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This work proposes a novel approach for coupling non‐isothermal fluid dynamics with fracture mechanics to capture thermal effects within fluid‐filled fractures accurately. This method addresses critical aspects of calculating fracture width in enhanced geothermal systems, where the temperature effects of fractures are crucial. The proposed algorithm features an iterative coupling between an interface‐capturing phase‐field fracture method and interface‐tracking thermo‐fluid‐structure interaction using arbitrary Lagrangian–Eulerian coordinates. We use a phase‐field approach to represent fractures and reconstruct the geometry to frame a thermo‐fluid‐structure interaction problem, resulting in pressure and temperature fields that drive fracture propagation. We developed a novel phase‐field interface model accounting for thermal effects, enabling the coupling of quantities specific to the fluid‐filled fracture with the phase‐field model through the interface between the fracture and the intact solid domain. We provide several numerical examples to demonstrate the capabilities of the proposed algorithm. In particular, we analyze mesh convergence of our phase‐field interface model, investigate the effects of temperature on crack width and volume in a static regime, and highlight the method's potential for modeling slowly propagating fractures. [ABSTRACT FROM AUTHOR]

Significant interest and developments in phase-field fracture modeling have emerged. It approximates fracture continuously using a length-scale parameter, accurately simulating fracture initiation and crack propagation in brittle materials like Polymethyl Methacrylate (PMMA) with nonlinear elasticity. This study proposes a phase-field approach for simulating PMMA fracture behavior using ABAQUS with a nonlinear elastic material model (UMAT) and a three-layered element composition (UEL). The staggered approach sequentially solves displacements and phase-field variables. Numerical results are validated against experiments considering various geometries, stress concentrators, and pre-cracks. The computational approach accurately predicts fracture initiation and crack growth in complex patterns and diverse loading conditions. [ABSTRACT FROM AUTHOR]

To capture the stress corrosion cracking (SCC) in metallic materials, a phase‐field framework considering localized plastic deformation and stress states is established. A new function of critical energy release rate is proposed to describe the degradation of cracking resistance of materials in the SCC process. This proposed framework can reproduce SCC results consistent with experimental observations in C‐ring steel SCC tests, especially capturing the directionally characteristic of the cracks. Furthermore, the influences of localized plastic deformation and stress states on the SCC process are studied. This novel phase‐field framework can capture (1) the influences of coupled electricity, mechanics to the SCC mechanisms; (2) the contribution of plastic strain energy as the driving force for the phase‐field; (3) the potential and preferential crack initiation and propagation morphology within the complex stress and strain domain; and (4) the dependence of SCC rate and propagation direction on stress state and localized plastic deformation. Highlights: A phase‐field framework for SCC prediction of elastoplastic materials is established.The novel framework is implemented in finite element model and validated by tests.The framework can capture SCC morphology within the complex stress and strain domain.Influences of stress states and localized plastic deformation on SCC are clarified. [ABSTRACT FROM AUTHOR]

In this work, a three-dimensional crystal-plasticity-based phase-field model considering three kinds of inelastic deformation mechanisms, i.e., martensitic transformation, dislocation slip in austenite, and dislocation slip in martensite, is established to simulate the stress-assisted two-way shape memory effect (SATWSME) of NiTi single crystals and its cyclic degradation. The simulation results show that the ability of the SATWSME of NiTi single crystal increases as increasing the constant stress in the range discussed in this work (10–100 MPa), which is due to the increase of reoriented martensite formed in the cooling process due to the enhanced variant-selection capability of increased constant stress. The martensitic transformation and its reverse in the cyclic process reflecting the SATWSME show more and more obvious localization characteristics, resulting in the accumulation of significantly heterogeneous plastic deformation (mainly caused by the dislocation slip in austenite), which leads to the cyclic degradation of SATWSME. The simulation results and the conclusions drawn from this work are helpful for further understanding the mechanism of functional cyclic degradation of NiTi alloys. [ABSTRACT FROM AUTHOR]

