Article
Metallurgy & Metallurgical Engineering
Jun Cheng, Tingting Guo, Matthew R. Barnett
Summary: This paper examines the temperature sensitivity of tensile twinning in a magnesium single crystal during nanoindentation. It is found that the generation of twinning is temperature-dependent, with a decrease in pop-in load as temperature increases. The activation energy obtained from thermal activation analysis is consistent with the observations.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Materials Science, Multidisciplinary
Katherine L. Hull, Younane N. Abousleiman
Summary: The study investigated nanoindentation pop-ins in composite source shale and defined two types, Type I and Type II, based on the slopes of load-displacement curves as Delta p/Delta h = 0 or Delta p/Delta h > 0. Pop-ins were mainly observed when indenting perpendicular to the shale layers, with a wide variation in the estimate of pop-in energy dissipation magnitude across shale matrix phases. Type III pop-ins with Delta p/Delta h < 0 were never observed.
MRS COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Javier Varillas, Giovanni Ciccotti, Jorge Alcala, Lamberto Rondoni
Summary: Mathematical relations concerning particle systems require applicability conditions. The Jarzynski equality, a mechanical theory, shows surprising generality in determining free-energy variations for non-equilibrium processes. However, it can be process-dependent and its verification may be challenging.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Bo Li, Deng Pan, Xin Zhang, Lei Liu, Lina Gao, Shaolong Li, Yuanbin Qin, Yabo Fu, Shufeng Li
Summary: This paper investigates the role of nano-TiB whiskers in the micromechanical behaviors of two common titanium composite particles (TCPs). The experimental results reveal that when the particle size decreases, the flow stress and contact yield stress of the TCPs exceed the yield strength of bulk composite pillars. The study also demonstrates a remarkable pinning capacity induced by the nano-TiBw network.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2024)
Article
Chemistry, Physical
Stephania Kossman, Maxence Bigerelle
Summary: This study successfully differentiated load-displacement curves with and without pop-in using a deep learning model, achieving an accuracy of approximately 93% in both training and validation datasets. These results confirm the powerful capabilities of artificial intelligence and computer vision models in analyzing nanoindentation data.
Article
Materials Science, Ceramics
Xufei Fang, Hanna Bishara, Kuan Ding, Hanna Tsybenko, Lukas Porz, Marion Hoefling, Enrico Bruder, Yingwei Li, Gerhard Dehm, Karsten Durst
Summary: The study demonstrates a size-dependent brittle to ductile transition in SrTiO3 ceramics at room temperature, showing a competition between dislocation-mediated plasticity and crack formation during nanoindentation pop-in events. This finding sheds light on the deformation mechanism in ceramics at the nano-/microscale level involving plasticity and cracking, providing insights for further study on dislocation-based mechanics and functionalities in these materials.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Multidisciplinary Sciences
Sangram Kadam, Kiran Kumari, Vinoth Manivannan, Shuvadip Dutta, Mithun K. K. Mitra, Ranjith Padinhateeri
Summary: The authors provide a quantitative description of chromatin as bead-spring polymers, predicting the 3D size of chromatin beads and quantifying their stretchability, bendability, and softness. They systematically coarse-grain chromatin using Micro-C data and derive essential quantities for polymer representation. They also challenge the prevailing notion by showing that chromatin beads must be considered soft particles that can overlap, and in doing so, they derive an effective inter-bead soft potential and quantify an overlap parameter. Additionally, they analyze bond lengths and bond angles to gain insights into chromatin folding and local bendability.
NATURE COMMUNICATIONS
(2023)
Review
Chemistry, Physical
Takahito Ohmura, Masato Wakeda
Summary: The paper discusses the phenomenon of pop-in during indentation-induced deformation at a very small scale, emphasizing its importance as a fundamental deformation behavior in various materials and analyzing its mechanical and physical principles.
Article
Nanoscience & Nanotechnology
Jinjie Zhou, Yingle He, Jinchuan Shen, F. A. Essa, Jingui Yu
Summary: Nickel-based single crystal alloys have excellent mechanical properties due to their unique structure and interface. By simulating nanoindentation and microstructural evolution, the hardness of the Ni3Al phase was found to be the highest and dislocations can penetrate the interface into the Ni phase. Furthermore, the starting point of adhesion force recovery was found to be related to the material's elastic recovery, and the variation of potential energy was related to stacking fault energy.
Article
Chemistry, Physical
Rong-Guang Xu, Hengxu Song, Yongsheng Leng, Stefanos Papanikolaou
Summary: The pop-in effect in nanoindentation of metals and the indentation size effect were studied through large scale molecular dynamics simulations, investigating the coupled effects of prestrain, resulting dislocations, and surface morphology on the mechanical response in indentation processes. The study provides detailed insights into the deformation mechanisms and microstructure-property relationships of nanoindentation in the presence of residual stresses and strains.
