The interface reaction of SiC/Al composites by spark plasma sintering

As a promising thermal management material, the 50 vol% SiC/Al composites with different SiC particle size and Al alloy composition were prepared by Spark Plasma Sintering. Thermal properties, microstructures, interface reaction products of the composites were investigated by XRD, SEM, and TEM. The components of composites and sintering process parameters in the SPS process were optimized. Microstructures, thermal properties, interface reaction product of the composites were investigated. The result shows that SiC particle size and sintering process parameters were the key parameters to get high thermal-mechanical properties of the composites. The best physical properties of 16 µm SiC/6061Al composites were obtained at 50 MPa, 8 min and 520 ℃ sintered. The bending strength was up to 649 MPa, the thermal conductivity was 189 W/(m·K), and the average coefficient of thermal expansion was only 7.9 × 10−6 K−1 at 50–100 °C. Meanwhile, X-Ray Diffraction and scanning electron microscopy detects no hazardous reaction product Al4C3 at the interface between the SiC particle and the Al matrix, and MgAl2O4 and Mg2Si grew together at the interface.