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研究了8090Al-Li 合金在缓慢冷却时的凝固过程,结果表明:L→α-Al+L′反应是基本凝固过程,贯彻始终。由于溶质元素 Cu 的严重偏析,使得合金终凝固温度显著降低,凝固温度区间扩大,终凝温度在525℃左右,但熔体的90%以上在635—590℃之间凝固,在最后凝固区溶质大量富集,从而形成了 T_2相等低熔点共晶化合物。杂质元素 Fe,Si 具有强烈偏析倾向。在缓冷过程中,形成粗大的 Al_3Fe,AlLiSi,Al_7Cu_2Fe 等金属间化合物。
The solidification process of 8090Al-Li alloy during slow cooling was studied. The results show that the reaction of L → α-Al + L ’is the basic solidification process. Due to the serious segregation of solute element Cu, the final solidification temperature of the alloy decreased significantly, the solidification temperature range expanded, the final solidification temperature was about 525 ℃, but more than 90% of the solidified solidified at 635-590 ℃. In the final solidification zone, A large number of enrichment, thus forming a T_2 equivalent low melting point eutectic compound. Impurity elements Fe, Si have a strong tendency to segregation. In the slow cooling process, the formation of coarse Al_3Fe, AlLiSi, Al_7Cu_2Fe intermetallic compounds.