Physical characterization and wear behavior of laser processed and PVD coated WC/Co in dry sliding and dry turning processes

Abstract

The present study is an attempt to integrate the laser surface modification techniques with PVD-coatings. AlTiN and AlCrN coatings were deposited on different laser shock peened (LSP) and laser surface textured (LST) WC/Co surfaces. The developed surfaces and PVD coatings were characterized for surface morphology, elemental composition, surface topography, substrate/coating phases, and adhesion behavior. Tribological tests were performed to understand the friction and wear performance of developed surfaces against Ti6Al4V counter pair at varying sliding speeds. Tribo test results revealed that the coatings deposited on laser processed surfaces are helpful in reducing the coefficient of friction (COF) and wear loss. The associated wear mechanisms are discussed with the help of proposed wear models. For laser textured surfaces, the experimental evidence of texture induced micro cutting mechanism has been reported. The generation of weaker carbides for LSP surfaces reduced the coating adhesion and resulted in poor tribological performance. For machining of Ti6Al4V, improved performance of coated LST surfaces was achieved. Apparent friction coefficient and flank wear were reduced by 64% and 65% respectively.