Crater wear mechanism of TiAlN coatings during high-speed metal turning

The influence of the aluminium content (x) on crater wear mechanisms of Ti1-xAlxN coated WC-Co inserts in high-speed turning of 316L stainless steel was investigated. Electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the wear behaviour. Ti1-xAlxN coatings with x ≤ 0.53 showed, after 1/3 of the tool life, a thick adhered layer composed of oxides and metallic species from the steel, and no diffusion of workpiece material into the coating. These coatings presented the best wear resistance and least abrasive wear. The high aluminium content Ti0·38Al0·62N coating showed the worst crater wear resistance. This is assigned to interdiffusion of workpiece elements and oxygen into the coating as a consequence of spinodal decomposition of the cubic TiAlN-phase, resulting in more severe abrasive wear. •Influence of Al-content (x) Ti1-xAlxN coatings on crater wear in high-speed turning.•Primary wear mechanism is high-temperature abrasion for all x.•Low Al-content coatings outperformed high Al-content in terms of crater resistance.•Spinodal decomposition facilitated diffusion of workpiece into the coating.