Solidification of Al-xCu alloy under high pressures

In this study, Al-xCu alloy containing x=15, 33, and 40wt.% Cu was solidified under different pressures (atmospheric pressure, 1GPa, 2GPa, and 3GPa). The effects of the solidification pressure and aging treatment on the microstructural evolution and mechanical property of these alloys were investigated. The eutectic Al2Cu phase varied between dendritic to spherical morphology in Al-15Cu alloy with the application of pressure. Both the secondary arm spacing in Al-33Cu alloy and the size of primary Al2Cu in Al-40Cu alloy had decreased under the influence of high pressure during solidification. As a result of solid solution strengthening, the Vickers hardness increases significantly for the Al-xCu alloys with high-pressure solidification. The microstructure variation was further explained based on undercooling theory.