Secondary phase changes after traditional aging and creep aging and corresponding effects on mechanical properties of Mg-9Gd-2Nd-0.5Zr alloys were studied. The results reveal that the presence of stress during the creep aging increases the concentration of dislocations in the alloy and provides abundant nucleus positions for β′ phase, promoting the precipitation rate of β′ phase in the alloy, which plays a critical role in shortening the peak aging time. In addition, the creep aging under unidirectional stress leads to the anisotropy of the solute atomic diffusion coefficient in the alloy, and the diffusion coefficient (Da/D) along the direction of tensile stress gradually decreases. At the same time, the tensile stress reduces the system energy and releases more energy to the ${\beta }^{\prime }$ variants (C₁) perpendicularly to the stress direction, resulting in preferentially-oriented precipitation and a decrease in alloy strength. There is a decrease in yield strength (YS) from 180.1 MPa to 166.8 MPa and ultimate tensile strength (UTS) from 321.3 MPa to 292.3 MPa after doing creep aging. Moreover, the presence of unidirectional stress during creep aging reduces the angle between the texture pole and basal plane texture, promoting the rotation of the grain orientation towards the basal plane in the alloy and increasing the alloy elongation to 9.5%.

研究了传统时效和蠕变时效后二次相变及其对Mg-9Gd-2Nd-0.5Zr合金力学性能的影响。结果表明，蠕变时效过程中应力的存在增加了合金中的位错浓度，为β'相提供了丰富的核位，促进了合金中β'相的析出速率，对缩短时效起着关键作用。峰值老化时间。此外，单向应力下的蠕变时效导致合金中溶质原子扩散系数各向异性，扩散系数（Da/D）沿拉应力方向逐渐减小。同时，拉应力降低了系统能量并释放更多能量给${\beta }^{‘}$变体 (C ₁ ) 垂直于应力方向，导致优先取向析出和合金强度降低。进行蠕变时效后，屈服强度 (YS) 从 180.1 MPa 降低到 166.8 MPa，极限抗拉强度 (UTS) 从 321.3 MPa 降低到 292.3 MPa。此外，蠕变时效过程中单向应力的存在减小了织构极点与基面织构之间的角度，促进了合金中晶粒取向向基面的旋转，使合金延伸率提高到9.5%。