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Advanced metallic materials

Advanced metallic materials. Prof. Priit Kulu. Outline. High-strength structural steels High-performance tool steels Metallic-ceramic materials Light-weight metals and alloys Superalloys. 2. Metallic materials with superior properties. Structural alloys.

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Advanced metallic materials

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  1. Advanced metallic materials Prof. Priit Kulu

  2. Outline • High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 2

  3. Metallic materials with superior properties Structuralalloys Mg- and Al-alloys with superior properties, Al-metaglass, foams Superconductive NbTi, Nb3Sn, Nb3Ge Ti-alloys with thermomechanical properties, superalloys, maragingsteels, intermetallides, high-density alloys, shape-memory alloys Neodymium rare-earth magnets (alloysofNd, Fe and B) are strongestknownpermanentmagnets. Sm-Comagnets Amorphousalloyswithchemical and thermalproperties, Ni- and Fe aluminates Biocompatible Ti-alloys Advanced metallic materials Advanced metallic materials 3

  4. Strength groups of materials Classification based on tensilestrength (Rm) of materials • Low-strength (<250 N/mm2) • Mid-strength (250...750 N/mm2) • High-strength (750...1500 N/mm2) • Ultrahigh-strength (<1500 N/mm2) Advanced metallic materials 4

  5. Production technologies of hihg-strength steels and alloys Advanced metallic materials 5

  6. High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 6

  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” isdependent on level of development. Steel ReH > 355 MPa Advanced metallic materials 7

  8. Alloying of ferrite Hardening Ageing Ageing time, t Alloying elements, % Methods for increasing strength • structure refinement • alloying – B; microalloying elements – Nb, Ti, V and N • low carbon steels  transgranular fracture • two- and multi-phase structures – F+M; F+M+B • dispersion strengthening – micro- and nanosteels • deformation hardening: - low- & high-temperature - isothermal - marforming Advanced metallic materials

  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 Rp0,21000; Rm1500; A 7% Advanced metallic materials 9

  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 refinementHX340LADHX460LAD • Rp0,2560; Rm640 N/mm2; A – min 15% Advanced metallic materials 10

  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 Rp0,2750 N/mm2; Rm980 N/mm2; A – min 10% Advanced metallic materials 11

  12. - Multi-phase LITEC CP Rp0,2900; Rm980 N/mm2; A – 7% DP-steel CP-steel →good formability and high strength →ability of high energy absorption →high strain-hardening rate →good fatigue strength Advanced metallic materials 12

  13. Maraging (martensite-ageing) steels (1) Martensitic steels ( C%) • low ductility and toughness in case of high Rm • 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, Ni3Ti, NiAl, Ni3Mo etc.) Rm  2000 N/mm2, Rp0,2  1500 N/mm2, A = 10 - 12% Advanced metallic materials 13

  14. Maraging steels (2) Advanced metallic materials 14

  15. Termomechanically processed / deformation hardened high temperature low temperature isothermal marforming Advanced metallic materials 15

  16. Thermomechnical rolling

  17. TRIP-steels (Transformation Induced Plasticity) • Low alloy steels (car industry) 0,2 – 0,3 % C; 1,5 – 2,0 % Mn, Si + Al • High alloy Ni-Cr steeks 0,2 – 0,3 % C; 8 – 32 % Ni; 8 – 14 % Cr+Mn (0,5 – 2,5%), Mo, Si Quenching (985 – 1200 °C) → F, B, A Deformation (< Trecr = 250 – 550 °C), A → M Rm →1700, Rp0,2 → 1550, A =50 – 60 %, ↑KIC, σ-1

  18. Rp0,2 N/mm2 KTMT TMT + def. ageing 2000 Maraging steels (high-alloy) 1000 Low-alloy steels 20 40 60 60 A% Strength-plasticity of high-strength steels TRIP-steels TMT + def. ageing

  19. High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 19

  20. Advanced tool steels (1) I generation of high-speed steels (HSS) • carbide temper hardness steels 500 - 650 0C, e.g. HS 6 – 5 – 2 – 5W-Mo -V –Co • Intermetallic temper hardness steels650 - 750 0C, Co7W6, (CoFe)7W6 etc.(11 – 20%)W; 7% Mo; (1-3%)V; (20 – 25%)Co Structure (cast and rolled) Advanced metallic materials 20

