制备了不同稀土(RE)元素含量的铝合金铸锭,对其进行均匀化处理后再进行形变热处理,研究了RE含量对其显微组织、力学性能、导电率和耐热性能的影响,最后分析了RE的作用机理及存在形式。结果表明:适量RE的加入能细化铸态合金的晶粒尺寸,但对形变热处理后的组织没有显著影响;RE会降低合金的峰值硬度,提高合金的导电率,当RE的质量分数超过0.1%时会降低合金的拉伸性能;RE能够改善合金的耐热性;RE在合金中主要以β相(AlCuREFeSi)的形式存在。

Aluminum alloy ingots with different contents of RE element were prepared, and then homogenization treatment following by thermomechanical treatment were carried out to study the effects of RE on microstructure, mechanical properties, electrical conductivity and thermal-resistance. At last, the acting mechanisms and existing forms of RE were analyzed. The results show that appropriate amounts of RE could refine the grains of as-cast alloy, but this had no influences upon the microstructure after thermo-mechanical treatment. RE could decrease the peak hardness and increase electrical conductivity, and the tensile properties decreased when the quality fraction of RE was more than 0.1%. The thermal-resistance of the alloys were improved by adding RE, and RE existed mainly in the form of β phase (AlCuREFeSi).