Effect of Ca content on microstructure and strength of as-extruded Mg-1.0Al-xCa alloy

Abstract

In this work, the effects of Ca content and extrusion temperature on the microstructures and mechanical properties of Mg–1Al–xCa alloys have been investigated. For Mg–1.0Al–0.4Ca (wt-%, AX10) dilute alloy, decreasing extrusion temperature from 290°C to 260°C can inhibit the dynamic recrystallisation (DRX) process, and the yield strength (YS) is also increased from ∼266 ± 6 MPa to ∼309 ± 3 MPa. When increasing the Ca content, Mg–1.0Al–0.8Ca (wt-%, AX11), a higher density of the Al₂Ca phase is dispersed at the grain boundaries, which can further restrict the growth of DRXed grains, only ∼1.0 µm. Consequently, the higher YS of ∼330 ± 5 MPa can be obtained. The relevant results can shed light on designing other high-strength and low-alloyed Mg wrought alloys.