TY - JOUR

T1 - Stress recovery behavior of an Fe-Mn-Si shape memory alloy

AU - Gu, Xiang Lin

AU - Chen, Zhen Yu

AU - Yu, Qian Qian

AU - Ghafoori, Elyas

N1 - Funding Information: This study was supported by the Shanghai Science and Technology Committee Rising-Star Program (19QC1400400), China, and National Natural Science Foundation of China (Project No. 51878485, 51938013). We also thank re-fer AG in Switzerland for providing Fe-SMA materials. Publisher Copyright: © 2021 Elsevier Ltd

PY - 2021/9/15

Y1 - 2021/9/15

N2 - 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.

AB - 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.

KW - High activation temperatures

KW - Iron-based SMA

KW - Prestraining

KW - Re-activations

KW - Recovery stress

UR - http://www.scopus.com/inward/record.url?scp=85108319618&partnerID=8YFLogxK

U2 - 10.1016/j.engstruct.2021.112710

DO - 10.1016/j.engstruct.2021.112710

M3 - Article

AN - SCOPUS:85108319618

VL - 243

JO - Engineering structures

JF - Engineering structures

SN - 0141-0296

M1 - 112710

ER -