Pub Date : 2024-03-28DOI: 10.1088/1361-651x/ad38d1
Guanglong Huang, Alexander Mensah, Marcel Chlupsa, Zachary Croft, Liang Qi, Ashwin J. Shahani, Katsuyo Thornton
We present a phase-field model to simulate the microstructure evolution occurring in polycrystalline materials with a variation in the intra-granular dislocation density. The model accounts for two mechanisms that lead to the grain boundary migration: the driving force due to capillarity and that due to the stored energy arising from a spatially varying dislocation density. In addition to the order parameters that distinguish regions occupied by different grains, we introduce dislocation density fields that describe spatial variation of the dislocation density. We assume that the dislocation density decays as a function of the distance the grain boundary has migrated. To demonstrate and parameterize the model, we simulate microstructure evolution in two dimensions, for which the initial microstructure is based on real-time experimental data. Additionally, we applied the model to study the effect of a cyclic heat treatment on the microstructure evolution. Specifically, we simulated stored-energy-driven grain growth during three thermal cycles, as well as grain growth without stored energy that serves as a baseline for comparison. We showed that the microstructure evolution proceeded much faster when the stored energy was considered. A non-self-similar evolution was observed in this case, while a nearly self-similar evolution was found when the microstructure evolution is driven solely by capillarity. These results suggest a possible mechanism for the initiation of abnormal grain growth during cyclic heat treatment. Finally, we demonstrate an integrated experimental-computational workflow that utilizes the experimental measurements to inform the phase-field model and its parameterization, which provides a foundation for the development of future simulation tools capable of quantitative prediction of microstructure evolution during non-isothermal heat treatment.
{"title":"Phase-Field Modeling of Stored-Energy-Driven Grain Growth with Intra-Granular Variation in Dislocation Density","authors":"Guanglong Huang, Alexander Mensah, Marcel Chlupsa, Zachary Croft, Liang Qi, Ashwin J. Shahani, Katsuyo Thornton","doi":"10.1088/1361-651x/ad38d1","DOIUrl":"https://doi.org/10.1088/1361-651x/ad38d1","url":null,"abstract":"\u0000 We present a phase-field model to simulate the microstructure evolution occurring in polycrystalline materials with a variation in the intra-granular dislocation density. The model accounts for two mechanisms that lead to the grain boundary migration: the driving force due to capillarity and that due to the stored energy arising from a spatially varying dislocation density. In addition to the order parameters that distinguish regions occupied by different grains, we introduce dislocation density fields that describe spatial variation of the dislocation density. We assume that the dislocation density decays as a function of the distance the grain boundary has migrated. To demonstrate and parameterize the model, we simulate microstructure evolution in two dimensions, for which the initial microstructure is based on real-time experimental data. Additionally, we applied the model to study the effect of a cyclic heat treatment on the microstructure evolution. Specifically, we simulated stored-energy-driven grain growth during three thermal cycles, as well as grain growth without stored energy that serves as a baseline for comparison. We showed that the microstructure evolution proceeded much faster when the stored energy was considered. A non-self-similar evolution was observed in this case, while a nearly self-similar evolution was found when the microstructure evolution is driven solely by capillarity. These results suggest a possible mechanism for the initiation of abnormal grain growth during cyclic heat treatment. Finally, we demonstrate an integrated experimental-computational workflow that utilizes the experimental measurements to inform the phase-field model and its parameterization, which provides a foundation for the development of future simulation tools capable of quantitative prediction of microstructure evolution during non-isothermal heat treatment.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"121 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140370346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the molecular dynamics simulation of the repeated nanocutting of single crystal γ-Tial alloy was carried out by selecting different geometric parameters of the second cutting tool by single factor experiment. The cutting force, friction coefficient, subsurface defects, dislocation evolution and surface roughness of the second cutting were analyzed systematically. The results show that when the tool rake angle is 15°, the surface roughness is lower and the surface quality is better. The influence of different second cutting tool rake angle on the surface roughness is not strong. When the rake angle of the second cutting tool and the radius of edge are constant, the average normal cutting force decreases with the increase of the clearance angle of the tool. Under the machining parameters in this paper, the critical clearance angle of the second cutting of single crystal γ-TiAl alloy is between 10° and 15°. When the tool clearance angle is greater than the critical clearance angle, the average cutting force and the machined-surface roughness no longer change significantly. With the increase of the radius of the second cutting tool, the chip decreases, the subsurface defect increases, and the surface roughness of the machined surface also increases with strong regularity.