Corson (Cu-Ni-Si) alloys were unidirectionally solidified via the Mizuta method under air or water cooling. To replicate the microstructure of a Corson alloy during solidification, phase-field (PF) simulations were performed, and the numerical results were compared with the experimental findings. The comparison between the air- and water-cooling conditions revealed that the primary dendrite trunks were thinner, and the secondary dendrites were longer and more developed under air-cooling conditions. These results were consistent with the experimental observations. Furthermore, the secondary dendrite arm spacings were evaluated via PF simulations, and the calculated results were consistent with the experimental observations. The interface energy and its anisotropy adopted in the present PF simulations were reasonable for the Corson alloy when compared with the values reported in other studies. [ABSTRACT FROM AUTHOR]

Understanding hydrogen–grain boundary (GB) interactions is critical to the analysis of hydrogen embrittlement in metals. This work presents a mesoscale fully kinetic model to investigate the effect of GB misorientation on hydrogen diffusion and trapping using phase‐field‐based representative volume elements (RVEs). The flux equation consists of three terms: a diffusive term and two terms for high and low angle grain boundary (H/LAGB) trapping. Uptake simulations show that decreasing the grain size results in higher hydrogen content due to increasing the GB density. Permeation simulations show that GBs are high‐flux paths due to their higher enrichment with hydrogen. Since HAGBs have higher enrichment than LAGBs, due to their higher trap‐binding energy, they generally have the highest hydrogen flux. Nevertheless, the flux shows a convoluted behavior as it depends on the local concentration, alignment of GB with external concentration gradient as well as the GB network connectivity. Finally, decreasing the grain size resulted in a larger break‐through time and a larger steady‐state exit flux. [ABSTRACT FROM AUTHOR]

Triply periodic minimal surfaces (TPMS) are highly versatile porous formations that can be defined by formulas. Computationally based, load-specific shape optimization enables tailoring these structures for their respective application areas and thereby enhance their potential. In this investigation, individual sheet-based gyroid structures with varying porosities are specifically optimized with respect to their stiffness. A modified phase-field method is employed to establish a simulation framework for the shape optimization process. Despite constant volume and the preservation of the periodicity of the unit cells, volume redistribution occurs through displacement of the interfaces. The phase-field-based optimization process is detailed using unidirectional loading on three gyroidal unit cells with porosities of 75 %, 80 %, and 85 %. Subsequently, the gyroidal unit cell with a porosity of 85 % is shape-optimized under multidirectional loading. A subsequent experimental validation of the unidirectionally loaded cells confirms that the shape-optimized structures exhibit, on average, higher stiffness than the non-optimized structures. The highest increase of 40 % in effective modulus is achieved with the gyroid structure having a porosity of 75 %, while maintaining minimal alteration to the surface-to-volume ratio and preserving periodicity. Additionally, the experimental data show that the optimization process resulted in a shift in the linear elasticity and plasticity range. In summary, the phase-field method proves to be a valid optimization technique for complex porous structures, allowing the preservation of characteristic properties. [ABSTRACT FROM AUTHOR]

Understanding the probabilistic nature of brittle materials due to inherent dispersions in their mechanical properties is important to assess their reliability and safety for sensitive engineering applications. This is all the more important when elements composed of brittle materials are exposed to dynamic environments, resulting in catastrophic fatigue failures. The authors propose the application of a non-intrusive polynomial chaos expansion method for probabilistic studies on brittle materials undergoing fatigue fracture when geometrical parameters and material properties are random independent variables. Understanding the probabilistic nature of fatigue fracture in brittle materials is crucial for ensuring the reliability and safety of engineering structures subjected to cyclic loading. Crack growth is modelled using a phase-field approach within a finite element framework. For modelling fatigue, fracture resistance is progressively degraded by modifying the regularised free energy functional using a fatigue degradation function. Number of cycles to failure is treated as the dependent variable of interest and is estimated within acceptable limits due to the randomness in independent properties. Multiple 2D benchmark problems are solved to demonstrate the ability of this approach to predict the dependent variable responses with significantly fewer simulations than the Monte Carlo method. This proposed approach can accurately predict results typically obtained through 10 5 or more runs in Monte Carlo simulations with a reduction of up to three orders of magnitude in required runs. The independent random variables' sensitivity to the system response is determined using Sobol' indices. The proposed approach has low computational overhead and can be useful for computationally intensive problems requiring rapid decision-making in sensitive applications like aerospace, nuclear and biomedical engineering. The technique does not require reformulating existing finite element code and can perform the stochastic study by direct pre/post-processing. [ABSTRACT FROM AUTHOR]

