High temperature mechanical behavior of an extruded Mg-11Gd-4.5Y-1Nd-1.5Zn-0.5Zr (wt%) alloy

The microstructure-property relation of an extruded Mg-11Gd-4.5Y-1Nd-1.5Zn-0.5Zr (wt%) alloy was investigated by conducting hot compression and high temperature creep at temperatures upto 250 °C. The alloy exhibits an average compressive yield strength (σCYS) of 363±1 MPa and an average elongation to failure (εCF) of 10.5±0.2% at room temperature, 301±13 MPa and 12.8±1.1% at 200 °C. In creep the minimum creep strain rate (ε̇min) is 1.94×10−9 s−1 at 175 °C/160 MPa and 6.67×10−9 s−1 at 200 °C/100 MPa. The obtained stress exponent n is in the range of 3.7-4.7, suggesting that the creep is controlled by the dislocation climb mechanism. The improvement in compressive strength and creep resistance is attributed to the fine recrystallized grains, SFs in the grain interior, Mg5RE and LPSO phases at grain boundaries. The alloy exhibits a bimodal texture with 〈0001〉 and 〈101¯0〉 components. Its strengthening effect is determined by the competition between these two texture components. In compressive deformation, the textural evolution from 〈101¯0〉 to 〈0001〉 is mainly attributed to the operation of basal 〈a〉 slip and {101¯2}〈101¯1〉 tensile twinning. This texture evolution is not seen in creep.