Article
Nanoscience & Nanotechnology
Jiaqi Dong, Tejas Umale, Benjamin Young, Ibrahim Karaman, Kelvin Y. Xie
Summary: We investigated the structure and substructure of a solution-treated high temperature shape memory alloy using transmission electron microscopy and precession electron diffraction. It was found that the martensite plates contained high-density internal compound twins. Four martensite variants were observed, and the orientation relationships were determined. Additionally, several low-angle grain boundaries were observed near the variant interfaces.
SCRIPTA MATERIALIA
(2022)
Review
Construction & Building Technology
Iman Abavisani, Omid Rezaifar, Ali Kheyroddin
Summary: Shape memory materials (SMMs) are widely used in civil engineering due to their unique ability to memorize their original shape and return to it under stimuli. These materials, including shape memory alloys, magnetic shape memory alloys, shape memory polymers, and shape memory ceramics, have multifunctional properties and can be applied in various systems.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Y. Ge, M. Vronka, P. Vertat, M. Karlik, S. P. Hannula, O. Heczko
Summary: Three possible twinning modes and corresponding twin boundaries in 2H martensite of Cu 69.4 Ni 3.4 Al 27.2 single crystal were studied. The results show that these twin boundaries have differences and are closely related to twinning stress or twin-boundary mobility.
Article
Materials Science, Multidisciplinary
Bibek Karki, Peter Mullner, Robert Pond
Summary: The crystallographic characteristics of classical twins were first described by Bilby and Crocker over 60 years ago. Their work established that a twin boundary is an invariant plane and that adjacent crystals are related by a homogeneous simple shear. Subsequent studies revealed that classical twins actually grow through glissile motion of interfacial line defects known as disconnections. In this paper, experimental observations of non-classical twins in Ni2MnGa are analyzed, and it is concluded that these boundaries are immobile, misfit-free grain boundaries formed at the intersection of classical compound twins.
Article
Materials Science, Multidisciplinary
Xiaoliang Zhang, Zongbin Li, Dong Li, Bo Yang, Haile Yan, Weimin Gan, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: This study reports the unconventional twin deformation of seven-layered modulated (7M) martensite in a directionally solidified alloy under tension. It is evidenced that the deformation is achieved by the collective lattice reorientation instead of detwinning. This finding is expected to deepen the understanding of martensite deformation behaviors in shape memory alloys.
Article
Nanoscience & Nanotechnology
M. J. Szczerba
Summary: This study reports the first observations of giant magnetic-field-induced bending effect in Ni-Mn-Ga-Co-Cu alloys produced by the melt-spinning technique. The bending effect initiation was observed at a very low magnetic field, and the overall deformation was composed of plastic and elastic contributions, with the elastic contribution dominating in the later stages of the experiment.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Xiaoliang Zhang, Zongbin Li, Bo Yang, Haile Yan, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: This study investigates the reverse transformation from deformed martensite to austenite in a Ni50Mn30Ga20 alloy, revealing that it may not conform to the transformation crystallography of self-accommodated martensite. It involves more crystallographic routes and higher lattice discontinuity to resume the crystallographic orientation of austenite due to the activation of new twinning systems in the deformed martensite. Understanding the reverse transformation of deformed martensite is important for comprehending the shape memory behavior and the crystallographic reversibility of martensitic transformation.
Article
Materials Science, Multidisciplinary
Bin Chen, Chaoshuai Guan, Yong Li, Chong Yang, Junwei Zhang, Gang Liu, Lingwei Li, Yong Peng
Summary: This study accurately probes the reorientation behaviors of A-C and A-B macro-twin interfaces in magnetic shape memory alloys under uniaxial compression using in-situ transmission electron microscopy, filling a gap in the understanding of the intrinsic origin of high twinning stress. It is found that the grain boundary is the main contributor to the large twinning stress, and the A-C and A-B interfaces have twinning stresses of approximately 0.69 and 1.27 MPa, respectively. The study provides insights into the deformation mechanism of magnetic shape memory alloys and highlights the ineffectiveness of compression training in reducing twinning stress in non-modulated martensite in single crystal shape memory alloys.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Gokhan Kilic, Omar Abboosh, Gokhan Kirat, Mehmet Ali Aksan, Ayse Aydogdu, Yildirim Aydogdu
Summary: Ni46Mn41Sb13-xBx (x = 0, 1, 2, 3 and 4) (at.%) Heusler alloys were fabricated using arc melting method to investigate their electronic and magnetic properties. The martensite transformation temperatures increased as the B-content in the system increased. Alloys with x less than 2 were in the austenite phase at room temperature, while those with x larger than 2 exhibited a transformation to a martensite phase. The substitution of boron led to significant changes in lattice constants, influencing the electrical and magnetic properties of the alloys, and the observed hysteresis indicated a field-induced martensitic transformation.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Materials Science, Multidisciplinary
M. Takhsha Ghahfarokhi, F. Casoli, C. Minnert, S. Bruns, E. Bruder, R. Cabassi, K. Durst, O. Gutfleisch, F. Albertini
Summary: Nanoindentation was applied to study the effect of localized plastic deformation on the martensitic transformation of epitaxial Ni-Mn-Ga films on a MgO substrate. The cooling and heating curves for the nanoindented areas were analyzed, showing a thermodynamically governed local increase of the martensitic transformation temperature as a function of applied loads. The observed effect is local and disappears beyond a certain distance from the pile-ups around the residual impressions.
