5G 基站散热器用高导电(热)压铸 Al-Si-Fe 铝合金的热力学设计与试验

In view of the inversion problem between strength and electrical(thermal)conductivity of die-cast aluminum heat sinks in 5G base stations,effects of aging treatment on microstructure and conductivity of die-cast Al-7.5Si-0.8Fe aluminum alloys were investigated through a combination of thermodynamic calculations and experimental research by PANDAT thermodynamic calculations,metallographic microscopy,scanning electron microscopy,X-ray diffraction,and transmission electron microscopy. The results indicate that the conductivity of alloy is significantly improved after heat aging treatment at 320 ℃ for 1 h. Al-Fe-Si ternary phases and Si phase are precipitated along the grain boundaries and interior,respectively,thus reducing the solid solubility of Fe and Si in Al matrix. In addition,the continuity of eutectic Si network is deteriorated after aging,accompanied with the increased connectivity of the aluminum matrix,which is the main reason for the enhancement of conductivity.