Effects of microporosity on tensile properties of A356 aluminum alloy

The effect of microporosity on the tensile properties of A356 alloy was investigated through systematic experimental approaches, with a constitutive prediction that takes into account the strain rate sensitivity and strain-hardening exponent. The strain rate sensitivity was measured through the incremental strain rate change method, and the volumetric porosity and fractographic porosity were obtained from the measurements of bulk density and the quantitative fractography analyses on the fractured surface, respectively. The UTS and elongation exhibit a strong dependence upon the variation in microporosity, with a linear and inverse parabolic relationship, respectively. The constitutive prediction based on the fractographic rather than the volumetric porosity can more accurately predict the overall tensile properties of A356 alloy. The constitutive model should necessarily take into account the strain rate sensitivity and strain-hardening exponent for an exact theoretical prediction of the tensile properties.