Pub Date : 2024-09-18DOI: 10.1088/1361-651x/ad78f0
Peng Peng and Wensheng Lai
Due to their outstanding mechanical properties, anti-corrosion properties, and anti-irradiation swelling properties, Fe–Cr alloys have been fully improved and developed for nuclear energy applications as structural materials. To ensure the performance stability of γ-phase Fe–Cr alloys, the present study adopted molecular dynamics (MD) simulations to explore the plastic deformation mechanism of these alloys. The slip model was constructed, and the generalised stacking fault energy (GSFE) and Peierls–Nabarro (P–N) equations were solved, revealing that {110}<111> is the preferentially activated slip system. The twinning model was constructed and the generalised plane fault energy was solved, demonstrating that twinning is preferred over slipping in the {112}<111> system. The above findings are also verified through MD simulations in which Fe–Cr specimens are stretched along the [100] direction. In addition, in the 15 at.%–25 at.% Cr range, an increase in the Cr content has a negative effect on slip but a positive effect on twin formation.
{"title":"Plastic deformation mechanism of γ phase Fe–Cr alloy revealed by molecular dynamics simulations","authors":"Peng Peng and Wensheng Lai","doi":"10.1088/1361-651x/ad78f0","DOIUrl":"https://doi.org/10.1088/1361-651x/ad78f0","url":null,"abstract":"Due to their outstanding mechanical properties, anti-corrosion properties, and anti-irradiation swelling properties, Fe–Cr alloys have been fully improved and developed for nuclear energy applications as structural materials. To ensure the performance stability of γ-phase Fe–Cr alloys, the present study adopted molecular dynamics (MD) simulations to explore the plastic deformation mechanism of these alloys. The slip model was constructed, and the generalised stacking fault energy (GSFE) and Peierls–Nabarro (P–N) equations were solved, revealing that {110}<111> is the preferentially activated slip system. The twinning model was constructed and the generalised plane fault energy was solved, demonstrating that twinning is preferred over slipping in the {112}<111> system. The above findings are also verified through MD simulations in which Fe–Cr specimens are stretched along the [100] direction. In addition, in the 15 at.%–25 at.% Cr range, an increase in the Cr content has a negative effect on slip but a positive effect on twin formation.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"84 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1361-651x/ad761a
Maciej Makuch, Sasa Kovacevic, Mark R Wenman and Emilio Martínez-Pañeda
A nonlinear phase-field model is developed to simulate corrosion damage. The motion of the electrode−electrolyte interface follows the usual kinetic rate theory for chemical reactions based on the Butler−Volmer equation. The model links the surface polarization variation associated with the charging kinetics of an electric double layer (EDL) to the mesoscale transport. The effects of the EDL are integrated as a boundary condition on the solution potential equation. The boundary condition controls the magnitude of the solution potential at the electrode−electrolyte interface. The ion concentration field outside the EDL is obtained by solving the electro−diffusion equation and Ohm’s law for the solution potential. The model is validated against the classic benchmark pencil electrode test. The framework developed reproduces experimental measurements of both pit kinetics and transient current density response. The model enables more accurate information on corrosion damage, current density, and environmental response in terms of the distribution of electric potential and charged species. The sensitivity analysis for different properties of the EDL is performed to investigate their role in the electrochemical response of the system. Simulation results show that the properties of the EDL significantly influence the transport of ionic species in the electrolyte.
