Modeling the Distortion and Residual Stresses Caused by Heat Treating Aluminum Alloy Cast Components

In this publication we report on the development of a mathematical model and computer simulations that enable predicting the magnitude and sense of distortion and residual stresses that develop in aluminum alloy castings in response to typical heat treatment schedules. The model, which uses an extensive database that we developed specifically for A356.2 aluminum alloy, can account for all three steps of the typical precipitation-hardening heat- treatment process; i.e., the solutionizing, quenching, and aging steps; and it predicts the local thermal history, the distortion, and the residual stresses that develop in the cast component during each one of these steps. We have verified the model predictions against measurements made on a commercial casting that was heat-treated according to the standard T6 schedule and found the computer-predicted results to be in very good agreement with the measurements.