{"title":"Effect of repetitive nano-cutting tool parameters on surface quality and subsurface damage of γ-TiAl alloy","authors":"Yang Liu, Longyue Liu, Haiyan Li, Baocheng Zhou, Huidong Cao, Ruicheng Feng","doi":"10.1088/1361-651x/ad3665","DOIUrl":"https://doi.org/10.1088/1361-651x/ad3665","url":null,"abstract":"\u0000 In this paper, the molecular dynamics simulation of the repeated nanocutting of single crystal γ-Tial alloy was carried out by selecting different geometric parameters of the second cutting tool by single factor experiment. The cutting force, friction coefficient, subsurface defects, dislocation evolution and surface roughness of the second cutting were analyzed systematically. The results show that when the tool rake angle is 15°, the surface roughness is lower and the surface quality is better. The influence of different second cutting tool rake angle on the surface roughness is not strong. When the rake angle of the second cutting tool and the radius of edge are constant, the average normal cutting force decreases with the increase of the clearance angle of the tool. Under the machining parameters in this paper, the critical clearance angle of the second cutting of single crystal γ-TiAl alloy is between 10° and 15°. When the tool clearance angle is greater than the critical clearance angle, the average cutting force and the machined-surface roughness no longer change significantly. With the increase of the radius of the second cutting tool, the chip decreases, the subsurface defect increases, and the surface roughness of the machined surface also increases with strong regularity.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"204 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140223000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1088/1361-651x/ad33de
Kai-chieh Chiang, M. Koslowski
We present a mechano-chemical model that couples corrosion, mechanical response, and fracture. The model is used to understand the failure of Cu wires on Al pads in microelectronic packages using a multi-phase field approach. Under high humidity environments, the Cu-rich intermetallic compounds (IMC), Cu9Al4, formed at the interface between Cu and Al, undergo a corrosion degradation process. The IMC expands while undergoing corrosion, inducing stresses that nucleate and propagate cracks along the interface between the Cu-rich IMC and Cu. Furthermore, the volumetric expansion of the IMC may cause damage to the passivation layer and enhance the nucleation of new corrosion pits. We show that the presence of a crack accelerates the corrosion process. The model developed here can be extended to other systems and applications.
我们提出了一种将腐蚀、机械响应和断裂结合起来的机械化学模型。该模型采用多相场方法，用于理解微电子封装中铝垫上铜线的失效。在高湿度环境下，铜和铝界面上形成的富铜金属间化合物（IMC）Cu9Al4 会发生腐蚀降解过程。IMC 在腐蚀过程中会膨胀，从而产生应力，使富含 Cu 的 IMC 与 Cu 之间的界面产生裂纹并沿裂纹扩展。此外，IMC 的体积膨胀可能会对钝化层造成破坏，并促进新腐蚀坑的成核。我们的研究表明，裂纹的存在会加速腐蚀过程。此处开发的模型可扩展到其他系统和应用中。
{"title":"Corrosion-induced fracture of Cu-Al microelectronics interconnects","authors":"Kai-chieh Chiang, M. Koslowski","doi":"10.1088/1361-651x/ad33de","DOIUrl":"https://doi.org/10.1088/1361-651x/ad33de","url":null,"abstract":"\u0000 We present a mechano-chemical model that couples corrosion, mechanical response, and fracture. The model is used to understand the failure of Cu wires on Al pads in microelectronic packages using a multi-phase field approach. Under high humidity environments, the Cu-rich intermetallic compounds (IMC), Cu9Al4, formed at the interface between Cu and Al, undergo a corrosion degradation process. The IMC expands while undergoing corrosion, inducing stresses that nucleate and propagate cracks along the interface between the Cu-rich IMC and Cu. Furthermore, the volumetric expansion of the IMC may cause damage to the passivation layer and enhance the nucleation of new corrosion pits. We show that the presence of a crack accelerates the corrosion process. The model developed here can be extended to other systems and applications.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"2 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140241895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-12DOI: 10.1088/1361-651x/ad332f
Gustavo Cuba-Supanta, Pedro Amao, Fredi Quispe-Huaynasi, Milida Zarella Zarella Pinto Vergara, Elluz Pacheco, S. Flores, Carlos Soncco, Veronica Loaiza-Tacuri, Justo Alcides Rojas Tapia
