Post on 12-Jun-2018
1
January 2005
HYDROGEN EMBRITTLEMENT OF PIPELINE STEELS: CAUSES AND
REMEDIATION
P. Sofronis, I. Robertson, D. JohnsonUniversity of Illinois at Urbana-Champaign
Hydrogen Pipeline R&D Project Review MeetingOak Ridge National Laboratory, Oak Ridge TN
January 5-6, 2005
2
January 2005
Hydrogen Embrittlement: Long History
M.L. Cailletet (1868) in Comptes Rendus, 68, 847-850
W. H. Johnson (1875) On some remarkable changes produced in iron and steels by the action of hydrogen acids. Proc. R. Soc. 23, 168-175.
D. E. Hughes (1880) Note on some effects produced by the immersion of steel and iron wires in acidulated water, Scientific American Supplement, Vol. X, No 237, pp. 3778-3779.
Literature is voluminous
3
January 2005
Hydrogen Embrittlement: Long History
Proc. R. Soc. 23, 168-175, 1875
4
January 2005
Hydrogen Embrittlement: Long History
Proc. R. Soc. 23, 168-175, 1875
5
January 2005
Hydrogen Embrittlement: Definition
Material degradation caused by the presence of hydrogen under load. It is manifested in
Strain hardening rateTensile strengthReduction in areaFracture toughnessElongation to failureCrack propagation rate
Degraded material often fail prematurely and sometimes catastrophically after many years of service
Degradation is influenced by Microstructure and operating conditions
6
January 2005
Hydrogen-Induced Crack Propagation in IN903
a b c
d e f
0 s 17s 21s
29s 32 s 39s
Static crack in vacuum. Hydrogen gas introduced
thinning thinning
maincrack
maincrack
Micro-crackformed
Crack linkage
7
January 2005
Deformation band
hole
Direction of crack advance
Crack Propagation in IN 903 Due to Hydrogen
8
January 2005
Hydrogen Embrittlement Mechanisms
Several candidate mechanisms have evolved each of which is supported by a set of experimental observations and strong personal views
Viable mechanisms of embrittlementStress induced hydride formation and cleavage
Metals with stable hydrides (Group Vb metals, Ti, Mg, Zr and their alloys)Supported by experimental observations
Hydrogen enhanced localized plasticity (HELP)Increased dislocation mobility, failure by plastic deformation mechanismsSupported by experimental observations
Hydrogen induced decohesionDirect evidence is lackingSupported by First Principles Calculations (DFT)
Degradation is often due to the synergistic action of mechanisms
9
January 2005
Hydrogen Enhanced Localized Plasticity (HELP)
Failure is by localized shear processes occurring along slip planes: shear localization
Transgranular fracture surfaces are highly deformed despite the fact macroscopic ductility is reduced (localized shear processes occurring along slip planes)
Intergranular fracture occurs by localized ductility in the region adjacent to the grain boundaries
Applicable to all systemsNon-hydride forming systems (Fe, Ni, Al, 304, 310, 316 stainless steel, Ti3Al, Ni3Al)Hydride forming systems α-Ti, β-TiAlloy and high purity systemsBcc,fcc, hcp
Underlying principle is the hydrogen-induced shielding of the Interactions between microstructural defects
10
January 2005
Features on Intergranular Surfaces of a 0.28pct C Steel Fractured in Hydrogen
Decrease in the density and size of ductile features (tear ridges) as a function of crack length.
Observations such as these led Beachem to conclude that hydrogen impacts plastic processes.
C. D. Beachem, Met. Trans. 3,437, (1972)
11
January 2005
0
10
20
30
0.00 0.10 0.20 0.30
Hydrogen concentration (H/M)
Plas
tic e
long
atio
n (%
)
Fracture Surface of a Beta 21S Alloy in Absence of Macroscopic Ductility (Brittle Failure)
12
January 2005
Slip Lines on Brittle Intergranular Facets
310s stainless steel, 5.3 at% H 310s stainless steel, 5.3 at% H
Ulmer and Altstetter, in Hydrogen Effects on Materials Behavior Moody and Thompson, p. 421
13
January 2005
Instrumentation: Controlled EnvironmentTransmission Electron Microscope
JEOL 4000 Environmental cell TEM
Objective Lens Pole-pieceD. K. Dewald, T. C. Lee, J. A. Eades, I. M. Robertson and H. K. Birnbaum Review of Scientific Instruments, 62, 1438, 1991.