{"title":"A nonlinear phase-field model of corrosion with charging kinetics of electric double layer","authors":"Maciej Makuch, Sasa Kovacevic, Mark R Wenman and Emilio Martínez-Pañeda","doi":"10.1088/1361-651x/ad761a","DOIUrl":"https://doi.org/10.1088/1361-651x/ad761a","url":null,"abstract":"A nonlinear phase-field model is developed to simulate corrosion damage. The motion of the electrode−electrolyte interface follows the usual kinetic rate theory for chemical reactions based on the Butler−Volmer equation. The model links the surface polarization variation associated with the charging kinetics of an electric double layer (EDL) to the mesoscale transport. The effects of the EDL are integrated as a boundary condition on the solution potential equation. The boundary condition controls the magnitude of the solution potential at the electrode−electrolyte interface. The ion concentration field outside the EDL is obtained by solving the electro−diffusion equation and Ohm’s law for the solution potential. The model is validated against the classic benchmark pencil electrode test. The framework developed reproduces experimental measurements of both pit kinetics and transient current density response. The model enables more accurate information on corrosion damage, current density, and environmental response in terms of the distribution of electric potential and charged species. The sensitivity analysis for different properties of the EDL is performed to investigate their role in the electrochemical response of the system. Simulation results show that the properties of the EDL significantly influence the transport of ionic species in the electrolyte.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"13 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1088/1361-651x/ad747c
Liming Zhou, Pengxu Chen, Yan Gao, Jiye Wang
Magneto-electro-elastic (MEE) materials possess the ability to convert mechanical, electrical, and magnetic energies, playing a critical role in smart devices. To improve the accuracy and efficiency of solving the mechanical properties of MEE structures in mechanical-electrical-magnetic-thermal (MEMT) environments, an MEMT coupled multiphysics enriched finite element method (MP-EFEM) is proposed. Based on the fundamental equations and boundary conditions of MEE materials, the interpolation coverage function is introduced into the MEMT coupled finite element method (FEM) to construct higher-order approximate interpolation displacement shape functions, electric potential shape functions, and magnetic potential shape functions. Combined with the variational principle, MP-EFEM is proposed, and the governing equations of MP-EFEM are derived. Numerical examples validate the accuracy and high efficiency of MP-EFEM in solving the mechanical properties of MEE structures in MEMT environments. When compared to the MEMT coupled FEM (MEMT-FEM), the results show that this method offers higher accuracy and efficiency. Therefore, MP-EFEM can effectively analyze the mechanical properties of MEE structures under multiphysics coupling, providing a new method for the design and development of smart devices.
磁电弹性（MEE）材料具有转换机械能、电能和磁能的能力，在智能设备中发挥着至关重要的作用。为了提高在机电磁热（MEMT）环境中求解 MEE 结构力学特性的精度和效率，提出了一种 MEMT 耦合多物理场增强有限元法（MP-EFEM）。基于 MEE 材料的基本方程和边界条件，在 MEMT 耦合有限元法（FEM）中引入插值覆盖函数，构造高阶近似插值位移形状函数、电势形状函数和磁势形状函数。结合变分原理，提出了 MP-EFEM，并导出了 MP-EFEM 的支配方程。数值实例验证了 MP-EFEM 在求解 MEMT 环境中 MEE 结构的力学性能时的准确性和高效性。与 MEMT 耦合有限元（MEMT-FEM）相比，结果表明该方法具有更高的精度和效率。因此，MP-EFEM 能有效分析多物理场耦合下 MEE 结构的力学性能，为智能设备的设计和开发提供了一种新方法。
{"title":"Mechanical-electric-magnetic-thermal coupled enriched finite element method for magneto-electro-elastic structures","authors":"Liming Zhou, Pengxu Chen, Yan Gao, Jiye Wang","doi":"10.1088/1361-651x/ad747c","DOIUrl":"https://doi.org/10.1088/1361-651x/ad747c","url":null,"abstract":"Magneto-electro-elastic (MEE) materials possess the ability to convert mechanical, electrical, and magnetic energies, playing a critical role in smart devices. To improve the accuracy and efficiency of solving the mechanical properties of MEE structures in mechanical-electrical-magnetic-thermal (MEMT) environments, an MEMT coupled multiphysics enriched finite element method (MP-EFEM) is proposed. Based on the fundamental equations and boundary conditions of MEE materials, the interpolation coverage function is introduced into the MEMT coupled finite element method (FEM) to construct higher-order approximate interpolation displacement shape functions, electric potential shape functions, and magnetic potential shape functions. Combined with the variational principle, MP-EFEM is proposed, and the governing equations of MP-EFEM are derived. Numerical examples validate the accuracy and high efficiency of MP-EFEM in solving the mechanical properties of MEE structures in MEMT environments. When compared to the MEMT coupled FEM (MEMT-FEM), the results show that this method offers higher accuracy and efficiency. Therefore, MP-EFEM can effectively analyze the mechanical properties of MEE structures under multiphysics coupling, providing a new method for the design and development of smart devices.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"5 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1088/1361-651x/ad747e
Minh Tam Hoang, Nithin Mathew, Daniel N Blaschke and Saryu Fensin
Helium bubbles can form in materials upon exposure to irradiation. It is well known that the presence of helium bubbles can cause changes in the mechanical behavior of materials. To improve the lifetime of nuclear components, it is important to understand deformation mechanisms in helium-containing materials. In this work, we investigate the interactions between edge dislocations and helium bubbles in copper using molecular dynamics (MD) simulations. We focus on the effect of helium bubble pressure (equivalently, the helium-to-vacancy ratio) on the obstacle strength of helium bubbles and their interaction with dislocations. Our simulations predict significant differences in the interaction mechanisms as a function of helium bubble pressure. Specifically, bubbles with high internal pressure are found to exhibit weaker obstacle strength as compared to low-pressure bubbles of the same size due to the formation of super-jogs in the dislocation. Activation energies and rate constants extracted from the MD data confirm this transition in mechanism and enable upscaling of these phenomena to higher length-scale models.
