Ti-6Al-4V coatings: stresses during cold spraying and mechanical properties

Ti-6Al-4V is an attractive material for a wide range of applications thanks to its high strength, low density, and excellent corrosion resistance. Cold Spray Additive Manufacturing (CSAM) could be used to manufacture Ti-6Al-4V parts, competing with other additive manufacturing processes such as Binder Jetting, Laser Power Bed Fusion (L-PBF) or Laser Metal Deposition (LMD) for some applications. However, Ti-6Al-4V is quite challenging for the cold spray process. Its high strength leads to coatings with some porosities. Regarding CSAM, some characteristics of sprayed materials are interesting such as evolving stresses during deposition, residual stresses and mechanical properties. This work aims at studying these characteristics.

The evolution of the stresses was evaluated both during the deposition and the cooling of the sample with a setup from Reliacoat Technologies named In situ Coating Properties n°8 (ICP n°8). Different process parameters were investigated. The control of residual stresses is possible by means of suitable deposition parameters. Tensile tests were performed on as-sprayed and annealed samples. The specimens were annealed at various temperature levels. The results show promising prospects for the development of Cold Spray Additive Manufacturing of Ti-6Al-4V.