金刚石–SiC/Al复合材料的构型设计与导热性能

以SiC和镀钨金刚石增强体为原料制备预制体，通过气压浸渗技术在800 ℃，5 MPa条件下制备金刚石–SiC/Al复合材料。利用扫描电镜、红外热成像仪、激光导热仪等对复合材料性能进行分析，研究SiC和金刚石的含量与粒径比对复合材料构型的影响，从而优化复合材料导热性能。结果表明:在相同的SiC粒径下，金刚石体积分数的增加将使复合材料的导热性能明显提升。当金刚石体积分数为30%时，含F100 SiC的复合材料导热性能最佳，其热导率为344 W/(m?K)。当金刚石体积分数相同，粒径比从0.07增大到0.65时，复合材料导热性能依次提升；且在金刚石体积分数为15%时，复合材料的热导率增幅最大，从174 W/(m?K)增大到274 W/(m?K)，增长了57%。通过改善金刚石–SiC/Al复合材料中增强体的含量和粒径比可以调控复合材料构型，充分发挥复合材料的导热潜力。 

Configuration design and thermal conductivity of diamond-SiC/Al composites

The preforms were prepared with SiC and W-coated diamond reinforcements, and the diamond-SiC/Al composites were prepared by gas pressure infiltration technology at 800 ℃ and 5 MPa. The properties of composite materials were analyzed by scanning electron microscope, infrared thermal imager and laser thermal conductivity meter. The influences of the content and the particle size ratio R of SiC and diamond on the configuration of composites were investigated to optimize the thermal conductivity of the composites. The results show that with the same SiC particle size, the thermal conductivity of the composites will be significantly improved with the increase of diamond volume fraction. When the volume fraction of diamond is 30%, the thermal conductivity of the composites containing F100 SiC is the best, which reaches 344 W/(m?K). When the volume fraction of diamond is the same and the particle size ratio R increases from 0.07 to 0.65, the thermal conductivity of the composite increases in turn. Moreover, the thermal conductivity of composites with diamond volume fraction of 15% increases from 174 W/(m?K) to 274 W/(m?K), which achieves the largest increase of 57%.Therefore, by improving the content and the particle size ratio of reinforcements in the diamond-SiC/Al composites, the configuration of composites can be regulated to realize full potential of thermal conductivity.