{"title":"Effect of helium bubbles on the mobility of edge dislocations in copper","authors":"Minh Tam Hoang, Nithin Mathew, Daniel N Blaschke and Saryu Fensin","doi":"10.1088/1361-651x/ad747e","DOIUrl":"https://doi.org/10.1088/1361-651x/ad747e","url":null,"abstract":"Helium bubbles can form in materials upon exposure to irradiation. It is well known that the presence of helium bubbles can cause changes in the mechanical behavior of materials. To improve the lifetime of nuclear components, it is important to understand deformation mechanisms in helium-containing materials. In this work, we investigate the interactions between edge dislocations and helium bubbles in copper using molecular dynamics (MD) simulations. We focus on the effect of helium bubble pressure (equivalently, the helium-to-vacancy ratio) on the obstacle strength of helium bubbles and their interaction with dislocations. Our simulations predict significant differences in the interaction mechanisms as a function of helium bubble pressure. Specifically, bubbles with high internal pressure are found to exhibit weaker obstacle strength as compared to low-pressure bubbles of the same size due to the formation of super-jogs in the dislocation. Activation energies and rate constants extracted from the MD data confirm this transition in mechanism and enable upscaling of these phenomena to higher length-scale models.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"28 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1088/1361-651x/ad747d
Xipeng Li, Yuming Qi, Tengwu He, Min Zhao, Miaolin Feng
Titanium and its alloys are widely used as structural materials under extreme conditions due to their exceptional specific strength. However, comprehensive studies on their high-energy radiation damage remain limited. Considering electronic effects, molecular dynamics simulations were performed to explore high-energy radiation damage in hcp-titanium (hcp-Ti), focusing on displacement cascades induced by primary knock-on atoms (PKAs) with energies ranging from 1 to 40 keV. This study investigates the generation and evolution of point defects resulting from collisional cascades, particularly examining the influence of PKA energy. Additionally, the distribution and morphology of clustering defects from these events were quantitatively investigated and qualitatively visualized. The results show a significant dependence of surviving defects on PKA energies, highlighting a critical range that exhibits a shift in cascade morphology. Furthermore, it is demonstrated that PKA energy significantly influences the formation and growth of defect clusters, with both interstitials and vacancies showing increased cluster fraction and sizes at higher PKA energies, albeit with different tendencies in their formation and aggregation behaviors. Morphological analysis emphasizes the role of subcascades and provides further insights into the mechanisms of defect evolution behind high-energy radiation damage. Our extensive study across a broad range of PKA energies provides essential insights into the understanding of high-energy radiation damage in hcp-Ti.
{"title":"Molecular dynamics simulations of high-energy radiation damage in hcp-titanium considering electronic effects","authors":"Xipeng Li, Yuming Qi, Tengwu He, Min Zhao, Miaolin Feng","doi":"10.1088/1361-651x/ad747d","DOIUrl":"https://doi.org/10.1088/1361-651x/ad747d","url":null,"abstract":"Titanium and its alloys are widely used as structural materials under extreme conditions due to their exceptional specific strength. However, comprehensive studies on their high-energy radiation damage remain limited. Considering electronic effects, molecular dynamics simulations were performed to explore high-energy radiation damage in hcp-titanium (hcp-Ti), focusing on displacement cascades induced by primary knock-on atoms (PKAs) with energies ranging from 1 to 40 keV. This study investigates the generation and evolution of point defects resulting from collisional cascades, particularly examining the influence of PKA energy. Additionally, the distribution and morphology of clustering defects from these events were quantitatively investigated and qualitatively visualized. The results show a significant dependence of surviving defects on PKA energies, highlighting a critical range that exhibits a shift in cascade morphology. Furthermore, it is demonstrated that PKA energy significantly influences the formation and growth of defect clusters, with both interstitials and vacancies showing increased cluster fraction and sizes at higher PKA energies, albeit with different tendencies in their formation and aggregation behaviors. Morphological analysis emphasizes the role of subcascades and provides further insights into the mechanisms of defect evolution behind high-energy radiation damage. Our extensive study across a broad range of PKA energies provides essential insights into the understanding of high-energy radiation damage in hcp-Ti.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"5 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1088/1361-651x/ad6ea8
Y V Shan, A Redermeier, R Kahlenberg, E Kozeschnik
A model is developed that describes the kinetics of precipitate transformations in the course of natural and artificial aging of Al alloys containing Mg and Si additions. In our approach, the disordered Mg–Si-rich clusters, which form during natural aging in the highly supersaturated Al matrix, can directly transform into the monoclinic Mg5Si6 (β″), without prior dissolution of the clusters and independent nucleation of β″ in the Al matrix. The transformation rate is evaluated with classical nucleation theory (CNT), assuming that the clusters represent an infinitely large matrix phase in which the β″ precipitates can nucleate. The adapted CNT model is described, and the basic features of the precipitate transformation are discussed in a parameter study. The model can also account for the observation that, during natural aging, the parent clusters occur in a variety of Mg to Si ratios, all of which have a characteristic probability of either transforming into the β″ phase or dissolving.
