Article
Materials Science, Multidisciplinary
Zhijie Ge, Hongjun Li, Xiao Cheng
Summary: Nanoindentation experiments were conducted to study the plastic deformation mechanism of single crystal diamond. It was found that the plastic characteristic of diamond was due to phase transition rather than dislocation slip. The nucleation and growth of 1/2[110]{111} complete dislocation ring during the plastic deformation of diamond were determined by observing pop-in events and dislocation evolution. The formation and growth of the dislocation ring were attributed to the phase transition from disordered sp3 to ordered sp2 carbon atoms. It was concluded that phase transition is an important excitation source for plastic deformation at the atomic scale in diamond.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
J. -E. Brandenburg, J. Seo, K. Eto, D. A. Molodov, S. Tsurekawa
Summary: The study used nanoindentation to investigate the local mechanical properties near 1010 tilt grain boundaries in magnesium bicrystals with different misorientation angles. It was found that critical shear-stress for the second pop-in differed substantially for grain boundaries with different structures, indicating important mechanical property variations in these boundaries.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Avanish Mishra, Khanh Dang, Edward M. Kober, Saryu J. Fensin, Nithin Mathew
Summary: This study used atomistic simulations to investigate the high-strain rate deformation of bicrystal Cu nanopillars. Minimum grain boundary energy nanopillars were deformed to study the influence of macroscopic degrees of freedom on the stress-strain response, revealing that geometric parameters (Schmid factor) affect the response. The deformation of metastable grain boundaries showed that, in addition to geometric parameters, the local atomic arrangement also dictates the dislocation-GB interactions. These findings shed light on the response of nanopillars as a function of grain boundaries and highlight the importance of both macroscopic and microscopic degrees of freedom on the mechanical response.
MATERIALS RESEARCH LETTERS
(2023)
Article
Materials Science, Coatings & Films
Junyi Wang, Junqin Shi, Yang Lu, Ge Jin, Jiahang Wang, Yuxuan Jiang, Qing Zhou
Summary: This study examines the plastic deformation evolution of Cu/Ta and Ta/Cu nanoscale multilayers using molecular dynamics simulation. The results show that the plastic deformation mechanism is influenced by both the intrinsic property of monolayers and the interface characteristic, providing insights for the design of wear-resistant coatings and structural nanocomposites.
SURFACE & COATINGS TECHNOLOGY
(2022)
Article
Materials Science, Ceramics
Xing Luo, Zhibo Zhang, Yongnan Xiong, Yao Shu, Jiazhen He, Kaihong Zheng, Yuan Bao, Herbert M. Urbassek
Summary: Molecular dynamics simulation is used to study phase transformations during nanoindentation into the (0001) surface of monocrystalline AlN with wurtzite structure. The results show that with increasing indentation depth, surface tearing, nucleation and growth of a graphite-like phase, formation and flow of an amorphous phase, and generation of a tetragonal intermediate structure occur consecutively. The findings are consistent across a wide range of indentation speeds from 10-160 m/s.
CERAMICS INTERNATIONAL
(2021)
Article
Metallurgy & Metallurgical Engineering
Wenjing Lou, Lin Cheng, Runsheng Wang, Chengyang Hu, Kaiming Wu
Summary: The effects of randomly distributed hydrogen atoms on the mechanical response of pure iron under nanoindentation were investigated using molecular dynamics simulations. The aim was to gain a better understanding of the hydrogen embrittlement mechanism in steels. The simulations showed that hydrogen reduced the critical load of the pop-in event, promoted dislocation slipping, and decreased the size of the plastic region and dislocation density around the indenter compared to the hydrogen-free model. The different mechanical responses of the models with different surface normals were further explained in terms of the Schmid factor.
