Dry sliding wear behaviour of thixoformed Al-5.7Si-2Cu-0.3 Mg alloys at high temperatures using Taguchi method

摘要

Present work focused on the impact of high temperature on the tribological properties for thixoformed Al-5.7Si-2Cu-0.3 Mg alloy. A pin-on-disc tribometer was used for dry sliding wear experiments that were executed according to Taguchi method. Wear behaviour was investigated under four process parameters at three levels: process (as-cast, thixoforming, and thixoforming-T6), load (10, 50, and 100 N), sliding temperature (25, 150, and 300 degrees C), and sliding distance (1000, 3000, and 5000 m). Microstructure was characterized and evaluated by optical microscopy, scanning electron microscopy with energy dispersive X-ray detector, and X-ray diffraction. Results revealed that the thixoformed-T6 alloy consisted of fine globular structure and equiaxed grains, which showed excellent wear resistance at elevated temperature. The experimental values, which were within the permissible limits for the volume loss and coefficient of friction, were congruent to the predicted values because both performed at the rates of 96% and 89%, respectively. Despite increasing wear resistance of the thixoformed-T6 alloy at a sliding temperature of 300 degrees C, applied load of 100 N, and sliding distance of 3000 m, the best coefficient of friction was attained by the thixoformed-T6 alloy at a sliding temperature of 150 degrees C, applied load of 100 N, and sliding distance of 5000 m. The dominant wear mechanisms in tribological tests included abrasion, adhesion, and minor delamination.