Substrate pre-treatment mediated surface integrity and its effect on wear characteristics of TiAlN-coated tools

Abstract

This study systematically investigates the mediatory mechanism of different surface pre-treatment processes (rough grinding, fine grinding, polishing, and sandblasting composite pre-treatment) on the surface integrity and wear characteristics of TiAlN-coated Ti(C, N)-based cermet cutting tools. Experimental results show that substrate pre-treatment significantly affects the surface micro-morphology, mechanical properties, and film-substrate interfacial adhesion of TiAlN-coated tools. Among the pre-treatments, coatings deposited on substrates subjected to polishing composite pre-treatment exhibit the smoothest surface. Substrates subjected to sandblasting composite pre-treatment significantly enhance coating hardness, H/E∗ ratio, H³/E∗² ratio, and adhesion strength by introducing higher residual compressive stress on the coating surface, while also demonstrating the best oxidation resistance and the lowest oxidation weight gain. Tests on dry cutting of ductile iron show that, compared with rough grinding, fine grinding, and polishing pre-treatments, the sandblasted pre-treated tool exhibits the lowest flank face wear due to its excellent surface integrity (high hardness, high residual compressive stress, and high adhesion strength) and outstanding oxidation resistance, as well as the lowest cutting force and fluctuation index, which reduce the accumulation of cutting heat and stress impact. The tool wear failure modes are mainly characterized by local spalling and slight notch fracture, with its service life being 25 % longer than that of the rough grinding pre-treatment process and demonstrating superior wear resistance. This research provides a theoretical basis and technical reference for optimizing the surface pre-treatment process of high-performance coated cutting tools.