Aperturecones
Pumping port
SpecimenaxisJEOL 4000 Controlled
Environment Transmission Electron Microscope
CELL
14
January 2005
Instrumentation: Stages and Samples
Single-tilt straining stage Double-tilt straining stage
Single-tilt, low T strainingSingle-tilt, high T straining
Double-tilt stage Double-tilt, high T stage
15
January 2005
Influence of Hydrogen on Dislocation Mobility (Fe under constant Load and Increasing H Pressure)
16
January 2005
Dislocation Motion in Fe due to Introduction of Hydrogen Gas
14:60 14:77 18:50 18:90
20:7120:60 30:40 30:64
36:4136:16 38:41 41:21
Increasing hydrogen gas pressure
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January 2005
Hydrogen Effect on Dislocation Mobility in Ti
18
January 2005
Hydrogen-Deformation Interactions
Solute hydrogen atoms interact with an applied stress fieldHydrogen-induced local volume dilatation (2cm3/mole in Fe)Hydrogen-induced local elastic moduli changes (measurements in Nb)
Solute hydrogen diffuses through normal interstitial lattice sites (NILS) toward regions of lower chemical potential, i.e.
Tensile hydrostatic stressSoftened elastic moduli
19
January 2005
Iso-concentration Contours of Normalized Hydrogen Concentration around two Edge Dislocations in Niobium as the Separation
Distance Between the Dislocations Decreases
20
January 2005
Effect of Hydrogen Atmospheres around the Two Dislocations:Shear Stress on Dislocation 2 vs Separation along the Slip Plane
Hydrogen reduces the interaction between dislocations
21
January 2005
Reversibility of Hydrogen Effect on Adding and Removing Hydrogen
Pressure increase from 15 to 75 torr
Pressure increase from 15 to 75 torr
Pressure decrease from 75 to 9 torr
Material: high-purity Al
black - initial positionwhite - final position
22
January 2005
Influence of Hydrogen on Dislocation Separation in a Pile-up (310S Stainless Steel)
23
January 2005
Iso-concentrationcountours of normalized hydrogen concentration around an edge dislocation and a carbon atom with a tetragonal axis [100]
Carbon atom is modeled as a stress center with a tetragonal distortion
Hydrogen-Carbon Interaction
24
January 2005
Shielding of Interaction Between Edge Dislocation and Carbon Atom
25
January 2005
Hydrogen Effect on Dislocation Cross Slip in Aluminum An Alternative Explanation of Increasing Slip Localization
Comparison imagesIncreasing hydrogen pressure constant hydrogen pressure decreasing hydrogen pressure.
Change in line direction in (c) indicates cross-slip process has initiated.
Cross-slip process halted due to hydrogen, (c) and (d).
Cross slip process resumes as hydrogen pressure reduced (f).
Cross-slip in progress. Cross-slip process halted. Cross slip process resumes
26
January 2005
HELP: Conclusions
Hydrogen enhances the mobility of dislocations and decreases the separation distance between dislocations in a pile-up
Hydrogen restricts cross-slip by stabilizing edge character dislocations.
Hydrogen enhances crack propagation rates
Hydrogen reduces the stacking-fault energy of 310S stainless steel by 20%
27
January 2005
HELP and Hydrogen Embrittlement
5 110 sε − −>
0/ exp( / )BC C W KT=
T>473K
High temperatures•No atmposphere•No hydrogen effect
Ni is not embrittled
BKT W>
Low temperaturesor high strain rates
Atmosphere lags behind
•Both Ni and pure Fe hardened by hydrogen at
•Ni is hardened by hydrogen at
•Pure Fe is hardened at200KT <
100KT <
Intermediate temperaturesor low strain ratesAtmosphere moves with dislocation•Shielding Embrittlement
Fe 77 400KT< <
6 1Ni 200 300K; 10 sT ε − −< < <
•At higher strain rates atmospheremoves but lags behind hardening
•Increasing the temperaturegives serrated yielding
473KT >
28
January 2005
Critical Issues for the HELP Mechanism
How does the hydrogen effect on the microscale affect the mechanical behavior on the macroscale?
