Uniaxial Ratchetting of SiCP/6061Al Alloy Composites at Room and High Temperatures

Abstract

The uniaxial strain cyclic characteristics and ratcheting behaviors of T6-treated SiCP/6061Al alloy composites were studied experimentally at room and high temperatures (573K). The cyclic softening/hardening and ratcheting behaviors of T6-treated composites and un-reinforced matrix were investigated in different loading conditions and with two volume fractions of SiC particulates. It is shown that the cyclic softening/ hardening and ratcheting behaviors of the composites are similar to those of the un-reinforced matrix in macro-scale, i.e., the ratcheting also occurs in the composites during the cyclic stressing with non-zero mean stress, and the ratcheting strain increases with the increasing of stress amplitude and mean stress; however, the addition of SiC particulates into the matrix increases the resistance of the composite to the ratcheting, and the ratcheting strain decreases as the volume fraction of SiC particulates increases. It can be also concluded that the cyclic deformation of the composites has a great temperature-dependence. Some significant conclusions are obtained, which are useful to construct a constitutive model to describe the cyclic deformation of the composites.