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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,计算Mg-RE合金系金属间化合物Mg La、Mg Sc、Mg Y和Mg Lu 4相的形成焓、结合能、弹性常数及态密度。结果表明:合金化能力由强到弱依次为Mg La>Mg Y>Mg Sc>Mg Lu;稳定性由强到弱依次为Mg Lu>Mg La>Mg Y>Mg Sc;4相均为脆性相,且脆性由强到弱依次为Mg Sc>Mg Lu>Mg La>Mg Y;塑性由强到弱依次为Mg Y>Mg La>Mg Lu>Mg Sc;4相中均存在弱离子键和金属键,金属键由强到弱依次为Mg Y>Mg La>Mg Sc>Mg Lu。由此可知,4相中Mg La和Mg Y的各向性能都较好,具有一定的应用价值。
The formation enthalpies, bonding energies, elastic constants and density of states of Mg La, Mg Sc, Mg Y and Mg Lu 4 phases of Mg-RE alloy intermetallic compounds were calculated by the first principle pseudopotential plane wave method based on density functional theory . The results show that the order of Mg La> Mg Y> Mg Sc> Mg Lu from high to weak is as follows: Mg Lu> Mg La> Mg Y> Mg Sc; the four phases are brittle phase , And the order of brittleness from strong to weak is Mg Sc> Mg Lu> Mg La> Mg Y; the order of Mg Y> Mg La> Mg Lu> Mg Sc from strong to weak is weak; the weak ion bonds and the metal Key, the order of the metal bonds from strong to weak is Mg Y> Mg La> Mg Sc> Mg Lu. It can be seen that the four phases Mg La and Mg Y of the anisotropy are better, has a certain application value.