In vesicle membranes, the minimum of the elastic bending energy determines the equilibrium shape. We can reformulate the energy using a phase‐field function and optimize it using the standard gradient flow approach. The method, in its typical formulation, allows topological changes in the membrane; however, in certain events, like in the simulation of blood cells, maintaining the initial topology of the membrane is crucial. In this study, we add a constraint on the phase‐field method to preserve the topology. We note that even if the phase‐field method is formulated using a hyperbolic tangent function, during a change in topology, the membrane's profile deviates from the tanh function. Owing to this idea, the constraint imposes an additional requirement on the profile to maintain the tanh shape, thus preserving the topology. We perform extensive experiments in two‐dimensional and three‐dimensional scenarios to demonstrate that our method preserves the topology during the simulation. [ABSTRACT FROM AUTHOR]

By incorporating two different fracture mechanisms and salient unilateral effects in rock materials, we propose a thermomechanical phase-field model to capture thermally induced fracture and shear heating in the process of rock failure. The heat conduction equation is derived, from which the plastic dissipation is treated as a heat source. We then ascertain the effect of the non-associated plastic flow on frictional dissipation and show how it improves the predictive capability of the proposed model. Taking advantage of the multiscale analysis, we propose a phase-field-dependent thermal conductivity with considering the unilateral effect of fracture. After proposing a robust algorithm for solving involved three-field coupling and damage-plasticity coupling problems, we present three numerical examples to illustrate the abilities of our proposed model in capturing various thermo-mechanically coupled behaviors. [ABSTRACT FROM AUTHOR]

This paper presents a procedure for determining the elastoplastic parameters of phase-field fracture of sintered material. The material considered was sintered steel Astaloy™ Mo+0.2C of three densities: 6.5, 6.8 and 7.1 g/ cm 3 . The stress–strain curve and Wöhler curve, which are experimentally obtained, are utilized for validation of the numerical simulations. For modelling of damage evolution, a CCPF (Convergence check phase-field) algorithm was used as a numerical framework. During calibration of the numerical parameters, two-dimensional as well as three-dimensional modelling was used. A comparison of different fatigue degradation functions known from the literature is also made. To improve the efficiency of numerical simulations of fatigue behaviour, the cycle skip technique is also employed. [ABSTRACT FROM AUTHOR]

Understanding the relation between the microstructure and the material's effective behavior is an important aspect in inverse computational materials engineering. Especially in the context of localized, inelastic phenomena like plasticity and crack growth, the microstructure morphology plays a crucial role. Due to the stochastic nature of heterogeneous media, a statistical analysis over multiple simulations is necessary, since even with the same material, the simulated crack paths and effective crack lengths are highly dependent on the specific locations of microstructural features. A relevant factor that limits this type of investigation is the high cost of real microstructure data. This work presents a digital workflow for exploring the fracture properties of materials. Therein, the required statistical analyses are facilitated by an algorithm that reconstructs multiple realization of a material structure given a single example. The reconstructed structures are discretized with a regular non-conforming mesh with a diffuse interface and crack representation. Crack phase-field simulations are conducted in order to analyze the effective response. An in-depth introduction to the required methods is given together with a statistical evaluation of the conducted numerical experiments. It is concluded that the statistical variation of the effective material behavior overshadows morphological trends in the presented case. This confirms the relevance and utility of complementing simulation-based workflows with microstructure reconstruction and statistical analyses. [ABSTRACT FROM AUTHOR]

