SiCp／Zn基复合材料的制备与显微组织的观察

为探讨颗粒增强低熔点金属基复合材料的制备工艺和性能，扩大锌合金的应用范围，本项工作采用旋涡搅拌法制备了ＳｉＣｐ／Ｚｎ基复合材料，并讨论了搅拌工艺参数，增强颗粒表面处理对复合效果的影响。显微组织观察表明：ＳｉＣｐ分布均匀程度取决于颗粒的表面处理以及复合工艺参数的控制。ＳｉＣｐ经高温焙烧后，其表面获得一层稳定的ＳｉＯ２，从而有利于改善ＳｉＣｐ与基体锌合金的浸润性能。在基体中加入Ｍｇ等金属粉末，对于Ｓｉ

Fabrication of SiC_p/Zn Alloy Composite and Its Microstructure Observation

The SiCp/zinc alloy composite was prepared by means of revolving-blade stirring method so as to explore the fabrication technology and properties of particulate-reinforced low-melting-point metal matrix composite and broaden its application. The effect of stirring technologic parameters and particulate surface treatments upon the microstructure of the composite is discussed in this paper. The observation of the microstructure shows that the distribution of SiCp in the composite depends on its surface treatments and the control of technologic parameters. After being roasted at high temperature, SiC particles gaining a layer of SiO2 on their surface, are suitable to be wetted by the zinc alloy. The addition of some pure metal powders, i. e. Mg, into the matrix plays a good role in the improvement of SiCp distribution and bonding feature in the composite. On the other hand, the speed, time and temperature of revolving-blade stirring are important factors upon the properties of the composite. If the stirring speed is too high, much air is drawn into the material, leading to the composite with a high proportion of porosity. SiC particles, however,can not be incorparated into the zinc alloy due to lack of enough revolving energy at a too low stirring speed. The increase of stirring temperature is advantageous to improve the wettability between SiCp and the matrix, but its effect is not so significant. Morever, the additive velocity and the diameter of the particles also markedly affect the characteristics of the composite.