Achievements and Perspectives on Fe-Based Shape Memory Alloys for Rehabilitation of Reinforced Concrete Bridges: An Overview

Shape memory alloy (SMA), a type of smart material, is widely used in the design of reinforcement and repair, isolation, and shock absorption of building structures because of its outstanding characteristics, such as the shape memory effect (SME), superelasticity (SE), and high damping. It not only improves the bearing capacity, ductility, and mechanical properties of the structural components of buildings but can also effectively slow down the strong response of engineering structures under the effect of an earthquake. It plays a key role in energy dissipation and shock absorption as well as sustainable development. To promote the application of SMA in building structures, this paper summarizes the research on the use of SMA as a reinforcing material in building structures, including work related to SMA material characteristics and types, SMA-reinforced structural components, and SMA isolation devices. In addition, the shortcomings of SMA applications in building structures are analyzed, and valuable suggestions for future research methods are put forward. SMA has been applied to engineering practice in the form of embedded and external reinforcement, which shows that it has broad application prospects in future buildings.

Section: Sma Characteristics and Typesmentioning

confidence: 99%

The Utilization of Shape Memory Alloy as a Reinforcing Material in Building Structures: A Review

Xu,

Zhu,

Zhao

et al. 2024

“…This unique property has propelled extensive research into various SMA materials for diverse applications across sectors including aerospace, automotive, and biomedical industries [ 1 , 2 , 3 ]. Amongst the array of SMAs, Fe-Mn-Si-based alloys have attracted considerable interest due to their cost-effectiveness, excellent mechanical properties, and particularly, their potential for significant ductility and high damping capacity [ 4 , 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…Research into these conventional processes has focused extensively on understanding the thermomechanical behaviors and the effects of alloying elements on the martensitic transformation, which is fundamental to the shape memory effect. Studies have shown that the addition of elements like Cr and Ni can significantly influence phase transformation temperatures, improving mechanical properties and corrosion resistance [ 8 , 10 ]. Especially, adding V and C elements can improve pseudo-elasticity via decreasing the grain size and precipitation of VCs [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Laser-Directed Energy Deposition of Fe-Mn-Si-Based Shape Memory Alloy: Microstructure, Mechanical Properties, and Shape Memory Properties

Liu,

Yao,

Kang

et al. 2023

Fe-Mn-Si shape memory alloys (SMAs) have gained significant attention due to their unique characteristics. However, there remains a gap in the literature regarding the fabrication of these alloys using laser-directed energy deposition (LDED). This study fills this void, investigating the properties of Fe-Mn-Si SMAs produced by LDED. The shape memory performance of as-deposited Fe-Mn-Si SMAs was studied using a tensile method. Alloys underwent different degrees of deformation to assess their shape memory effect. Microstructural evaluations were conducted post-deformation to observe the internal structures of the alloys. The tensile tests revealed that shape recovery rates for deformation levels of 3%, 7%, 11%, and 15% were 68.1%, 44.2%, 31.7%, and 17.6%, respectively. Notably, the maximum recoverable deformation of the LDED-formed Fe-Mn-Si-based shape memory alloy reached 3.49%, surpassing the traditional deformation processing SMAs (<3%). The presence of a significant number of stacking faults was linked to the enhanced shape memory performance. The LDED technique demonstrates promising potential for the fabrication of Fe-Mn-Si SMAs, producing alloys with enhanced shape memory performance compared to traditionally processed SMAs. The study’s findings offer new insights and broaden the applicability of LDED in the field of SMAs.

“…Discovered in 1982 by Sato et al [6][7][8] in a seminal series of papers on Fe-Mn-Si single crystals, and later by Murakami et al [9] in polycrystals, the Fe-Mn-Si-based family evolved towards Fe-Mn-Si-Cr-Ni, to improve the corrosion resistance [10][11][12]. Because of the indicated properties, this family of SMA is becoming extremely suitable for numerous applications, particularly within the field of civil engineering [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. This material exhibits a martensitic transformation from an FCC γ austenite to an HCP ε martensite, which occurs by the motion of a/6<112> Shockley partial dislocations on every two (111) close-packed planes of the FCC structure, according to the model of Olson and Cohen [29].…”

Section: Introductionmentioning

confidence: 99%

Additive Manufacturing of Fe-Mn-Si-Based Shape Memory Alloys: State of the Art, Challenges and Opportunities

Del-Río,

Nó,

Gómez

et al. 2023

Additive manufacturing (AM) constitutes the new paradigm in materials processing and its use on metals and alloys opens new unforeseen possibilities, but is facing several challenges regarding the design of the microstructure, which is particularly awkward in the case of functional materials, like shape memory alloys (SMA), as they require a robust microstructure to withstand the constraints appearing during their shape change. In the present work, the attention is focused on the AM of the important Fe-Mn-Si-based SMA family, which is attracting a great technological interest in many industrial sectors. Initially, an overview on the design concepts of this SMA family is offered, with special emphasis to the problems arising during AM. Then, such concepts are considered in order to experimentally develop the AM production of the Fe-20Mn-6Si-9Cr-5Ni (wt%) SMA through laser powder bed fusion (LPBF). The complete methodology is approached, from the gas atomization of powders to the LPBF production and the final thermal treatments to functionalize the SMA. The microstructure is characterized by scanning and transmission electron microscopy after each step of the processing route. The reversibility of the ε martensitic transformation and its evolution on cycling are studied by internal friction and electron microscopy. An outstanding 14% of fully reversible thermal transformation of ε martensite is obtained. The present results show that, in spite of the still remaining challenges, AM by LPBF offers a good approach to produce this family of Fe-Mn-Si-based SMA, opening new opportunities for its applications.