Influence of the Al2Ca phase on microstructure and mechanical properties of Mg–Al–Ca alloys

Abstract

In this work, the microstructure and mechanical properties of Mg–Al–Ca alloys containing different contents (1, 2, 4 and 6 wt.%) of the Al2Ca phase have been investigated. The results show that the Al2Ca phase formed along the interdendritic regions in as-cast alloys. As the content of the Al2Ca phase is 4 wt.%, the finest microstructure of the as-cast Mg–Al–Ca alloy is observed. After hot extrusion, the extruded Mg-2.32Al-1.7Ca (Mg-4Al2Ca) alloy exhibits superior mechanical properties with the UTS of 324 MPa, the YS of 275 MPa and the elongation of 10.2%. This is mainly attributed to the combined effects of fine dynamically recrystallized grains, nano-scale plate-like Al2Ca precipitation and high density of submicron Al2Ca particles dispersion in the α-Mg matrix, respectively.