稀土La与Y元素在Al-RE体系的固溶行为研究

Study of Solution Behavior of Rare Earth(La and Y) in Al-RE Binary

摘要:

本文采用基于密度泛函理论的第一性原理，计算了Al-La与Al-Y二元合金中金属间化合物的基态特征，在此基础上，研究了稀土La与Y元素在Al中的溶解度，并讨论了稀土铝合金中析出相的力学性能。结果表明，Al-La和Al-Y合金中的最稳定相均为Al2RE金属间化合物。对于含有微量稀土元素的铝合金中的优先析出相，Al3Y(R-3M)较Al3Y(PM-3M)和Al11La3(IMMM)具有更好的稳定性和强化效果。La和Y在Al中的溶解度计算结果显示，与La相比，Y在Al具有较高的溶解度。综合弹性模量和溶解度的结果可知，微量Y可以更加有效的达到强化Al合金基体的效果。

Abstract:

The appropriate ground states of the Al-La and Al-Y binary alloy are calculated by using the first-principles method based on density functional theory, the solubility of La and Y elements in Al are discussed, as well as the mechanical properties of the RE precipitates. The results show that the most stable phase of Al-La and Al-Y is Al2RE compound. For three of the priority precipitates (Al3Y(R-3M), Al3Y(PM-3M) and Al11La3(IMMM)), Al3Y(R-3M) has the highest stability and strengthening capability, and the difference of the calculated solubility for La and Y in Al indicates that Y has a high solubility limit. A comprehensive elastic modulus and solubility calculations, it can be concluded that Y is the better candidate as a potential addition to enhance the Al alloy matrix.