Investigations into friction and wear behavior of AlTiN and AlCrN coatings deposited on laser textured WC/Co using novel open tribometer tests

Abstract

During metal cutting with the textured tools, a variable local friction exists due to differences in the contact behavior owing to the presence of microtextures. The available periodic or aperiodic microscopic hierarchy on the textured tool surface changes the tribological characteristics and metal cutting performances. The friction and wear characteristics are difficult to ascertain in the metal cutting tests as the chips continuously slide over the tool rake face under dynamic wear conditions. The present study is conducted to closely predict the frictional coefficient and wear mechanisms for textured carbide cutting tools using an open tribometer. Tests have been performed to evaluate the tribological performance of hard coatings deposited by physical vapor deposition (PVD) method on laser textured WC/Co surfaces. PVD AlTiN and AlCrN coated plain and microhole textured WC/Co pins were tested against rotating Ti6Al4V counterpart to predict the extreme pressure tribological behavior. The results were evaluated in terms of the coefficient of friction, wear mechanisms, coating degradation behavior and surface damages. Coating and texturing on the carbide pins reduced the friction by 27% compared to uncoated plain carbide pins.