First-principle investigation of bismuth segregation atΣ5 (012) grain-boundaries in nickel

作     者：陈律 彭平 庄厚龙 周惦武 

作者机构：Department of Aeronautical Equip EngineeringChangsha Aeronautical Vocational and Technical CollegeChangsha 410124China School of Materials Science and EngineeringHunan UniversityChangsha 410082China School of Materials Science and EngineeringHunan UniversityChangsha 410082China School of Materials Science and Engineering Hunan University Changsha 410082China 

出 版 物：《中国有色金属学会会刊：英文版》 (Transactions of Nonferrous Metals Society of China)

年 卷 期：2006年第16卷第B2期

页      面：813-819页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 0702[理学-物理学] 

主　　题：铋 偏析系数 镍 晶界 表面能 材料性质 

摘      要：As an aid in establishing an understanding on the electronic level, the influence of bismuth on the cohesion of nickelΣ5 (012) grain boundary was determined using the plane wave pseudopotential (PWPP) method with the generalized gradient approximation. Based on the Rice-Wang model, the total energy calculations show that Bi behaves as an embrittler of the Ni grain-boundary, which predicts the experimentally known behavior. The total charge density, and difference charge density of the grain boundary also demonstrats that the Bi atom forms weaker bonds with neighboring Ni atoms in the grain boundary region. Total density of states (DOS) show that there exists significant covalent bonding for the grain boundary system with Bi segregated which help to embrittle the grain boundary and the change that Ni local d-DOS is narrowed due to segregation of Bi is also beneficial for the decohesion.