Texture Of Ti And Its Alloy

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Texture Of Ti And Its Alloy

  1. 1. TEXTURE OF TITANIUM AND ITS ALLOYS <ul><li>Presented by: </li></ul><ul><li>Gaurav Singh </li></ul><ul><li>PhD Student,Department of Materials Engg </li></ul><ul><li>IISc Bangalore </li></ul>
  2. 2. METALLURGY OF TITANIUM
  3. 3. β->α Transformation <ul><li>{0001} α ІІ {110} β </li></ul><ul><li><1120> α ІІ <111> β </li></ul>D α-Ti =10 -19 and D β-Ti =10 -18 m 2 /s β (slow cooling) ->α (lamellar) β (quenching) ->α (martensite) Hexagonal α ’ martensite Orthorhombic α ’’ martensite
  4. 4. Classification of Ti alloys <ul><li>α alloys </li></ul><ul><li>β alloys </li></ul><ul><li>α + β alloys </li></ul><ul><li>Near α </li></ul><ul><li>Metastable β </li></ul>a)lamellar microstructure b) Martensitic microstructure c) Bimodal microstructure α-stabilizer Al,O,N and C β-stabilizer Mo,V,Ta,Nb,Fe,Mn,Cr,Co,Ni,Cu,Si and H Neutral stabilizer Sn and Zr
  5. 5. TEXTURE IN TITANIUM <ul><li>Anisotropy in properties- presence of hcp α </li></ul><ul><li>Main textures of Titanium and its alloys </li></ul><ul><li>Rolling Texture </li></ul><ul><li>Annealing texture </li></ul><ul><li>Transformation texture </li></ul><ul><li>Solidification texture </li></ul>
  6. 6. Cold rolling Texture of pure Ti Initial texture {1013}[1210] basal texture {0001}[0110] Final texture {2115}[0110]
  7. 7. Annealing texture of Ti after cold rolling Ti sheet cold rolled upto 90% and then annealed at T=750°C (2115)[0Ī10](before annealing) (Ī013)[1210] (after annealing)
  8. 8. Hot rolling texture of Ti Hot rolled upto 96% reduction at a temperature between 700 to 900°C {2115}[0110] below 800°C {2110}[0110] and {2118}[8443] (800<T<850°C) {2110}[0110] (T>880°C)
  9. 9.
  10. 10. Hot Rolling Texture in Ti-6Al-4V alloy {2110}[0110] T< 850 °C {2110}[0110] and {2110}[0001] 850<T<1000°C {1010}[0001] T> 1000°C
  11. 11.
  12. 12. Hot Rolling Texture in high strength Ti alloy <ul><li>Main alloys </li></ul><ul><li>Ti-4Al </li></ul><ul><li>Ti-5Al-2.5Sn </li></ul><ul><li>Ti-6Al-2Sn-4Zr-2Mo </li></ul><ul><li>Ti-8Al-1M0-1V </li></ul><ul><li>Below β transus it will depend upon dispersion of α and β phase. </li></ul><ul><li>Above β transus it will depend upon the transformation property of the alloy. </li></ul>
  13. 13. Ti-4Al <ul><li>Above β transus </li></ul><ul><li>Main component {-2110}[0110] </li></ul><ul><li>Between β transus and recrystallization T of α {1019}[9092],{0001}[1100] </li></ul>
  14. 14. Hot rolling texture of Ti-5Al-2.5Sn <ul><li>Above β transus </li></ul><ul><li>Main component {1010}[1213] </li></ul><ul><li>Between β transus and Recrystallization T of α {2110}[0110] </li></ul><ul><li>Below Recrystallization T of α basal texture develop {0001}[1210] </li></ul>
  15. 15. Hot rolling texture of Ti-6Al-2Sn-4Zr-2Mo <ul><li>Volume fraction of β is more. </li></ul><ul><li>Below Recrystallization T of α (2110)[0110] </li></ul><ul><li>Between β transus and Recrystallization T of α (2110)[0110] and (2118)[8443] </li></ul><ul><li>Above β transus (2110)[0110] and (1010)[0001] </li></ul>
  16. 16. Transformation texture Ti alloys <ul><li>Amount of cold reduction. </li></ul><ul><li>Transformation behavior of the alloy , i.e microstructure. </li></ul><ul><li>Cooling Rate. </li></ul><ul><li>Al equivalent . (Al eq= wt %Al +1/3 %Si+1/6%Zr+10%O) </li></ul><ul><li>Planar disregistry </li></ul>
