中文摘要：

采用组织观察、拉伸试验和理论计算,研究了Y对镁合金AZ81的晶粒细化作用以及由此产生的细晶强化作用。结果表明,Y加入镁合金AZ81后可生成高熔点的Al2Y相,Al2Y相可成为α-Mg基体和β-Mg17Al12相的有效异质形核核心,从而细化合金的晶粒尺寸,改善β-Mg17Al12相的形貌,起到有效的细晶强化作用,提高合金的室温强度。

英文摘要：

The grain refinement effect and related grain-refinement strengthening of rare earth element Y in magnesium alloy AZ81 have been investigated by microstructure observation,tensile tests and theoretic calculation. The results show that the formation of Al2 Y phase with high melting point is observed in magnesium alloy AZ81 after Y addition. Al2 Y phase can be used as the heterogeneous nucleation core of α-Mg matrix and β-Mg17Al12 phase,and refine the grain size and improve the morphology of β-Mg17Al12 phase. These lead to the effective grain-refinement strengthening and enhance the yield strength of the alloy at room temperature.