【摘要】 对不同初始组织形态（铸态、固溶处理态、 T6处理态及挤压态）的Mg-8Gd-2Y-0.5Zr合金在200℃/70 MPa条件下进行100 h蠕变实验，探讨晶粒尺寸、铸态合金中初始第二相、时效析出相(β′相)对合金蠕变性能和蠕变机理的影响。结果表明：在相同蠕变条件下，时效态合金具有最佳的抗蠕变性能，挤压态合金的抗蠕变性能最低，在稳态蠕变阶段固溶态合金的蠕变性能稍高于铸态合金；晶粒尺寸细小是导致挤压态合金抗蠕变性能较低的主要因素；虽然在蠕变初期，铸态合金中初始第二相起到了蠕变强化作用，但晶内析出的大量与基体完全共格的β′相则是时效态合金以及固溶态合金具有较好抗蠕变性能的主要原因。更多还原

【Abstract】 The present research investigated the creep properties of the Mg-8Gd-2Y-0.5Zr alloys with different microstructures(ascast, as-solution, T6 and as-extruded) after creeping at 200 ℃/70 MPa for 100 hours. Effects of the microstructures, including grain size, Mg5(Gd, Y) phase in cast alloy, β′ phase on creep properties were studied. The as-extruded alloy shows the worst creep resistance due to the refined grains caused by dynamic recrystallization resulting from the extrusion process. Although the Mg5(Gd, Y) phase located at the grain boundary can improve the creep properties of the cast alloy in the early stage creep, the precipitates of β′ phase in T6 alloy and those formed during the creep process in as-solution alloy, which can effectively inhibit the dislocation gliding, can be attributed as an important factor in improving the high temperature creep performance of the alloys.Consequently, the alloy after T6 treatment exhibited the lowest creep rate and the as-solution alloy possessed a better creep resistance than that of the cast alloy during the steady-state creep.更多还原