Phase-field models of brittle fracture are typically endowed with a decomposition of the elastic strain energy density in order to realistically describe fracture under multi-axial stress states. In this contribution, we identify the essential requirements for this decomposition to correctly describe both nucleation and propagation of cracks. Discussing the evolution of the elastic domains in the strain and stress spaces as damage evolves, we highlight the links between the nucleation and propagation conditions and the modulation of the elastic energy with the phase-field variable. In light of the identified requirements, we review some of the existing energy decompositions, showcasing their merits and limitations, and conclude that none of them is able to fulfil all requirements. As a partial remedy to this outcome, we propose a new energy decomposition, denoted as star-convex model, which involves a minimal modification of the volumetric-deviatoric decomposition. Predictions of the star-convex model are compared with those of the existing models with different numerical tests encompassing both nucleation and propagation. [ABSTRACT FROM AUTHOR]

In the realm of fracture mechanics and phase-field modeling, the utilization of exponential finite element (EFE) shape functions has shown promise in accurately predicting fracture responses, particularly in scenarios with intricate crack propagation paths. However, the computational complexity associated with EFE shape functions, including higher integration schemes and orientation requirements, prompts the need for optimization. This study delves into the critical aspect of integration point density and aims to determine the ideal balance between accuracy and computational efficiency in the context of EFE shape functions. The research focuses on functionally graded materials, which inherently exhibit spatial variations in solution quantities due to their graded material system. Through a systematic investigation, the study aims to identify the optimal number of integration points required to maximize the computational advantages offered by EFE shape functions while minimizing the associated computational resources. By conducting a comprehensive analysis across various loading scenarios, such as tension and shear, this study intends to establish a quantitative relationship between integration point density and prediction accuracy for fracture responses. [ABSTRACT FROM AUTHOR]

In the present work, the conservative phase-field lattice Boltzmann model is applied to simulate plunging breakers in shallow waters. The solver is computationally efficient as it is explicit in time stepping and does not require a solution for the pressure Poisson equation. Nevertheless, the solver can simultaneously handle a large Reynolds number ( $ =10^4 $ = 10 4 ) and a high-density ratio of 1000. Simulations are performed by varying initial steepness and dispersion parameters, which influence the nonlinearity degree of wave (or the growth speed of instability) and the oscillatory motion (limited by the bottom) on the breaking characteristics. Detailed analyses of kinematics, air entrainment, vorticity, and energy dissipation are presented. [ABSTRACT FROM AUTHOR]

The atomic atmosphere and formation mechanism of the antiphase domain boundary (APB) may depend on the environmental variables of the phase transformation for the L12‐structural Ni3Al phase, which is the first important precipitate phase for Ni‐based superalloys. Herein, a discrete phase field method is used to reproduce the complete formation process of an APB without preset restrictions. Numerical calculations are performed to classify the atomic atmosphere, and its formation mechanism is revealed by calculating and analyzing the functional properties of the driving force. The formation process shows that four types of antiphase domains survive to form the APB. The numerical calculation results demonstrate that the atomic atmosphere has the same temperature dependence for hypostoichiometric, stoichiometric, and hyperstoichiometric systems. However, Al plays two opposite roles in influencing the atomic atmosphere according to the changes in the alloy system. The positive and negative values of the driving force determine whether the atomic atmosphere is segregated or depleted, and the magnitude of the absolute value determines the atomic atmosphere level. This atomic‐scale study of nanoscale ordered domain boundaries can provide theoretical information for further understanding of these and similar interfaces in ordered precipitation‐strengthened phases. [ABSTRACT FROM AUTHOR]

