Advertisement

Microstructural Evolution and Mechanical Behavior of Heat Treated Ti-6Al-4V Powders

  • Venkata Satish Bhattiprolu
  • Grant A. Crawford
Technical Article
  • 8 Downloads

Abstract

Plasma-atomized Ti-6Al-4V powder is widely used in a variety of powder-based manufacturing technologies due to its attractive properties. In many cases there is a desire to modify the microstructure of the as-atomized powder via heat treatment, to improve manufacturing characteristics (e.g., deformability in the case of cold spray deposition). Microstructure characterization of as-received and heat treated plasma-atomized Ti-6Al-4V powder was performed using optical microscopy and x-ray diffraction. Additionally, heat treated powder was characterized using back-scatter electron imaging and energy-dispersive x-ray spectroscopy. The as-received powder was characterized by martensitic alpha grain structures, while the heat treated powder was characterized by either equiaxed alpha or lamellar alpha phase grains, with intergranular beta phase structures. Bulk Ti-6Al-4V was heat treated similar to powders to establish a control, for effective comparison. Microstructure characterization of bulk Ti-6Al-4V using optical microscopy revealed a bright oxygen-rich region, also known as alpha case, near the surface with microstructures resembling heat treated powder. Hardness of the powder and bulk sample was evaluated using Vickers microhardness testing. The hardness values for the alpha case in bulk Ti-6Al-4V correlated with the hardness of heat treated powder and were twice as hard when compared to as-received powder. Overall, this study demonstrated the conversion of powders to alpha case, even during heat treatment in argon with close oxygen control.

References

  1. 1.
    B. Dutta, F.S. Froes, The additive manufacturing (AM) of titanium alloys, Metal Powder Report (2017)Google Scholar
  2. 2.
    R. Raoelison, C. Verdy, H. Liao, Cold gas dynamic spray additive manufacturing today: deposit possibilities, technological solutions and viable applications. Mater. Des. 133, 266–287 (2017)CrossRefGoogle Scholar
  3. 3.
    M. Smagorinski, P. Tsantrizos, Production of spherical titanium powder by plasma atomization. Adv. Powder. Metall. Part. Mater. 3, 3–248 (2002)Google Scholar
  4. 4.
    J. Capus, Titanium powder developments for AM–A round-up. Met. Powder Rep. 72(6), 384–388 (2017)CrossRefGoogle Scholar
  5. 5.
    V.S. Bhattiprolu, K. Johnson, O.C. Ozdemir, G.A. Crawford, Influence of feedstock powder and cold spray processing parameters on microstructure and mechanical properties of Ti-6Al-4V cold spray depositions. Surf. Coat. Technol. 335, 1–12 (2018)CrossRefGoogle Scholar
  6. 6.
    A. Birt, V. Champagne, R. Sisson, D. Apelian, Microstructural analysis of Ti–6Al–4V powder for cold gas dynamic spray applications. Adv. Powder Technol. 26(5), 1335–1347 (2015)CrossRefGoogle Scholar
  7. 7.
    Y. Kim, E.-P. Kim, Y.-B. Song, S.H. Lee, Y.-S. Kwon, Microstructure and mechanical properties of hot isostatically pressed Ti–6Al–4V alloy. J. Alloys Compd. 603, 207–212 (2014)CrossRefGoogle Scholar
  8. 8.
    W. Wong, P. Vo, E. Irissou, A. Ryabinin, J.-G. Legoux, S. Yue, Effect of particle morphology and size distribution on cold-sprayed pure titanium coatings. J. Therm. Spray Technol. 22(7), 1140–1153 (2013)CrossRefGoogle Scholar
  9. 9.
    S.K. Vajpai, M. Ota, T. Watanabe, R. Maeda, T. Sekiguchi, T. Kusaka, K. Ameyama, The development of high performance Ti-6Al-4V alloy via a unique microstructural design with bimodal grain size distribution. Metall. Mater. Trans. A 46(2), 903–914 (2015)CrossRefGoogle Scholar
  10. 10.
    C. Lee, J. Kim, Microstructure of kinetic spray coatings: a review. J. Therm. Spray Technol. 24(4), 592–610 (2015)CrossRefGoogle Scholar
  11. 11.
    W.A. Story, L.N. Brewer, Heat treatment of gas-atomized powders for cold spray deposition. Metall. Mater. Trans. A 49(2), 446–449 (2018)CrossRefGoogle Scholar
  12. 12.
    B. Vrancken, L. Thijs, J.-P. Kruth, J. Van Humbeeck, Heat treatment of Ti6Al4V produced by Selective Laser Melting: microstructure and mechanical properties. J. Alloys Compd. 541, 177–185 (2012)CrossRefGoogle Scholar
  13. 13.
    P. Vo, E. Irissou, J.-G. Legoux, S. Yue, Mechanical and microstructural characterization of cold-sprayed Ti-6Al-4V after heat treatment. J. Therm. Spray Technol. 22(6), 954–964 (2013)CrossRefGoogle Scholar
  14. 14.
    M.J. Donachie, Titanium: A Technical Guide (ASM International, Russell Township, 2000)Google Scholar
  15. 15.
    T. Ahmed, H. Rack, Phase transformations during cooling in α + β titanium alloys. Mater. Sci. Eng. A 243(1), 206–211 (1998)CrossRefGoogle Scholar
  16. 16.
    A. Birt, V. Champagne, R. Sisson, D. Apelian, Microstructural analysis of cold-sprayed Ti-6Al-4V at the micro-and nano-scale. J. Therm. Spray Technol. 24(7), 1277–1288 (2015)CrossRefGoogle Scholar
  17. 17.
    E. Dong, W. Yu, Q. Cai, L. Cheng, J. Shi, High-temperature oxidation kinetics and behavior of Ti–6Al–4V alloy. Oxid. Met. 88(5–6), 719–732 (2017)CrossRefGoogle Scholar
  18. 18.
    W. Xu, M. Brandt, S. Sun, J. Elambasseril, Q. Liu, K. Latham, K. Xia, M. Qian, Additive manufacturing of strong and ductile Ti–6Al–4V by selective laser melting via in situ martensite decomposition. Acta Mater. 85, 74–84 (2015)CrossRefGoogle Scholar
  19. 19.
    B. Sun, S. Li, H. Imai, J. Umeda, K. Kondoh, Oxygen solid solution strengthened pure titanium powder materials. Trans. JWRI 41(1), 59–64 (2012)Google Scholar
  20. 20.
    G.F. Vander Voort, S.R. Lampman, B.R. Sanders, G.J. Anton, C. Polakowski, J. Kinson, K. Muldoon, S.D. Henry, W.W. Scott Jr, ASM handbook, in Metallography and Microstructures, vol. 9, pp. 44073–40002 (2004)Google Scholar
  21. 21.
    J.R. Davis, A.S.F. Metals, ASM Handbook. 2. Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (ASM International, Russell Township, 1998)Google Scholar
  22. 22.
    J.-M. Oh, B.-G. Lee, S.-W. Cho, S.-W. Lee, G.-S. Choi, J.-W. Lim, Oxygen effects on the mechanical properties and lattice strain of Ti and Ti-6Al-4V. Met. Mater. Int. 17(5), 733–736 (2011)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature and ASM International 2018

Authors and Affiliations

  • Venkata Satish Bhattiprolu
    • 1
  • Grant A. Crawford
    • 1
  1. 1.Department of Materials and Metallurgical EngineeringSouth Dakota School of Mines and TechnologyRapid CityUSA

Personalised recommendations