Modeling of wear parameters and multi-criteria optimization by Box-Behnken design of AlCrN thin film against gamma-irradiated Ti6Al4V counterbody

Abstract

AlCrN film deposited on medical grade 316 LVM stainless steel was subjected to wear test against gamma-irradiated Ti6Al4V counterbody. In this tribological study, a statistical model was employed using Response surface methodology (RSM) based Box-Behnken design (BBD) to optimize and evaluate the individual and interactive effect of the three independent design parameters, namely applied load, sliding velocity, and sliding distance on the wear responses such as surface roughness, friction coefficient, disc mass loss, wear depth and hardness. The RSM was in good agreement with higher R2 and predicted R2 value for all the wear responses. The ANOVA and interactive contour maps clearly manifest the individual and relative effect of the design parameters on the wear responses suggesting a significant effect of sliding velocity and applied load on surface roughness, friction coefficient, and hardness and an important role of applied load on disc mass loss and wear depth. The worn surface analysis using SEM (with EDS) and XRD was also discussed, evincing the formation of relevant oxides on the interfacial tribolayer of the worn surface resulting in a lower friction coefficient, thus contributing to inhibition of severe wear mass loss of the AlCrN film. The wear debris originated from the dry sliding showcased the characteristics of the typical fatigue wear particle with irregular and sharp periphery.