Effect of Grain Statistics on Micromechanical Modeling: The Example of Additively Manufactured Materials Examined by Electron Backscatter Diffraction

Biswas, Abhishek; Prasad, Mahesh R. G.; Vajragupta, Napat; Kostka, Aleksander; Niendorf, Т.; Hartmaier, Alexander

doi:10.1002/adem.201901416

Cited by 7 publications

(11 citation statements)

References 33 publications

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“…To test the ability of this method to predict the YL of a realistic microstructure, an example of 316L stainless steel manufactured by selective laser melting is chosen from Biswas et al [33]. Using the statistical data from the microstructure of the material, an RVE is created consisting of 512 grains using the texture reconstruction in Biswas et al [34].…”

Section: Assessment Of the Calibrated Cyl Methodsmentioning

confidence: 99%

“…Using the statistical data from the microstructure of the material, an RVE is created consisting of 512 grains using the texture reconstruction in Biswas et al [34]. The material model and the corresponding parameters are taken from Biswas et al [33]. The EBSD map, the generated RVEs and the comparison of the calibrated CYL with the YL obtained from full-field CPFEM simulations are shown in figure 9.…”

Section: Assessment Of the Calibrated Cyl Methodsmentioning

confidence: 99%

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A hybrid approach for the efficient computation of polycrystalline yield loci with the accuracy of the crystal plasticity finite element method

Biswas

Kalidindi

Hartmaier

2022

Modelling Simul. Mater. Sci. Eng.

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Direct experimental evaluation of the anisotropic yield locus of a given material, representing the zeros of the material's yield function in the stress space, is arduous. It is much more practical to determine the yield locus by combining limited measurements of yield strengths with predictions from numerical models based on microstructural features such as the orientation distribution function (ODF; also referred to as the crystallographic texture). For the latter, several different strategies exist in the current literature. In this work, we develop and present a new hybrid method that combines the numerical efficiency and simplicity of the classical crystallographic yield locus (CYL) method with the accuracy of the computationally expensive crystal plasticity finite element method (CPFEM). The development of our hybrid approach is presented in two steps. In the first step, we demonstrate for diverse crystallographic textures that the proposed hybrid method is in good agreement with the shape of the predicted yield locus estimated by either CPFEM or experiments, even for pronounced plastic anisotropy. It is shown that the calibration of only two parameters of the CYL method with only two yield stresses for different load cases obtained from either CPFEM simulations or experiments produces a reliable computation of the polycrystal yield loci for diverse crystallographic textures. The accuracy of the hybrid approach is evaluated using the results from the previously established CPFEM method for the computation of the entire yield locus and also experiments. In the second step, the point cloud data of stress tensors on the yield loci predicted by the calibrated CYL method are interpolated within the deviatoric stress space by cubic splines such that a smooth yield function can be constructed. Since the produced yield locus from the hybrid approach is presented as a smooth function, this formulation can potentially be used as an anisotropic yield function for the standard continuum plasticity methods commonly used in finite element analysis.

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Section: Assessment Of the Calibrated Cyl Methodsmentioning

confidence: 99%

Section: Assessment Of the Calibrated Cyl Methodsmentioning

confidence: 99%

A hybrid approach for the efficient computation of polycrystalline yield loci with the accuracy of the crystal plasticity finite element method

Biswas

Kalidindi

Hartmaier

2022

Modelling Simul. Mater. Sci. Eng.

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“…To capture the anisotropic behavior of PBF-LB/M materials, the RVE must mimic the grain geometry and the crystallographic texture experimentally determined by EBSD. For generating a statistically equivalent RVE, the EBSD data used must contain a minimum of 10,000 grains [25]. Alternatively, smaller EBSD maps can be captured at various areas and stitched together [25].…”

Section: Rve From Ebsdmentioning

confidence: 99%

“…For generating a statistically equivalent RVE, the EBSD data used must contain a minimum of 10,000 grains [25]. Alternatively, smaller EBSD maps can be captured at various areas and stitched together [25]. The following subsections explain the procedure for generating the mesoscale RVEs in detail.…”

Section: Rve From Ebsdmentioning

confidence: 99%

“…Ahmadi et al [23] used CPFEM and a cohesive zone model (CZM) to study the effect of laser parameters, scan strategy, porosity, and grain orientations on the mechanical properties of PBF-LB/M 316L stainless steel. Some of the authors of the current research studied the effect of the microstructural features on the hardening behavior and the effect of grain statistics on the micromechanical modeling of PBF-LB/M 316L stainless steel using the CPFEM [24,25]. Kim et al [26] used CPFEM to predict the tensile behavior of PBF-LB/M AlSi10Mg.…”

