A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy is processed by solution treatment and high pressure torsion (HPT) at room temperature to produce a nanostructured light material with high hardness. The stability of this alloy is subsequently tested through isochronal annealing for 0.5 h at 373 K to 673 K. The results reveal a thermal stability that is vastly superior to that of conventional Mg-based alloys processed by severe plastic deformation: the grain size remains at around 50 nm on heating to 573 K, and as the temperature is increased to 673 K, grain growth is restricted to within 500 nm. The stability of grain refinement of the present alloy/processing combination allowing grain size to be limited to 55 nm after exposure at 573 K, appears to be nearly one order of magnitude better than for the other SPD processed Mg-RE type alloys, and 2 orders of magnitude better than those of SPD processed RE-free Mg alloys. This superior thermal stability is attributed to formation of co-clusters near and segregation at grain boundaries, which cause a thermodynamic stabilization of grain size, as well as formation of β-Mg₅RE equilibrium phase at grain boundaries, which impede grain growth by the Zener pinning effect. The hardness of the nanostructured Mg-Gd-Y-Zn-Zr alloy increases with increasing annealing temperature up to 573 K, which is quite different from the other SPD-processed Mg-based alloys. The high hardness of 136 HV after annealing at 573 K is mainly due to solute segregation and solute clustering at or near grain boundaries.

Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr（wt.%）合金在室温下通过固溶处理和高压扭转（HPT）加工，生产出高硬度的纳米结构轻质材料。随后通过在 373 K 至 673 K 下进行 0.5 小时的等时退火来测试该合金的稳定性。结果表明，其热稳定性远远优于经过剧烈塑性变形加工的传统镁基合金：晶粒尺寸保持在加热至 573 K 时，晶粒生长约为 50 nm，当温度升高至 673 K 时，晶粒生长被限制在 500 nm 以内。本合金/处理组合的晶粒细化稳定性使晶粒尺寸在 573 K 下暴露后限制在 55 nm，似乎比其他 SPD 处理的 Mg-RE 型合金好近一个数量级，并且 2比 SPD 处理的无稀土镁合金好几个数量级。这种优异的热稳定性归因于在晶界附近形成共簇并在晶界处偏析，从而导致晶粒尺寸的热力学稳定，以及在晶界处形成β-Mg ₅ RE平衡相，从而阻碍晶粒生长。齐纳钉扎效应。纳米结构Mg-Gd-Y-Zn-Zr合金的硬度随着退火温度升高至573 K而增加，这与其他SPD处理的镁基合金有很大不同。573 K 退火后达到 136 HV 的高硬度主要是由于溶质偏析和溶质在晶界或晶界附近聚集所致。