Article
Materials Science, Multidisciplinary
Toni Sprigode, Andreas Gester, Guntram Wagner, Thomas Mader, Bjorn Senf, Welf-Guntram Drossel
Summary: In this study, NiTiCu shape memory alloy wires were joined with silver-coated copper ferrules via ultrasonic spot welding, with tensile tests showing that the ultimate tensile strengths of the joints reached almost 100% of the base material. The ultrasonic welding process did not affect the transition temperatures of the shape memory alloy.
Article
Materials Science, Multidisciplinary
Dong Sun, Shuyong Jiang, Xiaodong Xing, Bingyao Yan, Junbo Yu, Yanqiu Zhang
Summary: Local canning compression is applied to equiatomic NiTi shape memory alloy with complete B19' martensite, leading to different grain sizes after annealing at 300, 450 and 600 degrees C. The highest elastic limit is achieved under annealing at 300 degrees C, while the highest yield stress and good plasticity are observed under annealing at 450 degrees C. Annealing at 600 degrees C results in a relatively low yield stress but still higher than the as-received NiTi SMA, with high plasticity as well.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Nanoscience & Nanotechnology
Xiebin Wang, Xiayang Yao, Dominique Schryvers, Bert Verlinden, Guilong Wang, Guoqun Zhao, Jan Van Humbeeck, Sergey Kustov
Summary: This work reports anomalous phenomena in superelastic cycling of NiTi shape memory alloys near the temperature border, including higher critical stress, plateau stress changes, and transition from good superelasticity to fully irreversible strain, which may be caused by defects generated during the first superelastic cycle near the border impeding stress-induced martensitic transformations.
SCRIPTA MATERIALIA
(2021)
Article
Instruments & Instrumentation
Tiegang Chen, Jun Jiang, Qiang Zhang, Hanlin Wang, Xiaoyong Zhang
Summary: A novel variable camber guide vane actuated with a shape memory alloy plate is proposed in this paper for active real-time control, with experiments and numerical models showing successful active control of deflection angles from 0 to 8.2 degrees. This work is expected to expand the applications of SMAs in variable guide vanes.
SMART MATERIALS AND STRUCTURES
(2021)
Article
Mechanics
Zhixiang Rao, Jiaming Leng, Zehong Yan, Limeng Tan, Xiaojun Yan
Summary: This paper proposes a three-dimensional phenomenological constitutive model for shape memory alloys (SMA) that considers various thermomechanical mechanisms, including transformation-induced plasticity, two-way shape memory effect, plastic yield, and tension-compression asymmetry. It introduces a new method to address the variation of transformation strain with stress levels and a transformation hardening function for accurate prediction of the transformation process. The proposed model is validated through experiments and simulations, demonstrating its effectiveness in capturing the thermomechanical response of SMA structures.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Chemistry, Physical
Victor Komarov, Roman Karelin, Irina Khmelevskaya, Vladimir Cherkasov, Vladimir Yusupov, Grzegorz Korpala, Rudolf Kawalla, Ulrich Prahl, Sergey Prokoshkin
Summary: The effect of a promising thermomechanical treatment method on the formation of nanocrystalline structure and property improvement in bulk NiTi shape memory alloy samples was investigated. Bi-axial severe plastic deformation was conducted on Ti-50.7at.%Ni alloy using the MaxStrain module at temperatures of 350 and 330 degrees C with accumulated true strains of e = 6.6-9.5. The resulting nanocrystalline structure exhibited grain/subgrain sizes below 80 nm. The formation of this nanocrystalline structure led to a total recoverable strain of 12%, surpassing previous records for bulk nickel-enriched NiTi samples.
Article
Engineering, Civil
Fedor S. Belyaev, Margarita E. Evard, Aleksandr E. Volkov
Summary: A model of plastic deformation in shape memory alloys is developed, focusing on dislocation slip at the microlevel and the interaction with martensitic transformations. The model accurately describes the effect of plastic strain on the shape memory effect, and can also capture the two-way shape memory effect. The proposed model considers deformation defects densities for a more comprehensive understanding.
