Microstructure-based Modeling Research Articles

Latent Pitfalls in Microstructure-Based Modeling for Thermally Aged 9Cr-1Mo-V Steel (Grade 91)

Abstract A case study was conducted on a mechanistic model development that predicted tensile strength deterioration with thermal aging of 9Cr-1Mo-V steel in supporting the 60-year design life expected for advanced nuclear reactors. For property prediction beyond practical testing times, mechanistic modeling is highly desired, as it taps into the physics of structure–property relationships and therefore can generate reliable results for extrapolation. Meanwhile, as mechanistic models are often complicated, reflecting the intricacy of microstructure and strengthening mechanisms, pitfalls that are difficult to detect often exist. This paper discusses latent pitfalls that are common in mechanistic modeling or specific in this 9Cr-1Mo-V case development through using the American Society of Mechanical Engineers verification and validation in computational solid mechanics (ASME V&V 10) standard for evaluating credibility of modeling in materials engineering. Suggestions are also made for enhancing reliability of microstructure-based modeling.

Microstructure-based digital twin thermo-electrochemical modeling of LIBs at the cell-to-module scale

As the application of lithium-ion batteries (LIBs) expands beyond conventional electric vehicles (EVs) to heavy vehicles such as electric trucks or trams, the importance of thermal management in LIB systems is increasing, even at the module or pack level. In particular, because monitoring the thermal behaviors of each cell is not feasible, thermo-electrochemical modeling and simulations in the module or pack level are essential for analyzing and ensuring thermal stability. However, because the conventional lumped thermo-electrochemical models cannot reflect the actual structure of LIB cells, there might be considerable differences may exist between simulation and experimental results. To fill these gaps, we have newly developed a 3D microstructure-based digital twin model of a battery module (8.8 Ah/18.5 V, five LIB pouch cells in series) for an unmanned railway vehicle. Unlike traditional lumped models, our digital twin model accurately well reflects the internal structure of cells and can calculate the heat generation of each component inside a cell. As a result, contrary to a lumped model, the digital twin model can not only simulate the inhomogeneous temperature gradient inside a cell, but also estimates higher local maximum temperatures (TDT, max/TL, max = 137.2 °C/123.9 °C @ 10C discharge) in cells which can trigger thermal runaway. Therefore, microstructure-based digital twin modeling can alleviate concerns regarding the thermal runaway of LIB cells, modules, and packs, and provide safe operating conditions.

Preliminary Study on Multi-Scale Modeling of Asphalt Materials: Evaluation of Material Behavior through an RVE-Based Approach

This study employs a microstructure-based finite element modeling approach to understand the mechanical behavior of asphalt mixtures across different length scales. Specifically, this work aims to develop a multi-scale modeling approach employing representative volume elements (RVEs) of optimal size; this is a key issue in asphalt modeling for high-fidelity fracture modeling of heterogeneous asphalt mixtures. To determine the optimal RVE size, a convergence analysis of homogenized elastic properties is conducted using two types of RVEs, one made with polydisperse spherical inclusions, and another made with polydisperse truncated cylindrical inclusions, each aligned with the American Association of State Highway and Transportation Official’s maximum density gradation curve for a 12.5 mm Nominal Maximum Aggregate Size (NMAS). The minimum RVE lengths for this NMAS were found to be in the range of 32–34 mm. After the optimal RVE size for each inclusion shape is obtained, computational models of heterogeneous Indirect Tensile Asphalt Cracking Test samples are then generated. These models include the components of viscoelastic mastic, linear elastic aggregates, and cohesive zone modeling to simulate the rate-dependent failure evolution from micro- to macro-cracking. Examination of load-displacement responses at multiple loading rates shows that both heterogeneous models replicate experimentally measured data satisfactorily. Through micro- and macro-level analyses, this study enhances our understanding of the composition-performance relationships in asphalt pavement materials. The procedure proposed in this study allows us to identify the optimal RVE sizes that preserve computational efficiency without significantly compromising their ability to capture the asphalt material behavior under specific operational conditions.

