Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

Abstract

As a promising candidate in the construction industry, iron-based shape memory alloy (Fe-SMA) has attracted lots of attention in the engineering and metallography communities because of its foreseeable benefits including corrosion resistance, shape recovery capability, excellent plastic deformability, and outstanding fatigue resistance. Pilot applications have proved the feasibility of Fe-SMA as a highly efficient functional material in the construction sector. This paper provides a review of recent developments in research and design practice related to Fe-SMA. The basic mechanical properties are presented and compared with conventional structural steel, and some necessary explanations are given on the metallographic transformation mechanism. Newly emerged applications, such as Fe-SMA-based prestressing/strengthening techniques and seismic-resistant components/devices, are discussed. It is believed that Fe-SMA offers a wide range of applications in the construction industry but there still remains problems to be addressed and areas to be further explored. Some research needs at material-level, component-level, and system-level are highlighted in this paper. With the systematic information provided, this paper not only benefits professionals and researchers who have been working in this area for a long time and wanting to gain an in-depth understanding of the state-of-the-art, but also helps enlighten a wider audience intending to get acquainted with this exciting topic.

NiTi shape memory alloy pipe couplers for ultra-high vacuum systems: development and implementation

“…This is a common drawback of other ternary NiTi-X alloy systems, such as NiTiFe [18,19], because the lower the unclamping temperature the more complex and time consuming the dismounting operations, leading to an increase of the radiation exposure of the technical personnel. More recently, ferrous (Fe)-based SMAs are also being considered as promising candidates for bulk industrial applications, as they are far less expensive than NiTi systems and exhibit a smaller thermal hysteresis with slightly lower memory strains and recovery stresses [28]. However, their functional degradation under cyclic thermo-mechanical loads and, above all, the intrinsically higher magnetic permeability limits their possible applications in particle accelerators vacuum systems.…”

Shape Memory Hybrid Composites

“…The properties of SMAs are mostly determined by their composition and heat treatments. The transformation temperatures of SMAs can be measured through many techniques such as differential scanning calorimetry, change in electrical resistivity with temperature, and dilatometry. ,,, Among all SMAs, the most commercially adopted are NiTi (NitiNOL, nickel titanium alloy named for its discovery at Naval Ordnance Laboratory), Cu-based, and Fe-based alloys. − SMAs with Cu and Fe as the base material are mostly adopted as a cost-effective replacement of NiTi because of their good shape memory properties, damping capability, and other properties that make them good functional materials. However, functional long-term use of these alloys is susceptible to stabilization of phase, energy hysteresis, and aging that may lead to brittleness and affect their service efficiency.…”

“…However, functional long-term use of these alloys is susceptible to stabilization of phase, energy hysteresis, and aging that may lead to brittleness and affect their service efficiency. On the other hand, for Fe-based alloys, the small strain recovery of these alloys limits their use in commercial applications. , Other groups of SMAs include Au–Cd alloys and Ni–Mn alloys. , …”

“…On the other hand, for Fe-based alloys, the small strain recovery of these alloys limits their use in commercial applications. 10,18 Other groups of SMAs include Au−Cd alloys and Ni−Mn alloys. 19,20 For high-temperature applications, HTSMAs, the transformation temperature is usually increased by addition of ternary alloys to NiTi.…”

Self-Centering Shape Memory Alloy-Viscoelastic Hybrid Braces for Seismic Resilience

“…In recent years, various improvement strategies have been proposed to address the issues associated with PT self-centering system mentioned above. For instance, shape memory alloys (SMAs) [ 47 , 48 , 49 , 50 ], especially superelastic NiTinol SMA, were introduced in self-centering systems [ 51 , 52 , 53 , 54 , 55 ] because of their good energy-dissipation ability, ductility, and fatigue resistance. Superelasticity refers to the capability to spontaneously recover when the load is removed from SMA elements after experiencing a large strain up to 8~10% [ 56 , 57 , 58 ].…”