高硅铝合金初晶硅变质效果的热分析研究

Thermal Analysis on Modification Effect of Primary Silicon in High-Silicon Aluminum Alloys

利用新开发的热分析技术研究了Al-20Si-1.5Cu-1Ni-0.5Mn合金的初晶Si变质效果。通过对不同的P变质剂加入量和保温时间下的热分析曲线和金相组织的分析表明,随着P加入量的增加(≤0.08%),初晶Si平均晶粒尺寸减小,初晶生长温度TG及其差值ΔTG不断增大;在变质处理后不同的保温时间下平均晶粒尺寸及ΔTG都变化不大。初晶生长温度差值ΔTG与平均晶粒尺寸具有很好的对应关系,ΔTG可以作为初晶Si变质效果的评判依据。

With the newly developed thermal analysis technique, the modification effect of primary silicon in the Al-20Si-1.5Cu-1Ni-0.5Mn alloy has been studied. According to the analysis result on the cooling curve and the microstructures of alloys modified with different P content and holding time, it is found that, with the increase of the P content （≤0.08% ）, the average grain size of the primary silicon decreases, the primary silicon growth temperature TG and its difference △TG increase; the different holding time has little effect on the average grain size of the primary silicon and △TG. The △TG has a better relationship with the average grain size of the primary silicon, and ATo can be used as the criterion of the modification effect of the high-silicon aluminum alloys.