Investigation of Fracture Performance and Interface Stress Behavior of Zn–Zn-Al Multilayer Coating–304 Stainless Steel Substrate System

Abstract

The maximum interface sheer stress and crack density can be used as criteria for the interfacial bonding property and fracture performance, respectively. In this paper, interface stress and crack density as a function of applied strain of Zn–Zn-Al multilayer coating/304 stainless steel substrate system with different coating thicknesses were studied using uniaxial tensile tests. For comparison, Zn and Zn-Al monolayer coatings also were prepared. The saturated crack density of the Zn–Zn-Al coating was the largest, and that of the Zn-Al coating was the smallest. Furthermore, the maximum interfacial shear stress of the Zn–Zn-Al coating substrate system with 0.24-mm coating thickness was the largest. Finite-element simulation was used to analyze the development of interfacial cracks of the multilayer coating–substrate system during three-point bending. The simulation results showed that the interfacial crack was dominated by shear stress in the Zn–Zn-Al multilayer coating–substrate system with a total coating thickness of 0.32 mm, which proves the accuracy of the experiment.