Effect of temperature on the mechanical behaviour of a SiC particulate reinforced Al alloy

The tensile behaviour of a particulate SiC reinforced aluminum alloy has been investigated over a range of temperatures, and for two different heat treatments. The fracture mode depends on testing temperature, with a transition from void nucleation at cracked SiC particles at room temperature to void nucleation by decohesion of the particulate/matrix interface at high temperatures. The strengthening afforded by the particulates also varies with temperature and with matrix temper, and is greatest when the matrix is soft. These effects cannot be explained using standard models such as those based on shear lag analysis. The effect of hold time at high temperature on fracture behaviour has also been studied and correlated with electron microscopy of the SiC/matrix interfacial region.