{"title":"A model for the precipitate transformation of Mg–Si-rich clusters into Mg5Si6 β″ in Al–Mg–Si aluminum alloys","authors":"Y V Shan, A Redermeier, R Kahlenberg, E Kozeschnik","doi":"10.1088/1361-651x/ad6ea8","DOIUrl":"https://doi.org/10.1088/1361-651x/ad6ea8","url":null,"abstract":"A model is developed that describes the kinetics of precipitate transformations in the course of natural and artificial aging of Al alloys containing Mg and Si additions. In our approach, the disordered Mg–Si-rich clusters, which form during natural aging in the highly supersaturated Al matrix, can directly transform into the monoclinic Mg<sub>5</sub>Si<sub>6</sub> (<italic toggle=\"yes\">β</italic>″), without prior dissolution of the clusters and independent nucleation of <italic toggle=\"yes\">β</italic>″ in the Al matrix. The transformation rate is evaluated with classical nucleation theory (CNT), assuming that the clusters represent an infinitely large matrix phase in which the <italic toggle=\"yes\">β</italic>″ precipitates can nucleate. The adapted CNT model is described, and the basic features of the precipitate transformation are discussed in a parameter study. The model can also account for the observation that, during natural aging, the parent clusters occur in a variety of Mg to Si ratios, all of which have a characteristic probability of either transforming into the <italic toggle=\"yes\">β</italic>″ phase or dissolving.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"10 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1088/1361-651x/ad6eaa
Zhe-Zhi Jiang, Jia-Lin Tsai
This study characterized the nonlinear tensile behavior of fiber metal laminates (FMLs). FMLs comprise layers of thin metallic sheets and fiber-reinforced composite layers, and a constitutive FML model includes the constitutive relationships of the FML’s constituent materials; however, nonlinear behavior is typically only considered for the metal components of an FML. In this study, a nonlinear constitutive relationship for the unidirectional fiber composites was modeled using a one-parameter plastic model. The nonlinear constitutive law for the metal was formulated using the J2 flow rule. These relationships were summed for each layer in accordance with laminated plate theory to obtain a constitutive FML model, which was then used for numerical predictions of nonlinear stress–strain curves. The model was validated by comparing its predictions with experimental results from the literature. Moreover, the effect of the inclusion of nonlinear fiber composite behavior on the model predictions was investigated. Results revealed that the difference between the model predictions and the experimental results was less than 4%. These predictions with nonlinear fiber composite behavior were substantially more accurate than those of the model without this behavior for FMLs with angle-ply fiber composites.
