Al_2O_(3f)/Mg-9Al-0.5Nd复合材料的组织与压缩性能

Microstructure and Compressive Behavior of Al_2O_(3f)/Mg-9Al-0.5Nd Composites

采用无压浸渗技术制备了Al2O3f/Mg-9Al-0.5Nd复合材料,利用扫描镜、X射线衍射仪、电脑伺服材料试验机,研究了复合材料的微观组织变化、压缩性能和断口形貌。结果表明,复合材料组织中出现了Mg2Si新相和少量的粒状和杆状稀土相;热处理后Mg2Si有增多的趋势,尺寸略有增大;复合材料经过T4和T6处理后压缩强度有所下降,由铸态的346.5MPa下降到250.5MPa和327.5MPa;经T6处理后,复合材料的压缩断裂方式由准解理断裂变为混合断裂,存在少量纤维从基体中拔出的现象。

Al2O3f/Mg-9Al-0.5Nd composites were prepared by pressureless infiltration method,and microstructure,compressive behavior and fracture morphology of the prepared composites were investigated by SEM(scanning electron microscope),XRD(X-ray diffraction)and computer servo-material experimental machine.The results show that presence of new Mg2Si phase and a little particle and rod-like RE phase can be observed in the composites.The Mg2Si phase with the slight increase of size is increased in the heat treated composites.The compressive strengthes of the composites after T4 and T6 heat treatment are declined from 346.5 MPa in as-cast ones to 250.5 MPa and 327.5 MPa,respectively.After T6 heat treatment,compressive fracture of the composites is characterized by a mixed fracture instead of quasi-cleavage fracture,meanwhile,a small amount of fiber pulled out from the matrix can be observed.