Computational Materials Science最新文献

{"title":"First-principles analysis of improved thermodynamic stability and mechanical properties in pseudo-binary Y1−xVxB2 alloys","authors":"","doi":"10.1016/j.commatsci.2024.113287","DOIUrl":"10.1016/j.commatsci.2024.113287","url":null,"abstract":"<div><p>This work explores a possibility of improving the mechanical behavior and thermodynamic stability of AlB₂ -type YB₂ through alloying with isostructural VB₂ using first-principles calculations. The analysis derived from the cluster-expansion model suggests Y_0.5V_0.5B₂, whose atomic configuration is represented by periodically alternating YB₂/VB₂ layers in the ¡0001¿ direction, is the only solution in the pseudo-binary YB₂–VB₂ system predicted to be stable from the thermodynamic viewpoint. By evaluating the influence of lattice dynamics on the Gibbs free energies of superlattice-structured Y_0.5V_0.5B₂ and its constituent compounds within the quasiharmonic approximation, the thermodynamic stability, elastic properties, and hardness at a given pressure and temperature of the three diborides can be accessed. The results reveal, at a given temperature, isotropic compression of the diborides to high pressures enhances the stability of Y_0.5V_0.5B₂ measured relative to YB₂ and VB₂, while raising the temperature at a given applied pressure can increasingly result in a driving force toward separation of Y_0.5V_0.5B₂ into YB₂ and VB₂. The thermodynamic stabilization of superlattice-structured Y_0.5V_0.5B₂, despite large distinctions in atomic radius and electronegativity between Y and V, can be explained in terms of band filling induced by introduction of V atoms in YB₂. Within the range of temperatures (0–1200 K) and pressures (0–15 GPa) studied, the band-filling effect is found to result in significant positive deviations in the values of shear strength, stiffness, and hardness of superlattice-structured Y_0.5V_0.5B₂ from those evaluated from its constituent compounds using the Vegard’s law, respectively, by <span><math><mi>∼</mi></math></span>8%, <span><math><mi>∼</mi></math></span>5%, and <span><math><mi>∼</mi></math></span>25%, and the hardness of superlattice-structured Y_0.5V_0.5B₂ is <span><math><mi>∼</mi></math></span>40 GPa potentially indicating its superhard nature. These consequences strongly underline the essential impact of band filling on improvement in mechanical behavior and stability of YB₂ through alloying with VB₂, and also they can be served as guidance for further advancement of hard-coating technology based especially on transition-metal diborides.</p></div>","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141979532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Room temperature dislocation loop dynamics in body-centered cubic refractory multi-principal element alloys","authors":"Patrick F. McNutt, Morgan R. Jones, Pulkit Garg, Irene J. Beyerlein","doi":"10.1016/j.commatsci.2024.113280","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113280","url":null,"abstract":"In this work, we study loop dynamics at room temperature across three refractory multi-principal element alloys (RMPEAs) using a phase field dislocation dynamics simulation method with Langevin dynamics. The analyses reveal two regimes in stress for all RMPEAs studied. In the low-stress regime, glide of the edge portions is smooth, and glide of the screw portions is jerky. In the high-stress regime, the edge to screw mobility ratio is approximately two and the edge mobility doubles from that in the low-stress regime. We also test a rapid density function theory-based method for generating energetic landscapes for large 3D crystals for simulation. As another key result, we find that dislocation mechanisms, velocities, and mobilities predicted between the two methods agree over a wide range of effective stresses, where the effective stress is the difference between the athermal lattice friction stress and the applied stress at 300 K. The second method is highly efficient, offering a way for performing dislocation dynamics quickly over a broad composition space.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical and molecular dynamics studies of critical resolved shear stress for rhombohedral twinning of sapphire","authors":"Dalei Xi, Yiyang Du, Aditya Nagaraj, Suk Bum Kwon, Dae Nyoung Kim, Sangkee Min, Woo Kyun Kim","doi":"10.1016/j.commatsci.2024.113278","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113278","url":null,"abstract":"Single crystalline sapphire (-) possesses superior mechanical, thermal, chemical, and optical properties over a wide range of temperatures and pressure conditions, allowing it for a broad spectrum of industrial applications. For the past few decades, research has aimed at comprehensive understanding of its plastic deformation mechanisms under mechanical loading. In this study, we have employed molecular dynamics (MD) simulations to study rhombohedral twinning of sapphire, which is of critical importance in understanding the plastic deformation of sapphire as one of most commonly observed deformation modes. Since the critical resolved shear stress (CRSS) plays a pivotal role in describing the activation of slip systems, it is adopted in this study as the key parameter for analysis. The CRSS is calculated during the uniaxial compression test of a cubic sapphire crystal, oriented to exclusively activate rhombohedral twinning deformation, under simulation conditions such as temperature, strain rate, and system size. Furthermore, a theoretical model of CRSS is constructed based on theories of thermal activation processes, then empirically fitted to CRSS data gathered from the MD simulations. This model accurately captures the relationships between CRSS and external parameters including temperature, strain rate, and system size and shows excellent agreements with the simulation results.