Effects of applied pressure on density, microstructure and tensile strength of Al–Zn–Mg–Cu alloy prepared by squeeze casting

Abstract

The effects of the applied pressure on the density, microstructure and tensile strength of the squeeze cast Al–Zn–Mg–Cu alloy were investigated. The density of the squeeze cast alloy increased steadily with the applied external pressure and it was almost constant with the pressure higher than 120 MPa. The applied pressure played an important role in solidification. It refined the grains, reduced the secondary dendrite arm spacing (SDAS) of the primary phase and thus improved the ultimate tensile strength, which could be explained by the changes of the heat transfer coefficients, the cooling rate and the nucleation rate induced by the applied pressure.