Article
Materials Science, Multidisciplinary
R. Santos-Guemes, L. Capolungo, J. Segurado, J. LLorca
Summary: Dislocation dynamics simulations were used to determine the critical resolved shear stress of an Al 4 wt. % Cu alloy containing theta'' precipitates, with results in good agreement with experimental data. The optimal strength of the alloy was found to be achieved with a homogeneous distribution of theta'' precipitates at an average size transitional between shearing and looping. Overall, the strategy presented in this study provides quantitative predictions of precipitate strengthening in metallic alloys.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Engineering, Mechanical
Jianshi Yang, Chunhui Liu, Peipei Ma, Longhui Chen, Lihua Zhan, Ning Yan
Summary: The effect of pre-deformation and post-ageing on the age hardening response and tensile properties of an Al-Cu alloy has been studied. It was found that moderate pre-deformation and specific temperature conditions can significantly improve the yield strength and uniform elongation of the alloy. Dislocations and precipitates play a major role in determining the strength of the alloy, while hard barriers can initiate void and deteriorate plasticity.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Chemistry, Physical
Shinji Muraishi
Summary: The study focused on evaluating the internal stress field of plate-shaped misfitting precipitates and their roles in dislocation overcoming the precipitates. The simulation results showed that the interaction force acted on the dislocation strongly depends on the stress field and geometry of misfit precipitates, with repulsive and attractive forces operating on the dislocations lying on the primary slip plane when approaching the misfit precipitates.
Article
Engineering, Mechanical
E. V. Fomin, A. E. Mayer, V. S. Krasnikov
Summary: The study reveals that the strength of clusters in aluminum alloy with copper content ranging from 20-100% depends on the number of copper atoms rather than the direct influence of copper concentration. Introducing copper-containing clusters into aluminum alloy can reduce the inhomogeneity of plastic deformation and aligns with experimental results.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Shweta Shukla, Balila Nagamani Jaya, V. S. Raja
Summary: The electrochemical kinetics of matrix precipitates-metastable MgZn2 (?') and GP II zones have been studied in relation to environmentally assisted cracking (EAC) using different testing methods. The presence of a high fraction of ?' and GP II zones in the alloy affected the hydrogen evolution, elongation values, and formation of defects in different solutions and conditions. The alloy with a higher volume fraction of GP II zones exhibited stronger trans-granular cracking, while the alloy with a higher fraction of ?' showed pitting and sub grain formation.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Pokula Narendra Babu, B. S. K. Gargeya, Bankim Chandra Ray, Snehanshu Pal
Summary: The deformation behavior of nanocrystalline Al and CNT-reinforced Al nanocomposites under torsional loading was studied using molecular dynamics simulations. The evolution of grain structure, crystal structure, and potential energy during torsional deformation were investigated. Fracture in both Al and CNT-reinforced Al nanocomposites occurred along the grain boundary, and the CNT fracture process in torsion was similar to tension. The CNT-NC Al nanocomposite exhibited a higher torsional failure strength compared to pure NC Al. The interactions between activated slip planes, stacking faults, and dislocation motion during torsion deformation were discussed, as well as the correlation between defect evolution and strain contour.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yaoxiang Duan, Han Chen, Zhe Chen, Lei Wang, Mingliang Wang, Jun Liu, Fengguo Zhang, Haowei Wang
Summary: The influence of different precipitate-dislocation interactions on PLC bands and surface roughness in AlMgScZr alloy was investigated. Shearable precipitates were found to decrease the number of PLC bands and surface roughness, providing guidance for designing structural materials with desirable mechanical property and surface quality.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Vasiliy S. Krasnikov, Alexander E. Mayer, Victor V. Pogorelko, Marat R. Gazizov
Summary: The study investigates the prolonged plastic deformation of aluminum containing theta' phase using a multistage approach combining MD, CM, and DDD. It is found that damage to the crystal structure of inclusions and activation of cross-slip of dislocation segments lead to a decrease in acting stresses in the MD system. The softening effect of inclusions is further introduced into the dislocation-precipitate interaction, causing a decrease in flow stress during deformation.
APPLIED SCIENCES-BASEL
(2021)
Article
Materials Science, Multidisciplinary
Jovid U. Rakhmonov, Sumit Bahl, Amit Shyam, David C. Dunand
Summary: The study found that the RR350 alloy has better creep resistance than the ACMZ alloy at low stresses due to a higher amount of intergranular precipitates and fewer precipitate-free zones near grain boundaries. At high stresses, compressive creep is controlled by dislocation creep, while tensile creep is influenced by cavitation at intergranular precipitates.
