Microstructure and properties of Sip/4032Al composite
(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: The environmental-friendly Sip/4032Al 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 4032Al matrix. The Sip/4032Al composite has low density (2.4g/cm3), low coefficient of thermal expansion (8.1×10 -6/℃), high thermal conductivity (161.3W/(m·℃)), and the annealing treatment can reduce the coefficient of thermal expansion and improve the thermal conductivity. Moreover, the composite has excellent special strength(131.8MPa·cm3/g)and special modulus (49.7GPa·cm3/g).
Key words: aluminum matrix composite； microstructure； thermal expansion； thermal conductivity； mechanical properties