Two-Body Abrasive Wear Behavior and Its Correlation with Mechanical Properties of Aged AA6063 Alloy

This study aims to correlate the abrasive wear performance with mechanical properties, considering AA6063 Al-Mg-Si alloy as the model material. The selected alloy specimens are subjected to artificial ageing at 150 °C for an ageing duration ranging from 1 to 672 h, covering severely under-aged (SUA) to peak-aged (PA) to severely over-aged (SOA) states. Apart from the hardness and tensile properties, two-body abrasive wear properties are also evaluated for differently aged alloys in terms of wear rate, coefficient of friction, and roughness of the abraded surfaces. Furthermore, the generated wear debris, surface, and sub-surface of the abraded specimens are critically examined to reveal the micro-mechanisms of abrasion. The lowest amount of wear rate is observed for a PA alloy with maximum hardness, while the OA alloy exhibits a slightly lower wear rate than the UA alloy at a similar level of hardness. Statistical analyses of wear rate and various mechanical properties of all heat-treated alloys establish a strong negative linear correlation between the wear rate and hardness, yield strength, tensile strength, and strength coefficient; whereas, a positive linear correlation with the strain hardening exponent. Relationships between wear rate and different roughness parameters are also discussed. Under the investigated wear condition, the aged alloys endure significant plastic deformation; micro-plowing, micro-cutting, and delamination are found to be the predominant mechanisms during abrasion.