Article
Materials Science, Multidisciplinary
Satyakam Kar, Yuki Ikeda, Klara Luenser, Thomas George Woodcock, Kornelius Nielsch, Heiko Reith, Robert Maass, Sebastian Fahler
Summary: Researchers have identified two distinct microstructural features in micrometer-thick austenitic Ni-Mn-Ga films of magnetic shape memory alloys. Firstly, pyramid-shaped defects originating from {1 1 1} growth twinning cause the breakdown of epitaxial growth, which can be prevented by a Cr buffer layer. Secondly, the reduced dimension of films results in variant selection and distinct premartensite variants, unlike its microstructure in bulk.
Article
Materials Science, Multidisciplinary
Sergey Kustov, Andrey Saren, Bruno D'Agosto, Konstantin Sapozhnikov, Vladimir Nikolaev, Kari Ullakko
Summary: In this study, special martensitic variant structures were created in Ni-Mn-Ga martensitic samples to investigate the dynamics of a highly mobile a/c twin boundary. It was found that the transitory internal friction observed at high ultrasonic frequencies had a magnetic origin, associated with the motion of the a/c twin boundary induced by thermal stresses. The non-equilibrium structure of a/b twins over a broad temperature range led to variable Young's modulus values in samples with maximum shear stress in a/b twinning planes.
Article
Materials Science, Multidisciplinary
Suvi Santa-aho, Mari Honkanen, Sami Kaappa, Lucio Azzari, Andrey Saren, Kari Ullakko, Lasse Laurson, Minnamari Vippola
Summary: This study thoroughly characterized two types of steels, ferrite and ferrite-pearlite, using multi-instrumental microscopy techniques to obtain detailed information about their microstructure and magnetic structure. The researchers observed the motion of magnetic domain walls and their interactions with different pinning sites, which provided explanations for changes in sample magnetization. The findings have significant implications for the non-destructive Barkhausen noise technique.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Physical
Anxo Fernandez Gonzalez, Konstantin Sapozhnikov, Pavel Pal-Val, Sergey Kustov
Summary: Magnetic hysteresis is a consequence of the non-equilibrium state of trapped magnetic domain walls. Our experiments showed that acoustic oscillations can equilibrate the metastable magnetic domain structure in a ferromagnet through triggering the motion of domain walls into more stable configurations. The observed effect is attributed to the stress anisotropy field induced by oscillatory mechanical stress. This equilibration of the domain structure was confirmed by the measurements of reversible Villari effect.
Article
Materials Science, Multidisciplinary
Ahmed Sameer Khan Mohammed, Huseyin Sehitoglu
Summary: The study explores the complexity and evolution capability of twin boundaries in NiTi, revealing the energy-minimal nanostructure and evolutionary mechanism of interface topology through the combination of multiscale energetics and theoretical frameworks.
Article
Materials Science, Multidisciplinary
Stuart Wright, Saransh Singh, Marc De Graef
MICROSCOPY AND MICROANALYSIS
(2019)
Article
Nanoscience & Nanotechnology
Tijmen Vermeij, Marc De Graef, Johan Hoefnagels
SCRIPTA MATERIALIA
(2019)
Article
Nanoscience & Nanotechnology
Nisrit Pandey, Maxwell Li, Marc De Graef, Vincent Sokalski
Article
Materials Science, Multidisciplinary
W. C. Lenthe, L. Germain, M. R. Chini, N. Gey, M. De Graef
Article
Physics, Applied
Maxwell Li, Anish Rai, Ashok Pokhrel, Arjun Sapkota, Claudia Mewes, Tim Mewes, Marc De Graef, Vincent Sokalski
APPLIED PHYSICS LETTERS
(2020)
Article
Physics, Applied
Arjun Sapkota, Anish Rai, Ashok Pokhrel, Jamileh Beik Mohammadi, Maxwell Li, Derek Lau, Marc De Graef, Vincent Sokalski, Tim Mewes, Claudia Mewes
JOURNAL OF APPLIED PHYSICS
(2020)
Article
Physics, Applied
Arthur R. C. McCray, Timothy Cote, Yue Li, Amanda K. Petford-Long, Charudatta Phatak
Summary: This study introduces the application of the PyLorentz open-source software suite for quantitative image analysis of Neel-type skyrmions in thin-film heterostructures. By enabling reconstruction of magnetic induction maps from experimental images and simulating LTEM images using micromagnetic simulation data, PyLorentz enhances the capabilities of Lorentz transmission electron microscopy. Simulation-assisted LTEM analysis is shown to be crucial for understanding complex magnetic spin textures.
