Article
Nanoscience & Nanotechnology
Zhiqiao Li, Houwen Chen, Jian-Feng Nie
Summary: In this work, the migrations of (1011) and (1013) coherent twin boundaries (CTB) in pure magnesium are studied using first-principles methods. The process of migration is divided into nucleation and gliding of twinning disconnection (TD), with TD nucleation approximated by rigid-shifting of CTB. Energetic maps obtained from this analysis reveal the necessity of applying shear strains simultaneously along the twinning direction η1 and along k1, which is normal to η1, to activate the migration of 2-layer CTB in these two different twinning modes. The energetic map identifies the most efficient external shear strain direction for initiating CTB migration, which lies between the Burgers vectors bTD-2 of the 2-layer-height TD and η1. The shear strain required to initiate TD gliding is smaller than that needed for TD nucleation, implying that the migrations of (1011) and (1013) CTBs are primarily governed by the TD nucleation.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Dinh-Quan Doan, Anh-Son Tran, Ngoc-Chien Vu
Summary: The nanoindentation response of FeCoCrNiCu high-entropy alloy was studied through molecular dynamics simulation. Various grain sizes and twin lamellae thicknesses were found to significantly affect the mechanical characteristics and plastic deformation. The study revealed an inverse Hall-Petch effect in the relationship between material strength, grain size, and twin lamellae thickness. The presence of grain boundaries and twin boundaries affected atom movement and resulted in asymmetrical dispersion of atomic displacement vectors during deformation. The results also showed that pile-up height increased with grain size and decreased with twin lamellae spacing. Microstructural evolution indicated that grain rotation and grain boundary movement were dominant mechanisms in deformation with grain size reduction. Dislocation nucleation at the intersections of twin and grain boundaries also significantly affected plastic deformation, with dislocation density increasing with grain size and twin lamellae thickness.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Yingbin Chen, Qishan Huang, Shuchun Zhao, Haofei Zhou, Jiangwei Wang
Summary: This study demonstrates the deformation behavior of penta-twinned nanomaterials under high shear stress, showing structural destruction and core reconstruction of the penta-twins. The intrinsic deformation behaviors enable the possibility of controlling the morphology of penta-twinned nanomaterials with unique properties.
Article
Chemistry, Physical
O. Madkhali, M. Jullien, Alaa E. Giba, J. Ghanbaja, S. Mathieu, C. Gendarme, S. Migot, Y. Alajlani, N. Can, F. Alnjiman, D. Horwat, A. Redjaimia, J. F. Pierson
Summary: Copper iodide is a transparent p-type material with a zinc blende structure, exhibiting p-type carrier behavior. Detailed investigation using HR-TEM revealed alternating twin crystallographic domains between grains. The optical properties show a wide band gap and blue emission.
SURFACES AND INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Amitava Moitra
Summary: In this study, the interaction between twin boundaries and Mg17Al12 precipitates was investigated using classical molecular dynamics methodology at different temperatures, precipitate sizes, and applied loads. The results revealed an attractive interaction when the twin boundary approached the precipitate and the formation of a network of dislocations when the twin boundary bypassed the precipitate. These findings provide valuable insights into the precipitate hardening mechanisms and suggest new approaches to improving the mechanical properties of Mg-Al alloys.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
X. Z. Jin, C. Y. Wang, S. Milenkovic, I. Sabirov, I. J. Beyerlein, M. T. Perez-Prado
Summary: This study investigates the influence of solute segregation on the twin activity of aged Mg alloys. The authors examine the binary Mg-8Al alloy and two ternary Mg-8Al-1 Zn and Mg-8Al-1Ag alloys. They find that while the binary alloy shows no significant changes in twin activity after precipitation, the aged ternary alloys exhibit a drastic reduction in twin activity, possibly due to the decrease of particle-matrix interface energy caused by Zn and Ag segregation.
Article
Nanoscience & Nanotechnology
Nan Yang, Bo-Yu Liu, Fei Liu, Zhi-Wei Shan
Summary: Deformation twinning in magnesium can undergo cross-transition, involving prismatic-basal interface migration, to broaden the understanding of twinning mechanisms.
SCRIPTA MATERIALIA
(2022)
Article
Nanoscience & Nanotechnology
Huhu Su, Xinzhe Zhou, Shijian Zheng, Hengqiang Ye, Zhiqing Yang
Summary: The formation and evolution of basal-prismatic/prismatic-basal (BP/PB) interfaces in a Mg alloy under cyclic deformation were studied and modeled based on atomic-resolution experimental observations and interfacial defects theory. It was found that BP/PB interfaces could be formed by emission of specific dislocations and twinning disconnections, and could transform into twin boundaries. The experimental results offer insights into the dislocation-assisted mechanisms of formation and evolution of BP/PB interfaces in hexagonal-close-packed materials.
