The microstructural and mechanical properties of Al-Si alloyed powder, prepared by gas atomization fallowed by hot extrusion, were studied by optical and scanning electron microscopies, hardness and wear testing. The gas atomized Al-Si alloy powder exhibited uniformly dispersed Si particles with particle size ranging from 5 to . The hot extruded Al-Si alloy shows the average Si particle size of less than . After heat-treatment, the average particle size was increased from 2 to . Also, mechanical properties of extruded Al-Si alloy powder were analyzed before and after heat-treatment. As expected from the microstructural analysis, the heat-treated samples resulted in a decrease in the hardness and wear resistance due to Si particle growth. The friction coefficient of heat-treated Al-Si alloyed powder showed higher value tough all sliding speed. This behavior would be due to abrasive wear mechanism. As sliding speed increases, friction coefficient and depth and width of wear track increase. No significant changes occurred in the wear track shape with increased sliding speed.

Wear behaviors of gas atomized and extruded Al-Si alloys were investigated using the dry sliding wear apparatus. The wear tests were conducted on Al-Si alloy discs against cast iron pins and vice versa at constant load of 10N with different sliding speed of 0.1, 0.3, 0.5m/s. In the case of Al-Si alloy discs slid against the cast iron pins, the wear rate slightly increased with increasing the sliding speed due to the abrasive wear occurred between Al-Si alloy discs and cast iron pins. Conversely, in the case of cast iron discs against Al-Si alloy pins, the wear rate decreased with increasing the sliding speed up to 0.3m/s. However, the wear rate increased with increasing the sliding speed from 0.3m/s to 0.5m/s. It could be due to adhesive wear behavior and abrasive wear behavior_between cast iron discs and Al-Si alloy pins.