SMART STRUCTURES AND SYSTEMS
(2022)
Article
Nanoscience & Nanotechnology
R. Karelin, V. Komarov, I. Khmelevskaya, V. Andreev, V. Yasupov, S. Prokoshkin
Summary: The effect of low-temperature equal-channel angular pressing (ECAP) on the structure formation and mechanical and functional properties of a near-equiatomic titanium nickelide (TiNi) shape memory alloy in shells is studied. ECAP with channel intersection angles of 120° and 110° is conducted at temperatures ranging from 20°C to 330°C after 1 pass. Pure iron is determined as the optimum material for shells as it remains undamaged after ECAP at room temperature. The optimal deformation temperature for ECAP in a shell is found to be 200°C. Deformation at low temperatures leads to the premature destruction of TiNi samples. ECAP of the TiNi core in a shell at 200°C after 1 pass results in the formation of an elongated, banded martensite structure with a bandwidth of approximately 100 nm. The best combination of mechanical and functional properties is achieved after ECAP of a TiNi sample with a diameter of 12 mm in core-shell mode at 200°C, followed by post-deformation annealing at 400°C for 1 hour.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Dong Sun, Shuyong Jiang, Yanqiu Zhang, Bingyao Yan, Junbo Yu
Summary: Equiatomic NiTi shape memory alloy subjected to severe plastic deformation through local canning compression exhibits different twin structures after solution treatment and subsequent annealing, which significantly influence the phase transformation behavior of the alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Y. Ren, A. Shuitcev, D. V. Gunderov, L. Li, R. Z. Valiev, Y. X. Tong
Summary: Ni50.3Ti29.7Hf20 alloy underwent high-pressure torsion process at room temperature and 300°C, resulting in different structures: a mixture of amorphous phase and nanocrystalline debris at room temperature, and oriented martensitic plates and nanocrystalline structure with narrow amorphous bands at 300°C.
Article
Nanoscience & Nanotechnology
Shan Liu, Jie Zhu, Xudong Lin, Xiebin Wang, Guangchun Wang
Summary: By combining repeated stretch-bending deformation, electric pulse, and age-hardening, the functional stability of Ti-50.8 at.% Ni alloy was improved through refining grain size, introducing dislocations, and multi-stage martensitic transformation behavior. The homogeneous distribution of nanoscaled Ni4Ti3 precipitates also contributed to the excellent functional stability achieved.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Qin Zou, Xihui Ye, Yanguo Li, Wenqi Luo, Xiaowei Yang, Yongan Luo
Summary: The effects of Ti on the microstructure and properties of the Fe-20Mn-6Si-8Cr-5Ni shape memory alloy prepared by powder metallurgy were investigated. The results showed that trace Ti elements could improve the alloy's mechanical properties and shape memory performance, but an excess of Ti had adverse effects. The Ti content also played a role in the corrosion resistance of the alloy.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Multidisciplinary Sciences
Cengiz Tatar, Azad Ibrahim Haji, Ibrahim Nazem Qader
Summary: Characterization of a high copper content NiTiCu shape memory alloy was conducted through arc-melting and aging at different temperatures to investigate its mechanical, thermal, and microstructural properties. The alloy exhibited a single phase transformation and a decrease in activation energy with increasing aging temperature. Additionally, the heat-treated alloy showed larger crystallite sizes and different hardness compared to equiatomic NiTi alloys and an as-casted NiTiCu alloy.
IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY TRANSACTION A-SCIENCE
(2021)
Article
Engineering, Industrial
Yanqiu Zhang, Shuyong Jiang, Ming Tang, Bingyao Yan, Junbo Yu, Chengzhi Zhao
Summary: The study investigated the influence of post-deformation annealing on the microstructure of NiTiFe shape memory alloy processed by local canning compression, showing differences in composition compared to binary NiTi SMA. The main reason for these differences is attributed to the greater deformation temperature relative to the martensite start temperature of NiTiFe SMA compared to binary NiTi SMA.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2021)
Article
Chemistry, Physical
Xin Liu, Heng Li, Yanhong Zhang, Zhiwei Yang, Qingfei Gu, Xinhao Wang, Yifan Zhang, Jingchao Yang
Summary: NiTiFe alloys are widely used in the aerospace industry due to their excellent shape memory properties. However, the deformation behavior and shape memory mechanism of NiTiFe alloys at cryogenic temperatures are still unclear. In this study, we investigated the deformation behavior and shape memory mechanism of Ni47Ti50Fe3 alloy at temperatures ranging from -190℃ to 150℃. The findings revealed that the deformation behavior of NiTiFe alloy can be classified into four classes corresponding to different deformation mechanisms. The best shape memory effect was observed at deformation temperatures near Mf (-180℃).
Article
Materials Science, Multidisciplinary
A. Ojha, S. Alkan, L. Patriarca, H. Sehitoglu, Y. Chumlyakov
PHILOSOPHICAL MAGAZINE
(2015)
Article
Engineering, Mechanical
Sertan Alkan, Piyas Chowdhury, Huseyin Sehitoglu, Richard G. Rateick, Hans J. Maier
INTERNATIONAL JOURNAL OF FATIGUE
(2016)
Article
Engineering, Mechanical
S. Alkan, H. Sehitoglu
INTERNATIONAL JOURNAL OF FATIGUE
(2017)
Article
Engineering, Mechanical
S. Alkan, H. Sehitoglu
INTERNATIONAL JOURNAL OF PLASTICITY
(2017)
Article
Materials Science, Multidisciplinary
H. Sehitoglu, Y. Wu, S. Alkan, E. Ertekin
PHILOSOPHICAL MAGAZINE LETTERS
(2017)
Article
Materials Science, Multidisciplinary
S. Alkan, Y. Wu, A. Ojha, H. Sehitoglu
Article
Materials Science, Multidisciplinary
S. Alkan, A. Ojha, H. Sehitoglu
Article
Engineering, Mechanical
Y. Wu, M. Bonisch, S. Alkan, W. Abuzaid, H. Sehitoglu
INTERNATIONAL JOURNAL OF PLASTICITY
(2018)
Article
Materials Science, Multidisciplinary
S. Alkan, A. Ojha, H. Sehitoglu
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2018)
Article
Materials Science, Multidisciplinary
S. Alkan, H. Sehitoglu
Article
Materials Science, Multidisciplinary
W. Abuzaid, Y. Wu, R. Sidharth, F. Brenne, S. Alkan, M. Vollmer, P. Krooss, T. Niendorf, H. Sehitoglu
SHAPE MEMORY AND SUPERELASTICITY
(2019)
Article
Engineering, Mechanical
S. Alkan, Y. Wu, H. Sehitoglu
EXTREME MECHANICS LETTERS
(2017)
Article
Materials Science, Multidisciplinary
S. Alkan, H. Sehitoglu
Review
Materials Science, Multidisciplinary
H. Sehitoglu, S. Alkan
SHAPE MEMORY AND SUPERELASTICITY
(2018)
Article
Materials Science, Multidisciplinary
Y. Liu, K. Zweiacker, C. Liu, J. T. McKeown, J. M. K. Wiezorek
Summary: The evolution of rapid solidification microstructure and solidification interface velocity of hypereutectic Al-20at.%Cu alloy after laser melting has been studied experimentally. It was found that the formation of microstructure was dominated by eutectic, alpha-cell, and banded morphology grains, and the growth modes changed with increasing interface velocity.
Article
Materials Science, Multidisciplinary
Bharat Gwalani, Julian Escobar, Miao Song, Jonova Thomas, Joshua Silverstein, Andrew Chihpin Chuang, Dileep Singh, Michael P. Brady, Yukinori Yamamoto, Thomas R. Watkins, Arun Devaraj
Summary: Castable alumina forming austenitic alloys exhibit superior creep life and oxidation resistance at high temperatures. This study reveals the mechanism behind the enhanced creep performance of these alloys by suppressing primary carbide formation and offers a promising alloy design strategy for high-temperature applications.