Laser quenching has significant advantages over conventional heat treatment. The main microstructure of C30E4 steel after quenching at a specific temperature is Martensite. Accurately obtaining the microscopic characteristics of the Martensite transformation process is the key to obtaining the best material properties, which is significant to material design. In this paper, the C30E4 steel was disk-laser-quenched, the metallographic and high-temperature confocal laser scanning microscope experiment was carried out. The microstructure of the fully phase-change hardened zone, heat-affected transition zone and matrix zone after quenching was obtained. The C30E4 martensitic transformation process in-situ was obtained. The mathematical physics model of Martensite transformation from metastable to steady state was established by phase field method. The finite-element method was used to solve the model, and the quenching Martensite transformation law was obtained. The Martensite formation process in austenite grain boundaries and microstructure defects was discussed. The experimental and the numerical simulation were compared to get consistent results, which verify the validity of the calculation method. This study lays a significant foundation for effectively revealing the Martensite formation and transformation during the disk laser quenching process, and provides a theoretical basis for quantifying the influence of Martensite transformation process on material properties. [ABSTRACT FROM AUTHOR]

In this paper, a mechanics-based phase-field model at the microscale is introduced for microstructure evolution during solidification. The couple phase-field model consists of Allen–Cahn equation for phase order parameter, Cahn–Hilliard equation for composition, heat conduction and elasticity equations. The introduced elastic energy allows for volumetric inelastic strains due to melting/solidification as well as a thermodynamically consistent solid-melt interface stress and consequently, residual stresses during solidification at the microscale and deformation can be captured. The computational microcell is considered at the melt-solid interface and the temperature as a time dependent function is used for its boundary conditions to solve the coupled phase-field model. Using COMSOL FE code, examples of columnar growth are studied. As result, the suppressive effect of elastic driving forces and the reduction in solidification rate, due to the volumetric inelastic strains, on solidification are revealed. The inelastic surface stress, concentrated inside the interface, can change the morphology of solidified structure but does not show a remarkable effect on the solidification rate. The thermal strain was included which reduced the effect of volumetric transformation strain and consequently, the internal stresses near constrained regions were decreased. The effect of undercooling was studied which showed that increasing the undercooling increased the temperature gradient in the vertical direction and near the interface and solidification rate and significantly changed the morphology of solidified structure, as a homogeneous growth was resolved for larger undercooling while a columnar growth was obtained for smaller undercooling. Solidification was studied under mechanical loading which showed external loading changes the stress distribution and magnitude and the morphology of solidified structure. Effect of an inclusion on solidification was also investigated. The inclusion represented a more homogeneous distribution of stress and temperature with different magnitudes compared to the rest of the sample, creating a directional solidification toward the inclusion. [ABSTRACT FROM AUTHOR]

Bone microstructure governs microcrack propagation complexity. Current research, relying on linear elastic fracture mechanics, inadequately considers authentic multi-level structures, like cement lines and osteons, impacting stress intensity at cracks. This study, by constructing models encompassing single or multiple osteons, delves into the influence of factors like crack length, osteon radius, and modulus ratio on the stress intensity factor at the crack tip. Employing a fracture mechanics phase-field approach to simulate crack propagation paths, it particularly explores the role of cement lines as weak interfaces in crack extension. The aim is to comprehensively and systematically elucidate the critical factors of bone microstructure in the context of crack propagation. [ABSTRACT FROM AUTHOR]

The D019-α2 / L10-γ alternate lamellae microstructure in TiAl alloys brings the superior mechanical property, the lamellae with multi-variant γ phase are key characteristic of morphology-property causality. The nucleation, growth and coarsening of multi-variants γ are investigated in TiAl alloys by using the three-dimensional phase-field simulation, the γ morphology, lamellar spacing (LS) and the predicted yield strength of alloy are in agreement with the experiment. It is found that the γ variants can nucleate and grow up separately to form the single-variant lamella, or through the symbiotic nucleation and growth to form multi-variant lamella, the growth of γ lamella follows the terrace-ledge-kink mechanism. The growth rate along the longitudinal direction is distinctly larger than that of the thickness direction, resulting in the lamellar structure. A three-stage growth kinetics, nucleation, growth and coarsening of γ lamella in thickness is revealed. As Al content changes, the LS is enlarged with the reduced lamella number. The influence of the LS on the mechanical properties is evaluated by using the Hall-Petch relationship. The results give an insight for the formation and evolution mechanisms of multi-variant γ lamella, and discover the internal relations of lamellar morphology and mechanical properties of TiAl alloys.