PHYSICAL REVIEW APPLIED
(2021)
Article
Nanoscience & Nanotechnology
Nisrit Pandey, Maxwell Li, Marc De Graef, Vincent Sokalski
Summary: The study reveals significant differences in magnetic properties and domain structures between Pt/Ni/Co asymmetric superlattices and Pt/Co/Ni structures, possibly due to changes in stacking sequence leading to alterations in interfacial magnetic anisotropy and Dzyaloshinskii-Moriya interaction.
Article
Materials Science, Multidisciplinary
Mohammed Salah El Hadri, Jonathan Gibbons, Yuxuan Xiao, Haowen Ren, Hanu Arava, Yuzi Liu, Zhaowei Liu, Amanda Petford-Long, Axel Hoffmann, Eric E. Fullerton
Summary: The investigation demonstrates that in ultrathin Au/Si multilayers, there is an enhanced effective spin-charge conversion efficiency, particularly in thinner individual Au layers, reaching exceedingly large values. The findings reveal the coexistence of interfacial spin-to-charge conversion effect and bulk spin Hall effect in ultrathin Au, suggesting the key role of intrinsic spin Hall effect enhancement and strong interfacial spin-orbit coupling-related effect in large spin-to-charge conversion.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
Maxwell Li, Anish Rai, Ashok Pokhrel, Arjun Sapkota, Claudia Mewes, Tim Mewes, Di Xiao, Marc De Graef, Vincent Sokalski
Summary: Through a combination of micromagnetic theory and Lorentz transmission electron microscopy, the substructures of magnetic domain walls in multi-layers have been examined, revealing the conditions for their presence and enabling the formation of a magnetic phase diagram. Additionally, it has been discovered that reduced thickness favors the formation of Q = ±1 substructures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Brian W. Casas, Yue Li, Alex Moon, Yan Xin, Conor McKeever, Juan Macy, Amanda K. Petford-Long, Charudatta M. Phatak, Elton J. G. Santos, Eun Sang Choi, Luis Balicas
Summary: By using high-resolution Lorentz transmission electron microscopy, it is discovered that Fe5-xGeTe2 exhibits various topological magnetic textures, including merons, anti-meron pairs, and Neel skyrmions. These textures have effects on thermal and electrical transport properties, and a topological Hall effect (THE) can be detected even at room temperature. The formation of different spin textures can be selectively driven by thermal energy. Additionally, an unconventional THE is observed in the absence of Lorentz force, which is attributed to the interaction between charge carriers and magnetic field-induced chiral spin textures. Fe5-xGeTe2 is therefore considered a promising candidate for the development of skyrmionics and meronics applications due to its unique magnetic properties and unconventional charge/heat transport.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Simon A. Meynell, Yolita M. Eggeler, Joshua D. Bocarsly, Daniil A. Kitchaev, Bailey E. Rhodes, Tresa M. Pollock, Stephen D. Wilson, Anton Van der Ven, Ram Seshadri, Marc De Graef, Ania Bleszynski Jayich, Daniel S. Gianola
Summary: Magnetic skyrmions, topologically-protected spin textures, can transition between in-plane and out-of-plane orientations in certain ferromagnetic materials. Experimental evidence and numerical modeling in Co8Zn8Mn4 demonstrate the controllable flop transition between these two types of skyrmions at room temperature, with the transition dependent on thickness. Furthermore, the findings suggest potential applications in a skyrmion-writing device.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Zihao Ding, Marc De Graef
Summary: In this study, a flexible and scalable framework (EBSD-CVAE/GAN) is proposed for simulating EBSD patterns, which can generate high-quality and accurate patterns. The model summarizes the distribution of backscattered electrons and addresses the issue of data scarcity.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Mia Maric, Rhys Thomas, Alec Davis, David Lunt, Jack Donoghue, Ali Gholinia, Marc De Graef, Tamas Ungar, Pierre Barberis, Florent Bourlier, Philipp Frankel, Pratheek Shanthraj, Michael Preuss
Summary: Hydride precipitation in zirconium alloys, specifically Zircaloy-4, was investigated using dictionary indexing of Kikuchi patterns, orientation relationship analysis, and x-ray diffraction. The presence of both delta and gamma hydride phases was confirmed, with the gamma phase exhibiting a distinct orientation relationship with the matrix. Local stresses influenced the morphology and orientation of the delta hydride, leading to changes during precipitation. By analyzing the orientation relationships, the stability of both delta and gamma hydrides at room temperature could be understood.
SCRIPTA MATERIALIA
(2024)
Article
Materials Science, Multidisciplinary
Anish Rai, Arjun Sapkota, Ashok Pokhrel, Maxwell Li, Marc De Graef, Claudia Mewes, Vincent Sokalski, Tim Mewes
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.
