以无序合金的实验数据为基础的Au3Cu,AuCu3,AuCuⅠ和AuCuⅡ的特征原子占据图

摘要

根据无序Au1-xCux合金的实验生成热和晶格常数得到只考虑近邻原子组态的特征原子的势能、体积和电子结构,计算L12-Au3Cu,L12-AuCu3和L10-AuCu化合物的特征原子占据(CAO)图、电子结构、能量和体积性质.Johasson-Linde(J-L)模型的CAO图表明,AuCuⅠ-AuCuⅡ转变是一个放热且体积缩小的反应,但正好与实验现象相反.根据Guymont-Feutelais-Legendre(G-F-L)模型的CAO图,AuCuⅡ晶胞由两个周期反相(PAD)的AuCuⅠ区域和两个PAD边界区域组成;从G-F-L模型的CAO图得出的公式可用来计算PAD AuCuⅠ区域和PAD边界区域的能量性质、体积性质和有序度及AuCuⅡ相的平均性质,计算结果与实验现象相吻合.%The potential energies, volumes and electronic structures of characteristic atoms coordinated by neighboring configurations were obtained from the experimental heats of formation and lattice parameters of disordered Au1-xCux alloys. From characteristic atom occupation (CAO) patterns of L12-Au3Cu, L12-AuCu3 and L10-AuCu compounds, their electronic structures, volumetric and energetic properties were calculated. The CAO pattern of Johasson-Linde(J-L) model shows that the transition AuCuⅠ→ AuCuⅡ is an exothermic and volume contraction reaction, which is opposite from experimental phenomena. According to CAO pattern of Guymont-Feutelais-Legendre(G-F-L) model, the AuCuⅡ cell consists of two periodic antidirection (PAD) AuCuⅠ regions and two PAD boundary regions. The equations derived from CAO pattern of G-F-L model can be used to calculate energetic properties, volumetric properties and ordering degrees of the PAD AuCul region and PAD boundary region, as well as corresponding average properties of the AuCuⅡ phase. The results are consistent with experimental phenomena.