Microstructure evolution and segregation behavior of thixoformed Al-Cu-Mg-Mn alloy

A commercial wrought Al-Cu-Mg-Mn alloy (2024) was thixoformed based on the recrystallization and partial melting (RAP) route, and the microstructure evolution and segregation behavior during the indirect thixoforming process were studied. The results show that fine spheroidal microstructures can be obtained by partial remelting of commercial extruded 2024 alloys without additional thermomechanical processing. During the indirect thixoforming, the stress distribution can be optimized by increasing the thickness of base region. Under three-dimensional compression stress state, the microstructures are homogeneous among different regions with no evidence of liquid segregation and micro-porosities, and the grains in the columns are deformed plastically. The distribution of tensile mechanical properties is consistent with the microstructures. Moreover, the distribution of deformation mechanism was discussed, and a technical method for improving the stress distribution was proposed.