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采用拉伸测试与透射电镜 (TEM) ,研究了稀土Ce对铸态Al 5 .3Cu 0 .8Mg 0 .6Ag(质量分数 )合金的组织和耐热性能影响。结果表明 ,添加质量分数为 0 .2 0 %～ 0 .45 %的Ce ,在室温到 3 0 0℃ ,铸态合金的室温抗拉强度和高温耐热性能得到了提高。金相显示 ,稀土Ce的添加能明显细化铸态合金的晶粒 ,减少晶界上Cu的偏析。透射电镜分析表明 ,合金中的主要强化相为Ω相 ;添加微量Ce能细化合金中的强化相 ,提高该相的析出密度。同时研究也表明 ,当合金中同时添加微量Ce和Ti时 ,铸态合金中形成了一种AlxTi6Ce3 Cu的大块稀土化合物相 ,这种化合物相严重降低了合金的拉伸性能。
The tensile test and transmission electron microscopy (TEM) were used to investigate the effect of rare earth Ce on the microstructure and heat resistance of the as-cast Al 5 .3Cu 0.8Mg 0.6Ag (mass fraction) alloy. The results show that room temperature tensile strength and high temperature heat resistance of as-cast alloy are improved by adding Ce with mass fraction of 0.2% ~ 0.45% at room temperature to 300 ℃. Metallography shows that the addition of rare earth Ce can significantly refine the as-cast alloy grains and reduce the segregation of Cu on the grain boundaries. Transmission electron microscopy analysis showed that the main strengthening phase in the alloy was Ω phase. Adding a small amount of Ce could refine the strengthening phase in the alloy and increase the precipitation density of the alloy. At the same time, the study also showed that when a small amount of Ce and Ti were added into the alloy, a bulk rare earth compound phase of AlxTi6Ce3Cu was formed in the as-cast alloy, which seriously degraded the tensile properties of the alloy.