ACTA METALLURGICA SINICA-ENGLISH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
S. Chandra, A. Alankar, N. N. Kumar, M. K. Samal, V. M. Chavan
Summary: Atomistic simulations were used to investigate dislocation activity in an FCC Cu bicrystal during plain strain compression, revealing that grain boundaries act as significant barriers to dislocation motion and heterogeneous deformation in crystals leads to differences in grain orientation distributions during deformation stages. The observed local lattice rotation fields were well correlated with geometrically necessary dislocation distributions, providing unique insights into the nanoscale deformation mechanisms. Discussions on the modeling approaches' role in bridging the gap between experiments and simulations were also included.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Multidisciplinary Sciences
Filipe Matusalem, Jessica Santos Rego, Maurice de Koning
Summary: There has been a growing interest in the mechanical properties of superionic (SI) phases of water ice, which play a potential role in the geophysical properties of Neptune and Uranus. This study assessed the mechanical response of high-pressure/temperature solid phases of water using density functional theory calculations and machine learning techniques. The results indicate that SI ices are highly ductile and the plastic flow of the internal icy layers in Neptune and Uranus may be significantly faster than previously foreseen.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Multidisciplinary
Matteo Baggioli, Ivan Kriuchevskyi, Timothy W. Sirk, Alessio Zaccone
Summary: This research reveals the existence of topological defects related to plastic instability in the nonaffine displacement field under deformation. The study of these defects uncovers new characteristics of plastic deformation in glasses and confirms the violation of Cauchy-Born rules and the impact of topological defects on plastic events.
PHYSICAL REVIEW LETTERS
(2021)
Editorial Material
Materials Science, Ceramics
Shengyao Yang, Liangchi Zhang, Zhonghuai Wu, Richard F. Webster, Charlie Kong, Shery L. Y. Chang
Summary: In this letter, we report the first observation of subsurface amorphization of potassium dihydrogen phosphate (KDP) after nanoindentation under transmission electron microscopy (TEM). The results agree well with our Molecular Dynamics (MD) simulation predictions, providing insights into the deformation mechanisms of KDP under nanoindentation and offering a sensitive approach for observing electron beam sensitive materials under TEM.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Mingqiang Li, Yidi Shen, Kun Luo, Qi An, Peng Gao, Penghao Xiao, Yu Zou
Summary: Dislocation motion is crucial for the hardening, processing, and application of various materials. Previous studies have observed dislocation motion in crystalline solids under mechanical loading. However, controlling dislocation motion solely using a non-mechanical field has been challenging.
Article
Chemistry, Physical
Jinming Li, Yuhua Huang, Yuqi Zhou, Fulong Zhu
Summary: Molecular dynamics simulations were used to investigate the repeated nanoindentation on aluminum substrate with varying thicknesses of boron nitride nanosheet coating. The study reveals that the hardness of the substrate increases with coating thickness. The pressure area of the aluminum substrate also increases with coating thickness. The coating force causes more atoms to move along the loading direction, leading to substrate slip and severe atomic strain. However, some aluminum atoms are able to elastically recover after unloading, despite being severely deformed. After multiple loadings, elastic deformations transition into plastic deformations, possibly accompanied by lattice structure destruction and the presence of amorphous atoms.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Xiaorong Liu, Dongpeng Hua, Wan Wang, Qing Zhou, Shuo Li, Junqin Shi, Yixuan He, Haifeng Wang
Summary: This study investigated the initial dislocation nucleation and motion mechanisms in TaTiZrV high-entropy alloys (RHEAs) and their dependence on temperature through molecular dynamics simulations. The short-range orders in the RHEA facilitate preferential inhomogeneous nucleation at low stress, while compositional fluctuation affects the slipping and moving rate of dislocations. Moreover, the difficulty of initial dislocation nucleation increases with temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Kenji Nishimura, Ken-ichi Saitoh
Summary: Nanoindentation simulations were conducted on single-crystalline cubic silicon carbide to investigate the temperature dependence of mechanical characteristics and lattice defect formation mechanisms. The results showed weak temperature dependence of elastic responses but strong temperature dependence of plastic deformation. The critical mean contact pressure for plasticity onset decreased with increasing temperature. At low temperatures, plastic deformation started with the nucleation and expansion of perfect dislocations, while at high temperatures, the dislocations dissociated into Shockley partial dislocations with stacking faults. Different atomic patterns were observed on the surfaces after unloading at different temperatures, and the ductile behavior was more influenced by temperature on the (1 1 1) surface than on the (001) surface.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Physics, Multidisciplinary
Yuanyuan Tian, Gangjie Luo, Qihong Fang, Jia Li, Jing Peng
Summary: The plastic-deformation behaviors of gradient nanotwinned metallic multilayers are studied using molecular dynamics simulation at the nanoscale, revealing the effect of different stacking fault energies (SFEs) on the deformation behavior. The influence of SFE on the transition from dislocation dynamics to twinning/detwinning is observed, along with the strengthening and softening mechanisms in the multilayers.
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.