Thermal stability and machining performance of arc evaporated Ti1-xAlxN hard PVD coatings with x=0.5 - 0.73 ratios using an integrative approach

Incorporating Al into TiN-based coatings plays a key role in enhancing their mechanical properties and thermal stability which are the crucial properties for cutting tool applications. In this paper, we study the effect of dif-ferent Al contents on the mechanical and thermal properties and consequent machining performance using an integrative approach. The results show that heat treatment of the Ti1-xAlxN coating decomposes them into their substituents, which is accompanied by the formation of c-AlN and c-TiN domains. The coherency strain between these domains results in increased hardness values under temperatures up to similar to 900-1000 degrees C. This growth was found to be substantial in cases with a single-phase cubic structure. In the coating sample with lower Al contents, where a cubic structure is present, the machining performance tended to be superior mainly due to improved adhesion to the substrate, higher hardness, and compressive residual stress.