High-Temperature Compressive Response of SiC_p/6092Al Composites under a Wide Range of Strain Rates

The high-temperature dynamic compressive properties of a 30 vol.% SiC_p/6092Al composite, fabricated using powder metallurgy, were experimentally investigated using the split Hopkinson pressure bar system with an electric furnace. Three different ambient temperatures, namely, room temperature, 200 °C, and 350 °C, were adopted, and the dynamic tests of the composite specimens were conducted at strain rates ranging from 1500 to 4500 s^-1. The experimental results showed that the flow stress of the composite was generally insensitive to strain rates at room temperature. However, the composite started exhibiting different strain-rate-dependent behaviors as the temperature increased, and the flow stress nonlinearly varied with increasing temperature. In addition, the microscopic images of the specimens showed that the microscopic failure mechanisms of the composite were greatly influenced by the ambient temperature and strain rate. Specifically, the percentage of failed particles decreased with rising temperature and the dominating failure mode of particles changed significantly as the strain rate increased.