熔渗温度对Si/Al复合材料组织及性能的影响

Effect of infiltration temperature on microstructure and properties of Si/Al composite

采用无压熔渗法制备Si/Al复合材料,研究了熔渗温度对所制备Si/Al复合材料Si相形貌的影响,对Si相间基体合金的凝固组织进行了分析,测试了Si/Al复合材料热膨胀系数、热导率及抗弯强度。结果表明,在相同熔渗时间下,随着熔渗温度升高,所制备Si/Al复合材料中Si相从颗粒状到形成网络状。Si相间的Al-Si基体合金中不再是典型的初生相和共晶组织,而是出现了类似离异共晶的结晶现象,即初晶Si和共晶Si是在原存的Si相上结晶长大。XRD分析显示在所制备复合材料中只有Si相和Al相。随着熔渗温度升高复合材料热膨胀系数、热导率以及抗弯强度均出现下降。

Si/A1 composite was fabricated by pressureless infiltration. Effect of infiltration temperature on Si phase shape in prepared Si/A1 composite was investigated. The matrix alloy solidification microstructure in Siphase interspace was analyzed. The coefficient of thermal expansion, thermal conductivity and bending strength of Si/A1 composite were tested. The results show that at same infiltration time, with infiltration temperature increasing Si phase is from particle shape to network shape in prepared Si/A1 composite. The microstructure of A1-Si matrix alloy in Si phase interspace is no typieal primary phase and eutectie mierostructure. There is a phe-nomenon similar to the separate-eutectic microstructure. Primary Si phase and eutectic Si phase crystallize and grow at origin Si phase. XRD analyzing shows that there are Si phase and A1 phase in prepared Si/A1 composite. With infiltration temperature increasing, the coefficient of thermal expansion, thermal conductivity and bending strength of Si/A1 composite decrease.