Metal ternary nanoalloys or trimetallic nanoparticles have emerged, in recent years, as novel and relevant materials in different fields due to the synergy of three metals in a single system that leads to unique physicochemical properties as compared to mono- and bimetallic nanoparticles. In this study, the influence of composition on the structural and thermodynamic properties of Cu-Ag-Au nanoalloys with 5083 atoms is analyzed using molecular dynamics simulations. Relevant thermodynamic quantities are used to describe the melting and solidification behaviors of three models of Cu-Ag-Au nanoalloys. Our results indicate that the melting temperature presents linear and quadratic dependencies with the composition, i.e., for Cu33 Ag67−x Aux , Ag33 Cu67−x Aux , and Au33 Ag67−x Cux are Tm = 912.6 + 1.9x, Tm = 882.3 + 2.7x, and Tm = 1056.6 − 4.9x + 0.07x2, respectively. In addition, most Ag atoms segregate to the surface and the Au and Cu atoms are localized in the center of the nanoalloy during the heating process, and this trend is maintained in the cooling process. The solidification temperature does not have an explicit correlation with the composition. Furthermore, the structural analysis of cooled nanoalloys exhibits local FCC and HCP symmetries, and the excess energy shows that Cu33Ag27Au40, Au33Ag17Cu50, and Ag33Cu37Au30 are relatively more stable to form nanoalloys. Finally, the possibility of controlling the composition in these metal nanoalloys opens up potential applications in plasmonic, catalysis, and bactericidal (by Ag surface segregation) fields.
{"title":"The composition effect on the structural and thermodynamic properties of Cu-Ag-Au ternary nanoalloys: A study via molecular dynamics approach","authors":"Gustavo Cuba-Supanta, Pedro Amao, Fredi Quispe-Huaynasi, Milida Zarella Zarella Pinto Vergara, Elluz Pacheco, S. Flores, Carlos Soncco, Veronica Loaiza-Tacuri, Justo Alcides Rojas Tapia","doi":"10.1088/1361-651x/ad332f","DOIUrl":"https://doi.org/10.1088/1361-651x/ad332f","url":null,"abstract":"\u0000 Metal ternary nanoalloys or trimetallic nanoparticles have emerged, in recent years, as novel and relevant materials in different fields due to the synergy of three metals in a single system that leads to unique physicochemical properties as compared to mono- and bimetallic nanoparticles. In this study, the influence of composition on the structural and thermodynamic properties of Cu-Ag-Au nanoalloys with 5083 atoms is analyzed using molecular dynamics simulations. Relevant thermodynamic quantities are used to describe the melting and solidification behaviors of three models of Cu-Ag-Au nanoalloys. Our results indicate that the melting temperature presents linear and quadratic dependencies with the composition, i.e., for Cu33 Ag67−x Aux , Ag33 Cu67−x Aux , and Au33 Ag67−x Cux are Tm = 912.6 + 1.9x, Tm = 882.3 + 2.7x, and Tm = 1056.6 − 4.9x + 0.07x2, respectively. In addition, most Ag atoms segregate to the surface and the Au and Cu atoms are localized in the center of the nanoalloy during the heating process, and this trend is maintained in the cooling process. The solidification temperature does not have an explicit correlation with the composition. Furthermore, the structural analysis of cooled nanoalloys exhibits local FCC and HCP symmetries, and the excess energy shows that Cu33Ag27Au40, Au33Ag17Cu50, and Ag33Cu37Au30 are relatively more stable to form nanoalloys. Finally, the possibility of controlling the composition in these metal nanoalloys opens up potential applications in plasmonic, catalysis, and bactericidal (by Ag surface segregation) fields.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"13 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140250187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-12DOI: 10.1088/1361-651x/ad332e
Shubham Agarwal, Sheldon I Green, A. Phani
