Numerical modeling and synchrotron diffraction measurements of residual stresses in laser powder bed fusion manufactured alloy 625

Malmelöv, Andreas; Hassila, Carl-Johan; Fisk, Martin; Wiklund, Urban; Lundbäck, Andreas

doi:10.1016/j.matdes.2022.110548

Cited by 14 publications

(14 citation statements)

References 35 publications

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“…This is known as competitive grain growth which has a significant influence on the grain textures of PBF-LB produced materials. The maximum heat flow direction in additive manufacturing is along the build direction which causes pronounced columnar grain textures oriented along the build direction as seen in Malmelöv et al [8].…”

Section: Introductionmentioning

confidence: 94%

“…flow direction in additive manufacturing is along the build direction which causes pro nounced columnar grain textures oriented along the build direction as seen in Malmelöv et al [8]. The mechanical properties of the produced material will vary depending on the obtained grain texture.…”

Section: Introductionmentioning

confidence: 99%

“…Such a model can be used to obtain a better understanding of how the grain texture of the printed material is influenced by the many process parameters in PBF-LB. The prediction is based on the temperature history obtained with a 3D FE heat transfer model for a set of process parameters from the work by Malmelöv et al [8]. The heat transfer model combined with a 2D CA model is proposed to efficiently compute grain growth and nucleation in alloys produced by PBF-LB.…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Evolution of Grain Texture during Solidification of Laser-Based Powder Bed Fusion Manufactured Alloy 625 Using a Cellular Automata Finite Element Model

Andersson,

Lundbäck

2023

Metals

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The grain texture of the as-printed material evolves during the laser-based powder bed fusion (PBF-LB) process. The resulting mechanical properties are dependent on the obtained grain texture and the properties vary depending on the chosen process parameters such as scan velocity and laser power. A coupled 2D Cellular Automata and Finite Element model (2D CA-FE) is developed to predict the evolution of the grain texture during solidification of the nickel-based superalloy 625 produced by PBF-LB. The FE model predicts the temperature history of the build, and the CA model makes predictions of nucleation and grain growth based on the temperature history. The 2D CA-FE model captures the solidification behavior observed in PBF-LB such as competitive grain growth plus equiaxed and columnar grain growth. Three different nucleation densities for heterogeneous nucleation were studied, 1 × 1011, 3 × 1011, and 5 × 1011. It was found that the nucleation density 3 × 1011 gave the best result compared to existing EBSD data in the literature. With the selected nucleation density, the aspect ratio and grain size distribution of the simulated grain texture also agrees well with the observed textures from EBSD in the literature.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling the Evolution of Grain Texture during Solidification of Laser-Based Powder Bed Fusion Manufactured Alloy 625 Using a Cellular Automata Finite Element Model

Andersson,

Lundbäck

2023

Metals

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“…The residual stresses of the LPBF parts have proven to have spatial distribution patterns [50,51]. As the last area to solidify, the thermal shrinkage at the top area is limited by the presolidified layers [52][53][54][55][56], resulting in the tensile residual stress perpendicular to the BD. The residual stresses on the top surface of the AB and HT samples were measured via XRD.…”

Section: The Effect Of Residual Stressmentioning

confidence: 99%

Mechanisms of Heat-Treatment-Induced Cracking in Additively Manufactured IN738 Alloy

Miao,

Ding,

et al. 2023

Materials

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The present study conducts a comprehensive study on heat-treatment-induced cracking of Inconel 738 (IN738) alloy fabricated by laser powder bed fusion (LPBF) using scanning electron microscopy (SEM), energy dispersion spectrum (EDS), and electron backscatter diffraction (EBSD). The results indicate that the macroscopic crack is dominantly triggered by the strain-age cracking mechanism and propagates along grain boundaries. The initiation of cracking is facilitated by the superimposition of residual stress induced by the LPBF process and contraction stress induced by precipitation, while the reopening of compress pores at grain boundaries weakens the grain boundaries and provides fast channels for cracking. These results revealed the coupling effects in triggering heat-treatment-induced cracking, offering a fundamental guideline for crack control during heat treatment of additively manufactured IN738 alloy.

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“…The mesoscale results enabled the creation of a macroscale model. Malmelöv et al [21] simulated residual stresses in additive-manufactured alloy 625 samples using a thermo-mechanical finite element model. A mechanism-based material model, that accounts for microstructural and relaxation effects, was used to describe the elastoplastic behaviour of the material.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Method in L-PBF of Ti-6Al-4V: Influence of Laser Power and Scan Speed on Residual Stress and Part Distortion

Palmeri,

Pollara,

Licari

et al. 2023

Metals

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Laser powder bed fusion (L-PBF) is widely used in automotive, aerospace, and biomedical applications thanks to its ability to produce complex geometries. In spite of its advantages, parts produced with this technology can show distortion due to the residual stresses developed during the printing process. For this reason, numerical simulations can be used to predict thermal gradients and residual stresses that can result in part distortion. Thus, instead of performing experimental tests and using a trial and error approach, it is possible to use numerical simulation to save time and material. In this work, the effect of laser power and scan speed on residual stress and part distortion was analysed using a commercial finite element analysis (FEA) software DEFORM-3D™ with a layer-by-layer approach. Moreover, the accuracy of the numerical model with respect to process parameters and the utilised mesh was also studied. The results obtained from the numerical simulation were compared to the actual distortions to evaluate the accuracy of the FEM model. The predicted distortions using FEM analysis well fit the trend of the measured ones. The accuracy of the numerical model increases by considering a finer mesh.

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Numerical modeling and synchrotron diffraction measurements of residual stresses in laser powder bed fusion manufactured alloy 625

Cited by 14 publications

References 35 publications

Modeling the Evolution of Grain Texture during Solidification of Laser-Based Powder Bed Fusion Manufactured Alloy 625 Using a Cellular Automata Finite Element Model

Modeling the Evolution of Grain Texture during Solidification of Laser-Based Powder Bed Fusion Manufactured Alloy 625 Using a Cellular Automata Finite Element Model

Mechanisms of Heat-Treatment-Induced Cracking in Additively Manufactured IN738 Alloy

Finite Element Method in L-PBF of Ti-6Al-4V: Influence of Laser Power and Scan Speed on Residual Stress and Part Distortion

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