Microstructure, mechanical properties, and cutting performance of TiAlSiN multilayer coatings prepared by HiPIMS

To explore mechanical properties of multilayer TiAlSiN coatings deposited on turning tools and their cutting performance against Inconel 718, TiAlSiN coatings with five different multilayer configurations, including single layer TiAlSiN-A (with higher adhesion strength), single layer TiAlSiN-B (with higher hardness), bilayer, four-layer, and eight-layer, were deposited using high power impulse magnetron sputtering (HiPIMS). The microstructure, chemical composition, hardness, adhesion, toughness and surface roughness of those coatings are measured and the cutting performance against Inconel 718 is analyzed. It is demonstrated that the multilayer structure results in an increase of both toughness and compressive stress of TiAlSiN coatings, and the one with eight-layer configuration shows the highest toughness among the five coatings. The results of the cutting experiment showed that eight layer coatings have maximum life while the TiAlSiN-A has minimum. This improvement of multilayer structure is believed to be due to the increasing toughness, which alleviates the damage caused by the frequent impact of Inconel 718 hard particles during cutting. This study also shows there is a negative correlation between spalling area of flank surface and adhesion of coatings.