Lithium Nickel Manganese Cobalt Oxides (NMC) are one of the most used cathode materials in lithium-ion batteries, and they will become more relevant in the following years due to their potential in electric vehicles. Unfortunately, this material experiences microcracking during the battery operation due to the volume variations, which is detrimental to the battery performance and limits the lifetime of the electrodes. Thus, understanding mechanical degradation is fundamental for the development of advanced batteries with improved capacity and limited degradation. In this work, we propose a chemo-mechanical model, including a stochastic phase-field fracture approach, to design structurally stable NMC electrodes. We include the degradation in the mechanical and chemical contributions. The heterogeneous NMC microstructure is considered by representing the material's tensile strength with a Weibull distribution function, which allows to represent complex and non-deterministic crack patterns.We use our model to provide a comprehensive analysis of mechanical degradation in NMC111 electrodes, including the effect of particle size, C-rate, and depth of charge and discharge. Then, we analyze the influence of the electrode composition (namely, Ni content) on the structural integrity. We use this information to provide design guides for functionally-graded electrodes with high capacity and limited degradation.

Lamella is a unique microstructure in matters that possesses special properties. The formation and evolution of lamellar microstructures are crucial for achieving super abilities, while the mechanisms of lamellar formation and evolution at the nanoscale are unclear. Driving by the interesting while uncovered micromechanism in lamellar microstructure evolution, we performed the phase-field simulation and experiment to investigate the multiple splitting behaviors of lamellar Ti-Al alloys. The splitting mode of lamella is discovered, inner splitting (IS) and outside splitting (OS). The originations of splitting are found to come from the high interfacial energy of step-like interface between γ variants for the IS, and the stress concentration at α2/γ interface drives step-like interface for the OS. The lamellar splitting is complied with the energy change in matter, decreasing in total free energy and elastic energy, while increasing in interfacial energy. These findings provide the new mechanisms of internal lamellar interface breaking driven by the interfacial energy. Therefrom, the expected matter features will be achieved by the strategy of microstructure modulation and optimization.

Point defects and dislocation can be induced in dual-phase stainless steels in the circumstance of irradiation. These defects affect the phase separation and the morphology evolution of Fe-Cr based alloys, increasing the hardening and damage of alloys. The influence of dislocation on the evolution of Cr-enriched α′ nanophase accompanying the vacancy and interstitial atoms is studied by the multi-phase-field model. Multi-dislocation loops are introduced to investigate the dragging effect of dislocation stress field on the solute atoms, and the dragging effect of solute atoms on the point defects. Tensile stress of dislocation drags the Cr atoms to accelerate the local phase separation, and the migration of Cr atoms drags the vacancies to form a two-dimensional vacancy loop around the α/α′ phase boundary. Large diffusion potential difference drives the atomic diffusion rapidly and accelerates the growth and coarsening of the α′ phase. The superposition of tensile and compressive stress field of multi-dislocation loops makes the redissolution of the α′ phase. The multi-interactions of stress–atoms–point defects are clearly presented in this work, and the dynamic effects are clarified for the dragging on solute atoms and point defects under dislocation stress. [ABSTRACT FROM AUTHOR]

This work studies crack propagation in particulate nanocomposites using the phase-field method. The crack propagation has been simulated in a wide range of loadings and the critical load for the crack growth has been obtained. Surface tension, as an inelastic stress, is introduced in the model in a thermodynamically consistent way. The effect of surface tension on the crack tip velocity and the crack evolution has been discussed. The finite element method via COMSOL multiphysics software has been utilized to solve the coupled phase-field and elasticity equations. Modeling and prediction of crack propagation for nanocomposites including different nanoparticles and under different loadings are the main purposes of this work. It is found that the kinetics and morphology of the crack propagation depend on the elastic moduli and the surface energy of nanoparticles as well as their longitudinal and angular distances to each other. [ABSTRACT FROM AUTHOR]

