Fatigue fracture surface at high temperature for SiC whisker reinforced A2024 matrix composite

The fatigue properties and fatigue fracture mechanism were examined for SiC whisker reinforced A2024 aluminum matrix (SiCw/A2024) composite at 150°C. The fatigue strength tested at 150°C increased with increasing volume fraction of SiC whiskers up to 20%, although it was generally lower than that tested at R.T. Fractographic analysis revealed that a Mode I fatigue crack was formed by a Stage I mechanism in SiCw/A2024 composite at 150°C in the same manner as that in A2024 matrix alloy. In the fatigue crack propagation region, the area fraction of dimple patterns for SiCw/A2024 composite tested at 150°C was smaller than that for the same composite tested at R.T.. It is suggested that SiC whiskers would have a great effect on Mode I crack initiation and propagation, but this effect becomes less significant at 150°C than that at R.T..