Article
Materials Science, Multidisciplinary
Jian Song, Qi Zhang, Songsong Yao, Kunming Yang, Houyu Ma, Jiamiao Ni, Boan Zhong, Yue Liu, Jian Wang, Tongxiang Fan
Summary: Recent studies have shown that achieving an atomically flat surface for metals can greatly improve their oxidation resistance and enhance their electronic-optical applications. Researchers have explored the use of graphene as a covering layer to achieve atomically flat surfaces. They found that high-temperature deposited graphene on copper surfaces formed mono-atomic steps, while annealed copper and transferred graphene on copper interfaces formed multi-atomic steps.
Article
Materials Science, Multidisciplinary
Jennifer A. Glerum, Jon-Erik Mogonye, David C. Dunand
Summary: Elemental powders of Al, Ti, Sc, and Zr are blended and processed via laser powder-bed fusion to create binary and ternary alloys. The microstructural analysis and mechanical testing show that the addition of Ti results in the formation of primary precipitates, while the addition of Sc and Zr leads to the formation of fine grain bands. The Al-0.25Ti-0.25Zr alloy exhibits comparable strain rates to Al-0.5Zr at low stresses, but significantly higher strain rates at higher stresses during compressive creep testing. Finite element modeling suggests that the connectivity of coarse and fine grain regions is a critical factor affecting the creep resistance of the alloys.
Article
Materials Science, Multidisciplinary
P. Jannotti, B. C. Hornbuckle, J. T. Lloyd, N. Lorenzo, M. Aniska, T. L. Luckenbaugh, A. J. Roberts, A. Giri, K. A. Darling
Summary: This work characterizes the thermo-mechanical behavior of bulk nanocrystalline Cu-Ta alloys under extreme conditions. The experiments reveal that the alloys exhibit unique mechanical properties, behaving differently from conventional nanocrystalline Cu. They do not undergo grain coarsening during extrusion and exhibit behavior similar to coarse-grained Cu.
Article
Materials Science, Multidisciplinary
Yiqing Wei, Jingwei Li, Daliang Zhang, Bin Zhang, Zizhen Zhou, Guang Han, Guoyu Wang, Carmelo Prestipino, Pierric Lemoine, Emmanuel Guilmeau, Xu Lu, Xiaoyuan Zhou
Summary: This study proposes a new strategy to modify microstructure by phase regulation, which can simultaneously enhance carrier mobility and reduce lattice thermal conductivity. The addition of Cu in layered SnSe2 induces a phase transition that leads to increased grain size and reduced stacking fault density, resulting in improved carrier mobility and lower lattice thermal conductivity.
Article
Materials Science, Multidisciplinary
Jia Chen, Zhengyu Zhang, Eitan Hershkovitz, Jonathan Poplawsky, Raja Shekar Bhupal Dandu, Chang-Yu Hung, Wenbo Wang, Yi Yao, Lin Li, Hongliang Xin, Honggyu Kim, Wenjun Cai
Summary: In this study, the structural origin of the pH-dependent repassivation mechanisms in multi-principal element alloys (MPEA) was investigated using surface characterization and computational simulations. It was found that selective oxidation in acidic to neutral solutions leads to enhanced nickel enrichment on the surface, resulting in reduced repassivation capability and corrosion resistance.
Article
Materials Science, Multidisciplinary
X. Y. Xu, C. P. Huang, H. Y. Wang, Y. Z. Li, M. X. Huang
Summary: The limited slip systems of magnesium (Mg) and its alloys hinder their wide applications. By conducting tensile straining experiments, researchers discovered a rate-dependent transition in the dislocation mechanisms of Mg alloys. At high strain rates, glissile dislocations dominate, while easy-glide dislocations dominate at low strain rates. Abundant glissile dislocations do not necessarily improve ductility.