This study unveils a numerical paradigm that amalgamates the partially saturated lattice Boltzmann method (PSLBM) with the non‐isothermal quantitative phase‐field (PF) model. This innovative integration equips us with a prognostic tool ready to elucidate the progression and motion of solid‐air dendritic growth in the presence of both natural and forced convection. The PSLBM is employed to compute the flow of the solution and the interaction forces between the fluid and solid dendrites. Concurrently, the PF model is utilized to simulate the formation of solid‐air dendrites. The reliability of calculating of interaction forces between the fluid and solid was confirmed through a numerical case study involving fluid flow around a stationary cylinder. The results indicate that this model is applicable for simulating the growth and evolution of single/multiple solid‐air dendrites under the influence of convection, whether they are stationary or in motion. The promotion of the upstream side dendritic arms and the inhibition of the downstream dendritic arms increase with the intensification of natural convection. As the initial undercooling is raised, the capacity of natural convection to reshape dendritic morphology gradually diminishes. With the enhancement of forced convection intensity, due to alterations in the flow pattern, the downstream dendritic arms do not consistently exhibit growth suppression. The motion of solid‐air dendrites induced by forced convection counteracts the influence of convection, resulting in slightly faster growth of the downstream dendritic arms compared to the upstream arms. Simultaneously, it fosters the formation of secondary dendritic branches in the upstream zone. [ABSTRACT FROM AUTHOR]

Physical Vapor Deposited (PVD) TiAlN coatings are extensively utilized as protective layers for cutting tools, renowned for their excellent comprehensive performance. To optimize quality control of TiAlN coatings for cutting tools, a multi-scale simulation approach is proposed that encompasses the microstructure evolution of coatings considering the entire preparation and service lifecycle of PVD TiAlN coatings. This scheme employs phase-field simulation to capture the essential microstructure of the PVD-prepared TiAlN coatings. Moreover, cutting simulation is used to determine the service temperature experienced during cutting processes at varying rates. Cahn-Hilliard modeling is finally utilized to consume the microstructure and service condition data to acquaint the microstructure evolution of TiAlN coatings throughout the cutting processes. This methodology effectively establishes a correlation between service temperature and its impact on the microstructure evolution of TiAlN coatings. It is expected that the present multi-scale numerical simulation approach will provide innovative strategies for assisting property design and lifespan prediction of TiAlN coatings. [ABSTRACT FROM AUTHOR]

Studying Arctic ice formation stays in the focus of research groups over the past decades in the context of ice cover changes, thermal budget and climate agenda in general. Nevertheless, the phenomenon's underlying mechanisms are still not completely understood and described. The main reason for the lack in understanding is the limited experimental access to the field data when it comes to the processes that occur below the ice floe. Thus, there is a need to build competent analogies between the natural (ocean water–ice) and laboratory (here: binary alloy) conditions of the experiment as a step of data preparation for the verification of the mathematical model. In the current paper, the existing qualitative models describing the process of melting and crystallization were expanded and the experimental method was developed copying the layering of the natural ocean water–ice mixture. The experimental set‐up for studying the solidification within the intermediate zone was designed for Al–Cu alloys being the system with appropriate solidus line for creating a sufficient concentration gradient and by that temperature dependent phase fraction under isothermal conditions. The gained experimental data were used for validating a binary phase‐field model for solidification considering moving boundaries. The model includes the description of the free energy of both phases and their respective diffusion coefficients. It allows modeling a binary system at a mesoscopic spatial level by including the concentration‐driven phase transition and resolidification in the two‐phase region. The novel results will help the quantitative understanding of solidification phenomena and are highly‐evaluated from interdisciplinary point of view, including glaciology and geosciences, being ultimately significant for the understanding the global climate change landscape. [ABSTRACT FROM AUTHOR]

