Microstructure and mechanical properties of Ca containing AZX310 alloy sheets produced via twin roll casting technology

Abstract

AZX310 alloy (Mg-3Al-1Zn-0.3Mn-0.5Ca in wt.%) sheets were produced via twin roll casting and subsequent warm rolling. The eutectic lamellae at the mid-thickness of the strip are changed during the rolling to fine spheroidal particles. The rolled sheets shows a large amount of fine Ca-rich particles which are homogeneously distributed through the whole sheet thickness. The AZX310 sheet shows excellent room temperature formability with the Erichsen index of 7.4, while the strength and ductility are maintained to the similar values of AZ31 sheets, i.e. tensile yield strength 189MPa, UTS 250 MPa and fracture strain 20%. The AZX310 sheet shows a relatively high corrosion resistance with the corrosion rate of 0.25mm/year, evaluated by neutral salt spray test at room temperature. The excellent mechanical performance of the AZX310 alloy sheet is related to the microstructure and texture. The high room temperature formability can be understood as a result of the texture randomization, while the relatively high strength and ductility of the AZX310 sheet is related to the existence of the fine Ca-rich particles.