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite-temperature grain boundary properties from quasistatic atomistics","authors":"Miguel Spínola, Shashank Saxena, Prateek Gupta, Brandon Runnels, Dennis M. Kochmann","doi":"10.1016/j.commatsci.2024.113270","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113270","url":null,"abstract":"Grain boundary (GB) properties greatly influence the mechanical, electrical, and thermal response of polycrystalline materials. Most computational studies of GB properties at finite temperatures use molecular dynamics (MD), which is computationally expensive, limited in the range of accessible timescales, and requires cumbersome techniques like thermodynamic integration to estimate free energies. This restricts the reasonable computation (without incurring excessive computational expense) of GB properties to regimes that are often unrealistic, such as zero temperature or extremely high strain rates. Consequently, there is a need for simulation methodology that avoids the timescale limitations of MD, while providing reliable estimates of GB properties. The Gaussian Phase-Packet (GPP) method is a temporal coarse-graining technique that can predict relaxed atomic structures at finite temperature in the quasistatic limit. This work applies GPP, combined with the quasiharmonic approximation for computing the free energy, to the problem of determining the free energy and shear coupling factor of grain boundaries in metals over a range of realistic temperatures. Validation is achieved by comparison to thermodynamic integration and quasiharmonic approximation (QHA), which confirms that the presented approach captures relaxed-energy GB structures and shear coupling factors at finite temperature with a high degree of accuracy, and it performs significantly better than QHA on hydrostatically expanded 0 K structures.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A level set approach to modelling diffusional phase transformations under finite strains with application to the formation of [formula omitted]","authors":"Erik Jacobsson, Håkan Hallberg, Johan Hektor, Srinivasan Iyengar, Matti Ristinmaa","doi":"10.1016/j.commatsci.2024.113284","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113284","url":null,"abstract":"This paper presents a sharp interface formulation for modelling diffusional phase transformations. Grain boundary motion is, in accordance with diffusional phase transformation kinetics, determined by the amount of flux towards the interface and is formulated in a level set framework. This approach enables a computational efficiency that can be expected to be higher than what can be achieved with conventional phase field methods. Compatibility of the interfaces is obtained through an interface reconstruction process, in which the locations of triple junction points are also determined. To ensure local equilibrium and a continuous chemical potential across the interfaces, the chemical composition is prescribed at the phase interfaces. The presented model is used to study the growth of the intermetallic compound (IMC) for a system with Sn electroplated on a Cu substrate. A finite strain formulation is incorporated into the model to investigate the effects of the volume change resulting from the IMC formation. In this formulation, the Cu and Sn phases are allowed to deform plastically. The numerical simulations demonstrate IMC growth rates in agreement with experimental measurements. Moreover, the IMC evolves into a scallop-like morphology, consistent with experimental observations.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ab initio study of Al-doping effect on helium behaviors in scandium hydrides","authors":"Jianzhou Lv, Yongxiu Sun, Rui Wang, Xiang Zhong, Kaimin Fan, Yi Luo, Yiqiang He, Jinghong Zhang, Qingqiang Sun","doi":"10.1016/j.commatsci.2024.113281","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113281","url":null,"abstract":"Helium (He) in rare-earth metal hydrogen storage materials tends to aggregate and produce bubbles and release them, which has an impact on the lifetime of the materials. Therefore, it is crucial to study the aggregation behavior of He to improve the lifetime of the materials. In this paper, two forms of interstitial doping and substitution doping are selected by density-functional theory (DFT) calculations, and the effects of Al doping in ScH on the geometries, formation energies, and binding energies of He atoms, as well as the migration behaviors of the doped Al atoms on the migration of the He atoms are investigated in detail. Finally, it is demonstrated that Al doping in ScH makes it difficult for He atoms to exist near and stabilize the vacancies close to Al atoms, which is likely to inhibit the formation of clusters of He, and provides a strong basis for the realization of the improvement of helium-solidifying properties of ScH materials.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mining the relationship between microstructural characteristics and dynamic compression properties of dual-phase titanium alloys via data-driven random forest and finite element simulation","authors":"Gan Li, Qunbo Fan, Guoju Li, Lin Yang, Haichao Gong, Meiqin Li, Shun Xu, Xingwang Cheng","doi":"10.1016/j.commatsci.2024.113279","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113279","url":null,"abstract":"To optimize the dynamic compression properties of titanium alloys, it is necessary to reveal the internal relationship between microstructural characteristics and dynamic mechanical properties. In this work, a dynamic compression numerical simulation approach, based on realistic microstructures and parametric modeling was proposed and validated experimentally. Following this, 4075 sets of dynamic compression simulation results for dual-phase TC6 titanium alloys were calculated by high-throughput simulation. Subsequently, a regression model and a four-classification model, aiming to predict the dynamic strength (σ) and dynamic plasticity (ε) of titanium alloys, were established by the data-driven random forest algorithm. The regression model attained a goodness-of-fit metric of 0.99, while the four-classification model achieved an F1-score of 0.88. Further, combined with the Shapley additive explanations (SHAP), it was found that the width of secondary α phase (Sw) and the volume fraction of primary α phase (Pf) were the most critical microstructural characteristics. Specifically, Pf was negatively correlated with σ and ε, whereas Sw was negatively correlated with σ but positively correlated with ε. Meanwhile, intrinsic mechanisms behind the above laws were revealed through local stress and adiabatic shear sensitivity analyses of typical microstructure models. Finally, the range of microstructural characteristics of excellent dynamic mechanical properties (a Sw of 1 μm and a Pf ranging from 0.1 to 0.2.) was determined by further analysis of datasets without dynamic plastic fracture. These findings can provide a significant reference for subsequent experimental efforts to optimize the dynamic mechanical properties of titanium alloys.