快速凝固/粉末冶金AZ91/SiC_p镁基复合材料的相组成及界面

Phase composition and interface of rapidly solidified/powder metallurgy AZ91/SiC_p Mg-based composite material

采用双辊雾化法制备快速凝固AZ91镁合金粉末,并用粉末冶金方法制备SiC颗粒增强的镁基复合材料棒材,研究AZ91/SiCp复合材料的微观组织、相组成及增强相与合金基体间的界面结构特点。结果表明:双辊雾化快速凝固AZ91镁合金粉末的相组成为α-Mg固溶体主相和微量细小的T-AlMg2Zn相,尺寸在0.2μm左右;在后续热挤压过程中合金基体中析出大量的球形β-Mg17Al12,尺寸在0.5μm左右,而T-AlMg2Zn相的形貌和尺寸无明显变化;复合材料在加热过程中,增强相SiC颗粒表面的SiO2层与合金基体之间发生界面反应。

Rapidly solidified （RS） AZ91 magnesium alloy powders and the Mg-based composite material reinforced by SiC particles were produced by twin-roller atomization method and powder metallurgy, respectively. The microstructure, phase compositions and interface characterization between Mg matrix and reinforcing particles of AZ91/SiCp composite material were investigated. The results show that the RS AZ91 magnesium alloy powders are composed of α-Mg and a small quantity of fine T-AlMg2Zn with grain size of about 0.2 μm. A large number of global β-Mg17Al12 with grain size of about 0.5 μm are observed after hot extrusion, but the appearance and grain size of T-AlMg2Zn phase is not changed remarkably during hot extrusion. In the heating process of the composite material, the interface reaction occurs between the layers of SiO2 on the surface of SiC particles and Mg matrix.