How does hydrogen enhance slip localization?
What are the synergistic effects of other solutes on HELP type fracture, particularly at grain boundaries?
What is the actual mechanism by which the enhanced plasticity leads to fracture?
Localized microvoid coalescence (seen in situ TEM)?Stroh crack due to compressed pile-ups?
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January 2005
MODELING OF HELP
Connectingthe microscopic to the
macroscopic
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January 2005
Initially homogeneous deformation localizes into a band of intense shear
Initially homogeneous deformation localizes into a narrow neck
Modeling of Hydrogen-Induced Instabilitiesin Plane Strain Tension
How does hydrogen affect these instabilities?
Important note
Shear band bifurcation or shear localization is a precursor to material failure.
Multiplicity of solutions
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January 2005
Lattice hydrogen
Equilibrium theory
Hydrogen in Equilibrium with Local Stress and Plastic Strain
Dilatational strainFlow stress reduction
ElastoplasticityProblem is
fully coupled
Solution incremental in time (load)
Stress-Plastic strain
, 0L kkC Cσ
Hydrogen trapped at dislocations
, pT LC C ε
L TC C+
0C
Plastic response assumptions:• Material rate independent• von Mises yielding• Hardens isotropically• H-induced softening• H-induced lattice dilatation
32
January 2005
Condition for Shear Banding Bifurcation
Dependence of the critical and tangent modulus on the
macroscopic strain for initial hydrogen concentrations of H/M =
0.1, 0.3, 0.5
hcrh
h = 13
∂σY∂ε p +
∂σY∂c
∂c∂ε p
( ) ( )
( )( ) ( )( )
22
2 220
1 12 39 1
4 3 1sin2
24 3 1
crII
II e e
h NG
NOG G
β µν νβ µν
ν σ σβ µ θν
++ += − − +−
− ++ − +
−
equals
0 200 400 600 800
-0.001
0
0.001
0.002
h
hcr
c0=0.1c0=0.3c0=0.5
bifurcation points
22 0ε ε
, crh h
σ III
σ I =σ 22ε22
33
January 2005
Critical Strain for Shear Banding Bifurcationin Plane-Strain Tension
6
28
11.88
10.852 105.55 10
3.329.2
300
3
3
3
cm /mole=0.174
m /moleNb atoms/m
kJ/mole
H
M
Lo
B
V
VN
a AWT K
α β
λ−
= ==
= ×
= ×
==
=10 16
0 10 , 2.0 100.1
ρ γξ
= = ×=
0
115 , 0.34400 , 10
E GPaMPa n
νσ
= == =
Present work Rudnicki and Rice(1975)13
( )3
3
Y Yp p
p
Y
kk
c hc
c c
ccK K
∂σ ∂σ ∂∂ε ∂ ∂ε
∂ β∂ε
∂σ ∂ µ∂ ∂σ
+ →
Λ→
− →
→
Hydrogen triggers shear localization which could never happen in the absence of hydrogen in a work hardening material in plane strain uni-axial tension
Niobium
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
200
400
600
800
1000
ε22
1
2
shear band
n
22
0
bεε
0c
σ III
σ I =σ 22ε22
34
January 2005
x2
x1
c0
c0 +∆c
u 2∆
l
/2l
s
s 0
x1
x2
c0
c0+ c0∆
Hydrogen Perturbation and Plastic Instability
Motivation: Hydrogen concentration at grain boundaries larger than concentration in the bulk of the grainIt has been estimated that in nickel at 253K there is a 70nm grain boundary zone in which . In this zone high resolution TEM showed that fracture is a highly localized ductile process
230zone bulkC C=
35
January 2005
Perturbation in H Concentration to Model Necking Bifurcation in Plane-Strain Tension
1.60001.50001.40001.30001.20001.10001.0000
0 20 40 600.0
0.5
1.0
1.5normalized true stressnormalized force F2/(2 w)σ0
σ22/σ0
homogeneous casec0=0.3 c0=0.3
c0=0.003∆ε22, σ22, F2
c0+ c0∆c0
elastic unloading point
ε22=37.2ε0b
1.02001.01671.01331.01001.00671.00331.0000
22 0/ 29.40ε ε = 22 0/ 42.92ε ε =
0 0.3 /c H M= 0 0 0.01c c∆ = Local flow stress dependson the local hydrogen concentration
Load attains its maximum at 22 0 28.4ε ε =
36
January 2005
0 0.1 0.2 0.3 0.4 0.5 0.632
34
36
38
40
42
with concentration perturbation
with geometric imperfection
Hydrogen Effect on Necking Bifurcation in Uniaxial Tension
220
bεε
Hydrogen reduces the macroscopic strain at which necking bifurcation commences
( )0 /c H M
37
January 2005
Hydrogen-Induced Decohesion
V,σ surface energy