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-transformation assisted twinning in Molybdenum nanowires","authors":"Afnan Mostafa, Linh Vu, Zheming Guo, Ali K. Shargh, Aditya Dey, Hesam Askari, Niaz Abdolrahim","doi":"10.1016/j.commatsci.2024.113273","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113273","url":null,"abstract":"Systematic molecular dynamics simulations were conducted to investigate deformation mechanisms in molybdenum (Mo) nanowires (NWs) under uniaxial tensile and compressive loading, and their correlations with bulk materials containing crack tips. Our study revealed striking, orientation-dependent phase transformation and slip/twinning mechanisms. Specifically, -loaded structures exhibited a unique bcc-fcc-bcc phase transition with twin boundary formation, while -loaded structures showed phase transformation under compression but not tension. -loaded structures displayed no phase transformation-assisted twinning, deforming solely by slip. Bulk structures with cracks exhibited similar behavior, underscoring the high stresses needed to activate phase transformations. Density Functional Theory (DFT) calculations confirmed the metastability of the fcc phase, critical for twin formation and bcc phase reorientation. These findings highlight the potential for designing stronger, more ductile Mo-based nanomaterials, opening new avenues for advanced applications in nanotechnology and materials science.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classification enhanced machine learning model for energetic stability of binary compounds","authors":"Y.K. Liu, Z.R. Liu, T.F. Xu, D. Legut, X. Yin, R.F. Zhang","doi":"10.1016/j.commatsci.2024.113277","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113277","url":null,"abstract":"As contemporary computational technologies and machine learning methodologies rapidly evolve, machine learning (ML) models for predicting formation enthalpies of materials exhibited convincible numerical precision and remarkable predictive efficiency, thus establishing a solid foundation for materials thermodynamic design. Despite achieving numerically high global probability accuracy, current ML models for formation enthalpy nonetheless exhibit suboptimal local accuracy within specific physical domain, which can be attributed to the misalignment between the physical constraints of chemical bonds and the critical descriptors capturing class-specific traits. Herein, we propose a novel approach to improve the local precision of the ML model for predicting formation enthalpy by utilizing Miedema theory-based classification, which segments data into distinct categories according to the electronegativity difference, electron density discontinuity and atomic size difference. Utilizing ML algorithms to build surrogate models guided by the classification strategy significantly improves the local predictive accuracy of formation enthalpy for specific binary compounds, significantly raising the R value from 0.4–0.9 to 0.8–0.9 compared to an unclassified method. Furthermore, feature importance analysis demonstrates that the pivotal factors for each category vary in some manner, highlighting the insufficiency of a sole ML model in classifying large-dimensional data, which can be addressed by adopting a physics-informed classification strategy. Our results suggest that employing physical-informed classification scheme into ML equips the models with broad applicability and local accuracy, which also shed light for other material properties predication.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural predictions and phonon-mediated superconductivity in platinum hydride under low pressure: Insight from first-principles calculations","authors":"Prutthipong Tsuppayakorn-aek, Peng Song, Wiwittawin Sukmas, Ryo Maezono, Thiti Bovornratanaraks","doi":"10.1016/j.commatsci.2024.113265","DOIUrl":"https://doi.org/10.1016/j.commatsci.2024.113265","url":null,"abstract":"Prioritizing the exploration of superconductivity (SC) is paramount, given that it constitutes one of the most intriguing and consequential phenomenon within the realm of condensed matter physics. Our study aim is to elucidate the metallic state of platinum hydrides, a critical step in predicting its superconducting behavior. In this study, we utilize first-principles calculations combined with an evolutionary algorithm to explore the thermodynamically stable configurations of platinum hydrides under low-pressure conditions. Our results reveal several thermodynamically stable phases that have not been previously reported, specifically PtH and PtH. To assess the potential for SC within these materials, our examination unveils that PtH demonstrates a of 14.7K, whereas PtH attains 19.5K at a pressure of 10GPa. Following the solution of the Allen–Dynes modified McMillan equation, we gain insight into a substantial rise in the overall electron–phonon coupling parameter linked to a relatively modest cutoff frequency, as indicated by a bandwidth function. Our discoveries imply that PtH and PtH, exhibiting SC at lower pressures that are experimentally reachable, merit synthesis and subsequent measurement of their superconducting properties in a laboratory environment.","PeriodicalId":10650,"journal":{"name":"Computational Materials Science","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}