“铝硅-铝/金刚石-铝硅”三明治复合结构制备及热传导性能研究

Study on Preparation and Thermal Conduction Performance of "Al/Si-Al/Diamond-Al/Si" Sandwich Composite Structure

利用压力浸渗法制备“铝硅-铝/金刚石-铝硅”三明治复合结构,测试其热传导性能。首先熔化铝合金锭,检测铝液质量以确定合适精炼工艺及浸渗时刻。对精炼后铝合金液施加80 MPa高压,使其充分浸渗入硅预制体粉料,获得铝硅复合材料,并对其进行热学性能测试。结果表明:硅粒径越大、体积分数越低,铝硅复合材料的热导率越高;而硅粒径越小、体积分数越高,该复合材料的热膨胀系数越低。基于上述结果,确定“硅-金刚石-硅”预制块结构,进而通过压力浸渗法一体制备“铝硅-铝/金刚石-铝硅”三明治复合结构。含最优硅粒径及体积分数的三明治复合结构热导率介于450~500 W/(m·K),高于铝硅复合材料及铝等纯金属的热导率。

The sandwich composite structure of "Al/Si-Al/Diamond-Al/Si" was prepared by pressure immersion method to test its heat conduction properties. Firstly, the aluminum alloy ingot was melted, and the quality of the molten aluminum was tested to determine the appropriate refining process and moment of infiltration. A high pressure of 80 MPa was applied to the refined aluminum alloy liquid to fully infiltrate the silicon preforms powder to obtain Al/Si composite materials, and the thermal performance was also tested. The results show that the larger the silicon particle size and the lower the volume fraction, the higher the thermal conductivity of the Al/Si composite. The smaller the silicon particle size and the higher the volume fraction, the lower the thermal expansion coefficient of the composite. Based on the above results, the "Si-Diamond-Si" prefabricated block structures are determined, and then "Al/Si-Al/Diamond-Al/Si" sandwich composite structures are prepared at one time by the pressure infiltration method. The thermal conductivity of the sandwich composite structure containing the optimal silicon particle size and volume fraction is between 450 W/(m·K) and 500 W/(m·K), which are higher than those of Al/Si composite materials and pure metals such as aluminum.