σ cohesive
r
B = −∂ 2V ∂r2
H − ∂V ∂r
Vcohesive
Basic premise: hydrogen reduces the local bond strength which results in the maximum force per unit area required to separate two half solids being reduced.
Problem: magnitude of the reduction is not known, especially under dynamic fracture conditions.
38
January 2005
Hydrogen-Induced Decohesion
Experimental evidenceCohesive energy: Unaffected by H in NbH fracture energy compared to NbSurface energy: Ni+300ppm H has equal surface free energy to pure NiCohesive stress (not measured)Phonon frequencies and force constant: Increased by H in VbmetalsBulk modulus: Increased by H in Vb metals
Ab-initio calculationsBased on equilibrium fracture considerations hydrogen was found to be a grain boundary embrittler at Ni Sigma 5 (210) GBIdeal fracture energy of Fe (110) decreases linearly with H coverage
39
January 2005
Hydrogen-Induced Fracture of beta-Titaniumas a Function of H Content
Plas
tic e
long
atio
n (%
)
0
10
20
30
0.00 0.10 0.20 0.30Hydrogen concentration (H/M)
Ductile microvoidcoalescence
Transgranular cleavage
40
January 2005
In situ TEM Deformation of beta-TitaniumNo New Hydrides at Crack Tip or Along Flanks
H/M=0.29
41
January 2005
Hydrogen-Induced Fracture of beta-Titanium
•No hydrides
•No HELP
•Sharp decrease in the fracture load with increasing hydrogen concentrationis consistent with a decohesion mechanism at the observed high H/M values
Jokl, Vitek, McMahon
cK
γHγ
HcK
Ideal work of brittle fracture 7.5p
p
d dn nγ γ
γ γ= =
A small reduction in brings about a dramaticreduction of the plastic work for fracture
γpγ
42
January 2005
Pipeline Steels
Hydrogen Embrittlement under
High-pressure GaseousHydrogen Environment
43
January 2005
Embrittlement Issues and Phenomenology“Mild” steels with yield strength less than 700 MPa and large fracture toughness
Hydrogen pressure of at least 14 Mpa for cost equity with natural gasFatigue due to cyclic loading from in-line compressors There are no studies of embrittlement under these conditions
Safety design does not allow hoop stress to exceed 80% of yield stress (plastic collapse approach)
Cracks propagate before plastic collapseNeed for an approach based on Elastoplastic Fracture Mechanics
Residual stresses at girth and longitudinal weldsA weld cannot be efficiently protected by coatingsLittle is known on the interaction between hydrogen solutes and elastoplasticity in the heat affected zone. Especially in the presence of “hard spots” of martensite upon cooling
Stronger steels X-80 and X-100 recently suggested to reduce thickness and diameter are more susceptible to embrittlement
44
January 2005
Embrittlement Issues and PhenomenologyNo difference in fracture response between burst and JIC testing (Robinson and Stoltz at A516-70 and A106-B)
Less cumbersome and less expensive JIC testing Hydrogen reduces JIC for crack initiation
Critical flaw size may be reduced from cm in natural gas to mm in high pressure hydrogen
Dramatic tenfold loss of crack growth resistance dJIC/da
Slope dJIC/da was found independent of hydrogen pressureHence supply of hydrogen is fast and not the rate limiting processIt is the plastic work that controls hydrogen degradation
Crack growth resistance dJIC/da impacts the stability of crack advanceFracture behavior needs to be investigated
2
2
2
2
Air 3.45 MPa H 6.90 MPa H 20.7 MPa H 34.5 MPa H
•
Robinson and StoltzHydrogen Effects in Metals, 1981, pp-987-995
IC
2
Jin lbin−
( )a in∆
1500
1250
1000
750
500
250
0.01 0.02 0.03 0.04 0.05
45
January 2005
Embrittlement Issues and Phenomenology
Fractographic evidence suggests
Hydrogen-assisted transgranular fracture by void or microcrack initiation through decohesion at second phase particles (precipitate/inclusion) ahead of a crack or notch accompanied by shear localization (HELP) leading to the linking of the void/microcrack with the tip of crack
