碳化硅泡沫陶瓷/铝双连续相复合材料结构特征及增强机制

Structural feature and reinforcement mechanism of silicon carbide foam ceramics aluminum matrix co-continuous phase composites

  • 摘要: 为了研究碳化硅泡沫陶瓷(SiCf)在铝基复合材料中的增强机制,采用高分子热解结合反应烧结的方法制备出具有三维连通网络结构特征的SiCf,利用挤压铸造的方法将熔融铝合金压注到泡沫陶瓷网孔中,获得了SiCf/铝双连续相复合材料并开展了复合材料高温膨胀系数(CTE)和压缩性能实验。实验结果表明:SiCf利用三维连通网络结构对基体铝合金具有整体增强机制,随温度升高也能保持良好的增强效果;对网孔中的碳化硅陶瓷颗粒(SiCp)及铝合金具有约束机制。SiCf和网孔中的SiCp协同作用可以有效降低复合材料的热膨胀系数,提高复合材料的高温抗压强度。在500℃时,最高抗压强度可以达到313.61 MPa、热膨胀系数为7.653×10−6−1

     

    Abstract: In order to study the structural feature and reinforcement mechanism of the silicon carbide foam ceramics (SiCf) in the aluminum matrix composites, the SiCf with 3D network structure characteristics were prepared by use of polymer pyrolysis and reaction sintering methods. The SiCf/aluminum matrix co-continuous phase composite materials were prepared by using the method of squeeze casting which the molten aluminum alloy was injected into the foam ceramic meshes and the coefficient of thermal expansion (CTE) and compression performance of the composites were experimented. The experimental results show that the SiCf has an overall reinforcement mechanism for the matrix aluminum alloy by using the 3D network structure, and it also keeps good reinforcement effect with the temperature increasing. It has confinement mechanism to silicon carbide ceramic particles (SiCp) and aluminum alloy in the meshes. The synergistic effects of the SiCf and SiCp in the meshes can effectively reduce the CTE and enhance the high temperature compression strength of the composites. The maximum compressive strength can reach 313.61 MPa and the CTE is 7.653×10−6−1 at 500℃.

     

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