An Investigation on Residual Stress Build-Up in Cold Sprayed Metallic Samples: Effect of Stress Relaxation Heat Treatment

Abstract

Residual stress formation during cold spraying process may result in deteriorative effects on the performance of coating materials. The objective of this investigation is to characterize residual stress built-up in some of well-known metallic alloys deposited by cold spraying. Two different nickel based super alloys (Inconel 625 and Inconel 718) and the most commercially used titanium alloy (Ti-6Al-4V) were considered for investigation in this study. The average residual stress was higher in Inconel samples compared to the titanium one. Stress relaxation heat treatment helped in the reduction of porosities. However, the recovery of residual stress was highest in Ti-6Al-4V compared to nickel-based samples. Mechanical properties such as hardness, porosities and crack formation were investigated in all samples and tribological behavior of Ti-6AL-4V was particularly studied. The relation between the crack formation and residual stress before and after heat treatment was established for Inconel samples. It was tried to define same relationship for wear resistance and residual stress in Ti-6Al-4V sample.