中文摘要：

利用XRD、SEM、TEM、EDS等测试方法对Mg-8.07Al-0.53Zn-1.36Nd镁合金微观组织结构进行表征与分析,并采用原位拉伸试验研究了合金显微组织对裂纹萌生及扩展行为的影响。结果表明：试验合金组织中主要包括α-Mg基体,β-Mg17Al12,α＋β共晶相,Al11Nd3针状相和Al2Nd颗粒相。Al2Nd存在孪晶结构,孪晶面为{11 1},Al11Nd3存在连续的凹凸界面结构。合金室温原位拉伸试验结果表明：裂纹主要在粗大的β-Mg17Al12相内部萌生,裂纹扩展方式包括沿晶扩展和穿晶扩展。裂纹穿晶扩展主要归因于沿晶界分布的Al11Nd3、Al2Nd相与周围组织界面结合能力较强,Al11Nd3凹凸界面对基体与共晶组织的啮合作用显著。

英文摘要：

Microstructure of Mg-8.07Al-0.53Zn-1.36 Nd magnesium alloy was characterized by XRD, SEM, TEM and EDS. The effect of microstructure on the behavior of crack initiation and propagation was investigated by in situ tensile tests. Results show that the microstructure of the Mg-8.07Al-0.53Zn-1.36 Nd consists of α-Mg matrix, β-Mg17Al12, eutectic phase α＋β, needle-like Al11Nd3 and particle Al2Nd phase. The twin structure exists in the Al2Nd phase, and the twin plane is {111 }. Moreover, a continuous concave and convex interface structure of the Al11Nd3 has been found. The crack initiation mainly occurs in the β-Mg17Al12phase, and the crack propagation modes include intergranular and transgranular expansion. Crack transgranular expansion is attributed to the strong binding ability between Al11Nd3 or Al2 Nd phases and the surrounding structure. In addition, the continuous concave and convex interface structure of the Al11）Nd3 provides a significant meshing effect on the matrix and eutectic structure.