The Influence of Loading Directions on the Failure of the Bicrystal in α-Ti with Grain-boundary Penetrating Dislocations
Some fatigue fracture of α and near α titanium alloys is believed to originate from the slip transfer from soft to hard grains under cyclic loading. Based on experimental observations,a model bicrystal is constructed with: 1) a soft-and a hard-oriented grain,connected by a prismatic-prismatic grain boundary; 2) dislocations gliding on the prismatic planes in the soft grain and penetrating into the hard. Molecular dynamics simulations are then carried out to investigate the interaction between the dislocations and the grain boundary,as well as the plastic deformation processes afterwards, in various loading directions. It is found that the loading direction has a pivotal influence on the resulted dislocations after the initial dislocations are absorbed by the grain boundary, since it determines the resolved shear stress on the slip plane of the transferred dislocations in the hard grain. As the direction changes, the hard grain exhibits various types of plastic deformation, including dislocation nucleation and cracking. Failures due to crack initiation in the hard grains and on the grain boundary are observed.
Dislocation grain boundary molecular dynamics dwell fatigue orientation
H. Wang D. S. Xu R. Yang D. Rugg A. J. Huang
Institute of Metal Research ,CAS,Shenyang 110016,CHINA Rolls-Royce pic ,Derby DE24 8BJ ,UK
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1219-1222
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）