SCRIPTA MATERIALIA
(2022)
Article
Metallurgy & Metallurgical Engineering
Qi Qian, Zheng-qing Liu, Yong Jiang, Yi-ren Wang, Xing-long An, Min Song
Summary: First-principles calculations were used to investigate the formation mechanism of GTBs in hcp Ti, revealing that GTBs can form from the gliding of CTBs and eventually restore CTB structures by forming twinning disconnections. The pile-up of twinning disconnections at twin boundaries can promote twin growth. Additionally, the study evaluated the possible effects of alloying elements on pinning twin boundaries in Ti alloys.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2021)
Article
Materials Science, Multidisciplinary
Jingpeng Hou, Keliang Qiu, Fengshi Li, Zhenyu Yang, Yonghai Yue, Yongjun Tian, Zhongchang Wang, Lin Guo
Summary: Twin boundary (TB) is a special and fundamental internal interface that alters the mechanical and physical properties of materials. The deformation mechanism of TB and its effect on material strength and plasticity are still under debate. This study discovered that the pseudoelastic strain of a TB can recover with decomposition and escape of pile-up dislocations, which opens up new possibilities for optimizing material properties by manipulating twin boundaries at the nanoscale.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
A. I. Kartamyshev, D. O. Poletaev, A. O. Boev, D. A. Aksyonov
Summary: This study reveals the penetration of Li ions into copper, especially at grain boundaries, which can result in the formation of Li-Cu alloys. By minimizing the amount of grain boundaries, the formation of these alloys can be prevented, leading to extended battery lifetimes.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Metallurgy & Metallurgical Engineering
Tao Sun, Aidong Tu, Hao Wang, Shu-Jun Li, Hui Peng, Jian-Ping Li
Summary: The mechanical response of a bi-crystal model with a 90 degrees grain boundary under external compressive and tensile loading parallel to the boundary plane normal was investigated with molecular dynamics simulations. The grain boundary was found to migrate along two opposite directions upon compressive and tensile straining, with the formation of inter-connected coherent twin boundary and basal/prismatic boundary. The atomic details of such grain boundary migration were unraveled, which indicated the role of interface dislocations. The temperature effect was also discussed.
ACTA METALLURGICA SINICA-ENGLISH LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Hui Guo, Jinhu Zhang, Xuexiong Li, Dongsheng Xu, Hao Wang, Shijian Zheng, Yingjie Ma, Rui Yang
Summary: The mechanical response of {1211} and {1212} coherency twin boundaries (CTB) in titanium and magnesium was studied using molecular dynamics simulations. Mutual transformation between {1211} and {1212} CTB was observed, with {1212} CTB transforming into two {1211} CTB to form a twin junction, and reversibly {1211} CTB transforming into {1212} CTB and another {1211} CTB to form another twin junction. This simulation result provides an explanation for the observed twin junction phenomenon. Furthermore, the mutual transformation between {1211} CTB and {1212} CTB allows for perceivable plastic strain accommodation, thanks to the geometric compatibility and mobility of the two junctions.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Lin Li, Jie Yang, Zhiyuan Yang, Qi Sun, Li Tan, Qinghui Zeng, Minhao Zhu
Summary: Deformation twins play a crucial role in plastic deformation and affect the microstructural evolution and fatigue behavior of magnesium alloys. The study investigated the fatigue behavior of a rolled magnesium alloy using SEM and EBSD, revealing that {1012} twinning dominates the fatigue deformation process and residual twins increase with fatigue cycles. Cracks tend to initiate and propagate along {1012} twinning boundaries and slip bands, with numerous extrusions found in twinned areas.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Multidisciplinary
Hongbo Xie, Hucheng Pan, Junyuan Bai, Dongsheng Xie, Peijun Yang, Shanshan Li, Jianfeng Jin, Qiuyan Huang, Yuping Ren, Gaowu Qin
Summary: The study discovered three- and five-layered discontinuous segregation patterns in twin boundaries in alloys, where not all sites are occupied by solutes larger than Mg, with some larger solutes taking compression sites. Nd/Mn solutes selectively segregate at substitutional sites, generating two new types of ordered two-dimensional TB superstructures or complexions.
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.