Article
Materials Science, Ceramics
Fenglin Gu, Hongtu He, Laixi Sun, Fang Wang, Qiuju Zheng, Jiaxin Yu
Summary: The role of graphene on indentation and scratch properties of soda lime silicate (SLS) glass is investigated in this study. It is found that graphene-coated glass has higher nanohardness and reduced modulus, as well as improved nanoscratch resistance. Furthermore, graphene can reduce subsurface damage and increase Vickers hardness and indentation fracture toughness of the glass.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Chemistry, Physical
Zhuhao Wen, Yunlong Hu, Weimin Chen, Qiang Zhang, Lijun Zhang, Yong Du
Summary: In this study, Co-Ni-W alloys were analyzed for their elasto-plastic properties using reverse analysis algorithms, and data related to composition were obtained using machine learning methods, showing potential applications in the field of multicomponent alloys research.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
H. Zhang, F. De Luca, H. Wang, K. Mingard, M. Gee
Summary: The deformation behavior of pure tungsten carbide (WC) was studied using nanoindentation tests. Different specimen preparation processes led to elastic to plastic deformation at different threshold loads, and staircase deformation was caused by dislocation motion and the formation of slip bands. Displacement discontinuities in the load-displacement curves were associated with dislocation loop nucleation at or near the theoretical shear strength.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Chemistry, Physical
Serena De Santis, Edoardo Rossi, Marco Sebastiani, Simona Sennato, Edoardo Bemporad, Monica Orsini
Summary: Surface free energy (SFE) of titanium surfaces plays a significant role in tissue engineering, affecting the effectiveness and long-term stability of active coatings and functionalization as well as the establishment of strong bonds to newly growing bone. This study used a high-resolution non-destructive elastic contacting nanoindentation method to investigate the SFE of micro- and nano-structured titanium surfaces, both immediately after preparation and after exposure to air. The effectiveness of different surface treatments in enhancing SFE was evaluated. The study observed a time-dependent decay of SFE within a few hours, with kinetics related to sample preparation. The fast, non-destructive method allowed for accurate measurement of SFE in very hydrophilic conditions, allowing for reliable comparison between surfaces with different properties.
Article
Nanoscience & Nanotechnology
Silvia Pomes, Nozomu Adachi, Masato Wakeda, Takahito Ohmura
Summary: This study found a precursor phenomenon to incipient plasticity before the first serration in Zr50Cu40Al10 at% bulk metallic glass via nanoindentation testing.
SCRIPTA MATERIALIA
(2023)
Article
Microscopy
Gregory Sparks, Paul A. Shade, Michael D. Uchic, Stephen R. Niezgoda, Michael J. Mills, Mark Obstalecki
Summary: The study investigates the angular precision of crystal orientation determination using cross-correlation of dynamically simulated electron diffraction patterns with experimental patterns via spherical harmonic analysis. The best precision found is 0.016 degrees, with a noise floor for dislocation density calculations at approximately 5x10(13) m(-2) at a 200 nm step size. Compared to conventional Hough-transform indexing, the method used in the study provides superior precision and lower noise levels, even with high-quality patterns.
Article
Materials Science, Multidisciplinary
Q. Rizzardi, P. M. Derlet, R. Maass
Summary: This study traces the formation and morphological characteristics of slip lines in high-entropy alloys, revealing two main types of events related to slip lines. The combination of these events represents the highest degree of spatial avalanche delocalization across the entire sample, linking the statistics of dislocation avalanches to a microstructural observable.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Physical
Mohammad Abboud, Amir Motallebzadeh, Ozgur Duygulu, Robert Maass, Sezer Ozerinc
Summary: Cu-Nb alloys produced by combinatorial magnetron sputtering exhibit different microstructures, resulting in significant variations in hardness and resistance to plastic flow depending on the composition, highlighting a vast design space for structure-property relationships in this otherwise immiscible binary alloy.
Article
Materials Science, Multidisciplinary
Ruitao Qu, Robert Maass, Zengqian Liu, Dominik Tonnies, Lin Tian, Robert O. Ritchie, Zhefeng Zhang, Cynthia A. Volkert
Summary: This study discovered the strongest metallic alloy known, which is flaw-insensitive at the micrometer scale and exhibits properties that deviate from traditional theories. The experimental results show that the fracture toughness of this ultra-strong glassy alloy increases with increasing sample size.
Article
Materials Science, Multidisciplinary
John D. Shimanek, Shipin Qin, Shun-Li Shang, Zi-Kui Liu, Allison M. Beese
Summary: A method integrating first-principles calculations is proposed to predict the strain-hardening behavior of pure Ni single crystals. The study found that elastic interactions of pure edge dislocations capture hardening behavior for small strains, while a strain-weighted linear combination of edge and screw flow resistance components captures hardening behavior for larger strains.
