Study on the friction drilling behaviors and tribological properties of aluminum matrix composites

Abstract

This study investigates Al 6063 matrix composites reinforced with different weight percentages of B4C (5%, 10%, 15%, and 20%) produced through powder metallurgy and hot extrusion. The resulting specimens were subjected to a comprehensive investigation to elucidate the effect of B4C reinforcement on the density, tensile strength, transverse rupture strength (TRS), hardness, tribological characteristics, and friction drilling behavior. The pin-on-disk wear tests were conducted in a dry environment, while the friction drilling experiments were performed under constant spindle speed and feed rate conditions, both in dry and minimum quantity lubrication (MQL) environments. The findings revealed a uniform B4C particle dispersion and strong interface bonding in the matrix and that the hardness, tensile strength, TRS, and wear resistance of the specimens increased as the weight fraction of the reinforcement increased. The 15 wt% and 20 wt% B4C composites showed the highest wear resistance, improving by 62.78% compared to Al6063. Higher B4C content reduced specific wear rates and reduced friction coefficients. Among the specimens under investigation, the Al6063 composite reinforced with 15 wt% B4C indicated the highest tensile, transverse rupture, whereas the Al6063 composite with 10 wt% B4C exhibited the best thread-pull-out strength (TPS). The friction-drilled 10 wt% B4C composites showed the highest thread-pull-out strength reaching 373.44 N/mm² in MQL and 329.74 N/mm² in dry conditions.