Study of wear performance and tribological characterization of AlTiN PVD coatings with different Al/Ti ratios during ultra-high speed turning of stainless steel 304

AlTiN coatings with different Al/Ti ratios (50/50, 60/40, 67/33, 70/30 and 73/27) deposited by cathodic arc PVD are investigated in this paper. An ultra-high speed of 420 m/min was applied during the finish turning tests of stainless steel 304 (SS304). The coating structure was characterized by SEM and XRD techniques. Assorted mechanical properties such as elastic modulus, coating adhesion, hardness and micro-scratch fracture toughness were assessed using nano-indentation and scratch testing. Chip characterization was performed to evaluate the tribological characteristics of the tool/chip interface. The wear performance study showed that cratering was the main wear mechanism. Tool life results have shown that the Al60Ti40 coating featured the longest tool life due to its favorable combination of tribological and micro-mechanical properties.