Towards Improving Cold Formability of a Concentrated Mg-Al-Zn-Ca Alloy Sheet

Concentrated Mg-Al-Zn-Ca alloy sheets usually show poor formability at room temperature (RT), which has been one of the key issues for their wider applications. In this study, we report that the RT stretch formability of a Mg-6Al-1Zn-2Ca (wt.%, AZX612) alloy sheet can be improved noticeably by applying a high temperature homogenization treatment. The AZX612 alloy sheet without homogenization treatment shows a moderate index Erichsen (I.E.) value of 7 mm. In contrast, the sheet with 420 degrees C for 48 h followed by 510 degrees C for 48 h homogenization treatment exhibits a large I.E. value of 8.1 mm. Microstructure characterization by means of X-ray diffraction, scanning electron microscope, and electron backscatter diffraction indicates that the significant improvement in the stretch formability of the AZX612 alloy sheet is mainly associated with a weakened basal texture and a reduced area fraction of Al2Ca second phase particles.