Ni_(3)Al中Re诱导缺陷对螺位错交滑移的影响  

Impact of Defects Induced by Re on Screw Dislocation Cross-Slip in Ni_(3)Al

作　　者：易洲 胡佳 邓永和[1] 陈义 文大东 高明 彭平[2] Yi Zhou;Hu Jia;Deng Yonghe;Chen Yi;Wen Dadong;Gao Ming;Peng Ping(School of Computational Science&Electronics,Hunan Institute of Engineering,Xiangtan 411104,China;School of Materials Science and Engineering,Hunan University,Changsha 410082,China;School of Mechanical Engineering,Hunan Institute of Engineering,Xiangtan 411104,China)

机构地区：[1]湖南工程学院计算科学与电子学院,湖南湘潭411104 [2]湖南大学材料科学与工程学院,湖南长沙410082 [3]湖南工程学院机械工程学院,湖南湘潭411104

出　　处：《稀有金属材料与工程》2022年第10期3689-3698,共10页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51871096,52071136)。

摘　　要：Ni_(3)Al的高温异常流变行为与1/2[110](111)超级部分位错的交滑移密切相关,本工作利用第一性原理计算探究Re在Ni_(3)Al晶体中的占位倾向及Re效应对Ni_(3)Al中位错形核与运动的影响。由Re占据Ni_(3)Al不同晶格点位所对应的点缺陷形成焓及能量因子E_(Re-Re)^(initial final),可知单个Re原子在Ni_(3)Al中优先占据Al位,2个Re原子优先占据Al-Al位。通过对Ni_(3)Al晶体[110](111)和[112](111)滑移系广义堆垛层错能的计算,发现Re原子占据Al位能促进1/2[110](111)超级部分位错的交滑移。2个Re原子垂直滑移方向排列比沿着滑移方向排列能有效阻碍位错形核与运动;2个Re原子排布在相邻(111)原子面上比排列在同一个(111)原子面上时会进一步促进螺位错的交滑移。分析缺陷R_(eA)和R_(eB)间的关联能△E^(Rea-Reb)对Ni_(3)Al晶体1/2[110](111)超级部分位错交滑移的影响,结果表明缺陷R_(eA)和R_(eB)间较弱的交互作用有利于改善高温时Ni_(3)Al的异常流变行为。Re原子优先占据Al位置提高Ni_(3)Al的屈服强度能够归功于Re_(Al)-Re_(Al)间的弱交互作用。The anomalous flow behavior of Ni_(3)Al at high temperature is closely related to the cross-slip of 1/2[110](111)super-partial dislocations.In this work,using a first-principles calculation,the impact of the occupation tendency of Re in Ni_(3)Al crystal and Re-effect on the nucleation and movement of dislocations in Ni_(3)Al was investigated.The analysis of energy factors initial final Re-Re E_(Re-Re)associated with the formation enthalpy of point defects reveals Re prefers to occupy Al sites,and the Re-Re pair prefers to occupy Al-Al sites inγ′-Ni_(3)Al phase.By calculating the generalized stacking fault energies for[110](111)and[112](111)systems in Ni_(3)Al,it is found that the Re atoms occupying Al sites can promote the 1/2[110](111)cross-slip of screw dislocations.A longitudinal arrangement of Re_(A) and Re_(B) defects should be able to effectively impede the nucleation and movement of dislocations compared with their horizontal layou t.Two Re atoms arranged on adjacent(111)atomic planes will further promote the cross-slip of screw dislocations than when they are arranged on the same(111)atomic plane.As their interaction is characterized and assessed by a correlation energy function ReA+ReBDE(d)between Re_(A) and Re_(B) point defects,a weak correlation is demonstrated to be favorable for the improvement of the anomalous flow of Ni_(3)Al at high temperature.The preferential occupation of Al sites by Re atoms for the improvement of yield strength of Ni_(3)Al can be attributed to a weak repulsive interaction between Re_(Al) and Re_(Al) defects.

关 键 词：Ni_(3)Al 广义堆垛层错能 交滑移 关联能 

分 类 号：TG146.15[一般工业技术—材料科学与工程]