Section: Introductionmentioning

confidence: 99%

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Micromechanical Modeling of AlSi10Mg Processed by Laser-Based Additive Manufacturing: From as-Built to Heat-Treated Microstructures

Rajan¹,

Krochmal

Wegener

et al. 2022

Materials

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The unique microstructure of the alloy AlSi10Mg produced by the laser-based powder bed fusion of metals (PBF-LB/M) provides high-strength and high-strain-hardening capabilities of the material. The microstructure and mechanical properties of 3D-printed, i.e., additively manufactured, AlSi10Mg are significantly altered by post-building heat-treatment processes applied in order to tailor the final properties of the parts. Using an accurate computational model to predict and improve the mechanical performance of 3D-printed samples considering their microstructural features can accelerate their employment in envisaged applications. The present study aims to investigate the correlation between microstructural features and the mechanical behavior of as-built, direct-aged, and T6 heat-treated samples of PBF-LB/M AlSi10Mg under tensile loading using experiment and microstructure-sensitive modeling approaches. Nanoindentation tests are used to calibrate the parameters of the constitutive models for the Al and Si-rich phases. The experimental investigations revealed that heat treatment significantly changes the sub-grain morphology of the Si-rich phase, and this can have a considerable effect on the mechanical behavior of the components. The effect of the modeling of the Si-rich phase in the representative volume elements on the prediction of mechanical behavior is investigated using the J2 plasticity model. The combination of the crystal plasticity model for Al and the J2 plasticity model for the Si-rich phase is used to predict the tensile properties of the as-built and heat-treated states. The predicted results are in good agreement with the experimental results. This approach can be used to understand the microstructure–property relationship of PBF-LB/M AlSi10Mg and eventually tailor heat treatment for PBF-LB/M AlSi10Mg based on the requirement of the application.

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Microstructure-Sensitive Crystal Plasticity Modeling for Austenitic Steel and Nickel-Based Superalloy Under Isothermal Fatigue Loading

Shahmardani

Hartmaier

2023

Metall Mater Trans A

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Intermittent mechanical loads combined with high temperatures appear during the operation of turbines in jet engines or in power plants, which can lead to high-temperature fatigue or to thermomechanical fatigue. Since the assessment of fatigue properties is a complex and time-consuming process, it is essential to develop validated material models that are capable of predicting fatigue behavior, thus allowing the extrapolation of experimental results into a broader range of thermomechanical conditions. To accomplish this, two representative volume elements (RVEs), mimicking the typical microstructure of single crystal Ni-based superalloys and polycrystalline austenitic steels, respectively, are introduced. With the help of these RVEs, the temperature and deformation-dependent internal stresses in the microstructure can be taken into account. In the next step, phenomenological crystal plasticity models are implemented and parameterized for cyclic deformation of these two materials. The RVE, constitutive model, and the material parameters for the Ni-based superalloy are taken from a former study. For the austenitic steel, however, an inverse procedure has been used to identify its material parameters based on several isothermal fatigue tests in a wide temperature range. With the identified material parameters, a valid description of the isothermal fatigue behavior at different temperatures is possible. The most important conclusion from the comparison of the isothermal fatigue behavior of the two different materials is that the kinematic hardening, which is responsible for the shape of the hysteresis loops, is entirely described by the internal stresses within the typical microstructure of the Ni-based superalloy, which is modeled in a scale-bridging approach. Hence, no additional terms for kinematic hardening need to be introduced to describe the cyclic plasticity in the superalloy. For the austenitic steel, in contrast, the Ohno–Wang model for kinematic hardening needs to be considered additionally to the internal stresses in the polycrystalline microstructure to obtain a correct description of its cyclic plasticity.

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Effect of Grain Statistics on Micromechanical Modeling: The Example of Additively Manufactured Materials Examined by Electron Backscatter Diffraction

Cited by 7 publications

References 33 publications

A hybrid approach for the efficient computation of polycrystalline yield loci with the accuracy of the crystal plasticity finite element method

A hybrid approach for the efficient computation of polycrystalline yield loci with the accuracy of the crystal plasticity finite element method

Micromechanical Modeling of AlSi10Mg Processed by Laser-Based Additive Manufacturing: From as-Built to Heat-Treated Microstructures

Microstructure-Sensitive Crystal Plasticity Modeling for Austenitic Steel and Nickel-Based Superalloy Under Isothermal Fatigue Loading

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