Residual Stress Formation During Cold Spraying of Nickel Based Superalloys

Residual Stress Formation During Cold Spraying of Nickel Based Superalloys

 

D. Shresta, F. Azarmi, X.W. Tangpong

Department of Mechanical Engineering, North Dakota State University, Fargo, USA, ND 58108-6050

 

Residual stress can be developed in most of thermal sprayed deposited coatings due to the momentum of molten particles during impact, and heat transfer during solidification of the splats. Splat curl-up during solidification and differences in thermal expansion coefficient between the impacted molten particles and the substrate are the other reasons for residual stress build up in thermally sprayed coatings. However, in cold spraying process, it is believed that the main reason for residual stress formation is plastic deformation during impact and flattening of solid particles.  Residual stresses can influence coating quality drastically and reduce their service time. In this study, residual stress will be measured for two well-known nickel based super alloys (In 625 and In 718) deposited via cold spraying technique. The paper pays special attention to the effect of heat treatment on reduction of residual stress in cold spraying deposited samples.