CHARACTERIZATION OF HYPEREUTECTIC Al-20wt%Si/TiCp METAL MATRIX COMPOSITE

Hypereutectic Al-Si alloys are one of the most interesting material for high strength structural components because they have low coefficient of thermal expansion (CTE) as well as high wear resistance and mechanical properties. However, Al-based alloys have lower hardness and wear resistance than ferrous alloys and these disadvantages restrict the use of al-based alloy. They could be overcome by making composite reinforced with ceramic particles. TiC was good candidate for the reinforcement of the alloy. Al-20wt%Si was fabricated by gas atomization and 1, 3 and 5wt%TiC were mixed to these powders by turbular mixer for 10h with 45rpm. The mixture was hot-pressed at 550℃C for 1h under 60MPa pressure. Relative density of the sintered samples was about 98% of theoretical density. The effect of reinforcements on mechanical properties and wear resistance of composite was investgated. Strength, hardness and wear resistance of the sintered sample were improved by the grain refinement and dispersion strengthening.