Non-woven cellulose fiber networks of low areal density are widely used in many industrial applications and consumer products. A discrete element method (DEM) modelling framework is advanced to simulate the formation of strongly anisotropic cellulose fiber network sheets in the dilute limit with simplified hydrodynamic and hydroelastic interactions. Our modelling accounts for in-plane fiber orientation and viscous drag indirectly by using theories developed by Niskanen (1989) and Cox (1970) respectively. Networks formed on a patterned and flat substrate are simulated for different fiber types, and their tensile response is used to assess the influence of the out-of-plane topographical pattern on their stiffness and strength. Sheets with the same grammage and thickness, but composed with a higher fraction of softwood fiber (longer fibers with large diameter), have higher strength and higher strain to failure compared to sheets made from hardwood fibers (short fibers with small diameter). However, varying the fiber fraction produces only an insignificant variation in the initial sheet stiffness. The above simulation predictions are confirmed experimentally for sheets comprised of fibers with different ratios of Eucalyptus kraft and Northern Bleached Softwood Kraft fibers. Sheets with out-of- plane topography show an unsymmetric mass distribution, lower tensile stiffness, and lower tensile strength compared to those formed on a flat substrate. The additional fiber deformation modes activated by the out-of-plane topography, such as bending and twisting, explain these differences in the sheet mechanical characteristics.
{"title":"Modelling and simulation of anisotropic cross-linked cellulose fiber networks with an out-of-plane topography","authors":"Shubham Agarwal, Sheldon I Green, A. Phani","doi":"10.1088/1361-651x/ad332e","DOIUrl":"https://doi.org/10.1088/1361-651x/ad332e","url":null,"abstract":"\u0000 Non-woven cellulose fiber networks of low areal density are widely used in many industrial applications and consumer products. A discrete element method (DEM) modelling framework is advanced to simulate the formation of strongly anisotropic cellulose fiber network sheets in the dilute limit with simplified hydrodynamic and hydroelastic interactions. Our modelling accounts for in-plane fiber orientation and viscous drag indirectly by using theories developed by Niskanen (1989) and Cox (1970) respectively. Networks formed on a patterned and flat substrate are simulated for different fiber types, and their tensile response is used to assess the influence of the out-of-plane topographical pattern on their stiffness and strength. Sheets with the same grammage and thickness, but composed with a higher fraction of softwood fiber (longer fibers with large diameter), have higher strength and higher strain to failure compared to sheets made from hardwood fibers (short fibers with small diameter). However, varying the fiber fraction produces only an insignificant variation in the initial sheet stiffness. The above simulation predictions are confirmed experimentally for sheets comprised of fibers with different ratios of Eucalyptus kraft and Northern Bleached Softwood Kraft fibers. Sheets with out-of- plane topography show an unsymmetric mass distribution, lower tensile stiffness, and lower tensile strength compared to those formed on a flat substrate. The additional fiber deformation modes activated by the out-of-plane topography, such as bending and twisting, explain these differences in the sheet mechanical characteristics.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"16 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140250458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-07DOI: 10.1088/1361-651x/ad312b
Daniel J. Long, Yang Liu, Chris Hardie, Fionn P.E. Dunne
This work addresses in-situ synergistic irradiation and thermomechanical loading of nuclear reactor components by linking new mechanistic understanding with crystal plasticity finite element modelling to describe the formation and thermal and mechanical annihilation of dislocation loops. A model of pressurised reactor cladding is constructed to extract realistic boundary conditions for crystal plasticity microstructural sub-modelling. Thermomechanical loads are applied to the sub-model to investigate (i) the unirradiated state, (ii) synergistic coupling of irradiation damage and thermal annihilation of dislocation loops, (iii) synergistic coupling of irradiation damage without thermal annihilation of dislocation loops, and (iv) a post-irradiated state. Results demonstrate that the synergistic coupling of irradiation damage and thermomechanical loads leads to the early onset of plasticity, which is exacerbated by the thermal annihilation of dislocations, while the post-irradiated case remains predominantly elastic due to substantial irradiation hardening. It is shown that full synergistic coupling leads to localisation of quantities linked with crack nucleation including geometrically necessary dislocations and stress.
