Microstructure and mechanical properties of an austenite NiTi shape memory alloy treated with laser induced shock

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:578

Article

Wang, Xi¹  Xia, Weiguang¹  Wu, Xianqian¹  Wei, Yanpeng¹  Huang, Chenguang¹ 

[1] Chinese Acad Sci, Inst Mech, Key Lab Mech Fluid Solid Coupling Syst, Beijing 100190, Peoples R China

关键词: Laser shock peening;    Shape memory alloy;    Plastic deformation;    Amorphization;    Superelasticity;   

DOI  :  10.1016/j.msea.2013.04.058

来源: Elsevier

【 摘 要 】

In this study, microstructure and mechanical properties of an austenite NiTi alloy treated with laser shock peening (LSP) was investigated. It was found that the thickness of shock affected layer is about 250-300 mu m. The surface hardness of the specimen is increased by approximately 10% after LSP. Laser induced shock introduces slightly residual compressive stress in the peened specimen. The superleastic stress-strain curves of the fully LSP processed NiTi material show no change in phase transition stress, about 100 MPa decrease in martensite yield stress, and a loss of maximum transition strain about 12% after LSP. The ultrahigh-strain-rate plastic deformation by LSP results in dislocation substructure and amorphization underneath the surface which are responsible for the hardness increase and superelastic strain loss. (C) 2013 Elsevier B.V. All rights reserved.

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