Dislocation self-interaction in TiAl:Evolution of super-dislocation dipoles revealed by atomistic simulations  

作　　者：Z.Zhen H.Wang C.Y.Teng C.G.Bai D.S.Xu R.Yang 

机构地区：[1]Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China.Shenyang 110016,China [3]School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China [4]Laboratory of Fundamental Research,AVIC China Aero-Polytechnology Establishment,Beijing 100028.China

出　　处：《Journal of Materials Science & Technology》2021年第10期138-147,共10页材料科学技术（英文版）

基　　金：the National Key Research and Development Program of China(No.2016YFB0701304 and 2017YFB0306201);the Natural Science Foundation of China(Nos.51671195 and 91960202);the Frontier and Key Projects of the Chinese Academy of Sciences(Nos.QYZDJ-SSW-JSC031-01 and XXH13506-304);the Natural Science Foundation of Liaoning(No.20180510032);the Aeronautical Science Foundation of China(No.20160292002);the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDC01000000);The Project is sponsored by the“Liaoning BaiQianWan”Talents Program。

摘　　要：As one of the fundamental outcomes of dislocation self-interaction,dislocation dipoles have an important influence on the plastic deformation of materials,especially on fatigue and creep.In this work,superdislocation dipoles inγ-TiAl andα_(2)-Ti_(3)Al were systematically investigated by atomistic simulations,with a variety of dipole heights,orientations and annealing tempe ratures.The results indicate that non-screw super-dipoles transform into locally stable dipolar or reconstructed cores at low temperature,while into isolated or interconnected point defect clusters and stacking fault tetrahedra at high temperature via short-range diffu sion.Non-screw super-dipoles inγ-TiAl andα_(2)-Ti_(3)Al exhibit similar features as fcc and hcp metals,respectively.Generally,over long-term annealing where diffusion is significant,60°superdipoles inγ-TiAl are stable,whereas the stability of super-dipoles inα2-Ti3 Al increases with dipole height and orientation angle.The influence on mechanical properties can be well evaluated by integrating these results into mesoscale or constitutive models.

关 键 词：TIAL DISLOCATION DIPOLE Mechanical property Atomistic simulation 

分 类 号：TG146.23[一般工业技术—材料科学与工程]