Thermal expansion/contraction behavior of AA7050 alloy in the as-cast condition relevant to thermomechanical simulation of residual thermal stresses

As-cast 7xxx series aluminum alloys experience a severe loss in ductility upon cooling and become brittle below 300 degrees C. In order to simulate the thermal stresses arising during casting, a thorough understanding of the thermal contraction behavior during solidification and cooling is required. In this study, some thermal properties of the AA7050 alloy are determined experimentally in the as-cast condition. Solidification contraction tests were performed to determine the onset of thermal contraction in the grain refined alloy and dilatometry tests were conducted to estimate the coefficient of thermal expansion/contraction of the alloy. Our simulation results showed that although the temperature dependence of the coefficients of thermal expansion/contraction obtained from the tests differ from the predictions of thermodynamic data-base, these differences are not crucial to the results of the thermomechanical simulations.