| MD simulation of asymmetric nucleation and motion of < 011 superdislocations in TiAl | |
| D. S. Xu; H. Wang; R. Yang; A. K. Sachdev | |
| 2014 | |
| Source Publication | Chinese Science Bulletin
 |
| ISSN | 1001-6538 |
| Volume | 59Issue:15Pages:1725-1737 |
| Abstract | The nucleation and propagation of < 011] superdislocations in intermetallic TiAl were investigated using molecular dynamics simulations and static energetics calculation, as part of our systematic effort to understand the twining and dislocation behavior of alloys based on gamma-TiAl. It was found that compared to ordinary dislocations in disordered crystals, superdislocations in ordered TiAl lattice behave differently when sheared in the two opposite senses along [0 (1) over bar1] direction. This difference is due to the lower L1(0) lattice symmetry compared with the face-centered cubic (fcc) lattice that it based on, with different yield stress and strain, and dislocation core dissociation and motion. Superdislocations nucleated in the form of loops dissociated in a planar manner into four Shockley partials separated by three kinds of faults: superlattice intrinsic stacking fault (SISF), anti-phase domain boundary (APB) and complex stacking fault (CSF), with partial separations depending on the sense of shearing and dislocation character. During loop expansion, the dislocation core changes both in width and dissociation manner depending on the character of the segment in the loop. The core contains four partials close to edge orientation, gradually changing to three fold near 60 degrees, and finally into twofold dissociation around 30 degrees character. Superdislocations may have multiple critical resolved shear stresses (CRSS) for motion depending on dissociation and shearing sense even for the same slip system, with lower critical stress for the motion when SISF is in leading position. |
| description.department | [xu, dongsheng ; wang, hao ; yang, rui] chinese acad sci, inst met res, shenyang 110016, peoples r china. [sachdev, anil k.] gen motors res & dev ctr, warren, mi 48090 usa. ; xu, ds (reprint author), chinese acad sci, inst met res, shenyang 110016, peoples r china. ; dsxu@imr.ac.cn |
| Keyword | Tial Superdislocation Molecular Dynamics Simulation Intermetallic Compound Asymmetry Dissociation Deformation Stacking-fault Tetrahedra Dislocation Core Structures Single-crystals Yield-stress Temperature-dependence Atomistic Simulation Dipole Annihilation Deformation Al Dissociation |
| URL | 查看原文 |
| Language | 英语 |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/72944 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | D. S. Xu,H. Wang,R. Yang,et al. MD simulation of asymmetric nucleation and motion of < 011 superdislocations in TiAl[J]. Chinese Science Bulletin,2014,59(15):1725-1737. |
| APA | D. S. Xu,H. Wang,R. Yang,&A. K. Sachdev.(2014).MD simulation of asymmetric nucleation and motion of < 011 superdislocations in TiAl.Chinese Science Bulletin,59(15),1725-1737. |
| MLA | D. S. Xu,et al."MD simulation of asymmetric nucleation and motion of < 011 superdislocations in TiAl".Chinese Science Bulletin 59.15(2014):1725-1737. |
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