  21. Advanced tool steels (2) II generation of high-speed steels – PM steels (PM/HIP) Uddeholmi steels Vanadis 4, 6, 10, 23, 30, 60 (Super Clean) (1,3 - 2,9%) C; → 6,5 W; (1,5 - 7%) Mo; (3,1 - 9,8%) V; → 10,5% Co Structure (PM / HIPed) Advanced metallic materials 21

  22. Advanced tool steels (3) III generation of high-speed steels – Sprayformed, SF + HIP PM steels, Vanadis 4 EXTRA WEARTEC 2,8 C; 8,9 V; 7,0 Cr; 2,3 Mo; Si; Mn ROLTEC 1,4C; 4,6Cr; 3,7 V; 3,2 Mo; Si; Mn TOUGHTEC 1,6C; 7,2V; 5,0 Cr; 2,3 Mo; Si; Mn Advanced metallic materials 22

  23. SF /HIP Similar to PM/HIP, slab formation by spraying methods High-Tech Materials & Technologies 23

  24. TRZ, GPa Diameter of carbide particles, m Strength of high-speed steels Advanced metallic materials 24

  25. High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 25

  26. Classification of wear resistant materials depending on volumetric content of hard phase Advanced metallic materials 26

  27. Metallic-ceramic composites Carbide steels and alloys • Ferro-TiC Steel (50 - 70)% -TiC • Double-reinforced MMC (Cr-steel + 20%VC) + 20%WC • Self-fluxing alloys NiCrSiB +  50% (WC-Co) Ceramic/metallic • TiC-NiMo – (50 - 60)% (NiMo)(2:1) 920 – 1620 HV10 • Cr3C2-NiCr – (50 - 60)% NiCr Advanced metallic materials 27

  28. High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 28

  29. Light-weight materials – Mg alloys Mg-alloys (Mg:  = 1740 kg/m3, Ts – 649 0C) Alloying elements: Al (3 - 10%); Zn, up to (5 – 6%); Mn; Zr Rm 300 N/mm2 (deformable alloys) Rm/  20 220 N/mm2 (cast alloy) Advanced metallic materials 29

  30. Light-weight materials – Al alloys Al-alloys • Al-Li alloys (Li is only dopant, which  Rm, E, however  = 2500 kg/m3) 2Li, 4Mg,  Rm = 220 – 350; Rp0,2 = 135 – 210 N/mm2 • Powder-aluminum-alloys • dispersion strengthened Al-alloys (SAP-Al2O315%, Al-C-alloys – Al4C3 20 volume%), allowed working temperature up to 550 0C • Foam-aluminum ( ~ 200 kg/m3) Advanced metallic materials 30

  31. High-strength structural steels • High-performance tool steels • Metallic-ceramicmaterials • Light-weight metals and alloys • Superalloys Advanced metallic materials 31

  32. Superalloys …alloys capable of service at high temperatures, usually above 1000 °C → heat-resistant high-temperature strength alloys • Ni-alloys • Co-alloys heat resistance (oxidation resistance > 600°C) refractory steels = heat res. + high temp. strength Advanced metallic materials 32

  33. Ni-alloys Ni uses: ca 60% – stainless steels 12% – Ni-alloys 10% – coatings 10% – alloy steels Heat resistant alloys (superalloys) • wrought (Inconel Ni – 20-23 Cr; Hastelloy Ni- 7-22 Cr-Co) • cast ( polycrystalline, directionally solidified, single crystal) • PM (HIP-ed, IN 100, Rene 95→ gasturbine disk) 718 (cast) Ni – (4,75 – 5,5%) Nb → aerospace, nuclear structural applications (-250 – +700 °C). MA 754 PM/HIP Ni – 1% Y2O3 Advanced metallic materials 33

  34. Co-alloys Co uses: ca 46% – superalloys 15% – steels 10% – cemented carbides Wear resistant alloys • Stellite – Co (10 –30%); Cr (1,5 –22) Ni; up to 15% W; 1 Mo Heat resistant alloys • wrought Co + (20 –30%) Cr; (14 –15%) W • cast Co +(23 –29%) Cr; (1 –10 %) Ni; 7 W Corrosion resistant alloys Ultimet Co + 26Cr; 9Ni; 5Mo; 2W Advanced metallic materials 34

  35. General stress-rupture behaviour of superalloys

  36. Thank you for your attention! TUT materials engineering web-site: www.ttu.ee/mti mti@ttu.ee

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