Microstructure And Properties Of Aluminum-Silicon Alloy Prepared By Rapid Solidification

The aluminum-silicon alloy prepared by rapid solidification has a good thermal conductivity and low expansion coefficient, so it is a hot-spot of packaging materials. The changes of droplet in thermal processes during atomized stage of Al-50%Si alloy were simulated, the microstructure of the Al-Si alloy powders by methods of X-ray diffraction analysis and microscope was observed; the samples of silicon-aluminum alloy was prepared by powder metallurgy, the effect of sintering temperatures and the size of particals on the sintered microstructure and properties of Al-Si alloy was studied, sintering mechanism of Al-Si alloy was studied through the solid-phase sintering principle. Results showed that, the cooling rates of the droplets of Al-50%Si alloy is between103and106K/s when particals size between10and200μm. The size of silicon phase is about5um, Si phase of Al-18%Si was smaller than of Al-50%Si. With the increase of partical size, the hardness and density of samples became larger, the electrical conductivity and thermal conductivity decreased. With the increase of sintering temperature, hardness of the samples decreased, electrical conductivity and thermal conductivity also decreased. Solid-phase diffusion existed among the particles of Al-Si alloy when sintered at560℃, while solid phase and liquid phase diffusion existed among the particles of Al-Si alloy when sintered at600℃, the density of the samples was increased.