Microstructure and performance of Al-Si alloy with high Si content by high temperature diffusion treatment

The Al-Si alloy with high Si content was prepared by pressure infiltration.Microstructure observation shows that three-dimensional structure(3D-structure) is obtained from irregular sharp Si particles via high temperature diffusion treatment(HTDT).Flat Si-Al interfaces transform to smooth curves,and Si phases precipitate in Al and Si-Al interface.The bonding of Si-Al interface is improved by HTDT,which improves the mechanical performance of Al-Si alloy.The bending strength of 3D-Al-Si alloy increases by 6% compared with that of Al-Si alloy,but the elastic modulus changes a little.The coefficient of thermal expansion(CTE) of the 3D-Al-Si alloy is 7.7×10-6/°C from 20 °C to 100 °C,which decreases by 7% compared with that of Al-Si alloy.However,HTDT has little effect on the thermal conductivity of Al-Si alloy.