Hong Kinam, Ji Sangwon, Kim Dohyung, Bae Jinyoung
Department of Civil Engineering, Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju 28644, Republic of Korea.
Dongnam Regional Division, Korea Institute of Industrial Technology, Yangsan 50623, Republic of Korea.
Materials (Basel). 2024 Aug 30;17(17):4304. doi: 10.3390/ma17174304.
This paper presents the experimental results of a study evaluating the mechanical and fatigue performance of welded Fe-Mn-Si SMA. For the experimental study, welded and welded-and-heat-treated Fe-Mn-Si SMA specimens were fabricated, and fatigue tests were performed at various stress amplitudes. In addition, direct tensile tests and recovery stress tests were also performed to evaluate the material properties of Fe-Mn-Si SMAs. The elastic modulus, yield strength, and tensile strength of the welded specimens were reduced by 35.4%, 12.1%, and 8.6%, respectively, compared to the values of the non-welded specimens. On the other hand, the elastic modulus, yield strength, and tensile strength of the welded-and-heat-treated Fe-Mn-Si SMA specimens were increased by 18.6%, 4.9%, and 1.3%, respectively, compared to the values of the welded specimens. Both welded and welded-and-heat-treated Fe-Mn-Si SMAs failed at lower cycles than the conventional Fe-Mn-Si SMAs at the same stress amplitude. High-cycle fatigue failure, characterized by cycles exceeding 10, typically occurs at relatively low stress levels within the elastic region, whereas low-cycle fatigue failure, generally occurring within cycles below 10, involves high stress levels that encompass both elastic and plastic deformation. Regardless of the welding condition, the stress amplitude at which Fe-Mn-Si SMA transitions from high-cycle to low-cycle failure exceeded the yield strength.
本文介绍了一项评估焊接铁锰硅形状记忆合金力学和疲劳性能的研究的实验结果。在实验研究中，制备了焊接及焊接后热处理的铁锰硅形状记忆合金试样，并在不同应力幅值下进行了疲劳试验。此外，还进行了直接拉伸试验和回复应力试验，以评估铁锰硅形状记忆合金的材料性能。与未焊接试样的值相比，焊接试样的弹性模量、屈服强度和抗拉强度分别降低了35.4%、12.1%和8.6%。另一方面，与焊接试样的值相比，焊接后热处理的铁锰硅形状记忆合金试样的弹性模量、屈服强度和抗拉强度分别提高了18.6%、4.9%和1.3%。在相同应力幅值下，焊接及焊接后热处理的铁锰硅形状记忆合金的失效循环次数均低于传统铁锰硅形状记忆合金。高周疲劳失效的特征是循环次数超过10，通常发生在弹性区域内相对较低的应力水平，而低周疲劳失效一般发生在低于10的循环次数内，涉及包括弹性和塑性变形的高应力水平。无论焊接条件如何，铁锰硅形状记忆合金从高周失效转变为低周失效的应力幅值均超过屈服强度。
