3D-Si/LG5复合材料微观组织及热物理性能研究

Study on Microstructure and Thermophysical Properties of 3D-Si/LG5 Composites

摘要:

采用压力浸渗技术制备Sip/LG5复合材料并对其进行高温扩散处理。组织观察表明：复合材料增强体形貌经过高温扩散处理后由不规则的尖角形状转变为三维网络结构(3D)。对3D-Si/LG5复合材料界面的研究表明，与高温扩散处理前复合材料的界面相比，三维网络结构3D-Si/LG5复合材料的界面更光滑，界面结合程度也更好。三维网络结构3D-Si/LG5复合材料界面处及基体合金内部有Si析出，基体合金中存在着孪晶；三维网络结构3D-Si/ LG5复合材料的平均线膨胀系数与高温扩散处理前相比，降低了10.5%；增强体三维网络化减少界面及基体中大量细小弥散的Si析出，使得三维网络3D-Si/ LG5复合材料的热导率变化不大。

Abstract:

Dense and uniform Sip/LG5 composites were fabricated by squeeze casting process, and then were treated by high temperature diffusion. Microstructure observation indicated that Si transformed from irregular sharp-particles to 3D network structure after high temperature diffusion treatment. Si-Al interface of 3D-Sip/LG5 composites is smoother and has better bonding degree, compared with the interface of the untreated composites. There are Si precipitation in the interface and the matrix of 3D-Sip/LG5 composites. Twin crystals were observed in the matrix of 3D-Sip/LG5 composites. The average linear thermal expansion (CTE) of the composites is decreased by 10.5% after high temperature diffusion treatment. However, the thermal conductivity of 3D-Sip/LG5 composites does not change significantly due to the decreased Si precipitation in the interface and matrix by 3D network structure of Si.