Re与Ru合金化对Ni／Ni_3Al相界电子结构影响的第一原理研究

A FIRST-PRINCIPLES STUDY ON ELECTRONIC STRUCTURES OF Ni/Ni_3Al INTERFACES WITH Re AND Ru ADDITIONS

采用第一原理赝势平面波方法研究了Re与Ru合金化前后γ-Ni/一γ′-Ni_3Al相界的电子与能态结构,断裂功计算结果显示：Re置换γ-Ni相区中的Ni或Ru置换γ′-Ni_3Al相区中的Al,均可提高Ni/Ni_3Al相界的断裂强度,Re与Ru在相界区复合合金化时,当Re与Ru分别占据共格(002)γ/γ′原子层邻近(001)γ原子层上的Ni原子位于(001)γ′原子层上的Al原了位时,γ-Ni/γ′-Ni_3Al相界的断裂强度可进一步提高,若其中的Ru置换γ′-Ni_3Al相区内层Al,则复合合金化Ni/Ni_3Al相界的断裂强度不仅没有提高,反而比Ru单独合金化时Ni/Ni_3Al相界的断裂强度还低．电子态密度与电子密度分布图的分析表明：Re与Ru合金化对γ-Ni/γ′-Ni_3Al相界断裂强度的影响可归因于Re和Ru与其最近邻Ni原子间强烈的电子相互作用引起的相界区域层间原子成键相互作用的改变．

Using a first-principles plane-wave pseudopotential method, the energetics and electronic structures of Ni/Ni3Al interface with Re and Ru additions have been calculated. The calculation of Griffith rupture work W demonstrated that either the substitution of Re atom for Ni atom in γ-Ni block or Ru atom for Al atom in γ＇-Ni3Al block are profitable to improve the rupture strength of the interface. The multiple addition of Re and Ru can further improve the strength of the interface when Re and Ru atoms occupy respectively at Ni and Al sites at （001） atomic layers adjacent to the coherent （002） interfacial atomic layer. Whereas, when Ru atom locates at Al site in γ＇-Ni3Al block and far away from the coherent （002） interfacial layer, the multiple addition will decrease the interface strength to a lower value than that with only Ru addition. The analysises of electron densities of states （DOS） and the distributions of valence electron densities revealed that the effect of Re and Ru is attributed to the stronger electronic interactions of Re-Ni and Ru-Ni within first nearest neighbor.