Evolution of mechanical properties and microstructure of selective laser melted AlSi10MgMn alloy with different post heat treatments

This study investigated the effects of various post heat treatments on the mechanical properties and microstructure evolution of an AlSi10MgMn alloy containing 0.5 wt% Mn produced by the selective laser melting process for the first time. The microstructures under different conditions were analyzed using optical microscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. In the as-manufactured (F) condition, the alloy exhibited an ultimate tensile strength (UTS) of 486 MPa, a yield strength (YS) of 299 MPa, and an elongation of 10.3 %. After a T5 treatment, the UTS and YS increased to 532 MPa and 386 MPa, respectively, resulting in a remarkable 30 % improvement in YS compared to the F state. The tensile properties achieved by the new alloy were considerably higher than those reported for conventional AlSi10Mg alloys in the F, T5, and T6 conditions. The T5 treatment promoted the precipitation of a large fraction of Si-rich nanoparticles and MgSi-based precipitates without disrupting the Si-rich network. After a T6 treatment, the Si-rich network completely disappeared, and the main strengthening phase was MgSi-based precipitates accompanied by α-Al(Mn,Fe)Si dispersoids induced by the Mn addition. Using microstructure-based constitutive models, the strengthening contributions of various microstructural components to mechanical strength in different processing conditions were analyzed.

Microstructure-based modelling of formability for advanced high strength dual-phase steels

The macroscopic formability of advanced high strength dual-phase steels (AHSDPSs) relies highly on the microstructure. Therefore, building the relationship between the microstructure and the formability is vital to enhancing the formability by microstructure optimisation. In this study, a formability model based on microstructure for AHSDPSs was proposed. The tensile simulation of representative volume element (RVE) was implemented to acquire the stress-strain curve (SSC). The forming limit curve (FLC) was constructed based on the method developed in our previous research. The simulation of hole-expansion with the pre-damage of the central-hole induced by the blanking process was conducted to obtain the hole-expansion ratio (HER), in which the vital failure model is developed based on the simulated FLC. For a typical advanced high strength dual-phase steel of DP1180 steel, the prediction errors of SSC, FLC and HER are 5.83 %, 6.85 % and 10.71 %, respectively. The results also depicted that the damage of the prefabricated hole has a noticeable influence on the HER, which could not be ignored for the hole-expansion simulation.

Creep condition-oriented design of molybdenum alloys with La2O3 addition assisted by microstructure-based crystal plasticity modeling

Molybdenum (Mo) alloys are essential for applications requiring outstanding mechanical properties at high temperatures across various industrial sectors. Understanding and predicting the creep properties of Mo alloys is crucial for service safety and the design of new materials. This study introduces a physics-based crystallographic creep model dedicated to the characteristic hierarchical microstructure of Mo–La2O3 alloys. By sourcing most parameters from existing literature and calibrating others within recommended ranges, the model efficiently predicts creep behavior beyond its initial calibration scope. Through the integration of microstructure descriptors, we systematically explored the impact of different microstructural features on the creep behavior and identified the underlying mechanisms. This analysis yielded two pivotal concepts: the minimum acceptable grain size and the necessary nanoparticle number density. These metrics, readily obtainable from the model, quantify the requisite grain size and nanoparticle content to achieve the target steady-state creep rates for operational demands, thus providing essential insights for the creep condition-oriented design of Mo–La2O3 alloys. The model is also expected to be adaptable for developing other Mo alloys reinforced by second phase particles, aimed at achieving desired creep properties under specified conditions, assuming that relevant parameters are accessible through literature or lower-scale simulations.

Quantifying pore-level non-uniformity of pore-water distribution in unsaturated soils

Quantifying the magnitude and distribution of degree of saturation (Sr) in unsaturated soils is crucial to understand the grain-scale hydromechanical behavior, but it has been a major experimental challenge. This study proposes a new method to quantify the pore-water distribution non-uniformity, in terms of Sr, based on three-dimensional (3D) X-ray computed tomography images. The algorithm constructs vectors that consider the 3D spatial distribution of Sr for each REV. A weighted water distribution tensor (G, characterizing the spatial distribution of Sr) was derived to calculate a scalar parameter A that represents the non-uniformity. Application of the algorithm on sand samples demonstrated that the Sr distributions could be highly non-uniform at different drying states. The algorithm captured pore-water transport between the dilated and non-dilated zones of samples subjected to pre-peak shearing. The evolution of A with matric suction and axial strain showed potential in incorporating the pore-water distribution into microstructure-based constitutive models.

