采用X射线衍射、差热分析及透射电镜研究了Mg_(65)Cu_(25)Y_(10)合金熔体在大气压下和高压(2—5 GPa)下熔淬时的组织结构,实验结果表明,压力对Mg_(65)Cu_(25)Y_(10)合金凝固时形成的相结构有影响,高压下有利于生成纳米级Cu_2(Y,Mg)相。Cu_2(Y,Mg)为一亚稳相,高温退火后转变为稳定的Mg_2(Cu,Y)相,讨论了压力对晶粒度影响的机制。 The microstructures of Mg65Cu25Y10 alloy melt melted under atmospheric pressure and high pressure (2-5 GPa) were investigated by X-ray diffraction, differential thermal analysis and transmission electron microscopy. The experimental results show that , The pressure has an effect on the phase structure of the Mg 65 Cu 25 Te 10 alloy during solidification, which is favorable for the formation of nanoscale Cu 2 (Y, Mg) phase under high pressure. Cu 2 (Y, Mg) is a metastable phase, which is transformed to a stable Mg 2 (Cu, Y) phase after high temperature annealing. The mechanism of the effect of pressure on the grain size is discussed.