The effect of Nb additive on Te-induced stress corrosion cracking in Ni alloy: a first-principles calculation  

作　　者：刘文冠 韩晗 任翠兰 阴慧琴 怀平 邹杨 徐洪杰 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences [2]Key Laboratory of Nuclear Radiation and Nuclear Energy Technology,Chinese Academy of Sciences [3]Key Laboratory of Interfacial Physics and Technology,Chinese Academy of Sciences

出　　处：《Nuclear Science and Techniques》2014年第5期90-94,共5页核技术（英文）

基　　金：Supported by Science and Technology Commission of Shanghai Municipality(No.11JC1414900);Project supported by the National Basic Research Program of China(No.2010CB934501);Thorium Molten Salts Reactor Fund(No.XDA02000000);the National Natural Science Foundation of China(No.11005148),the National Natural Science Foundation of China(No.51371188);the Special Presidential Foundation of the Chinese Academy of Science,China(No.29)

摘　　要：Nb can improve the resistance of Ni-based Hastelloy N alloy to Te-induced intergranular embrittlement.First-principles calculations are performed to research this mechanism by simulating the Ni(111) surface and the 5(012) grain boundary. The calculated adsorption energy suggests that Te atoms prefer diffusing along the grain boundary to forming the surface-reaction layer with Nb on surface of the Ni alloy. First-principles tensile tests show that the Nb segregation can enhance the cohesion of grain boundary. The strong Nb-Ni bonding can prevent the Te migration into the inside of the alloy. According to the Rice-Wang model, the strengthening/embrittling energies of Nb and Te are calculated, along with their mechanical and chemical components.The chemical bonds and electronic structures are analyzed to uncover the physical origin of the different effects of Te and Nb. Our work sheds lights on the effect of Nb additive on the Te-induced intergranular embrittlement in Hastelloy N alloy on the atomic and electronic level.Nb can improve the resistance of Ni-based Hastelloy N alloy to Te-induced intergranular embrittlement. First-principles calculations are performed to research this mechanism by simulating the Ni（111） surface and the ∑ 5（012） grain boundary. The calculated adsorption energy suggests that Te atoms prefer diffusing along the grain boundary to forming the surface-reaction layer with Nb on surface of the Ni alloy. First-principles ten- sile tests show that the Nb segregation can enhance the cohesion of grain boundary. The strong Nb-Ni bonding can prevent the Te migration into the inside of the alloy. According to the Rice-Wang model, the strengthen- ing/embrittling energies of Nb and Te are calculated, along with their mechanical and chemical components. The chemical bonds and electronic structures are analyzed to uncover the physical origin of the different effects of Te and Nb. Our work sheds lights on the effect of Nb additive on the Te-induced intergranular embrittlement in Hastelloy N alloy on the atomic and electronic level.

关 键 词：第一原理计算 镍合金 添加剂 应力腐蚀 铌 开裂 NI合金 晶界扩散 

分 类 号：TL341[核科学技术—核技术及应用]