高导热共晶Al-Si合金的制备及其性能

Preparation and Properties of the Eutectic Al-Si Alloy with the High Thermal Conductivity

采用OM、激光导热及直读光谱等手段,研究了Sr、B变质及退火对共晶Al-Si合金组织及热导率的影响。结果表明,通过B+Sr复合变质,共晶Si相由层片状转变为纤维状,杂质含量降低,合金的导热性能得到显著提升。B、Sr加入顺序对合金组织及导热性能有显著影响。经0.02%的B+0.03%的Sr复合变质处理合金的热导率为159.5W/(m·K),较未变质合金提升约31.2%。经350℃×4h退火处理,B+Sr复合变质合金的热导率为178.8 W/(m·K),较其铸态合金提升约10.93%。

The effects of Sr-B modification and annealing on the microstructure and thermal conductivity of eutectic Al-Si alloy were investigated by the optical microscope,laser flash apparatus and optical emission spectrometer.The results indicate that the flake-like eutectic Si is transformed into the fibrous structure,and the Al matrix purity is improved through B＋Sr compound modification,which obviously enhances the thermal conductivity.The addition order of Sr-B has the remarkable effects on the microstructure and thermal property.The thermal conductivity of 0.02%B＋0.03%Sr modified alloy reaches159.5 W/（m·K）,increased by 31.2%than that of the unmodified alloy.With the annealing treatment at 350 ℃for 4 h,the thermal conductivity of 0.02%B＋0.03%Sr modified alloy reaches 178.8 W/（m·K）,increased by 10.93%than that of the untreated alloy.