Review
Materials Science, Multidisciplinary
Fuzhen Sun, Xinxin Feng, Haizhen Wang, Xinjian Cao, Xiao Liu, Yang Liu, Yan Li, Zhongli Liu, Xiaoyang Yi
Summary: Shape memory alloys are smart materials that have superior properties and are widely used in aerospace, naval, automobile, and biomedicine industries. Functionally graded shape memory alloys are created to achieve accurate controllability for progressive movement. This review paper discusses the classification, fabrications, microstructural features, and performances of functionally graded shape memory alloys. Creating various gradients in shape memory alloys can widen the transformation temperature intervals and transformation stress intervals, leading to excellent performances and wider application range.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Adelaide Nespoli, Enrico Bassani, Elena Villa, Francesca Passaretti
Summary: This torsional device utilizes shape memory alloy elements to function as a torque limiter, with pseudoelastic NiTi tapes working in series configuration. By adjusting the number of tapes, the torque output can be tuned from pulsating to continuous. The temperature-dependent response enabled by NiTi material provides a stable cyclic response for the device.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
A. Sibirev, S. Belyaev, N. Resnina
Summary: The study investigates the influence of counter-body stiffness on the recovery stress, recoverable strain, and work output during thermal cycling of NiTi cylindrical samples in the actuator regime. Results show a nonlinear relationship between stiffness values and shape memory effect/recovery stress, and a gradual decrease in recovery stress, work output values during thermal cycling.
SENSORS AND ACTUATORS A-PHYSICAL
(2021)
Article
Materials Science, Multidisciplinary
Won-Seok Ko, Jong Bae Jeon
Summary: This study investigates the orientation-dependent mechanical responses of nickel-titanium shape-memory alloys during nanoindentations, highlighting the importance of anisotropy in martensite formation. The results suggest that the orientation-dependency of indentation load-depth curves is primarily driven by the anisotropy in the preferred growth direction of the martensite phase and the amount of martensite phase formed beneath the indenter tip.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Engineering, Manufacturing
Ze Pu, Dong Du, Kaiming Wang, Guan Liu, Dongqi Zhang, Haoyu Zhang, Rui Xi, Xiebin Wang, Baohua Chang
Summary: In this study, NiTi shape memory alloys were successfully in-situ synthesized using dual-wire-feed electron beam additive manufacturing. The as-built NiTi alloys exhibited continuous coarse columnar grains and uniform composition distribution, and showed good static compressive property and shape memory response.
ADDITIVE MANUFACTURING
(2022)
Article
Physics, Applied
S. Liu, C. B. Ke, S. Cao, X. Ma, Y. F. Xu, X. P. Zhang
Summary: The stress-induced martensitic transformations and superelasticity behavior in the NiTi alloy are studied using molecular dynamics simulations. A proposed atomic tracing method is used to identify specific numbers of martensite variants. It is found that the twist grain boundary induces an increase in the martensite start temperature and brings about the acceleration of martensite nucleation and an earlier occurrence of stress plateau.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Won-Seok Ko, Won Seok Choi, Guanglong Xu, Pyuck-Pa Choi, Yuji Ikeda, Blazej Grabowski
Summary: The study used molecular dynamics simulations to understand the functional degradation of nano-scaled NiTi shape memory alloys containing amorphous regions. The influence of amorphous-like grain boundaries or surface regions on the mechanical response under cyclic compression was revealed. The degraded superelasticity under cyclic loading was attributed to accumulated plastic deformation and retained martensite from a synergetic contribution of amorphous and crystalline regions, with proposed methods for recovery and sustainable operation.
Article
Nanoscience & Nanotechnology
Sam Bakhtiari, Yingchao Li, Satyajit Sarkar, Hong Yang, Lishan Cui, Yinong Liu
Summary: This study investigated the effect of tensile deformation on the transformation behaviour of NiTi within the constrained environment of NiTi-Nb composites. The presence of a second phase within the NiTi matrix hinders the lattice distortion martensitic transformation, and after deformation, the NiTi-Nb microparticle composite exhibited the highest stabilisation effect.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
A. Sibirev, S. Belyaev, N. Resnina
Summary: The influence of fraction of the forward and reverse martensitic transformations on the variations in the recoverable strain, recovery stress, work output and irreversible strain was studied. The equiatomic NiTi alloy was subjected to thermal cycling under torque stress and pre-deformed by various strain. The results showed that thermal cycling at different strains caused changes in these characteristic parameters.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Materials Science, Multidisciplinary
Sara Fazeli, Mohammadreza Izadifar, Jorge S. Dolado, Ali Ramazani, Sayed Khatiboleslam Sadrnezhaad
Summary: This study investigates the impact of crystallographic orientation on the twinning/detwinning mechanisms in NiTi shape memory alloys through MD and DFT computational methods. The findings highlight the significant influence of crystallographic orientation on twinning and detwinning mechanisms, which ultimately affects the fracture toughness of the material.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Jiayi Liu, Yunlai Deng, Xiaobin Guo
Summary: This study investigates the effect of energy densities on the microstructure, phase transformation behavior, and shape memory effect of NiTi shape memory alloys (SMAs) fabricated by powder bed fusion (PBF). The results show that increasing energy density leads to larger grain size and different grain orientations. Aging treatment improves the stability of the shape memory effect and increases the recovery strain of the NiTi alloy.
MATERIALS CHARACTERIZATION
(2023)
Article
Nanoscience & Nanotechnology
Junyu Chen, Liping Lei, Gang Fang, Dongwei Wang
Summary: This study investigates the grain size dependence of the elastocaloric effect of NiTi and finds a suitable grain size that yields good cooling properties. The grain size has different effects on various refrigeration metrics, such as adiabatic temperature variation, isothermal entropy change, energy dissipation, cyclic stability, and working temperature span. The 30 nm grain size specimen demonstrates excellent comprehensive performance and repeatability, making it a promising elastocaloric refrigerant candidate.
MATERIALS TODAY NANO
(2023)
Article
Mechanics
William S. LePage, John A. Shaw, Samantha H. Daly
Summary: The study revealed that crystallographic texture significantly affects the fatigue performance of NiTi sheet, with strong orientation-dependent mechanisms of plasticity, transformation, and twinning on both functional and structural fatigue. Under stress-controlled cycling, tension along textures similar to that of the TD demonstrated better fatigue performance.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Zifan Wang, Jingwei Chen, Cyril Besnard, Lenka Kuncicka, Radim Kocich, Alexander M. Korsunsky
Summary: The study revealed that the hot swaging process led to changes in grain morphology and an increase in microstrain. The thermal expansion coefficients of martensite and austenite variants were weakly affected by texture, and the reorientation of martensite was weakly related to the initial microstructure and showed correlation with detwinning.
Article
Chemistry, Multidisciplinary
Douglas E. Nicholson, Santo A. Padula, Othmane Benafan, Jeffrey R. Bunn, E. Andrew Payzant, Ke An, Dayakar Penumadu, Raj Vaidyanathan
Summary: Thermoelastic deformation mechanisms in polycrystalline biomedical-grade superelastic NiTi are studied using in situ neutron diffraction during multiaxial loading and heating. The reversible R-phase variant microstructure is able to accommodate stress and strain mismatch in different loading conditions.
ADVANCED MATERIALS
(2021)
