Microstructure and tensile behavior of high-ductility extruded Mg-2.5Y-1Ce-0.5Mn-xZn (x=0, 1, 3 and 5 wt%) alloys

The microstructure and mechanical properties of the extruded Mg-2.5Y-1Ce-0.5Mn-xZn (x = 0, 1, 3 and 5 wt%) alloys were investigated in this paper. Microstructure observations showed that the grain size was slightly refined and exhibited the random orientation when the addition of Zn increased from 0 wt% to 3 wt%. When the addition of Zn increased to 5 wt%, the grain size decreased and transformed into a distinct basal texture. The volume fraction of the precipitate phases increased from 3.0 % to 8.2 % with increasing Zn content. The uniaxial tensile tests demonstrated that the yield strength, and ultimate tensile strength of the extruded Mg-2.5Y-1Ce0.5Mn-xZn alloys increased from 147.3 MPa to 194.3 MPa and 215.5 MPa-267.5 MPa with increasing Zn content, and elongation decreases from 33.7 % to 26.5 %, respectively. The highest strength of the extruded Mg2.5Y-1Ce-0.5Mn-5Zn alloys was mainly due to the combined strengthening effect of grain boundary strengthening, texture strengthening and precipitate phase strengthening, and the ductility was attributed to the large amounts of precipitate phase particles, the strong basal texture and the decrease of solute atom Y.