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采用基于密度泛函理论的第一性原理赝势平面波方法,对Mg-Nd二元合金中各种金属间化合物进行了结构优化,得到了其基态能量,并从合金形成热和结合能两方面研究了这些金属间化合物的结构稳定性。结果表明:各金属间化合物结合能的绝对值随Nd含量的增加而升高,其中MgNd结合能的绝对值最大,而Mg12Nd结合能的绝对值最小。这表明在Mg-Nd形成的金属间化合物中,MgNd的结构最为稳定,而Mg12Nd的稳定性最差。这一结果与实验数据相一致,在Mg-Nd合金相图中并没有出现Mg12Nd相。另外,还对这些结构的电子态密度进行了计算,从电子结构的角度对这一结论进行了解释。
The first-principle pseudo-potential plane wave method based on density functional theory was used to optimize the structure of various intermetallic compounds in Mg-Nd binary alloys. The ground state energies were obtained and the heat and the binding energy were obtained from the alloys The structural stability of these intermetallic compounds was investigated. The results show that the absolute value of the binding energy of each intermetallic compound increases with the increase of Nd content, and the absolute value of the binding energy of MgNd is the largest, while the absolute value of the binding energy of Mg12Nd is the smallest. This indicates that the structure of MgNd is the most stable among the intermetallic compounds formed by Mg-Nd, whereas the stability of Mg12Nd is the worst. This result is consistent with the experimental data, Mg12Nd phase did not appear in the Mg-Nd alloy phase diagram. In addition, the electronic density of states of these structures are also calculated, and this conclusion is explained from the perspective of electronic structure.