期刊
INTERMETALLICS
卷 52, 期 -, 页码 20-31出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.intermet.2014.03.009
关键词
Nickel aluminides based on Ni3Al; Ternary alloy systems; Defects: dislocation geometry and arrangement; Defects: planar faults; Ab-initio calculations
资金
- National Science Foundation [CMMI 13-33884]
- Directorate For Engineering
- Div Of Civil, Mechanical, & Manufact Inn [1333884] Funding Source: National Science Foundation
We report theoretical results on dislocation slip and twinning in Ni-3 (Al, Ti, Ta, Hf) compositions with L1(2) crystal structures utilizing first-principles simulations. The lattice parameters of Ni3Al, Ni3Al0.75Ta0,25, Ni3Al0.5Ta0.5, Ni3Ta, Ni3Ti and Ni3Al0.75Hf0.25 are calculated, and the crystal structures with lower structural energies are determined. We established the Generalized Stacking Fault Energy (GSFE) and Generalized Planar Fault Energy (GPFE), and calculated stacking fault energies APB (anti-phase boundary) and CSF (complex stacking fault) matched other calculations and experiments. Based on the extended Peierls-Nabarro model for slip and the proposed twin nucleation model, we predict slip and twinning stress and the results show a general agreement with available experimental data. The results show that in the studied intermetallic alloys, twinning stress is lower than slip stress; Ta and Hf ternary addition are substantial to increase flow stress in Ni3Al. The models proposed in the paper provide quantitative understanding and guidelines for selecting optimal precipitate chemistry and composition to obtain higher mechanical strength in Shape Memory Alloys. (C) 2014 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据