Microstructure and mechanical properties of ZE10 magnesium alloy prepared by equal channel angular pressing

ZE10 magnesium alloy was subjected to equal-channel angular pressing (ECAP) up to 12 passes in a die with an angle of 120° between the two channels at 250-300°C. An inhomogeneous microstructure of bimodal grains including fine grains of 1-2 μm as well as coarse grains of about 20 μm was obtained after the initial 1-4 ECAP passes. The grain size became increasingly homogeneous with further ECAP processing and the grains were significantly refined to 1-2 μm after 8 passes and further refined to 0.5-1 μm after 12 passes. The alloy's yield strength changed slightly but the ductility improved greatly initially up to 4-6 passes corresponding to the bimodal grain microstructure. And after the subsequent pressing of more than 8 passes, the tensile strength including yield strength improved while the elongation decreased gradually.