Effects of single-pass large-strain rolling on microstructure and mechanical properties of Mg-Al-Ca alloy sheet

A new wrought magnesium alloy sheet, the Mg-1.8Al-1.8Ca wt.% alloy, with high strength and good ductility has been fabricated by the one-step extrusion and subsequent single-pass large-strain rolling process. The microstructure analysis shows that a large amount of un-dynamically recrystallized (un-DRXed) regions exist in the as-extruded alloy. After the large-strain rolling process, the grain size of the sheet is refined and the microstructure becomes more uniform, as compared with the as-extruded counterpart. The average grain size of Mg-1.8Al-1.8Ca alloy is refined from the ~ 2.42 μm in the as-extruded state, to be ~ 1.68 μm and ~ 1.42 μm, after rolling at 350 °C and 300 °C, respectively. The wrought Mg-1.8Al-1.8Ca alloy sheet, which was rolled at 300 °C by one-pass thickness reduction of ~ 78%, exhibits the highest absolute strengths with yield strength of ~ 298 MPa and ultimate tensile strength of ~ 319 MPa, and the moderate elongation to failure of ~ 6% is also obtained.