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

In order to study the structural feature and reinforcement mechanism of the silicon carbide foam ceramics (SiC_f) in the aluminum matrix composites, the SiC_f with 3D network structure characteristics were prepared by use of polymer pyrolysis and reaction sintering methods. The SiC_f/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 SiC_f 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 (SiC_p) and aluminum alloy in the meshes. The synergistic effects of the SiC_f and SiC_p 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℃.