 49-121.

Luetjering, G., & Williams, J. C. (2003). Titanium. Berlin, Heidelberg: Springer-

Verlag.

Majumda, P., Singh, S. B. & Chakraborty, M. (2008). Elastic modulus of biomedical

titanium alloys by nano-indentation and ultrasonic techniques - A

comparative study. Materials Science and Engineering A 489, pp 419–425.

Makhlouf, K., Sidhom, H.,. Triguia, I., & Braham, C. (2003). Corrosion fatigue crack

propagation of a duplex stainless steel X6 Cr Ni Mo Cu 25-6 in air and in

artificial sea water. International Journal of Fatigue 25, pp. 167-179.

Marcus P. (ed.). (2002). Corrosion Mechanisms in Theory and Practice (2nd Ed.).

Revised and Expanded, New York: Marcel Dekker, Inc.

Mudali, U. K., Sridhar, T. M., & Raj, B. (2003). Corrosion in bio implants.

Sadhana-Academy Proceeding Engineering Science 28 (3- 4), pp. 601–637.

Mueller, M. (1982). Theoretical consideration on corrosion fatigue crack initiation.

Metallurgical and materials Transactions A 13A, pp. 649-655.

Murakami, Y., Endo, M. (1992). Experimental evidence and application. In:

Proceeding of the theoretical concepts and numerical analysis of fatigue.

Birmingham, (UK). Warley: Engineering Materials analysis Advisory service

Ltd., Cradley Health, pp. 51-57.

Murtaza, G., & Akid, R. (1996). Corrosion fatigue short crack growth behaviour in a

high strength steel. International Journal of Fatigue 18, pp. 557-566.

123

Murtaza, G., & Akid, R. (2000). Empirical corrosion fatigue life prediction models

of a high strength steel. Engineering Fracture Mechanics 67, pp. 461-474.

Nan, Z. Y., Ishihara, S., & Goshima, T. (2008). Corrosion fatigue bihaviour of

extruded magnesium alloy AZ31 in sodium chloride solution. International

Journal of Fatigue 30, pp. 1181-1188.

Nasab, M. B., & Hassan, M. R. (2010). Metallic Biomaterials of knee and hip-a

review. Trend in Biomaterial Artificial Organs, 24(1), pp 69-82.

Nastasi, M., & Mayer, M. (2006). Ion Implantation and Synthesis of Materials.

Berlin, Germany: Springer.

Niinomi, M. (1998). Mechanical properties of biomedical titanium alloys. Materials

Science and Engineering A, 243, pp 231–236.

Niinomi, M. (2003). Recent research and development in titanium alloys for

biomedical applications and healthcare goods. Science and Technology of

Advanced Materials, 4, Pp. 445–454.

Niinomi, M.(2008). Metallic biomaterials, Journal of Artificial Organs 11, pp. 105-

110.

Oyane, A., Kim, H.-M., Furuya, T., Kokubo, T., Miyazaki, T., & Nakamura, T.

(2003). Preparation and assessment of revised simulated body fluid. Journal

of Biomedical Materials Research 65A, pp. 188-195.

Palmquist, A., Omar, O. M., Esposito, M., Lausmaa, J., & Thomsen, P. (2010).

Titanium oral implants: surface characteristics, interface biology and clinical

outcome. Journal of the Royal Society Interface 7(5), pp. 515-527.

Papakyriacou, M., Mayer, H., Pypen, C., Plenk Jr, H., & Stanzl-Tschegg, S. (2000).

Effects of surface treatment on high cycle corrosion fatigue of metallic

implant materials. International Journal of Fatigue 22, pp. 873-886.

Paris, P. C., Gomez, M. P., & Anderson, W. E. (1961). A rational analytic theory of

fatigue. The Trend in Engineering 13, pp. 9-14.

Pompe, W., Worch, H., Epple, M., Friess, W., Gelinsky, M., & Greil, P. (2004).

Functionally graded materials for biomedical applications. Materials Science

and Engineering A362, pp. 40–60.

Pourbaix, M. (1966). Atlas of electrochemical equilibria in aqueous solutions. New

York: Pergamon Press, pp. 307-321.

Pourbaix, M., (1974) Atlas of electrochemical equilibria in aqueous solutions. 2nd

English ed., Houston.

124

Raman, V., Tamilselvi, S., Nanjundan, S., & Rajendran, N. (2005). Electrochemical

behaviour of titanium and titanium alloy in artificial saliva. Trends in

Biomaterials Artificial Organs, 18(12), pp. 137-140.

Ramsamooj, D. V., & Shugar, T.A. (2001a). Modeling of corrosion fatigue in metals

in an aggressive environment. International Journal of Fatigue 23(1), pp.

301-309.

Ramsamooj, D. V., & Shugar, T.A. (2001b). Model predicting of fatigue crack

propagation in metal alloys in laboratory air. International Journal of Fatigue

23(1), pp. 287-300.

Rautray, T. R., Narayana, R., & Kim, K.-H. (2011). Ion implantation of titanium

based biomaterials. Progress in Materials Science, 56, pp. 1137-1177.