Correlating mechanical properties of Al/Al bimetal composite and its constituents using combined experiment and microstructure-based multiscale modeling approach

A combined experiment and multiscale modeling approach was presented to correlate the mechanical properties of a roll-bonded AA1050/AA3004 bimetal clad sheet and constituents. The mechanical responses of the 2-ply AA1050/AA3004 and constituents were measured under various loading conditions. For the measurements, each constituent was separated from the clad sheet using electrical discharge machining and uniaxial tensile tests. Continuum-scale yield functions such as isotropic von Mises and anisotropic/non-quadratic Yld2000-2d were developed for the two constituents and the bimetal clad sheet. A grain-scale crystal plasticity finite element (CPFE) simulations were also performed incorporated with newly developed representative volume element considering measured microstructural attributes. These CPFE predictions were used to identify the anisotropy coefficients for Yld2000-2d. Using the identified yield functions, finite element modeling was followed in which the mechanical properties of each constituent sheet were addressed separately. This is a new approach developed in the current work and it enables a fundamental correlation between multilayered material and its constituents. The mechanical properties of the bimetal clad sheet under the uniaxial tensions were predicted using those of the constituents and compared with calculations based on known rule of mixture (ROM) approach. The two approaches well reproduced stress–strain curves and r–value evolutions. The two FE modeling approaches were also applied to an independent test (i.e., the limiting dome height). The predictions were in good agreement with the experimental data. Finally, the mechanical properties of the bimetal clad sheet and constituents were correlated, and proper modeling scheme for multilayered materials is proposed.

Utilizing integrated neutron diffraction and elastoplastic self-consistent crystal plasticity model to quantitatively assess the strengthening mechanism in Al–12.5Ce and Al–12.5Ce–0.4Mg alloys

An integrated in-situ neutron diffraction and elastic plastic self-consistent crystal plasticity (EPSC-CP) modeling scheme is performed on a binary Al–12Ce alloy and a ternary Al–12Ce–0.4Mg alloys. Using this scheme, the constitutive parameters, i.e. elastic constants and slip system parameters of individual phases can be calibrated which can be used in microstructure-based CP models to predict materials performance. From this study, it is shown that the elastic constants of Al11Ce3 intermetallics calculated from density function theory calculation in the literature are rather accurate. When applied to the EPSC-CP model, the lattice strains of both the binary and ternary alloys are correctly predicted as compared with experiments, and large lattice strain differences between Al (100) plane and Al11Ce3 (010) plane are demonstrated. The slip system parameters calibrated by the scheme shows that the addition of 0.4 wt% Mg in the alloy has little influence on the critical resolved shear stress of initial dislocation glide in the Al matrix which caused plastic yield in the material. This can be explained by the very dilute Mg solute content in the Al solid solution, causing large spacing of Al–Mg lattice misfit sites and little impact on resistance of dislocation glide at initial yield. The 0.4 wt% Mg addition, on the other hand, has a large influence on the hardening term in the slip system parameters, indicating those Al–Mg misfit sites do help dislocation accumulation during the deformation. The impact of dilute Mg addition on the Al slip system parameters is also reflected in the flow behavior of the ternary alloy: little impact on the yield stress, but a large impact on working hardening and tensile strength of the materials which is consistent with the literature.

Creep anisotropy of additively manufactured Inconel-738LC: Combined experiments and microstructure-based modeling

The current lack of quantitative knowledge on processing-microstructure–property relationships is one of the major bottlenecks in today’s rapidly expanding field of additive manufacturing. This is centrally rooted in the nature of the processing, leading to complex microstructural features. Experimentally-guided modeling can offer reliable solutions for the safe application of additively manufactured materials. In this work, we combine a set of systematic experiments and modeling to address creep anisotropy and its correlation with microstructural characteristics in laser-based powder bed fusion (PBF-LB/M) additively manufactured Inconel-738LC (IN738LC). Three sample orientations (with the tensile axis parallel, perpendicular, and 45° tilted, relative to the building direction) are crept at 850 °C, accompanied by electron backscatter secondary diffraction (EBSD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. A crystal plasticity (CP) model for Ni-base superalloys, capable of modeling different types of slip systems, is developed and combined with various polycrystalline representative volume elements (RVEs) built on the experimental measurements. Besides our experiments, we verify our modeling framework on electron beam powder bed fusion (PBF-EB/M) additively manufactured Inconel-738LC. The results of our simulations show that while the crystallographic texture alone cannot explain the observed creep anisotropy, the superlattice extrinsic stacking faults (SESF) and related microtwinning slip systems play major roles as active deformation mechanisms. We confirm this using TEM investigations, revealing evidence of SESFs in crept specimens. We also show that the elongated grain morphology can result in higher creep rates, especially in the specimens with a tilted tensile axis.

