Analysis of Interface Fracture of Cold-Sprayed Coatings Due to Thermal Cycling

Abstract

Driving mechanisms for the interface delamination of cold-sprayed chromium on a steel substrate subjected to cyclic thermal loading are studied by using thermomechanical analysis. First, the equilibrium stress states of the coating system due to residual stresses are determined for different coating thickness vales. This system is then subjected to periodic heating and cooling cycles. The potential of crack initiation and growth is simulated with and without embedded micro-cracks. The corresponding crack-driving forces are characterized using the interface stresses and energy release rate as a function of the thermal cycles. The effects of coating thickness, location of the embedded micro-cracks and initial residual stress on these driving forces are investigated systematically to demonstrate the risk of coating fracture and delamination.