Post-fire mechanical behavior of iron-based shape memory alloy used for structural damping

• Published in: Journal of constructional steel research Vol. 221; p. 108920
• Main Authors: Dai, Shuyang, Li, Chunbin, Gu, Yueyue, Fang, Cheng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2024
• Subjects: Cooling; iron-based shape memory alloy; Low cycle fatigue (LCF); Multi-hazard; Post-fire seismic resistance; Multi-hazard; iron-based shape memory alloy; Cooling; Post-fire seismic resistance; Low cycle fatigue (LCF)
• ISSN: 0143-974X
• DOI: 10.1016/j.jcsr.2024.108920

This study sheds light on the post-fire mechanical behavior of Fe-SMA by conducting a series of tests at material level, with a particular focus on the low-cycle fatigue (LCF) performance. Three temperatures (500 °C, 750 °C, 1000 °C) and three cooling methods (air cooling, water spray quenching, water quenching) are considered to simulate different fire-cooling scenarios. After the heating-cooling cycle, 10 monotonic tensile specimens and 20 LCF specimens are tested. Essential material parameters for Manson-Coffin model and combined hardening model are also calibrated based on the experimental data. The failure mechanism and possible factors affecting the post-fire LCF performance of Fe-SMA are further explored by scanning electron microscope (SEM), metallographic observation (MO), electron backscattered diffraction (EBSD) and X-ray diffraction (XRD) analysis. Results show that Fe-SMA could exhibit even better LCF resistance after undergoing the considered fire-cooling procedure, especially those heated up to 750 °C and 1000 °C. Even under rapid cooling, no signs of brittle fracture are observed, which is superior to traditional structural steels. Different heating temperatures and cooling methods affect the grain sizes and microstructure of Fe-SMA, leading to variations in its post-fire LCF behavior.
•Post-fire monotonic tensile and low-cycle fatigue performances of Fe-SMA were tested.•Three heating temperatures (500 °C, 750 °C, 1000 °C) were considered.•Three cooling methods (air/spray/water cooling) were used.•Effects of fire-cooling processes on microstructure of Fe-SMA were analyzed.•Numerical simulation was conducted to calibrate essential material parameters.