DFT-supported phase-field study on the effect of mechanically driven fluxes in Ni4Ti3 precipitation
DFT-supported phase-field study on the effect of mechanically driven fluxes in Ni4Ti3 precipitation
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DOI：
10.1088/0965-0393/22/3/034003
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发表时间：
2014-04-01
影响因子：
1.8
通讯作者：
Steinbach, Ingo
中科院分区：
文献类型：
--
作者：
Kamachali, Reza Darvishi;Borukhovich, Efim;Steinbach, Ingo
Ni4Ti3 沉淀的形成对 NiTi 合金的形状记忆性能有很大影响。在这项工作中，使用相场建模和密度泛函理论 (DFT) 计算研究了这种沉淀物的生长。利用第一性原理计算，获得了 B2 相的成分依赖性稳定性和弹性性能。与成分相关的弹性常数被纳入我们的相场模型中，以研究沉淀物周围的应力场和浓度场之间的相互作用。该模型引入了由于机械松弛引起的扩散源，机械松弛伴随着 B2 相的局部软化/硬化。根据之前的实验和模拟研究对结果进行了讨论。
Formation of the Ni4Ti3 precipitate has a strong effect on the shape memory properties of NiTi alloys. In this work, growth of this precipitate is studied using phase-field modelling and density functional theory (DFT) calculations. Using first-principles calculations, the composition-dependent stability and elastic properties of the B2 phase are obtained. Composition-dependent elastic constants are incorporated into our phase-field model to investigate the interplay between stress and concentration fields around the precipitate. The model introduces a source of diffusion due to mechanical relaxation which is accompanied by local softening/hardening of the B2 phase. The results are discussed in light of previous experimental and simulation studies.