Microstructure-Based Modeling of Deformation and Damage Behavior of Extruded and Additively Manufactured 316L Stainless Steels.

In this study, we investigated the micromechanical deformation and damage behavior of commercially extruded and additively manufactured 316L stainless steels (AMed SS316L) by combining experimental examinations and crystal plasticity modeling. The AMed alloy was fabricated using the laser powder bed fusion (LPBF) technique with an orthogonal scanning strategy to control the directionality of the as-fabricated material. Optical microscopy and electron backscatter diffraction measurements revealed distinct grain morphologies and crystallographic textures in the two alloys. Uniaxial tensile test results suggested that the LPBFed alloy exhibited an increased yield strength, reduced elongation, and comparable ultimate tensile strength in comparison to those of the extruded alloy. A microstructure-based crystal plasticity model was developed to simulate the micromechanical deformation behavior of the alloys using representative volume elements based on realistic microstructures. A ductile fracture criterion based on the microscopically dissipated plastic energy on a slip system was adopted to predict the microscopic damage accumulation of the alloys during plastic deformation. The developed model could accurately predict the stress-strain behavior and evolution of the crystallographic textures in both the alloys. We reveal that the increased yield strength in the LPBFed alloy, compared to that in the extruded alloy, is attributed to the higher as-manufactured dislocation density and the cellular subgrain structure, resulting in a reduced elongation. The presence of annealing twins and favorable texture in the extruded alloy contributed to its excellent elongation, along with a higher hardening rate owing to twin-dislocation interactions during plastic deformation. Moreover, the grain morphology and defect state (e.g., dislocations and twins) in the initial state can significantly affect strain localization and damage accumulation in alloys.

Spatial reconstruction, microstructure-based modeling of compressive deformation behavior, and prediction of mechanical properties in lightweight Al-based entropy alloys

Lightweight Al-based entropy alloys are newly emerged materials with promising potential for structural applications; however, their modeling and strengthening prediction require further exploration. In this study, the spatial distributions of various phases in three Al-based entropy alloys were investigated. A closely interconnected intermetallic compound (IC) network comprising Al2Cu and Al45Cr7 phases was identified. Finite element (FE) modeling was conducted based on the reconstructed three-dimensional microstructure to simulate compressive deformation behavior. The IC network served as the main stress bearer during deformation. Thin sections in the Al2Cu network were the weak sites where stress concentration and damage first occurred. However, the breakage of this limited region contributes to relatively coordinated deformation and extended plasticity. The breakage of large particles accounts for the final alloy failure. The results of the FE model were compared with the experimentally measured stress–strain behavior and mechanical properties, showing very good agreement. Given the non-uniform distribution of strain and stress during deformation, a strengthening model, merging the Voigt and Reuss models, was also developed to predict the mechanical properties of Al-based entropy alloys with the aim of facilitating Al-based entropy alloy development.

Exceptional strength and wear resistance in an AA7075/TiB2 composite fabricated via friction consolidation

The friction consolidation method successfully reinforced aluminum 7075 alloy (AA7075) with high-volume fractions (12 and 24 vol%) of titanium diboride (TiB2) by high pressure and severe plastic deformation at elevated temperatures. The consolidated AMCs have a uniform dispersion of submicron- and micron-sized TiB2 particles in the AA7075 matrix, with significant refinement of the matrix grain size and the particles. The addition of TiB2 significantly increases hardness by up to 50 %, Young’s modulus by up to 62 %, and ultimate tensile strength by up to 28 % to 672 MPa, while reducing ductility by 80 %. Wear resistance of 7075/24 vol% TiB2 improves seven-fold compared to baseline, making it comparable to that of carburized steels. Microstructure-based finite element modeling provided a theoretical strength limit of ∼730 MPa for the composites and indicated that high triaxiality in conjunction with severe equivalent plastic strain in a narrow area between the TiB2 particles led to early fracture initiations, limiting the ductility.

Microstructure-based modeling of primary cilia mechanics.

