Internal pressure as a key thermodynamic factor to obtain high-temperature superelasticity of shape memory alloys
Internal pressure as a key thermodynamic factor to obtain high-temperature superelasticity of shape memory alloys
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DOI：
10.1016/j.matlet.2017.09.034
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发表时间：
2018-01-01
影响因子：
3
通讯作者：
Maier, Hans J.
中科院分区：
文献类型：
--
作者：
Gerstein, Gregory;L'vov, Victor A.;Maier, Hans J.
基于铁弹性相变理论计算了说明形状记忆合金 (SMA) 超弹性行为的应力-应变环。该理论的预测表明，由于加热时 SMA 的膨胀，应力-应变依赖性可能会发生剧烈变化。具体而言，计算时考虑了表现出高温超弹性的Co-Ni-Ga合金的特性。研究表明，SMA 中小颗粒和晶体缺陷的出现或化学顺序的变化可能导致晶格膨胀，从而导致 (i) SMA 超弹性行为的温度范围扩大到高温； (ii) 高温下超弹性应变增加； (iii) 达到超弹性应变平台所需的应力增加，以及 (iv) 应力诱导马氏体转变的滞后范围扩大。理论结果与 Co-Ni-Ga 合金获得的实验数据定性一致。 (C) 2017 Elsevier B.V. 保留所有权利。
Stress-strain loops illustrating the superelastic behaviour of shape memory alloys (SMAs) were computed based on the theory of ferroelastic phase transitions. The predictions of the theory demonstrate the possibility of drastic changes in the stress-strain dependences due to the expansion of the SMA upon heating. Specifically, the computations were carried out taking into account the characteristics of Co-Ni-Ga alloys, which exhibit a high-temperature superelasticity. It is shown that the expansion of crystal lattice, which can be caused by the appearance of small particles and crystal defects, or change of chemical order in SMA, can induce (i) an extension of the temperature range of superelastic behaviour of SMA to high temperatures; (ii) an increase of the superelastic strain at elevated temperatures; (iii) an increase of the stress needed to reach the superelastic strain plateau and (iv) a widening of the hysteresis of stress-induced martensitic transformation. Theoretical results are in a qualitative agreement with experimental data obtained for Co-Ni-Ga alloys. (C) 2017 Elsevier B.V. All rights reserved.