Anomalous stress-strain behavior of NiTi shape memory alloy close to the border of superelastic window

SCRIPTA MATERIALIA

卷:204

Article

Wang, Xiebin^1,2  Yao, Xiayang³  Schryvers, Dominique³  Verlinden, Bert⁴  Wang, Guilong¹  Zhao, Guoqun¹  Van Humbeeck, Jan⁴  Kustov, Sergey⁵ 

[1] Shandong Univ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Minist Educ, Jingshi Rd 17923, Jinan 250061, Peoples R China

[2] Suzhou Inst Shandong Univ, Ruoshui Rd 388, Suzhou 215123, Peoples R China

[3] Univ Antwerp, Electron Microscopy Mat Sci EMAT, Groenenborgerlaan 171, B-2020 Antwerp, Belgium

[4] Univ Leuven KU Leuven, Dept Mat Engn, Kasteelpk Arenberg 44 Bus 2450, B-3001 Heverlee, Belgium

[5] Univ Illes Balears, Dept Fis, Cra Valldemossa Km 7-5, E-07122 Palma De Mallorca, Spain

关键词: Shape memory alloy;    NiTi;    Plastic deformation;    Superelasticity;    Functional fatigue;   

DOI  :  10.1016/j.scriptamat.2021.114135

来源: Elsevier

【 摘 要 】

In this work, we report an anomalous phenomenon on superelastic cycling of NiTi shape memory alloys when deforming at the temperature close to the border of superelastic window. New unexpected effects are found-(i) critical stress for inducing martensite transformation during the second loading cycle is higher than that of the first cycle; ( ii ) the plateau stress of the second cycle decreases to the original level when the strain overcomes the limit of the first cycle; ( iii ) transition from good superelasticity in the first cycle to fully irreversible strain in the second. We propose that defects generated during the first superelastic cycle close to the border of superelastic window impede following stress-induced martensitic transformations, leading to the increase of critical stress beyond yield stress of the B2 matrix, and thus functional fatigue of NiTi alloys. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

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