Machining performance and wear of PVD multilayer TiAlN-TiAlCrN coatings in machining 316L stainless steel

Stainless steels have a wide range of applications due to their high corrosion resistance and strength. However, their machining remains challenging, hence limiting the performance and sustainability of machining operations. Tool wear is one of such key limiting factors, which is attributed to low thermal conductivity, work-hardening tendency and high forces in machining. In this study the performance of a new multilayer TiAlN-TiAlCrN PVD coatings with varying Cr content is compared to the commercial TiAlN reference in longitudinal machining of 316L stainless steel. In general, TiAlN-TiAlCrN coatings have higher crater wear rate than TiAlN, where high-Cr content variants are more prone to cratering. However, the new multilayer coatings have comparable or lower rate of flank and notch wear. Further analysis of crater wear revealed that the high-Cr content coatings exhibit increased oxidation and diffusion wear rates at the tool–chip interface, accelerating coating degradation