EFFECT OF REINFORCEMENT COATING, ALLOY CHEMISTRY AND AGING TREATMENT ON THE MODULI OF ELASTICITY AND RUPTURE OF Al/SiC_p COMPOSITES

摘要

The effect of reinforcement coating, alloy chemistry and aging treatment on the moduli of elasticity and rupture of Al/SiC_p composites prepared by pressureless infiltration was investigated. Preforms of 50 percent porosity prepared with SiC particles uncoated and coated with colloidal silica were used in infiltration tests with two Al-Si-Mg alloys in Ar→N_2, at 1200°C for 120 min. The composites were heated in solution treatments at 350°C for 180 min, and artificial aging at 170°C for 1, 3 and 5 h. Results show that the mechanical properties are influenced by alloy composition, SiC surface-condition and aging-time. The highest moduli of elasticity and rupture are obtained with alloy 2; while the highest magnitude of E is obtained with uncoated SiC particles, the highest MOR is obtained with coated particles. Notably, the unwanted Al_4C_3 phase is not formed neither during infiltration nor during the heat treatments, maintaining the soundness of the Al/SiC interface.