Investigation of the Thermal Creep properties of Al/SiC Composites made by the Powder Metallurgy Technique

摘要

We report on the effect of Cu additions on the high-temperature hardness and creep resistance of non-reinforced and reinforced Al-alloys made by a powder metallurgy technique consisting of mixing powders of elementally pure metal and SiC followed by sintering and hot-pressing. Indentation hardness tests were performed at room temperature, 100, 200, 300, 400, and 500°C while creep tests were performed at 550°C. The hardness and the creep resistance of the non-reinforced material decreased significantly with increasing temperature and Cu content while the hardness of the reinforced (20 vol% SiC) material decreased by a much smaller amount. The creep resistance of the reinforced material also decreased significantly with increasing Cu content, we suggest that the fabrication technique used in this study results in non-homogeneous Cu distribution through the material. This causes decreased hardness and creep resistance with increasing Cu content in the non-reinforced material. The addition of SiC as a reinforcement produces an MMC with hardness that is not affected by the Cu content but with creep resistance that decreases with increasing Cu content. The creep resistance of the reinforced material is, therefore, more dependent on the properties of the matrix than is the indentation hardness.