Dry Sliding Wear Behaviour of Al6061 Hybrid Metal Matrix Composites using Response Surface Methodology

Abstract

This paper presents an investigation of the dry sliding wear behaviour of Al6061 hybrid metal matrix composites reinforced with B4C (3 wt.%) and eggshell ash (3, 6, 9 and 12 wt.%) fabricated through the stir casting process. A four factors and five-level central composite design (CCD) were used for experiments through response surface methodology. The factors considered for design were eggshell ash (0-12 wt.%), load (10-50 N), sliding speed (0.8-4 m/s) and sliding distance (300-1500 m). The experiments were performed using a pin-on-disc tribometer according to the ASTM G99 standard at room temperature for 30 combinations. Based on experimental results, a regression model was developed to predict the wear rate, and its adequacy was checked with analysis of variance (ANOVA) and confirmation tests. The ANOVA results showed that sliding speed was the most significant factor followed by the load, which significantly influences the response. Wear rate increased with the increase in load and sliding distance, whereas it decreased with the increase in wt.% of eggshell ash and sliding speed. The increase in wear rate with the increase in load can be caused by the increase in tip pressure, and in case of sliding distance it may be due to increase in contact time. Whereas, decrease in wear rate with the increase in sliding speed can be caused by the decrease in contact time and higher wt.% of eggshell also reduced the wear rate and it may be due to the increase in composites hardness.