Metal‐based additive manufacturing can make complicated parts that are complex or expensive to cast and process. Rapid cooling rates increase laser powder bed fusion (LPBF's) mechanical properties during manufacturing. The objective of this study is to examine the impact of process parameters in the L‐PBF technique on the characteristics of microstructure and mechanical properties, specifically, on the nanohardness influenced by Si segregation. The microstructures of the produced specimens are examined using field‐emission scanning electron microscopy and the analysis identifies the existence of bimodal equiaxed α‐Al grains, accompanied by Si phases located within their grain boundaries. In addition, the solidified sample exhibits the segregation of secondary precipitates, particularly Mg2Si, which results in enhanced mechanical properties. Both cellular walls and Si precipitates impede the motion and generation of dislocations, thereby influencing the overall behavior of dislocations. The examination of segregation at the top layer is conducted in a comprehensive manner, subsequently using energy‐dispersive X‐ray spectroscopy for analysis. The presence of Mg2Si, Al2MgSi2, and other phases in all samples is confirmed through X‐ray diffraction. The as‐built samples' residual stress under different process conditions is also investigated. Additionally, the obtained microstructure is compared to a phase‐field model to forecast the evolution of the microstructure. [ABSTRACT FROM AUTHOR]

The precipitation kinetics of γ′-Ni3(Al, Ta) phase and creep properties of Ni-15Al-xTa at.% superalloys are investigated by the crystal plasticity phase-field simulation. The results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage, while the creep lifetime is shorter. The large external strain intensifies the creep damage and shortens the creep life of Ni-15Al-3Ta at.% superalloy. The kinetics evolution and elements distribution are revealed in the quaternary Ni-10Al-8.5Cr-xTa (x = 1.5 at.%, 2.0 at.%, 2.5 at.%) superalloys by the multi-component phase-field simulation. The anti-phase boundary (APB) changes the coarsening mechanism of γ′ phase, and Ta promotes the precipitation of γ′ phase with an increasing volume fraction and particle number. The composition difference between γ′ and γ phases increases with the rising of Ta content, the strong partitioning of Ta to γ′ phase strengthens the partitioning of Ni and Cr to γ matrix, and Ta shows a superiority than Al in the lattice site occupation of L12-Ni3(Al, X) phases. As an important γ′ phase forming element, the optimization of Ta content is essential for improving the mechanical properties of Ni-based superalloys. [ABSTRACT FROM AUTHOR]

Brittle material Mode I fracture may be characterized by the double cleavage drilled compression test. For linear elastic materials, the critical energy release rate, or fracture toughness, can be estimated simply using the linear elastic fracture mechanics. For other types of constitutive behavior, the material parameter has to be determined with numerical fracture modeling. In this paper, we have used two approaches, the phase-field damage model and the cohesive elements, in order to estimate the critical energy release rate of an elastoplastic material. Firstly, we assessed the numerical models and discussed their parameters by comparison of available data from double cleavage drilled compression experimental tests run on a silica glass. Both phase-field damage and cohesive zone models were able to reproduce fracture initiation at the observed macroscopic stress for the linear elastic material. However, the material toughness could not be predicted by the phase-field approach due to the result dependence on the model regularization parameter. Secondly, an elastoplastic methyl methacrylate polymer was submitted to the compression test in our lab. Both models were then extended for elastic-perfectly plastic materials. Crack initiation was obtained at the observed macroscopic strain for similar critical energy release rate ranges for both approaches, providing good confidence in the estimated material toughness. [ABSTRACT FROM AUTHOR]

The state-of-the-art fractographic guidelines for glasses and fine ceramics, ASTM C1678, are only applicable to limited fracture scenarios. This work outlines a new method to analyze fracture scenarios outside ASTM C1678′s scope. The proposed methodology consists of a two-step process: initially, optical images of the fracture surfaces are obtained, and visual analysis is used to highlight the characteristic fractographic features. Next, the selected features are automatically compared to a baseline set of virtual fracture patterns tailored to any relevant fracture scenarios obtained by numerical phase-field simulations. As validation, scenarios with fractures originating at the glass plates' edges for both sharp and chamfered corners were analyzed. Strength estimates within 6% of experimental results were achieved with the proposed method. In the future, this technique could be implemented to carry out fractographic analysis on brittle components of arbitrary shapes and loadings, hence substantially extending the application range and accuracy of fractographic methods. [ABSTRACT FROM AUTHOR]