第一性原理研究铱金属的致脆机理

发布时间：2018-03-03 06:31

本文选题：铱金属　切入点：第一性原理　出处：《材料导报》2015年02期 　论文类型：期刊论文

【摘要】：采用基于密度泛函理论的第一性原理方法对铱金属的致脆机理进行了研究。建立了Ir、Cu、Au、Si的晶胞模型,计算分析其电子结构、能带结构、力学性质等。根据金属塑性经验判据G/B比较得出,Cu和Au的塑性都非常好,而同样为面心立方金属的Ir却有着和非金属Si相似的脆性。分析电子结构发现,Cu和Au的电子云为均匀的圆球形,呈各向同性,这有利于原子间相互运动,从而有利于金属的塑性变形。Ir和Si的电子云有着相似的"花瓣状",极化严重,方向性明显;Ir原子间存在"伪共价"结构,这都对金属塑性变形产生了极大的阻力。能带结构和态密度的分析得出,Ir、Si相对于Cu和Au有着非常高的键强,这都不利于其塑性变形。因此,Ir的本征特点决定了其高的室温脆性。
[Abstract]:The brittleness mechanism of iridium metal was studied by using the first-principle method based on density functional theory. The cell model of Ir-Cu-Au-Si was established, and its electronic structure and band structure were calculated and analyzed. Mechanical properties and so on. According to the empirical criterion G / B of metal plasticity, it is concluded that both Cu and au have very good plasticity. On the other hand, ir, which is also a face-centered cubic metal, has a brittleness similar to that of non-metallic Si. By analyzing the electronic structure, it is found that the electron clouds of Cu and au are uniform spherical and isotropic, which is beneficial to the mutual movement of atoms. Therefore, the electron cloud, which is favorable to the plastic deformation of metal. Ir and Si, has similar "petal shape", and polarization is serious, and there is a "pseudo-covalent" structure between the atoms of ir with obvious directivity. The analysis of the energy band structure and the density of states shows that the Ir-Si has a very high bond strength relative to Cu and au, which is not conducive to its plastic deformation. Therefore, the intrinsic characteristics of ir determine its high room temperature brittleness.
【作者单位】：昆明理工大学稀贵及有色金属先进材料教育部重点实验室云南省新材料制备与加工重点实验室;
【基金】：国家自然科学联合基金(u0837601) 云南省创新团队(2009CI003)
【分类号】：TG146.34

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