合金化效应对Fe3Si结构稳定性和力学性能的影响

Influence of Alloying Effects on Structural Stability and Elastic Properties of Fe3Si

摘要:

采用基于密度泛函理论的赝势平面波法，研究了Ni、Co、Cr元素对Fe3Si金属间化合物结构稳定性、弹性性能和电子结构。合金形成热和结合能的计算结果显示，Fe3Si-Ni具有最强的合金化形成能力，且结构最稳定。力学常数的计算结果表明，Ni和Cr的加入可提高化合物的塑性和延性，而Co可提高其硬度，其中Fe3Si-Ni的塑性最好，Fe3Si-Co的热稳定性最好。态密度和布居分析的计算结果表明，Fe3Si-Ni结构最稳定且塑性最佳的原因主要在于其体系的Fermi能级最接近于赝能隙的底部，Fe—Ni键布居数最大，合金化后体系的金属性增强最明显

Abstract:

Based on the density functional theory (DFT), the plane-wave pseudo-potential method was used to calculate structural stabilities, elastic properties and electronic structures of Fe3Si and Fe3Si-X (X=Ni, Co, Cr) compounds. The stability of the solid solution alloy increases with the addition of Ni or Cr, especially Fe3Si-Ni, and the stability of the solid solution alloy decreases with the addition of Co. The calculated elastic constants show that addition of Ni or Cr could enhance the plasticity and ductility, and Co could improve the hardness of compounds. Fe3Si-Ni has a better plasticity, but Fe3Si-Co has the best high temperature stability. Calculation of the density of states and Mulliken electronic populations shows that the reason why Fe3Si-Ni has the highest structural stability and optimal plasticity is attributed to its Fermi level close to the bottom of the pseudogap. And Fe3Si-Ni has the biggest Mulliken population with the metallic bonding of the alloying system increasing.