The effect of B4C amount on wear behaviors of Al-Graphite/B4C hybrid composites produced by mechanical alloying

Abstract

In this study, wear behavior of composite materials produced by mechanical alloying method adding different amounts of B4C in the Al-Gr matrix were investigated. After adding 2% (vol.) graphite to the aluminum matrix, 3 different amounts (3%, 6% and 9%) of B4C were added. The composite powders prepared were mechanically alloyed for 60 minutes. The milled powders were cold-pressed under 700 MPa pressure. The green compacts produced were sintered at 600 °C for 120 minutes. The sintered B4C reinforced aluminum composite materials were characterized by the Scanning Electron Microscope, X-ray diffraction, and hardness and density measurements. Wear tests were performed on a standard pin-on-disc wear testing device with a load of 20 N at a sliding speed of 0.5 ms-1 and four different sliding distances (between 250-1000 m) according to ASTM G99 standard. As a result of the studies, the hardness increases as the amount of B4C in the composite material increases, while the density of AMC decreases. As a result of the wear tests, the highest weight loss was obtained in the non-reinforced Al-Gr matrix alloy, while the lowest weight loss was obtained in 9% B4C reinforced composite materials. However, it was observed that there was a decrease in the friction coefficient with increasing amount of reinforcement.