稀土对铝合金微观组织的影响

Effect of Cerium-rich Mixtures of Rare Earth on Microstructure of Aluminum Alloys

研究了添加RE(富铈混合稀土)元素对细晶铝锭及细晶铝锭制造的A356、3003铝合金显微组织的影响。结果发现,RE在铝合金中形成何种化合物,既与铝合金中所含元素的种类有关,又与RE含量有关;在细晶铝锭中,RE与Fe的交互作用较强,与Si的作用较弱,生成Al-Fe-RE化合物,但当RE含量超过0.3%时,除形成Al-Fe-RE化合物外,还形成AlCe3、Al2La;在含硅量较高的T5处理的A356铝合金中,0.3%RE与Mg、Fe的交互作用较弱,与Si的交互作用较强,Ce、La与Si形成CeSi、La5Si3,Mg与Si主要形成Mg2Si;而在含Fe、Mn较高的3003铝合金中,0.3%RE主要生成Al3Ce、LaSi、CeSi2等化合物,而与Fe、Mn的作用较弱。

The effect of cerium-rich rare earth mixture addition on the microstructure of Grain-refining Aluminum Ingots （GRAD, A356 and 3003 aluminum alloys produced with GRAl has been studied by OM, SEM and EDAX. The results show that of intermetallic compound containing RE formed depends on both elements in aluminium alloy and the content of rare earth. In GRAl, since RE have stronger interaction with Fe than with Si, thus forms Al-Fe-RE intermetallic compound,. When RE is above 0.3wt% AlCe3 and Al2La are formed besides Al-Fe-RE. In A356 aluminum alloys, 0.3wt% RE and Si have strongly interaction, forming CeSi and La5Si3. However, RE and Mg, Fe have weak interaction. Mg reacts with Si forming Mg2Si. In 3003 aluminum alloys, 0.3% RE addition mainly forms Al3Ce, LaSi and CeSi2, and RE has weak interaction with Fe and Mg.