3 3 Metallic materials with superior properties Superconductive
NbTi, Nb 3 Sn, Nb 3 Ge Structural alloys Neodymium rare-earth
magnets (alloys of Nd, Fe and B) are strongest known permanent
magnets. Sm-Co magnets Mg- and Al-alloys with superior properties,
Al-metaglass, foams Ti-alloys with thermomechanical properties,
superalloys, maraging steels, intermetallides, high-density alloys,
shape-memory alloys Biocompatible Ti-alloys Amorphous alloys with
chemical and thermal properties, Ni- and Fe aluminates
Slide 4
4 Strength groups of materials Classification based on tensile
strength (R m ) of materials I. Low-strength ( < 250 N/mm 2 )
II. Mid-strength (250...750 N/mm 2 ) III. High-strength (750...1500
N/mm 2 ) IV. Ultrahigh-strength (
Slide 5
5 Production technologies of hihg-strength steels and alloys
Advanced metallic materials 5
7 High-strength steel... what is it? The end of 1920-s Steel St
52 (S355) for bridge construction Today S355 is standard grade
Definition for high-strength is dependent on level of development.
Steel R eH > 355 MPa 7 Advanced metallic materials
Slide 8
8 Alloying of ferrite Hardening Ageing Alloying elements, %
Ageing time, t Methods for increasing strength 1. structure
refinement 2. alloying B; microalloying elements Nb, Ti, V and N 3.
low carbon steels transgranular fracture 4. two- and multi-phase
structures F+M; F+M+B 5. dispersion strengthening micro- and
nanosteels 6. deformation hardening: - low- & high-temperature
- isothermal - marforming Advanced metallic materials
Slide 9
9 Heat treatable boron-steels 0,003% of B increased
through-hardenability 0,002...0,003% of B in solid solution has the
same effect on hardenability than 0,7% Cr; 0,5% Mo or 1% Ni
Through-hardenability diameter up to 200 mm C24CR R p0,2 1000; R m
1500; A 7% 9 Advanced metallic materials
Slide 10
10 Low-alloy high-strength steels Also known as HSLA steels C =
0,2..0,3% ; alloying el: Mn, Si Micro alloying with Nb, Ti and/or V
dispersion strengthening + grain refinement HX340LAD HX460LAD R
p0,2 560; R m 640 N/mm 2 ; A min 15% 10 Advanced metallic
materials
Slide 11
11 Two- and multi-phased steels Also known as duplex (DP) and
complex (CP) steels Ultra-High-strength (UHS) ductile steels -
Two-phase LITEC DP R p0,2 750 N/mm 2 ; R m 980 N/mm 2 ; A min 10%
11 Advanced metallic materials
Slide 12
12 good formability and high strength ability of high energy
absorption high strain-hardening rate good fatigue strength
DP-steelCP-steel 12 Advanced metallic materials - Multi-phase LITEC
CP R p0,2 900; R m 980 N/mm 2 ; A 7%
Slide 13
13 Maraging (martensite-ageing) steels (1) Martensitic steels (
C%) - low ductility and toughness in case of high R m - M
decomposition, formation of carbide phase brittleness Maraging
steels in 1980 - low C-content ( 0,03%) transgranular fraction -
alloying el. Ni (17...25%), Mo + Ti, Al, Ta etc. Quenching C-free
martensite, Ageing intermetallides (4 5) nm, (NiTi, Ni 3 Ti, NiAl,
Ni 3 Mo etc.) R m 2000 N/mm 2, R p0,2 1500 N/mm 2, A = 10 - 12% 13
Advanced metallic materials
29 Light-weight materials Mg alloys Mg-alloys (Mg: = 1740 kg/m
3, T s 649 0 C) Alloying elements: Al (3 - 10%); Zn, up to (5 6%);
Mn; Zr R m 300 N/mm 2 (deformable alloys)R m / 20 220 N/mm 2 (cast
alloy) 29 Advanced metallic materials
Slide 30
30 Light-weight materials Al alloys Al-alloys Al-Li alloys (Li
is only dopant, which R m, E, however = 2500 kg/m 3 ) 2Li, 4Mg, R m
= 220 350; R p0,2 = 135 210 N/mm 2 Powder-aluminum-alloys -
dispersion strengthened Al-alloys (SAP-Al 2 O 3 15%, Al- C-alloys
Al 4 C 3 20 volume%), allowed working temperature up to 550 0 C
Foam-aluminum ( ~ 200 kg/m 3 ) 30 Advanced metallic materials