{"title":"Synergistic coupling of thermomechanical loading and irradiation damage in Zircaloy-4","authors":"Daniel J. Long, Yang Liu, Chris Hardie, Fionn P.E. Dunne","doi":"10.1088/1361-651x/ad312b","DOIUrl":"https://doi.org/10.1088/1361-651x/ad312b","url":null,"abstract":"\u0000 This work addresses in-situ synergistic irradiation and thermomechanical loading of nuclear reactor components by linking new mechanistic understanding with crystal plasticity finite element modelling to describe the formation and thermal and mechanical annihilation of dislocation loops. A model of pressurised reactor cladding is constructed to extract realistic boundary conditions for crystal plasticity microstructural sub-modelling. Thermomechanical loads are applied to the sub-model to investigate (i) the unirradiated state, (ii) synergistic coupling of irradiation damage and thermal annihilation of dislocation loops, (iii) synergistic coupling of irradiation damage without thermal annihilation of dislocation loops, and (iv) a post-irradiated state. Results demonstrate that the synergistic coupling of irradiation damage and thermomechanical loads leads to the early onset of plasticity, which is exacerbated by the thermal annihilation of dislocations, while the post-irradiated case remains predominantly elastic due to substantial irradiation hardening. It is shown that full synergistic coupling leads to localisation of quantities linked with crack nucleation including geometrically necessary dislocations and stress.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"17 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140260053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-04DOI: 10.1088/1361-651x/ad2fd6
Lauren T. W. Fey, Abigail Hunter, Irene Beyerlein
In this work, we employ a phase field dislocation dynamics technique to simulate dislocation motion in body centered cubic refractory metals with diffusing interstitials. Two distinct systems are treated, Nb with O interstitials and W with H interstitials, to consider both relatively small and large atomic size interstitials. Simulations without and with driving stress are designed to investigate the role of interstitial type and mobility on the glide of edge- and screw-character dislocations. The simulations reveal the various short- and long-range dislocation–interstitial interactions that can take place and their dependency on interstitial type, site occupation, stress state, and mobility of the interstitials relative to dislocations. We show that while interstitial O increases the breakaway stress for both screw and edge dislocations in Nb, interstitial H in low H concentrations makes screw dislocations easier and the edge dislocations harder to move. The simulations find that screw dislocation glide is enhanced by the presence of interstitials in both systems. Edge dislocation glide is enhanced in W-H and inhibited in Nb-O.
在这项研究中，我们采用相场位错动力学技术来模拟具有扩散间隙的体心立方难熔金属中的位错运动。我们处理了两个不同的系统，即含有 O 间隙的 Nb 和含有 H 间隙的 W，以考虑相对较小和较大原子尺寸的间隙。设计了无驱动应力和有驱动应力的模拟，以研究间隙类型和迁移率对边缘位错和螺旋位错滑行的作用。模拟揭示了位错与间隙之间可能发生的各种短程和长程相互作用，以及它们对间隙类型、位点占据、应力状态和间隙相对于位错的流动性的依赖性。我们发现，在铌中，间隙 O 会增加螺位错和边位错的脱离应力，而低 H 浓度的间隙 H 则会使螺位错更容易移动，边位错更难移动。模拟发现，在这两种体系中，间隙的存在会增强螺位错的滑动。边缘位错滑行在 W-H 中得到增强，而在 Nb-O 中受到抑制。
{"title":"Role of diffusing interstitials on dislocation glide in refractory body centered cubic metals","authors":"Lauren T. W. Fey, Abigail Hunter, Irene Beyerlein","doi":"10.1088/1361-651x/ad2fd6","DOIUrl":"https://doi.org/10.1088/1361-651x/ad2fd6","url":null,"abstract":"\u0000 In this work, we employ a phase field dislocation dynamics technique to simulate dislocation motion in body centered cubic refractory metals with diffusing interstitials. Two distinct systems are treated, Nb with O interstitials and W with H interstitials, to consider both relatively small and large atomic size interstitials. Simulations without and with driving stress are designed to investigate the role of interstitial type and mobility on the glide of edge- and screw-character dislocations. The simulations reveal the various short- and long-range dislocation–interstitial interactions that can take place and their dependency on interstitial type, site occupation, stress state, and mobility of the interstitials relative to dislocations. We show that while interstitial O increases the breakaway stress for both screw and edge dislocations in Nb, interstitial H in low H concentrations makes screw dislocations easier and the edge dislocations harder to move. The simulations find that screw dislocation glide is enhanced by the presence of interstitials in both systems. Edge dislocation glide is enhanced in W-H and inhibited in Nb-O.