Microstructure and properties of Si_p/4032Al composite

The environmental-friendly Si_p/4032A1 composite with high content of silicon particles (65%, mass fraction) was 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 a high density of stacking faults, 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 4032A1 matrix. The Si_p/4032A1 composite has low density (2. 4 g/cm³), low coefficient of thermal expansion (8.1 × 10^-6/°C), high thermal conductivity (161.3 W/(m · °C)), and the annealing treatment can reduce the coefficient of thermal expansion and improve the thermal conductivity. Moreover, the composite has excellent special strength(131. 8 MPa · cm³/g) and special modulus (49. 7 GPa · cm³/g).