Influence of Powder Microstructure on the Microstructural Evolution of As-Sprayed and Heat Treated Cold-Sprayed Ti-6Al-4V Coatings
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Cold spray repair of high-value titanium alloy components has gained considerable interest; however, the influence of deposition conditions on the resulting microstructure and properties is not well established. This work examines the influence of feedstock powder type on the microstructural evolution of cold spray-deposited Ti-6Al-4V powders following deposition and after low-temperature heat treatment. Plasma-atomized, gas-atomized, and hydride de-hydride Ti-6Al-4V powders were deposited on Ti-6Al-4V substrates using cold spray technology and subsequently annealed at 550 °C for 5 h. Powders and cold spray depositions were characterized using x-ray diffraction, optical microscopy, scanning electron microscopy, and electron backscatter diffraction. Atomized and hydride de-hydride powders were characterized by a martensitic alpha and equiaxed alpha microstructure, respectively. Phase analysis revealed hydride de-hydride powders to contain beta phase regions near alpha grain boundaries; however, beta phase was not observed in atomized powders. Atomized coatings retained their powder microstructure in particle interiors but demonstrated ultra-fine grain formation near particle boundaries, likely due to dynamic recrystallization. In contrast, hydride de-hydride powders showed a larger increase in microstrain after deposition, without ultra-fine grain formation. Heat treatment resulted in recovery and recrystallization for all coatings and, in the case of atomized coatings, resulted in beta phase precipitation in regions that experienced large plastic strains.
Keywordsannealing cold gas dynamic spraying Ti-6Al-4V precipitation EBSD
The authors are thankful for the financial support of U.S. Army Research, Development and Engineering Command under Contract No. WI5QKN-16-C-0094.
Compliance with Ethical Standards
Conflict of interest
The authors have no conflicts of interest to disclose.
- 20.A.W.-Y. Tan, W. Sun, A. Bhowmik, J.Y. Lek, I. Marinescu, F. Li, N.W. Khun, Z. Dong, and E. Liu, Effect of Coating Thickness on Microstructure, Mechanical Properties and Fracture Behaviour of Cold-Sprayed Ti6Al4V Coatings on Ti6Al4V Substrates, Surf. Coat. Technol., 2018, 349, p 303-317CrossRefGoogle Scholar
- 22.M. Smagorinski and P. Tsantrizos, Production of Spherical Titanium Powder by Plasma Atomization, Adv. Powder. Metall. Part. Mater., 2002, 3, p 3-248Google Scholar
- 27.H. Chandler, Heat Treater’s Guide: Practices and Procedures for Nonferrous Alloys, ASM International, Geauga County, 1996Google Scholar
- 28.B.D. Cullity and S.R. Stock, Elements of X-ray Diffraction, Pearson Education, London, 2014Google Scholar
- 33.T. Hussain, Cold Spraying of Titanium: A Review of Bonding Mechanisms, Microstructure and Properties, Key Engineering Materials, Trans Tech Publications, Zürich, 2013, p 53-90Google Scholar
- 37.B.V. Vincente, D.R.N. Correa, T.A.G. Donato, V.E. Arana-Chavez, M.A.R. Buzalaf, and C.R. Grandini, The Influence of Small Quantities of Oxygen in the Structure, Microstructure, Hardness, Elasticity Modulus and Cytocompatibility of Ti-Zr Alloys for Dental Applications, Metals, 2014, 7(1), p 542-553Google Scholar
- 40.G. Welsch, R. Boyer, and E. Collings, Materials Properties Handbook: Titanium Alloys, ASM International, Geauga County, 1993Google Scholar
- 43.F.J. Humphreys and M. Hatherly, Recrystallization and Related Annealing Phenomena, Elsevier, Amsterdam, 2012Google Scholar
- 44.M.J. Donachie, Titanium: A Technical Guide, ASM International, Geauga County, 2000Google Scholar
- 45.J.R. Davis and A.S.F. Metals, ASM Handbook 2. Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM International, Geauga County, 1998Google Scholar
- 50.R.E. Reed-Hill, R. Abbaschian, and R. Abbaschian, Physical Metallurgy Principles, Van Nostrand, New York, 1973Google Scholar
- 54.M. Simonelli, Microstructure Evolution and Mechanical Properties of Selective Laser Melted Ti-6Al-4V. Marco Simonelli, 2014Google Scholar
- 58.C.M. Kay and J. Karthikeyan, High Pressure Cold Spray: Principles and Applications, ASM International, Materials Park, 2016Google Scholar