Effect of pre and post mechanical treatment on pvd coated tools' characteristics and machining performance

Abstract

The current study investigates the influence of micro blasting as pre-treatment and post treatment technique separately and also in combined way on various characteristics of multilayer AlTiN and dual layer AlCrN/TiAlN coatings and compared the results with as deposited coating i.e. without any micro blasting either of substrate or coating. Pre and post micro blasting were carried out using Al2O3 granulates at different pressure for both the treatments. The changes in the microstructure, elemental composition and crystallographic phases of pre-treated, post-treated as well as combined in comparison with as deposited coated tools were examined using Scanning electron microscopy, Energy dispersive X-ray spectroscopy and X-ray diffraction test. Micro hardness test was carried out using Vickers hardness tester to determine the changes in the hardness value of the samples after surface treatment. The results revealed that both pre and post blasting have significant effect on physical, mechanical and machining characteristics of multilayer AlTiN and dual layer AlCrN/TiAlN coated tools. The results during dry turning of AISI 316L grade austenitic stainless steel with various pre and post treated coated tools revealed that reduction in flank wear upto maximum of 23.426 % and decrease in cutting force upto 32.315 % was observed for combined pre and post treated tool having layers of TiAlN/AlCrN and AlTiN coatings respectively.