| Among various processes in fabricating metal matrix composites, melt-stirring technology is much more attractive route in industrial application because it is simpler and less expensive compared to squeeze casting or powder metallurgy. In the present study, effects of size and volume fraction of reinforcing particles on tensile strength and thermal expansion coefficients of α-Al₂O₃_(p)/AC8A composite, which was made by melt-stirring process, were investigated. And the effect of Mg addition on the above properties was also investigated. Composites with 3%Mg showed better wettability and distribution of particles than that of composites with no Mg. The addition of Al₂O₃ particles was not effective in increasing the tensile strength of the composite except the composite materials with 3%Mg, which showed an increased strength in the case of 5vol% addition of 16 ㎛ α-Al₂O₃ particles. On the other hand, thermal expansion coefficients of the composites decreased with increasing the volume fraction of reinforcing particles and Mg contents. |
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