  17. 17. Texture development during ECAP of Ti <ul><li>During first pass, deformation by glide of dislocation on basal plane and {10-10}twinning. </li></ul><ul><li>Low dislocation density in first pass (10 9 /cm 2 ) </li></ul><ul><li>Most shear is accommodated by twinning on {1010} plane. </li></ul><ul><li>During second ECAP pass deformation on secondary slip system due to </li></ul><ul><li>decrease in grain size strain hardening of the slip system. </li></ul><ul><li>critical stress for twin nucleation increases. </li></ul><ul><li>Strong basal texture is observed. </li></ul>
  18. 18. Texture formation in ECAE of Ti-6Al-4V Occurs at T=800°C (moderate strain rate) During First pass, deformation occurs by glide of dislocation and twinning. During second pass deformation occurs mainly by twinning.
  19. 19. <ul><li>Nucleation of Mechanical twins- </li></ul><ul><li>requires very large stress </li></ul><ul><li>Regions of high stress concentration. </li></ul><ul><li>Non-planar dissociation of slip dislocation. </li></ul><ul><li>Deformation by twinning on {1010}plane. </li></ul><ul><li>low value of critical stress for twin nucleation. </li></ul><ul><li>separation of twin partial is more. </li></ul>(0001)Pole figure.a) as received b) one ECAE pass c)two ECAE pass in Ti-64
  20. 20. Effect of magnetic field on texture of Titanium <ul><li>Cold rolled Ti to 82% reduction and then annealed at T=750 °C in a magnetic field H=19.4T with varying the orientation of the Sheet. </li></ul>Major cold rolling texture of Ti (2115)[0110] transform to (1013)[1210] by rotation of 30° about c axis. Two driving force for grain growth curvature effect 2 σ /R magnetic driving force H 2 ∆M(cos 2 θ 1 - cos 2 θ 2 ) Growth rate will be more for grain whose <0001> is perpendicular to H. strong basal texture is observed
  21. 21. Effect of texture on mechanical property of Ti alloy
  22. 22. Conclusion- <ul><li>Texture of Ti and it alloy strongly depend upon alloying element, cooling rate transformation behavior , microstructure, prior orientation of the parent phase, amount of cold reduction and cooling rate. </li></ul><ul><li>ECAE texture of Ti-64 will depend upon the separation of the twin partial. </li></ul><ul><li>Transformation texture will depend upon prior cold reduction, cooling rate, and planar disregistry. </li></ul><ul><li>Magnetic field can also effect texture of the Titanium alloy. </li></ul><ul><li>Mode of loading and orientation of the crystallite can effect mechanical properties of the Titanium alloy. </li></ul>
  23. 23. References- <ul><li>Cold rolling texture of Titanium by H.Inagaki. </li></ul><ul><li>Texture and mechanical anisotropy in cold rolled Titanium by H.Inagaki. </li></ul><ul><li>Hot rolling texture of Titanium by H.Inagaki. </li></ul><ul><li>Evolution of texture and microstructure in thermomechanical Ti-64 by H.Inagaki. </li></ul><ul><li>Hot rolling texture in High strength Titanium alloys. </li></ul><ul><li>Scripta Materilia ,vol 34,No-8,pp-1281-1286,1996. </li></ul><ul><li>Acta Materialia 51(2003) 983-996 </li></ul><ul><li>Acta Materialia 54(2006) 3755-3771 </li></ul><ul><li>Acta Materialia 52(2004) 4347-4383 </li></ul><ul><li>Material science and engineering A 319-321(2001) 409-414. </li></ul>

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