Article
Materials Science, Multidisciplinary
Shweta Shukla, Balila Nagamani Jaya, V. S. Raja
Summary: The electrochemical kinetics of matrix precipitates, eta' and GP II zones, were investigated in terms of environmentally assisted cracking (EAC). It was found that a higher fraction of eta' resulted in increased hydrogen evolution and decreased elongation values in the alloy. Pitting and sub-grain formation were observed on the eta'-dominated alloy, while transgranular cracks were observed on the GP II-dominated alloy. The dislocation density was also found to be higher in the alloy with a higher volume fraction of GP II zones, leading to a higher drop in tensile strength in the cathodically charged condition.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Xiang Wang, Sixue Zheng, Shuhei Shinzato, Zhengwu Fang, Yang He, Li Zhong, Chongmin Wang, Shigenobu Ogata, Scott X. Mao
Summary: As the sample size decreases to the nanoscale, surface-related mechanisms become crucial in the deformation of nanoscale crystals, including diffusion-induced nucleation behaviors and the potential for mass transport facilitated by the ultrahigh surface-to-volume ratio.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Nipal Deka, Alexander Stukowski, Ryan B. Sills
Summary: We present a method called Interfacial Line Defect Analysis (ILDA) for identifying and extracting interfacial dislocations and disconnections without requiring detailed input on the nature of the interface. ILDA can provide exact Burgers vectors by only providing the orientations and coherency strains of the crystals at a coherent reference state of the interface. Alternatively, these orientations and strains can be estimated using local atomic deformation gradients, making ILDA fully automated and providing estimated Burgers vectors. ILDA also determines the step height associated with each defect line segment, in case the associated defect is a disconnection. The method relies on the identification of atoms residing at coincidence sites between the two crystals and the construction of a surface mesh connecting these sites to compose Burgers circuits and insert defect line segments. The performance of ILDA is demonstrated in two test cases: a twist grain boundary and a phase boundary.
Article
Nanoscience & Nanotechnology
F. J. Dominguez-Gutierrez, S. Papanikolaou, A. Esfandiarpour, P. Sobkowicz, M. Alava
Summary: The study investigates the effects of high temperature on the mechanical deformation properties of single crystalline Mo under nanoindentation, revealing that temperature increase changes dislocation densities, mechanisms, atomic displacements, and hardness. The characteristic formation of [001] dislocation junctions and high-temperature stability may be responsible for the persistent thermomechanical stability of Mo, contrasting with other BCC metals.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Mouparna Manna, Snehanshu Pal
Summary: This study investigates the radiation damage in irradiated copper specimens using molecular dynamics simulations. The results show that nanostructured copper specimens have fewer defects and grain boundaries serve as effective radiation sinks.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Dongshuai Hou, Qingrui Yang, Zuquan Jin, Pan Wang, Muhan Wang, Xinpeng Wang, Yue Zhang
Summary: The bonding properties of the epoxy-concrete interface can be significantly improved by GO modification, as demonstrated in molecular dynamics simulations. Epoxy adhered to the GO sheet exhibits higher resistance to pulling forces, indicating improved bonding performance.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Polina N. Mayer, Alexander E. Mayer
Summary: In most cases, uniformly dissolved hydrogen does not change the tensile strength of aluminum significantly; alumina can significantly reduce the tensile strength of solid aluminum, but the decrease is less significant in a molten state; the presence of non-collapsing hydrogen bubbles in the aluminum melt causes a sharp decrease in tensile strength.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Engineering, Mechanical
Alexander E. Mayer
Summary: The micromechanical model developed in this study can describe the deformation of metal powder under different compression states, including compression stage, percolation transition of pore system, and collapse stage of pores. By using molecular dynamics simulations, it was found that dislocation activity is the main driver of plastic deformation of metal nanoparticles during compaction, and the presence of twins was observed in copper and magnesium nanoparticles.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Egor S. Rodionov, Victor G. Lupanov, Natalya A. Gracheva, Polina N. Mayer, Alexander E. Mayer
Summary: Taylor impact tests and numerical methods were used to study the dynamic plasticity of cold-rolled OFHC copper. The experimental part revealed the existence of pore-like structures and refinement of grain structure in the deformed parts of the sample. The numerical modeling included a dislocation plasticity model and an artificial neural network to optimize the material model for cold-rolled OFHC copper.
