A TAGUCHI-TOPSIS HYBRID TECHNIQUE TO ENHANCE THE FRETTING WEAR CHARACTERISTICS FOR SiC AND SILICA-ENRICHED BLA-REINFORCED AZ91D Mg ALLOY-BASED MMCs

Abstract

This investigation intends to come up with a cost-efficient and easily available bamboo leaf ash (BLA) which has high content of Silica, as an effective and complimenting reinforcement for the production of magnesium alloy-based metal matrix composites. By incorporating SiC and BLA reinforcement to AZ91D Mg alloy, the composites were made using the bottom pouring stir casting technique. The ratio between SiC and BLA in the composite, respectively, varied as 0:0, 6:0, 0:6, 4:2, 3:3, 2:4 wt.%. Fretting wear is one of the fundamental modes of wear for any mating parts which have vibration with low amplitude. In this study, an integrated Taguchi-TOPSIS is adapted to make the process variables more optimal for fretting wear of composites. Material composition, load, temperature, time, frequency and stroke length are selected as process parameters. The objective is to minimize the coefficient of friction, volume loss and surface roughness. Using the TOPSIS approach, the multi-criteria optimization approach was reduced to a single-criteria issue. The results revealed AZ91D/2 wt.% SiC/4 wt.% BLA, 10N, room temperature, 30-min, 30 Hz and 0.7 mm stroke as optimal parameters. Microscopic study demonstrates that fretting wear occurs in the partial slip zone for the composite tested at optimal condition. With temperature, the wear regime in composites shifts from partial slip to mixed fretting, whereas in alloys, the wear regime shifts from mixed fretting to gross slip. When the correct set of circumstances are available, hybrid composite can function well as a replacement for traditional materials in machineries vulnerable to fretting wear.