Article
Multidisciplinary Sciences
Q. Rizzardi, C. McElfresh, G. Sparks, D. D. Stauffer, J. Marian, R. Maass
Summary: Plastic deformation in crystals is mediated by the motion of line defects known as dislocations. The conventional understanding of plasticity as a homogeneous process has been challenged by the discovery of long-range correlated and intermittent collective dislocation processes, termed avalanches. In this study, the authors investigate the temperature-dependent microplasticity in body-centered cubic Nb and reveal the dominance of athermal screw dislocation activity during intermittent slip. The results suggest that plasticity can be understood in terms of the coexistence of mild and wild modes of deformation, providing insights for the design of better alloys.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
P. M. Derlet, H. Bocquet, R. Maass
Summary: Atomistic simulation reveals how thermally activated structural excitations quantitatively mediate transport and microplasticity in a model binary glass at the microsecond timescale, demonstrating the important role of geometrical frustration in both glass structure and its underlying dynamics through the evolution of a disclination network describing the spatial connectivity of topologically distinct bonding environments.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
Y. Shimada, Y. Ikeda, K. Yoshida, M. Sato, J. Chen, Y. Du, K. Inoue, R. Maass, Y. Nagai, T. J. Konno
Summary: The experimental conditions inside a transmission electron microscope (TEM), such as ultra-high vacuum and high-energy electron irradiation, can cause unexpected microstructural changes during in situ thermal-annealing experiments. This paper reports on the microstructural changes of a Fe-15%Si alloy during in situ TEM annealing and observes the precipitation of alpha-Fe both at the sample surface and inside the sample. Vacancies on Si sites induced by high-energy electron irradiation and enhanced thermal diffusion of Fe atoms contribute to this unexpected microstructural evolution.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Q. Rizzardi, P. M. Derlet, R. Maass
Summary: In this study, we demonstrate the gradual transition from scale-free powerlaw scaling to exponential and scale-dependent distribution by introducing various microstructural features in an Al-Cu binary alloy system. The statistics of intermittent microplasticity exhibit fat-tailed contributions as long as the obstacles to dislocation motion can be sheared. The introduction of incoherent precipitates leads to a complete transition in the statistical behavior, suggesting that microstructural length scales and obstacle pinning-strengths are of secondary importance.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
John D. Shimanek, Shun-Li Shang, Allison M. Beese, Zi-Kui Liu
Summary: This study investigates the effect of alloying elements on the ideal shear strength of dilute Ni-based alloys through first-principles calculations. The results demonstrate the significant impact of atomic properties, such as size and electronegativity, on the variations in ideal shear strength. Additionally, the study reveals a strong linear relationship between the shear moduli of the alloys and their ideal shear strengths, indicating that the shear moduli of the individual alloying elements are not indicative of alloy shear strength. The research also showcases the potential application of Ni alloy data in identifying a set of atomic features suitable for machine learning applications to mechanical properties.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
M. Thuy, A. Spyrantis, M. Boehning, U. Niebergall, R. Maass
Summary: The fracture surface of a semicrystalline polyethylene during environmental stress cracking exhibits isotropic roughness at the local scale but clear position dependence at the macroscopic scale. The roughness exponent varies in the range of 0.1 to 0.4, indicating non-trivial exponents in the small length-scale regime. The variation of the exponent suggests a link to the dominating dissipation processes during craze cracking.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Adnan Eghtesad, John D. Shimanek, Shun -Li Shang, Ricardo Lebensohn, Marko Knezevic, Zi-Kui Liu, Allison M. Beese
Summary: This study successfully integrates first-principles calculations based on density functional theory (DFT) into the dislocation density hardening law of the crystal plasticity fast Fourier transform (CPFFT) model, improving the robustness of the model and reducing the uncertainties in calibrating the macroscopic flow response.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
P. M. Derlet, R. Maass
Summary: This study examines the limits of structural rejuvenation in a highly excited model binary glass using the creation relaxation algorithm. The highly energized structure exhibits a direct transition to homogeneous plastic flow and a microstructure that is largely insensitive to this flow, suggesting the presence of a porous system-spanning network.
PHYSICAL REVIEW MATERIALS
(2022)
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
Amlan Das, Catherine Ott, Dinesh Pechimuthu, Robabeh Moosavi, Mihai Stoica, Peter M. Derlet, Robert Maass
Summary: Metallic glasses have a strong yield strength but exhibit unpredictable behavior after yielding, with large scatter in flow stress levels and strains at failure. X-ray tomography reveals that a strain-dependent internal evolution of shear-band cavities explains this postyielding response. The growth of cavities during plastic flow follows a power law and exhibits self-similar surface properties after fracture. These findings explain the large variability in plastic flow behavior and the coexistence of internal microcracking and shear-band plasticity in metallic glasses.
PHYSICAL REVIEW MATERIALS
(2023)