Article
Materials Science, Multidisciplinary
V. S. Krasnikov, M. R. Gazizov, A. E. Mayer, P. A. Bezborodova, V. V. Pogorelko, R. O. Kaibyshev
Summary: The effect of precipitate hybridization on macroscopic strengthening in aluminum alloys was investigated using a multiscale approach. The results showed that the shear strength of the alloy with hybrid precipitates was 20% higher than that for non-hybrid plates.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Alexander E. Mayer, Vasiliy S. Krasnikov
Summary: This study investigates the nucleation of dislocations in copper single crystals under different pressure ranges. Artificial neural networks are trained to approximate material properties and improve the accuracy of the dislocation nucleation theory.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Alexander E. Mayer, Mikhail Lekanov, Natalya A. Grachyova, Eugeniy Fomin
Summary: In this study, molecular dynamics simulations were used to explore the deformation behavior of copper single crystal under different loading paths, and the obtained data was utilized to develop a machine-learning-based model for copper's elastic-plastic deformation. Artificial neural networks approximated the elastic stress-strain relation, as well as the thresholds for homogeneous nucleation of dislocations, phase transition, and the initiation of spall fracture. The plastic portion of the MD curves was used to calibrate the dislocation plasticity model, enabling the application of the developed constitutive model to simulate shock waves in thin copper samples under dynamic impact.
Article
Engineering, Mechanical
Vasiliy S. Krasnikov, Polina A. Bezborodova, Alexander E. Mayer
Summary: In this study, the effect of hydrogen accumulation on 0' strengthening precipitates in Al-Cu alloy was investigated. The results showed that hydrogen accumulation leads to a decrease in the shear resistance of precipitates and causes a change in the dislocation-precipitate interaction mechanism, resulting in a reduction in the alloy's shear strength.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Polina N. Mayer, Victor V. Pogorelko, Dmitry S. Voronin, Alexander E. Mayer
Summary: In this study, a mechanical model of spall fracture of copper is developed and verified, which covers both solid and molten states. The optimal parameters of the model are identified using a machine-learning-type Bayesian algorithm. The influence of initial size distribution of pores or non-wettable inclusions on the strain rate dependence of spall strength in copper is analyzed. This investigation contributes to the development of atomistically-based machine learning approaches in understanding the strength properties of metals and deepening the understanding of the spall fracture process.
Article
Materials Science, Multidisciplinary
Alexander E. E. Mayer, Polina N. N. Mayer, Mikhail V. V. Lekanov, Boris A. A. Panchenko
Summary: By studying the plastic flow behavior of nanoporous metals under tension using molecular dynamics simulations and artificial neural networks, a possible framework for constructing mechanical models of spall fracture in metals has been proposed.
Article
Chemistry, Physical
Vasiliy Krasnikov, Alexander Mayer, Polina Bezborodova, Marat Gazizov
Summary: This paper investigates the impact of Cu atom concentration at grain boundaries (GBs) on plastic relaxation mechanisms and mechanical response in nanocrystalline aluminum using molecular dynamics simulations. The study reveals a nonmonotonic relationship between the critical resolved shear stress and Cu content at GBs, which is attributed to changes in plastic relaxation mechanisms. At low Cu content, GBs slip via dislocation walls, whereas an increase in Cu content leads to dislocation emission from GBs and grain rotation with GB sliding.
Article
Nanoscience & Nanotechnology
M. R. Gazizov, A. N. Belyakov, R. Holmestad, M. Yu. Gazizova, V. S. Krasnikov, P. A. Bezborodova, R. O. Kaibyshev
Summary: The coarsening behavior of strengthening particles in peak-aged Al-Cu-Mg-Ag alloy during creep at 150 degrees C and 165 degrees C has been studied. It was found that the average thickness and diameter of {111}Al omega plates strongly depend on creep time and less on applied stress levels and plastic strain during creep. The volume fraction of omega particles increased during long-term creep and exceeded the value after peak aging. S-phase and theta'-phase independently nucleate and intergrow to form precipitate complexes. The size of the complex particles is sensitive to the plastic strain level achieved at different applied stresses during creep.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Egor S. Rodionov, Victor V. Pogorelko, Victor G. Lupanov, Polina N. Mayer, Alexander E. Mayer
Summary: Current progress in numerical simulations and machine learning allows for the identification of parameters in plasticity models using complex loading conditions. A combined experimental-numerical approach is developed and applied to the study of cold-rolled OFHC copper. Profiled projectiles are proposed for the Taylor impact problem for the first time for material characterization, which allows for large plastic deformations with high strain rates. The optimized numerical model is successfully validated using experimental data.
Article
Mechanics
N. A. Gracheva, M. Lekanov, A. E. Mayer, E. Fomin
Summary: A technique has been developed using artificial neural networks to describe the relationship between stresses, strains, and the onset of plastic flow in metal single crystals. The datasets for training are generated using molecular dynamics modeling, showing promising results in simulating shock wave propagation and studying dislocation nucleation.
MECHANICS OF SOLIDS
(2021)