{"title":"Characterizing nonlinear constitutive behaviors of fiber metal laminates","authors":"Zhe-Zhi Jiang, Jia-Lin Tsai","doi":"10.1088/1361-651x/ad6eaa","DOIUrl":"https://doi.org/10.1088/1361-651x/ad6eaa","url":null,"abstract":"This study characterized the nonlinear tensile behavior of fiber metal laminates (FMLs). FMLs comprise layers of thin metallic sheets and fiber-reinforced composite layers, and a constitutive FML model includes the constitutive relationships of the FML’s constituent materials; however, nonlinear behavior is typically only considered for the metal components of an FML. In this study, a nonlinear constitutive relationship for the unidirectional fiber composites was modeled using a one-parameter plastic model. The nonlinear constitutive law for the metal was formulated using the J<sub>2</sub> flow rule. These relationships were summed for each layer in accordance with laminated plate theory to obtain a constitutive FML model, which was then used for numerical predictions of nonlinear stress–strain curves. The model was validated by comparing its predictions with experimental results from the literature. Moreover, the effect of the inclusion of nonlinear fiber composite behavior on the model predictions was investigated. Results revealed that the difference between the model predictions and the experimental results was less than 4%. These predictions with nonlinear fiber composite behavior were substantially more accurate than those of the model without this behavior for FMLs with angle-ply fiber composites.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"33 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1088/1361-651x/ad6eab
David E Page, David T Fullwood, Robert H Wagoner, Eric R Homer
Grain boundaries strengthen metals and act as hardening agents, impeding plastic flow macroscopically. The interactions between grain boundaries and dislocations are complex and difficult to predict. To understand the connection between resolved shear stresses and transmission events we simulated dislocation-grain boundary interactions in a number of [11―2] asymmetric tilt grain boundaries designed for optimal transmission of dislocations. By shearing the cell containing the grains on either side of the boundary, we drove the dislocation into the grain boundary and observed the interaction. The key findings include: (i) roughly half of the observed dislocation-grain boundary interactions resulted in transmission, which is a lower than expected transmission rate of incident dislocations; (ii) a rejection of a hypothesized monotonic relationship between applied stress and transmission of dislocations based on observations; (iii) significant restructuring of the grain boundaries resulting from the applied stress and incident dislocation interactions; and (iv) a suggestion that transmission events appear to be better described as separate absorption and nucleation events, with each event affecting and affected by the evolving grain boundary structure. Together, these point to continued challenges and opportunities surrounding dislocation-grain boundary interactions. The challenges relate to the difficulty in extracting absorption and nucleation criteria. The opportunities suggest that mesoscale models can treat all these events independently based on relevant criteria if they can be obtained.
{"title":"Atomistic simulations of incident dislocation interactions with nickel grain boundaries","authors":"David E Page, David T Fullwood, Robert H Wagoner, Eric R Homer","doi":"10.1088/1361-651x/ad6eab","DOIUrl":"https://doi.org/10.1088/1361-651x/ad6eab","url":null,"abstract":"Grain boundaries strengthen metals and act as hardening agents, impeding plastic flow macroscopically. The interactions between grain boundaries and dislocations are complex and difficult to predict. To understand the connection between resolved shear stresses and transmission events we simulated dislocation-grain boundary interactions in a number of <inline-formula>\u0000<tex-math><?CDATA $left[1,overline{1},2right]$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mn>1</mml:mn><mml:mstyle scriptlevel=\"0\"></mml:mstyle><mml:mover><mml:mn>1</mml:mn><mml:mo accent=\"true\">―</mml:mo></mml:mover><mml:mstyle scriptlevel=\"0\"></mml:mstyle><mml:mn>2</mml:mn><mml:mo>]</mml:mo></mml:mrow></mml:mrow></mml:math><inline-graphic xlink:href=\"msmsad6eabieqn1.gif\"></inline-graphic></inline-formula> asymmetric tilt grain boundaries designed for optimal transmission of dislocations. By shearing the cell containing the grains on either side of the boundary, we drove the dislocation into the grain boundary and observed the interaction. The key findings include: (i) roughly half of the observed dislocation-grain boundary interactions resulted in transmission, which is a lower than expected transmission rate of incident dislocations; (ii) a rejection of a hypothesized monotonic relationship between applied stress and transmission of dislocations based on observations; (iii) significant restructuring of the grain boundaries resulting from the applied stress and incident dislocation interactions; and (iv) a suggestion that transmission events appear to be better described as separate absorption and nucleation events, with each event affecting and affected by the evolving grain boundary structure. Together, these point to continued challenges and opportunities surrounding dislocation-grain boundary interactions. The challenges relate to the difficulty in extracting absorption and nucleation criteria. The opportunities suggest that mesoscale models can treat all these events independently based on relevant criteria if they can be obtained.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1088/1361-651x/ad6fc0
Gerfried Millner, Manfred Mücke, Lorenz Romaner, Daniel Scheiber
In this work we apply data-driven models for predicting tensile strength of steel coils from chemical composition and process parameters. The data originates from steel production and includes a full chemical analysis, as well as many process parameters and the resulting strength properties from tensile tests. We establish a data pre-processing pipeline, where we apply data cleaning and feature engineering to create a machine-readable dataset suitable for various modeling tasks. We compare prediction quality, complexity and interpretability of pure machine learning (ML) models, either with the full feature set or a reduced one. Dimensionality reduction methods are used to reduce the number of features and therefore reduce complexity, either with a smart selection method or feature encoding, where features are combined and the included information is preserved. In order to determine key features of our models, we are investigating feature importance ratings, which can be used as a feature selection criteria. Furthermore, we are highlighting methods to explain predictions and determine the impact of every feature in every observation applicable for any ML model.
