Stress recovery behavior of an Fe-Mn-Si shape memory alloy

authored by

Xiang Lin Gu, Zhen Yu Chen, Qian Qian Yu, Elyas Ghafoori

Abstract

This study investigated the stress recovery behavior of an Fe-Mn-Si-Cr-Ni-VC shape memory alloy for prestressed strengthening, focusing on high-temperature activation of the alloy. The effects of different prestrain levels (1%, 2%, 4%, 6% and 8%), activation temperatures (100, 150, 200, 250, 300, 350, and 455 °C), and initial preloads (50, 100 and 150 MPa) on recovery stress were evaluated to propose an optimum activation strategy. In addition, mechanical properties of the Fe-SMA after activation, including the performance under a second high-temperature activation (up to 455 °C) and high-cycle fatigue (HCF) loadings (stress-controlled with a stress range of 57 MPa), were studied. According to the results, a prestrain level of 2% was found to be the optimum level when the activation temperature was below 200 °C. However, at higher activation temperatures, an increased prestrain resulted in an increase in the recovery stress. In this study, the specimens prestrained by 4 and 8% and activated by 350 °C led to a recovery stress of 421 and 445 MPa, respectively. According to the fatigue test results, the recovery stress decreased by 12 – 15% after two million load cycles, regardless of the activation temperature.

External Organisation(s)

Tongji University
Swiss Federal Laboratories for Material Science and Technology (EMPA)

Type

Article

Journal

Engineering structures

Volume

243

ISSN

0141-0296

Publication date

15.09.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Civil and Structural Engineering

Electronic version(s)

https://doi.org/10.1016/j.engstruct.2021.112710 (Access: Closed)