Intergranular cracking in welds by hydrogen-induced lowering of grain boundary or matrix/carbide interfacial cohesion in the HAZ
Our contention, which needs to be verified through experiment, is that embrittlement is a result of the synergistic action of the HELP and decohesion mechanisms
46
January 2005
Identify mechanisms of failureTransgranular vs intergranular Role of inclusions and precipitatesFatigue or static loading conditions
Explore for optimum microstructureTempered bainite or tempered martensite superior to pearlitic or pearlite-ferrite steels with speroidized in betweenC: increasing H content gives higher strength but higher H susceptibilityMn : ferrite strengthener but reduces fracture toughness in HSi: potent ferrite strengthener, neutral to H, problems with formability and weldabilityTi and Ni: alloying additions may helpMorphology and volume fraction of inclusions is controlled by S levelsSilicon steel rather than manganese with fine spheroidizedcarbides may be a promising system to explore
Objectives
47
January 2005
Objectives (Cont’d)
Model the failure processes
Provide an insight to the critical flaw size and its stability
Device a fracture criterion with predictive capabilities for theincubation period in subcritical crack growth and remnat life of the pipeline
Study the viability of using high strength steelsH incompatibilty increases with strength
48
January 2005
Objectives (Cont’d)
Mitigate hydrogen embrittlement by adding water vapor in the transported hydrogen
Water vapor is cheapWater vapor is separated easily at final destination stations through coolingWater vapor lowers crack growth rates (Robinson, Wei)
Reaction Fe+O FeO is 108 faster than Fe+H2O FeO+H2
O (inhibitor of crack growth) and H (promoter of crack growth) compete for adsorption sites on the metal surface
At high transport pressures it is expected that the surface reactions will not be the controlling step. Embrittlement depends on the transport of hydrogenEffects of water vapor or O need to be carefully explored in particular at high pressures
49
January 2005
Objectives (Cont’d)
Understand the hydrogen or water vapor effects on interfacial cohesion by
studying the fracture of a thin film attached to a substrate orthrough using “hour-glass radiused” uniaxial tension specimens
50
January 2005
OUTLINE OF AN EXAMPLE STUDY
Transgranular CrackingInitiation - Propagation
51
January 2005
Modeling of Ductile Transgranular Fracture: Initiation
Hydrogen concentration set by the adsorptionsurface reactions
X1
X2
Crack tip
Crack face
Crack tip
Ti =KI2πR
fij θ( )ni
n
Hydrogen flux to the fracture process zone
JH
R
C = C0
C = C0
JH = 0 X1
X2
Boundary concentrationof hydrogen
X2
X1
JH
JHr
MACRO
MESO
MICROHydrogen mixed with water vapor
Surface reactionsthat release hydrogen and oxygen
inclusion
Hydrogenatmosphere
Zone of intense shear
•Decohesion at inclusion•Void formation•Linking with crack through shear banding•Fracture mechanisms assisted by transient hydrogen adsorption and diffusion
52
January 2005
Modeling of Ductile Transgranular Fracture: Initiation
Address the role of significant parameters, such asMaterial flow characteristicsMaterial trapping characteristics (type of traps, trap density, and binding energy)Hydrostatic stressPlastic strainHydrogen concentrationLoading rateLoading in terms of the applied J-integralAdsorption kinetics (ab-initio modeling)Cohesive properties of the inclusion/matrix interface (ab initio)Lattice cohesion in a direction perpendicular to the slip band (ab-initio)Effect of water vapor or other crack growth inhibitors
Hydrogen boundary conditions on the crack face are set by the local adsorption kinetics
Assumption of first order kinetics leads to hydrogen coverage
( ) ( ) 11h h o o o h hk p k p
− Γ Γ + Γ = +
53
January 2005
Modeling of Ductile Transgranular Fracture: Propagation
X-1 0 1 2
0
0.5
1
1.5
2
KI(disp.)
