Tailoring the residual stress during two-step cold gas spraying and friction-stir surface integration of titanium coating

Abstract

In this article, a novel processing route combining cold gas spraying (CGS) and friction-stir processing (FSP) was employed to fabricate a dense titanium surface coating with high integrity and superior mechanical property. After subsequent implementation of CGS and FSP processes, a coating layer with refined grain structure (<1 μm) and enhanced hardness (up to seven times higher) was deposited on the surface, and influenced the residual stress. The residual stress and its distribution largely depended on the plunge depth of FSP modification step, and became more compressive with a maximum negative value of around 400 MPa at the advancing side by increasing the depth of tool plunging and promotion of coating integration.