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"77 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140080304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-25DOI: 10.1088/1361-651x/ad2285
Jianping Xiao, Li Yang, Shuqun Wang
Accurate and rapid bandgap prediction is a fundamental task in materials science. We propose graph neural networks with transfer learning to overcome the scarcity of training data for high-fidelity bandgap predictions. We also add a perturbation-based component to our framework to improve explainability. The experimental results show that a framework consisting of graph-level pre-training and standard fine-tuning achieves superior performance on all high-fidelity bandgap prediction tasks and training-set sizes. Furthermore, the framework provides a reliable explanation that considers node features together with the graph structure. We also used the framework to screen 105 potential photovoltaic absorber materials.
{"title":"Accurate and rapid predictions with explainable graph neural networks for small high-fidelity bandgap datasets","authors":"Jianping Xiao, Li Yang, Shuqun Wang","doi":"10.1088/1361-651x/ad2285","DOIUrl":"https://doi.org/10.1088/1361-651x/ad2285","url":null,"abstract":"\u0000 Accurate and rapid bandgap prediction is a fundamental task in materials science. We propose graph neural networks with transfer learning to overcome the scarcity of training data for high-fidelity bandgap predictions. We also add a perturbation-based component to our framework to improve explainability. The experimental results show that a framework consisting of graph-level pre-training and standard fine-tuning achieves superior performance on all high-fidelity bandgap prediction tasks and training-set sizes. Furthermore, the framework provides a reliable explanation that considers node features together with the graph structure. We also used the framework to screen 105 potential photovoltaic absorber materials.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139596187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-25DOI: 10.1088/1361-651x/ad2286
Y. Jiao, Wenshi Ma
Many polymers have been used to design polymer/metal composite structures with high bond strength through nano-moulding technology. However, whether high-molecular-weight polymers flow deeply into nanostructures and whether polymer entanglement hinders complete infiltration remain contentious issues in theoretical studies. In this study, the effects of the injection pressure, molecular weight of the semi-rigid polymer [polyphenylene sulfide (PPS)], and nanostructure size of the metal surface on the replication quality were investigated by molecular dynamics simulations. Increasing the injection pressure and polymer molecular weight increased the replication quality at practical temperatures. PPS with various chain lengths could completely infiltrate the nanopores. The nanostructure size of the metal surface was weakly negatively correlated with the filling rate, but it was substantially negatively correlated with the infiltration behaviour of the entire PPS chain. The reasons for infiltration of long-chain PPS and the steady evolution of the entanglement density were investigated. The steady entanglement density of PPS indicates that entanglement is not the main reason for the low filling rate. From the mobility of a single chain, the PPS chain flows into nanopores in a snake-like fashion. These results provide new insights to improve the adhesion strength between polymers and metals in nano-injection moulding.