Article
Materials Science, Multidisciplinary
M. S. Szczerba, M. J. Szczerba
Summary: Inverse temperature dependences of the detwinning stress were observed in face-centered cubic deformation twins in Cu-8at.%Al alloy. The detwinning stress increased with temperature when the pi detwinning mode was involved, but decreased when the pi/3 mode was involved. The dual effect of temperature on the detwinning stress was due to the reduction of internal stresses pre-existing within the deformation twins. The complete reduction of internal stresses at about 530 degrees C led to the equivalence of the critical stresses of different detwinning modes and a decrease in the yield stress anisotropy of the twin/matrix structure.
Article
Materials Science, Multidisciplinary
Taowen Dong, Tingting Qin, Wei Zhang, Yaowen Zhang, Zhuoran Feng, Yuxiang Gao, Zhongyu Pan, Zixiang Xia, Yan Wang, Chunming Yang, Peng Wang, Weitao Zheng
Summary: The interaction between the electrode and the electric double layer (EDL) significantly influences the energy storage mechanism. By studying the popular alpha-Fe2O3 electrode and the EDL interaction, we find that the energy storage mechanism of the electrode can be controlled by modulating the EDL.
Article
Materials Science, Multidisciplinary
Matthew R. Barnett, Jun Wang, Sitarama R. Kada, Alban de Vaucorbeil, Andrew Stevenson, Marc Fivel, Peter A. Lynch
Summary: The elastic-plastic transition in magnesium alloy Mg-4.5Zn exhibits bursts of deformation, which are characterized by sudden changes in grain orientation. These bursts occur in a coordinated manner among nearby grains, with the highest burst rate observed at the onset of full plasticity. The most significant burst events are associated with twinning, supported by the observation of twinned structures using electron microscopy. The bursts are often preceded and followed by a stasis in peak movement, indicating a certain "birth size" for twins upon formation and subsequent growth at a later stage.
Article
Materials Science, Multidisciplinary
Vaidehi Menon, Sambit Das, Vikram Gavini, Liang Qi
Summary: Understanding solute segregation thermodynamics is crucial for investigating grain boundary properties. The spectral approach and thermodynamic integration methods can be used to predict solute segregation behavior at grain boundaries and compare with experimental observations, thus aiding in alloy design and performance control.
Article
Materials Science, Multidisciplinary
Feiyu Qin, Lei Hu, Yingcai Zhu, Yuki Sakai, Shogo Kawaguchi, Akihiko Machida, Tetsu Watanuki, Yue-Wen Fang, Jun Sun, Xiangdong Ding, Masaki Azuma
Summary: This study reports on the negative and zero thermal expansion properties of Cd2Re2O7 and Cd1.95Ni0.05Re2O7 materials, along with their ultra-low thermal conductivity. Through investigations of their structures and phonon calculations, the synergistic effect of local structure distortion and soft phonons is revealed as the key to achieving these distinctive properties.
Article
Materials Science, Multidisciplinary
Thomas Beerli, Christian C. Roth, Dirk Mohr
Summary: A novel testing system for miniature specimens is designed to characterize the plastic response of materials for which conventional full-size specimens cannot be extracted. The system has an automated operation process, which reduces the damage to specimens caused by manual handling and improves the stability of the test results. The experiments show that the miniature specimens extracted from stainless steel and aluminum have high reproducibility, and the results are consistent with those of conventional-sized specimens. A correction procedure is provided to consider the influence of surface roughness and heat-affected zone caused by wire EDM.
Article
Materials Science, Multidisciplinary
Rani Mary Joy, Paulius Pobedinskas, Nina Baule, Shengyuan Bai, Daen Jannis, Nicolas Gauquelin, Marie-Amandine Pinault-Thaury, Francois Jomard, Kamatchi Jothiramalingam Sankaran, Rozita Rouzbahani, Fernando Lloret, Derese Desta, Jan D'Haen, Johan Verbeeck, Michael Frank Becker, Ken Haenen
Summary: This study investigates the influence of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond thin films. The results provide insights into the mechanical properties and intrinsic stress sources of these films, and demonstrate the potential for producing high-quality nanocrystalline diamond films under certain conditions.