在这项工作中，我们应用数据驱动模型，根据化学成分和工艺参数预测钢卷的抗拉强度。数据来源于钢铁生产，包括完整的化学分析、许多工艺参数以及拉伸试验得出的强度属性。我们建立了一个数据预处理流水线，应用数据清理和特征工程来创建适合各种建模任务的机器可读数据集。我们比较了纯机器学习（ML）模型的预测质量、复杂性和可解释性，无论是使用完整特征集还是缩减特征集。降维方法可用于减少特征数量，从而降低复杂性，降维方法可采用智能选择方法或特征编码方法，即对特征进行组合并保留其中的信息。为了确定模型的关键特征，我们正在研究可用作特征选择标准的特征重要性评级。此外，我们还在强调解释预测的方法，并确定适用于任何 ML 模型的每个观测中每个特征的影响。
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Pub Date : 2024-08-29DOI: 10.1088/1361-651x/ad6c6b
S Caleb Foster, Justin W Wilkerson
Metal alloys frequently contain distributions of second-phase particles that deleteriously affect the material behavior by acting as sites for void nucleation. These distributions are often extremely complex and processing can induce high levels of anisotropy. The particle length-scale precludes high-fidelity microstructure modeling in macroscale simulations, so computational homogenization methods are often employed. These, however, involve simplifying assumptions to make the problem tractable and many rely on periodic microstructures. Here we propose a methodology to bridge the gap between realistic microstructures composed of anisotropic, spatially varying second-phase void morphologies and idealized periodic microstructures with roughly equivalent mechanical responses. We create a high-throughput, parametric study to investigate 96 unique bridging methods. We apply our proposed solution to a rolled AZ31B magnesium alloy, for which we have a rich dataset of microstructure morphology and mechanical behavior. Our methodology converts a µ-CT scan of the realistic microstructure to idealized periodic unit cell microstructures that are specific to the loading orientation. We recreate the unit cells for each parameter set in a commercial finite element software, subject them to macroscopic uniaxial loading conditions, and compare our results to the datasets for the various loading orientations. We find that certain combinations of our parameters capture the overall stress–strain response, including anisotropy effects, with some degree of success. The effect of different parameter options are explored in detail and we find that excluding certain particle populations from the analysis can give improved results.
{"title":"A high-throughput statistical homogenization technique to convert realistic microstructures into idealized periodic unit cells","authors":"S Caleb Foster, Justin W Wilkerson","doi":"10.1088/1361-651x/ad6c6b","DOIUrl":"https://doi.org/10.1088/1361-651x/ad6c6b","url":null,"abstract":"Metal alloys frequently contain distributions of second-phase particles that deleteriously affect the material behavior by acting as sites for void nucleation. These distributions are often extremely complex and processing can induce high levels of anisotropy. The particle length-scale precludes high-fidelity microstructure modeling in macroscale simulations, so computational homogenization methods are often employed. These, however, involve simplifying assumptions to make the problem tractable and many rely on periodic microstructures. Here we propose a methodology to bridge the gap between realistic microstructures composed of anisotropic, spatially varying second-phase void morphologies and idealized periodic microstructures with roughly equivalent mechanical responses. We create a high-throughput, parametric study to investigate 96 unique bridging methods. We apply our proposed solution to a rolled AZ31B magnesium alloy, for which we have a rich dataset of microstructure morphology and mechanical behavior. Our methodology converts a <italic toggle=\"yes\">µ</italic>-CT scan of the realistic microstructure to idealized periodic unit cell microstructures that are specific to the loading orientation. We recreate the unit cells for each parameter set in a commercial finite element software, subject them to macroscopic uniaxial loading conditions, and compare our results to the datasets for the various loading orientations. We find that certain combinations of our parameters capture the overall stress–strain response, including anisotropy effects, with some degree of success. The effect of different parameter options are explored in detail and we find that excluding certain particle populations from the analysis can give improved results.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"8 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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