Razavi, R. S, Gordani, G. R, & Man, H. C. ( 2011). A review of the corrosion of

laser nitrided Ti-6Al-4V. Anti-Corrosion Methods and Materials 58, pp. 140-

154.

Rezaie, A., Fahrenholtz, W. G., & Hilma, G.E. (2007). Effect of hot pressing time

and temperature on the microstructure and mechanical properties of ZrB2–

SiC. Journal of Materials Science 42, pp. 2735-2744.

Ritchie, R.O. (1999). Mechanisms of fatigue-crack propagation in ductile and brittle

solids. International Journal of Fracture 100, pp 55–83.

Sajuri, Z. B., Miyashita, Y., & Mutoh, Y. (2005). Effect of humidity and temperature

on fatigue behaviour of an extruded AZ61 magnesium alloy. Fracture of

Engineering Materials and Structures 28, pp. 373-379.

Sajuri, Z. B. (2005). Study on Fatigue Behaviour of Magnesium Alloy. Unpublished

PhD Thesis, Nagaoka University of Technology, Nagaoka, Japan.

Salazar, J. M., & Calleja, F. J. B. (1983). Correlation of hardness and microstructure

in unoriented lamellar polyethylene. Journal of Materials Science 18, pp.

1077-1082.

Saryanto, H., Sebayang, D., Untoro, P., & Sujitno, T. (2009). Ion implantation

process of lanthanum and titanium dopants into a substrate of Fe80Cr20 alloys.

Proceedings of the Malaysian Metallurgical Conference '09 (MMC'09)

UNIMEP, Perlis.

Schijve, J. (2009). Fatigue of Structure and Materials. Chapter 2, pp. 13-57.

http://www.springer.com/ISBN:978-1-4020-6807-2.

125

Shikha, D., Jha, U., Sinha, S. K., Barhai, P. K., Kalavathy, S., Nair, K. G. M.,

Dash, S., Tyagi, A. K., & Kothari, D. C. (2008), Improvement in Corrosion

Resistance of Biomaterial Alumina after 60 keV Nitrogen Ion Implantation,

International Journal of Applied Ceramic Technology, 5(1), pp. 44-48.

Shivaee, H. A., Golikand, A. N., Hosseini, H. R. M., & Asgari, M. (2010). Influence

of annealing on the electrochemical behaviour of finemet amorphous and

nanocrystalline alloy. Journal Materials Science 45, pp. 546-551.

Silvaa, H. M., Schneiderb, S. G., & Moura N. C. (2004) Study of nontoxic

aluminum and vanadium-free titanium alloys for biomedical applications.

Materials Science and Engineering C 24, pp. 679–682.

Sirimamilla, A. Furmanski, J. & Rimnac, C. (2013) Peak stress intensity factor

governs crack propagation velocity in crosslinked ultrahigh-molecular-weight

polyethylene, Journal of Biomedical Materials Research 101B (3), pp. 430-

435.

Sriraman, M. R., & Pidaparti, R. M. (2010). Crack initiation life of materials under

pitting corrosion and cyclic loading. Journal of Materials Engineering and

Performance 19(1), pp.7-12.

Sivakumar, M., K Mudali, U. K., & Rajeswari, S. (1994). Investigation of failures in

stainless steel orthopaedic implant devices: Fatigue failure due to improper

fixation of a compression bone plate. Journal Mater. Sci. Lett. 13 (2), pp.

142–145.

Sivaprasad, S., Tarafder, S., Ranganath,V. R., Tarafder, M., & Ray, K. K. (2006).

Corrosion fatigue crack growth behaviour of naval steels. Corrosion science

48, pp 1996-2013.

Spitzlsperger, G,. (2003). Very brief introduction to ion implantation for

semiconductor manufacturing. http://www.gs68.de/tutorials, May, 2003.

Son, C-Y, Yoon, T. S, & Lee, S. (2009). Correlation of microstructure with hardness,

wear resistance, and corrosion resistance of powder-injection-molded

specimens of Fe-alloy powders. Metallurgical and Materials Transaction A.

40, pp. 1110-1117.

Song, H.-J. Kim, M.-K. Jung, G.-C. Vang, M.-S. & Park, Y.-J. (2007). The effect of

spark anodizing treatment of pure titanium metals and titanium alloys on

corrosion characteristics. Surface & Coating Technology 201, pp. 8738-8745.

126

Stephens, R. I., Fatemi, A., Stephens, R., & Fuchs, H. O. (2001). Metal Fatigue in

Engineering. (2nd Ed.), New York: John Wiley & Sons, Inc.

Stroosnijder, M. F. (1998). Ion implantation for high temperature corrosion

protection. Surface and Coatings Technology, 100-101, pp. 196-201.

Sun, Q. Y., Song, X. P. & Gu, H. C. (2001). Cyaclic deformation behaviour of

commercially pore titanium at cryogenic temperature. International Journal

of Fatigue, 32, pp. 187-191.