{"title":"Simulating the Replication and Entanglement of Semi-Rigid Polymers in Nano-Injection Moulding","authors":"Y. Jiao, Wenshi Ma","doi":"10.1088/1361-651x/ad2286","DOIUrl":"https://doi.org/10.1088/1361-651x/ad2286","url":null,"abstract":"\u0000 Many polymers have been used to design polymer/metal composite structures with high bond strength through nano-moulding technology. However, whether high-molecular-weight polymers flow deeply into nanostructures and whether polymer entanglement hinders complete infiltration remain contentious issues in theoretical studies. In this study, the effects of the injection pressure, molecular weight of the semi-rigid polymer [polyphenylene sulfide (PPS)], and nanostructure size of the metal surface on the replication quality were investigated by molecular dynamics simulations. Increasing the injection pressure and polymer molecular weight increased the replication quality at practical temperatures. PPS with various chain lengths could completely infiltrate the nanopores. The nanostructure size of the metal surface was weakly negatively correlated with the filling rate, but it was substantially negatively correlated with the infiltration behaviour of the entire PPS chain. The reasons for infiltration of long-chain PPS and the steady evolution of the entanglement density were investigated. The steady entanglement density of PPS indicates that entanglement is not the main reason for the low filling rate. From the mobility of a single chain, the PPS chain flows into nanopores in a snake-like fashion. These results provide new insights to improve the adhesion strength between polymers and metals in nano-injection moulding.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139596455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.1088/1361-651x/ad2187
Yongbo Liu, Mingtao Wang, Qingcheng Liu, J. Jin, Qing Peng, Y. Zong
A combination of phase-field simulations and experimental validation is utilized to examine the effect of annealing tension on the microstructure evolution of 439 ferrite stainless steel (FSS). The study reveals the competing mechanisms of texture under tensile stress. Furthermore, a phase field model that incorporates anisotropic grain boundary (GB) energy and elastic energy is established. The microstructure of 439 FSS is created using a 3D reconstruction strategy based on the 2D EBSD characterization proposed in this work. Elastic constants are calibrated using actual alloy data and determined through molecular dynamics simulations. Finally, simulations of the grain coarsening process in 439 FSS are successfully achieved, considering both tensile stress and anisotropic GB energy effects. The results reveal that the presence of low-angle grain boundaries (LAGBs) deviates from Hillert model predictions in terms of grain size distribution and slows down the average grain size evolution over time. A significant deviation in the grain size distribution, compared to Hillert predictions, is observed in the textured system under tensile stress. The results of growth kinetics indicate that tensile stress promotes grain growth more than GB energy anisotropy retards microstructure evolution. Both experiment and simulation results consistently demonstrate that grains with <111>//ND orientation experience a better growth proficiency compared to grains of other orientations under tensile stress. This investigation offers fresh insights into managing the ferritic microstructure of FSS to enhance its formability capabilities.
{"title":"Microstructure evolution in 439 stainless steels under tensile: phase field simulation and experiment","authors":"Yongbo Liu, Mingtao Wang, Qingcheng Liu, J. Jin, Qing Peng, Y. Zong","doi":"10.1088/1361-651x/ad2187","DOIUrl":"https://doi.org/10.1088/1361-651x/ad2187","url":null,"abstract":"\u0000 A combination of phase-field simulations and experimental validation is utilized to examine the effect of annealing tension on the microstructure evolution of 439 ferrite stainless steel (FSS). The study reveals the competing mechanisms of texture under tensile stress. Furthermore, a phase field model that incorporates anisotropic grain boundary (GB) energy and elastic energy is established. The microstructure of 439 FSS is created using a 3D reconstruction strategy based on the 2D EBSD characterization proposed in this work. Elastic constants are calibrated using actual alloy data and determined through molecular dynamics simulations. Finally, simulations of the grain coarsening process in 439 FSS are successfully achieved, considering both tensile stress and anisotropic GB energy effects. The results reveal that the presence of low-angle grain boundaries (LAGBs) deviates from Hillert model predictions in terms of grain size distribution and slows down the average grain size evolution over time. A significant deviation in the grain size distribution, compared to Hillert predictions, is observed in the textured system under tensile stress. The results of growth kinetics indicate that tensile stress promotes grain growth more than GB energy anisotropy retards microstructure evolution. Both experiment and simulation results consistently demonstrate that grains with <111>//ND orientation experience a better growth proficiency compared to grains of other orientations under tensile stress. This investigation offers fresh insights into managing the ferritic microstructure of FSS to enhance its formability capabilities.","PeriodicalId":503047,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139604458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：