R=2m
Hierarchical Modeling
200µmx200µm
Crack tip: Fracture Process zone
X0 0.5 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cohesive elements characterized bya traction-separation law based on the voidcell model
54
January 2005
Modeling of Ductile Transgranular Fracture: Propagation
X
Y
0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
X0 0.5 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
X
Y
0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
X0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
X0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
X0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
X0 0.5 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Initial void volume fraction f0=0.001, Triaxiality=3
X0 0.5 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
X0 0.5 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
X0 0.5 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1No hydrogen
With hydrogen / 3initial refL Lc c =
Ee=2.5% Ee=5.0% Ee=7.5% Ee=10% Ee=15%
EP21.81.61.41.210.80.60.40.20
Material Data for A533B Pressure Vessel Steel
55
January 2005
Modeling of Ductile Transgranular Fracture: Propagation
0.0
1.0
2.0
3.0
4.0
5.0
0 0.5 1 1.5
U33/D
Σ33
/ σ0
No hydrogen
T=1.0
T=1.5T=2.0
T=2.5
T=3.0T=3.5
T=4.0
f0=0.001
11 22 33 33 11/ , ( ) / 3,m e m eT Σ Σ Σ Σ Σ Σ Σ Σ Σ= = + + = −
33 33,U Σ
11 11,U Σ
AxisymmetricModel
Void shape at high T
Void shape at low T
•Peak stress controls initiationJIC
•Area underneath controls R-CurvedJIC/da
Material Data for A533B Pressure Vessel Steel
56
January 2005
Modeling of Ductile Transgranular Fracture: Propagation
0
1
2
3
4
5
0 0.1 0.2 0.3 0.4
u33
σ33
/ σy
No hydrogenSmin=0.9SySmin=0.7SySmin=0.5Sy 0
0 0
00
[ ] ,
( 1) 1 1
[ ]
1
yN
yN
if softening effect then
cc
elsesoftening effect
ασ
εσ σ ξε
ασ
εσ ασε
≥
= − + +
<
= +
Softening model
f0=0.001, T=3, HCon=3
2max 0 0
2max 0 0
2max 0 0
2max 0 0
: / 4.32, 58.2 kJ/m ( 200 )( 0.9) : / 3.91, 51.3 kJ/m (88%)( 0.7) : / 3.81, 36.8 kJ/m (63%)( 0.5) : / 3.77, 27.4 kJ/m (
without softening D mwith softeningwith softeningwith softening
σ σ Γ µα σ σ Γα σ σ Γα σ σ Γ
= = == = == = == = = 47%)
Material Data for A533B Pressure Vessel Steel
•Peak stress controls initiationJIC
•Area underneath controls R-CurvedJIC/da
57
January 2005
SUMMARY AND CONCLUSIONS
Hydrogen EmbrittlementDirect experimental evidence and solid mechanics finite element calculations support the hydrogen enhanced localized plasticitymechanism as a viable mechanism for hydrogen embrittlement
Indirect experimental evidence, thermodynamic considerations, and ab-initio calculations indicate that hydrogen-induceddecohesion can also be a viable mechanism of hydrogen embrittlement
PipelinesIt appears that do have the capability of assessing whether existing structural material systems can be used for hydrogen transport
Advanced knowledge and technology are available for the design of new structural materials with hydrogen compatibility