C_f表面修饰增强Mg_2Si-SiC复合材料的性能

Properties of Mg_2Si-SiC composites reinforced by surface-modified carbon fiber

用化学镀的方法对碳纤维表面进行镀铜处理,采用机械合金化+热压烧结的方法制备Cf/Mg2Si-SiC复合材料,研究碳纤维体积分数对该复合材料维氏硬度、强度、导电性能的影响.结果表明:碳纤维经表面镀Cu修饰后可以抑制其与Mg2Si的界面反应,SiC颗粒主要分布在Mg2Si的晶界处,碳纤维平直地分布在基体中并且与基体结合良好.随Cf体积分数的增加,Cf/Mg2Si-SiC复合材料的致密度减小,硬度、抗压强度、抗弯强度和电导率先增大后减小,Cf体积分数为3%时,Cf/Mg2Si-SiC复合材料具有最佳的综合性能,其强化机制主要是SiC的细晶强化、弥散强化和纤维拔出.

Carbon fiber surface was coated with copper by means of chemical plating and Cf/Mg2 Si-SiC composite was prepared with mechanical alloying combined with hot-press sintering. The effect of carbon fiber content on Vickers hardness, strength and conductivity of the composite was investigated. The result showed that carbon fiber coated with copper could inhibit its interface reaction with Mgz Si, SiC particles would distribute mainly in the grain boundaries of Mg2 Si matrix, and the carbon fiber would distribute flatly and linearly in the matrix and well adhere to the matrix. With the increase of carbon fiber content, the compactness of the composite would decrease, hardness, compressive strength, bending strength and electrical conductivity increase first and then decrease. When carbon fiber volume-fraction content was 3%, the composites would exhibit optimal comprehensive properties. The strengthening mechanism of the composites was mainly the grain refining strengthening, dispersion strengthening of SiC and fiber pull-out.