A primary cilium, made of nine microtubule doublets enclosed in a cilium membrane, is a mechanosensing organelle that bends under an external mechanical load and sends an intracellular signal through transmembrane proteins activated by cilium bending. The nine microtubule doublets are the main load-bearing structural component, while the transmembrane proteins on the cilium membrane are the main sensing component. No distinction was made between these two components in all existing models, where the stress calculated from the structural component (nine microtubule doublets) was used to explain the sensing location, which may be totally misleading. For the first time, we developed a microstructure-based primary cilium model by considering these two components separately. First, we refined the analytical solution of bending an orthotropic cylindrical shell for individual microtubule, and obtained excellent agreement between finite element simulations and the theoretical predictions of a microtubule bending as a validation of the structural component in the model. Second, by integrating the cilium membrane with nine microtubule doublets and simulating the tip-anchored optical tweezer experiment on our computational model, we found that the microtubule doublets may twist significantly as the whole cilium bends. Third, besides being cilium-length-dependent, we found the mechanical properties of the cilium are also highly deformation-dependent. More important, we found that the cilium membrane near the base is not under pure in-plane tension or compression as previously thought, but has significant local bending stress. This challenges the traditional model of cilium mechanosensing, indicating that transmembrane proteins may be activated more by membrane curvature than membrane stretching. Finally, we incorporated imaging data of primary cilia into our microstructure-based cilium model, and found that comparing to the ideal model with uniform microtubule length, the imaging-informed model shows the nine microtubule doublets interact more evenly with the cilium membrane, and their contact locations can cause even higher bending curvature in the cilium membrane than near the base.

Microstructure-Based Modeling of Laser Beam Shaping During Additive Manufacturing

Microstructure-Based Modeling of Laser Beam Shaping During Additive Manufacturing

Microstructure-based modeling to characterize low pore density open-cell foams and its experimental validation.

Microlattices with large pore sizes are involved in many multifunctional applications, so it is essential to understand their acoustic properties. However, for these low pore density microlattice foams, the classical homogenization or "equivalent fluid" methods fail abruptly. This paper proposes and discusses a microstructure-based direct fluid model (DFM) that would help to predict the acoustic performance of low pore density periodic open-cell foams with spherical pores. The DFM is simulated directly, including the microscale geometric features inherent in the unit cell. A comparative study is performed for designed three-dimensional (3D) body-centered-cubic (BCC) porous foams having pores per inch (PPI) ranging from 1 to 12 over the frequency range of 500-4100 Hz with equivalent fluid models and experiments. The study shows the extent of deviation in homogenization-based methods from the experiment for PPI < 5. On the other hand, the acoustic performance parameters predicted with the DFM agree well with experiments on 3D-printed samples fabricated by additive manufacturing of varying PPI starting from 1. This study shows that the DFM is a valid method to predict the acoustics of low PPI microlattices. Furthermore, the gradual transition from dissipative to the reactive regime with a decrease in PPI is also brought out.

Behavior of TRIP-aided medium Mn steels investigated by in situ synchrotron X-ray diffraction experiments and microstructure-based micromechanical modelling

Medium Mn steels belong to a new generation of advanced high-strength steels whose superior mechanical properties are explained by their ultrafine-grained ferrite/austenite/martensite microstructures and a possible transformation induced plasticity (TRIP) related to the stability of retained austenite. The mechanical behaviour of a set of model medium Mn steels is investigated during tensile testing using a combination of high-energy X-ray diffraction (HEXRD) and digital image correlation (DIC) measurements. HEXRD allows for the time-resolved determination of transformation kinetics and in situ stress partitioning among the different constituting phases. DIC provides precise spatiotemporal information on the strain evolution along the gauge length, particularly at the position of the diffracting volume. These experiments served to calibrate an innovative mean field micromechanical model which accounts for the local behaviour of each phase, as well as the strain-induced martensitic transformation (SIMT) of retained austenite. The work-hardening of both austenite and ferrite is modeled using a dislocation-based size-sensitive approach which includes kinematic hardening contributions. The behaviours of fresh and strain-induced martensite are predicted using a genuine model derived from the continuous composite approach. The model for SIMT is based on a thermodynamic assessment of the stability of retained austenite. The overall model is thus sensitive to the size of the microstructure components, their local chemistry, and their respective stability.