Sundararajan, T., & Praunseis, Z. (2004). The effect of nitrogen-ion implantation on

the corrosion resistance of titanium comparison with oxygen- and argon-ion

implantations. Materiali in Technologije, 38(1-2), pp. 19 – 24.

Suresh, S. (1998). Fatigue of Materials, 2nd

edition, Cambridge Univ. Press,UK.

Suzuki, K. (2010). Analysis of ion implantation profiles for accurate process/device

Simulation: Ion implantation profile data based on tail function. FUJITSU

Science and Technology Journal 46(3), pp. 307-317.

Tam, B., Khan, M. I., & Zhou, Y. (2011). Mechanical and functional properties of

laser-welded Ti-55.8 Wt pct. Ni Nitinol wires. Metallurgical and Materials

Transactions A 42, pp. 2166-2175.

Tamilselvi, S., & Rajendra, N. (2006). Electrochemical studies on the stability and

corrosion resistance of Ti-5Al-2Nb-1Ta alloy for biomedical applications.

Trends in Biomaterials Artificial Organs 20(1), pp. 49-52.

Tanaka, T., Hakayama, H. & Kato, M (1996) Improvement of fatigue properties by

ion implantation method, Paper presented at the Fatigigue'96: Proceeding of

the Sixth International Fatigue Congress, Berlin.Germany.

Teoh, S. H. (2000). Fatigue of biomaterials: a review. International Journal of

Fatigue 22, pp. 825-837.

Upadhyaya, Y. S., & Sridhara, B. K. (2012) Fatigue life prediction: A continuum

damage mechanics and fracture mechanics approach.. Materials and Design,

35. pp. 220-224.

Vadiraj, A., & Kamaraj, M. (2007). Effect of surface treatments on fretting fatigue

damage of biomedical titanium alloys. Tribology International 40, pp. 82–88.

Van Noort, R. (1987). Titanium: the implant material for today. Journal of Material

Science 22, pp. 3801-3811.

Vardiman, R. G., & Kant, R. A. (1982). The improvement of fatigue life in TI6Al4V

by ion implantation. Applied Physics, 53, pp. 690-694.

127

Velten, D., Biehl, V., Aubertin, F., Valeske, B., W. Possart, W., & Breme, J. (2002).

Preparation of TiO2 layers on cp-Ti and Ti6Al4V by thermal and anodic

oxidation and by sol-gel coating techniques and their characterization.

Journal Biomedical Materials Research, A59(1), pp. 18-28.

Vera, R., Rosales, B. M., & Tapia, C. (2003). Effect of the exposure angle in the

corrosion rate of plain carbon steel in a marine atmosphere. Corrosion

Science, 45: pp. 321-337.

Wahab, M. A., & Sakano, M. (2001). Experimental study of corrosion fatigue

behaviour of welded steel structures. Journal of Materials Processing

Technology 118, PP. 117-122.

Wen, F. L., & Lo, Y.-L. (2007). Surface modification of SKD-61 steel by ion

implantation technique. Journal of Vacuum Science and Technology 25(4),

pp. 1137-1142.

Williams, D. F. (2008). On the mechanisms of biocompatibility. Biomaterials 29, pp.

2941–2953.

Winston, R. R., & Uhlig, H. H. (2008). Corrosion and Corrosion Control: An

Introduction to Corrosion Science and Engineering (4th ed.). Canada: John

Wiley.

Woolley, E. (1997). Surface hardening by ion implantation, Materials World 5(10),

pp. 515-516.

Xie, J., Alpas, A. T., & Northwood D. O. (2002). A mechanism for the crack

initiation fatigue of Type 316L stainless steel in Hank‟s solution. Materials

Characterization 48, pp. 271-277.

Xiang, Y., Lu, Z., & Liu, Y. (2010). Crack growth-based fatigue life prediction using

an equivalent initial flaw model. Part I: uniaxial loading. International

Journal of Fatigue, 32(2) pp. 341–349.

Xu, W., Liu, J., & Zhu, H. (2011). A study on the hardness and elastic modulus of

friction stir welded aluminum alloy thick plate joints using micro-

indentation. Journal of Materials Science,46(5), pp. 1161–1166.

Yu, J., Zhao, Z.J., & Li, L.X. (1993). Corrosion fatigue resistance of surgical implant

stainless steels and titanium alloys. Corrosion Science 35 (1-4), pp.587–597.

Zavanelli, R. A., Guilherme, E. P. H., Ferreira, I., & de Alamida Rollo, J. M. D.

(2000). Corrosion-fatigue life of commercially pure titanium and Ti-6Al-4V

128

alloys in different storage environments. Journal of Prosthetic Dentistry 84,

pp. 274-279.

Zhang, Y., Bae, I- T., Sun, K., Wang, C., Ishimaru, M., Zhu, Z., Jiang, W., & Weber,

W. J. (2009). Damage profile and ion distribution of slow heavy ions in

compounds. Journal Applied Physics 105(10)104901.doi:10.1063/1.3118582.

Ziegler, J. F., Biersack, J. P., & Littmark, U. (1985 ). The Stopping and Range of

Ions in Solids. New York: Pergamon Press.