Effects of roller burnishing process parameters on surface roughness of A356/5%SiC composite using response surface methodology

Abstract

In this study, a simple roller burnishing tool was made to operate burnishing processes on A356/5%SiC metal matrix composite fabricated by electromagnetic stir casting under different parameters. The effects of burnishing speed, burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured. Scanning electron microscopy (SEM) graphs of themachined surface with PCD (insert-10) tool and roller burnished surface with tungsten carbide (WC) roller were taken into consideration to observe the surface finish ofmetal matrix composites. The mechanical properties (tensile strength, hardness, ductility) of A356/5%SiC metal matrix composites were studied for both unburnished samples and burnished samples. The results revealed that the roller burnished samples of A356/ 5%SiC led to the improvement in tensile strength, hardness and ductility. In order to find out the effects of roller burnishing process parameters on the surface roughness ofA356/ 5%SiC metal matrix composite, response surface methodology (RSM) (Box–Behnken design) was used and a prediction model was developed relevant to average surface roughness using experimental data. In the range of process parameters, the result shows that roller burnishing speed increases, and surface roughness decreases, but on the other hand roller burnishing force and number of passes increase, and surface roughness increases. Optimum values of burnishing speed (1.5 m/s), burnishing force (50 N) and number of passes (2) during roller burnishing of A356/5%SiC metal matrix composite to minimize the surface roughness (predicted 1.232 lm) have been found out. There was only 5.03% error in the experimental andmodeled results of surface roughness.