Effect of Ni4Ti3 precipitation on martensitic transformation in Ti-Ni
Effect of Ni4Ti3 precipitation on martensitic transformation in Ti-Ni
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DOI：
10.1016/j.actamat.2010.08.033
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发表时间：
2010-12-01
期刊：
影响因子：
9.4
通讯作者：
Wang, Y.
中科院分区：
文献类型：
--
作者：
Zhou, N.;Shen, C.;Wang, Y.
Ni4Ti3的析出是决定Ni-Ti形状记忆合金马氏体转变路径和温度的关键因素。本研究采用相场法定量测定了Ni4Ti3共相干析出物的平衡形状及其周围的浓度和应力场。采用晶格参数、弹性常数、沉淀-基体取向关系和热力学数据库的最新实验数据作为模型输入。通过成核马氏体颗粒与现有组织的相互作用能，分析了浓度和应力场对马氏体相变的影响。结果表明，在B19′相形成之前，r相的形成可以归因于直接的弹性相互作用和应力诱导的Ni4Ti3析出物附近浓度的空间变化。r相的优先形核位置靠近透镜状Ni4Ti3析出相的宽边，在那里，向习惯面法向的张力最高，Ni浓度最低。(C) 2010材料学报Elsevier Ltd.出版。版权所有。
Precipitation of Ni4Ti3 plays a critical role in determining the martensitic transformation path and temperature in Ni-Ti shape memory alloys. In this study, the equilibrium shape of a coherent Ni4Ti3 precipitate and the concentration and stress fields around it are determined quantitatively using the phase field method. Most recent experimental data on lattice parameters, elastic constants, precipitate-matrix orientation relationship and thermodynamic database are used as model inputs. The effects of the concentration and stress fields on subsequent martensitic transformations are analyzed through interaction energy between a nucleating martensitic particle and the existing microstructure. Results indicate that R-phase formation prior to B19' phase could be attributed to both direct elastic interaction and stress-induced spatial variation in concentration near Ni4Ti3 precipitates. The preferred nucleation sites for the R-phase are close to the broad side of the lenticular-shaped Ni4Ti3 precipitates, where tension normal to the habit plane is highest, and Ni concentration is lowest. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.