Numerical analysis of residual stresses in quenching of aluminum alloy thick plates

Aluminum alloy thick plates have been widely used as the key material of aircraft structures. Quenching process is one of the most important methods for improving material performance, which introduces a high level of residual stresses and easily lead to distortion and quench cracks, resulting in the performance deterioration. In this paper, the effect of aluminum alloy dimensions and quenching medium temperatures on quenching residual stress was investigated using the finite element program ANSYS. A non-linear heat transfer analysis is carried out by taking into account of the temperature dependence of the thermo-physical properties and transient condition of convection. The results show that for thin aluminum alloy plate, with increasing plate thickness the quenching residual stress increases considerably, while for thick aluminum alloy plate, the quenching residual stress remains almost unchanged. It is believed that improving hardenability of aluminum alloy is the only effective approach for thick aluminum alloy to obtain combination of high mechanical properties and low quenching residual stress after quenching.