Micro-blasting effect on fracture resistance of PVD-AlTiN coated cemented carbide cutting tools

The dry micro-blasting effects on the fracture resistance of PVD-AlTiN coated cemented carbide cutting tools were studied. The AlTiN coatings with the composition of (Al0.60Ti0.40)N were deposited using cathodic arc evaporation method. The two types of coatings, which had a compressive residual stress of 0.1GPa (Low-σ) and 2.6GPa (High-σ), were prepared. The coated samples were subjected to the dry micro-blasting treatment by Al2O3 grains at pressures of 0.11MPa, 0.14MPa, and 0.17MPa. A milling test using AISI 4140 (42CrMo4) steel as the workpiece material was carried out for evaluating the fracture resistance of the prepared samples. The tool life cutting distance of Low-σ sample micro-blasted at 0.14MPa and 0.17MPa was 2.9m and 7.2m, respectively, largely extended as compared to that of as-deposited Low-σ sample, 1.0m. On the other hand, the tool life of High-σ sample micro-blasted at 0.14MPa was 8.6m, almost same with that of as-deposited High-σ one, 8.8m. Those results indicate that the dry micro-blasting effect on the fracture resistance is larger for the Low-σ coating than for the High-σ one. •A dry micro-blasting effect on the fracture resistance of PVD-AlTiN coated cemented carbide cutting tools was studied.•Two types of coatings, having a low (Low-σ) and a high (High-σ) compressive residual stresses, were prepared.•The fracture resistances of the prepared samples were evaluated by a face milling test.•The fracture resistance strongly depended on the residual stresses of the coatings.•A compressive residual stress of the substrate played an important role to enhance the fracture resistance of Low-σ sample.