Three-Dimensional Microstructure-Based Deformation Predictions in Battery Electrodes

To give insight on the deformation behavior of the porous electrodes for a lithium-ion battery induced by mechanical stresses, a three-dimensional microstructure-based modeling method (3DMS) is developed [1,2]. The 3DMS simulation applies a Finite Element Analysis (FEA) based solid-stress model to track the composite (active material (AM) and binder) porous electrodes response to compression (external forces), reversible expansion (intercalation dependent), and irreversible expansion (aging dependent).The microstructures used for the electrodes were generated using a modified version of the opensource program MATBOX, developed by NREL, in conjunction with in-house code to create a cutout section of a representative lithium-ion cell. Both anode and cathode structures are stochastically generated and applied with an advanced volume element generation technique to resolve small interface and boundary domains created by binder generation. The applied solid-stress model couples different stresses from local mechanical behavior for the different materials present in the system, considering the individual materials respective mechanical properties. The coupled stresses are used to predict deformation in the microstructure domain. Further analysis on the behavior of the deformation is enacted to gain insights on the design of the porous electrodes.Predictions of the electrodes’ deformation will be validated using experimental work at various length scales and compared to continuum porous electrode models from previous works. Furthermore, development of techniques using the FEA solid stress-model platform will be implemented to predict full cell-level deformation for various macro cell designs including jell-roll, pouch cells, and full module assemblies [3-8]. Ultimately, insights gained from the simulations will be used to understand irreversible deformation in electrodes after cycling and inform microstructure design- particularly for automotive-relevant applications [9]. J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, ECSarXiv (2022).J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, J Electrochem Soc, 170, 020530 (2023).D. J. Pereira, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 166, A1251 (2019).D. J. Pereira, M. A. Fernandez, K. C. Streng, X. X. Hou, X. Gao, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 167, 080515 (2020).D. J. Pereira, A. M. Aleman, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 169, 020577 (2022).T. R. Garrick, K. Kanneganti, X. Y. Huang and J. W. Weidner, J Electrochem Soc, 161, E3297 (2014).T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3592 (2017).T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3552 (2017).T. R. Garrick and J. W. Weidner, in Electrochemical Society Meeting s 233, p. 1345 (2018).

Quantifying Volume Change in Battery Electrode Microstructures

A three-dimensional microstructure-based modeling method (3DMS) is developed [1, 2] to predict the mechanical behaviors of porous electrode that includes both active material (AM) and binders inside lithium-ion battery during compression, reversible expansion (intercalation dependent), and irreversible expansion (aging dependent). The geometry of both AM and binder is generated stochastically to create microstructures by using a modified MATBOX opensource program with our in-house code. The advanced technique of volume element generation is also established to overcome the interfacial error due to complexity of binder distribution. The Finite Element Analysis (FEA) based solid-stress model is applied to predict local mechanical activities including stress-strain relationship and microstructure evolution during compression, intercalation, and aging.The predictions of behavior in the porous electrode under compressive loads will be presented and the insights into the microstructure deformation will be discussed. Further, the analysis results will be validated using experimental testing results acquired at various length scales. This work can be used for the model-based FEA platform to predict the impact of volume change under charge/discharge cycles, volume change of a jelly-roll during formation, and the response of the active material in typical pouch cells during battery module assembly.The predictions of reversible expansion in the porous electrode during cycling will be presented and the insights into the microstructure expansion as compared to continuum porous electrode models from previous work [3-8] will be discussed.Finally, insights into the linkage between irreversible volume expansion in the porous electrode during aging cycling will be discussed and compared to testing acquired for automotive-relevant large format [9] pouch cells.References J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, ECSarXiv (2022).J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, J Electrochem Soc, 170, 020530 (2023).D. J. Pereira, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 166, A1251 (2019).D. J. Pereira, M. A. Fernandez, K. C. Streng, X. X. Hou, X. Gao, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 167, 080515 (2020).D. J. Pereira, A. M. Aleman, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 169, 020577 (2022).T. R. Garrick, K. Kanneganti, X. Y. Huang and J. W. Weidner, J Electrochem Soc, 161, E3297 (2014).T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3592 (2017).T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3552 (2017).T. R. Garrick and J. W. Weidner, in Electrochemical Society Meeting s 233, p. 1345 (2018).

A microstructure-based modeling of delayed hydride cracking in Zr-2.5Nb pressure tube material

In this work, a microstructurally sensitive computational model is developed to simulate delayed hydride cracking (DHC) in Zr-2.5Nb alloy. The model is validated by comparing threshold stress intensity factor (KIH) predictions available in the literature. The anisotropy of Zr-2.5Nb is considered through microstructures containing grains and grain boundaries with different orientations and strengths at the mesoscale. A physically consistent damage model with evolving characteristics based on hydride formation is employed to simulate DHC. Results show that the grain anisotropy and grain boundary strength significantly affect the DHC, which may not be generally noticed in the traditional models.