【摘要】 本文利用透射电子显微镜（Transmission Electron Microscopy,TEM）和维氏显微硬度计,研究了Mg-10.7 wt.%Gd二元合金180℃时效时在欠时效、峰时效和过时效阶段析出相的特征。结果发现,Mg-10.7 Gd合金在180℃时效强化效应显著,时效298 h后硬度达到峰值。β’相是合金的主要强化相,沿（■）_Mg、（■）_Mg;和（■）_Mg三个晶面方向析出,绕[0001]_Mg晶带轴形成120°旋转对称的三变体。在时效初期,基体中有20 nm左右的碟状亚稳相β"析出。时效时间延长至63 h,β"相呈颗粒状,同时基体中有少量短条状β’相存在。当时间达到500 h,发生过时效。β’相明显长大,多个β’相以链状连接,围绕[0001]_Mg晶带轴呈三角形排列分布,同时基体中有针状相析出。更多还原

【Abstract】 The characteristic of precipitated phases at the under-ageing,peak-ageing and over-ageing stage of the Mg-10.7 wt.%Gd binary alloy aged at 180℃ was investigated by using Transmission Electron Microscopy（TEM） and Vickers Micro Hardness Tester.It is found that the Mg-10.7 Gd alloy exhibited obvious age-hardening effect after aging at 180℃,and hardness peaked after 298 h.The β’ phase was the main strengthening phase.It precipitated along three orientations of（■）_Mg,（■）_Mg,（■）_Mgand formed a 120° rotationally symmetric triple variant around the [0001]_Mg axis.At the initial stage of aging,the disc-shaped metastable β " phase of 20 nm in diameter was precipitated in the matrix.When aging time prolonged to 63 h,the β" phase grew into granules and there was a small amount of short barlike β’ phases in the matrix.When time reached 500 h,over-aging occurred.The β’ phase significantly grew up.Multiple β’ phases were connected in chains and distributed in triangles around the [0001]Mg axis.Simultaneously,needle-like phases precipitated in the matrix.更多还原