Comparative Evaluation of High Temperature Wear Behavior of Chill Cast Al-B4C Composite

Abstract

Operating temperature has a significant effect on the wear behavior of the component materials. The present research work focuses on the evaluation of wear behavior of boron carbide particulate reinforced aluminum matrix composite under high temperature conditions. Induction furnace was used for melting and stainless steel, cast iron and copper end chills were used as mold materials. The dry sliding wear behavior of the chill cast composite was investigated using pin-on-disc wear testing machine according to ASTM standard. The wear test was conducted at room temperature, 75°C and 150°C, keeping other parameters constant. The results indicate that the wear rate increases with the increase in temperature. The analysis of worn surface by scanning electron microscope reveals the fragmentation of the boron carbide particles and orientation of the particles in the sliding direction. Higher wear rate was recorded at 150°C than at room temperature and at 75°C. The study also demonstrates that the wear rate significantly decreases with the reinforcement of boron carbide particles. The wear rate was found to be significantly less in case of the castings obtained using copper chills in comparison with the stainless steel and cast iron chills. This is attributed to higher heat transfer rate due to higher value of thermal conductivity of copper chill which leads to fine grained structure with higher hardness and wear resistance.