Microstructure and properties of environmental-friendly Si_p/LD11 composite

The environmental-friendly Si_p/LD11 composites with high volume fraction of 65% silicon particles were fabricated by squeeze-casting method. The results show that the composite is dense and silicon particles are distributed uniformly. Transmission electron microscope observations show that stacking faults with high density, twins and dislocations are found in silicon particles. The Si-Al interfaces are well-bonded and no interface reactants are found. The dislocations and eutectic silicon precipitates are observed in LD11 matrix. Si_p/LD11 composite has low density of 2.4 g/cm³, low coefficient of thermal expansion (CTE) of 8.1 × 10^-6/K, high thermal conductivity of 161.3 W/(m·K), and the annealing treatment can reduce the CTE and improve the thermal conductivity. Moreover, the composite has excellent special strength and special modulus.