Acoustic emission monitoring and failure mechanism analysis of rolling contact fatigue for Fe-based alloy coating

The aim of present study is to monitor rolling contact fatigue (RCF) behavior and analyze failure mechanism of the coating by acoustic emission (AE) technology. The results show that AE amplitude and counts are sensitive to RCF damage process, and variation regularities are different during different damage stages. Spalling is the key failure mode. RCF damage process is composed of five stages, such as elastic deformation, plastic deformation, crack initiation and propagation, crack stable growth, and unstable growth. Fatigue cracks are liable to initiate and grow along the direction of defects within the coating, such as pores and cracks.