Numerical modeling of microstructure evolution during laser additive manufacturing of a nickel-based superalloy

Nie, Pulin; Ojo, O.A.; Li, Zhuguo

doi:10.1016/j.actamat.2014.05.039

Cited by 330 publications

(114 citation statements)

References 39 publications

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“…However, as 3D printing involves fast cooling, the γ′ precipitates are either undetectable12 or excessively small with uneven sizes and rounded corners13,14 and hence less stable during high‐temperature service. At some superalloy compositions and 3D‐printing parameters, detrimental Laves phase particles are reported 15. More importantly, a high density of dislocations build up in the heat‐affected zone (HAZ), due to unavoidable (often local) deformation under high thermal stresses during printing 16,17.…”

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confidence: 99%

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

Chen

Huang

et al. 2020

Advanced Materials

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The repair of damaged Ni‐based superalloy single‐crystal turbine blades has been a long‐standing challenge. Additive manufacturing by an electron beam is promising to this end, but there is a formidable obstacle: either the residual stress and γ/γ ′ microstructure in the single‐crystalline fusion zone after e‐beam melting are unacceptable (e.g., prone to cracking), or, after solutionizing heat treatment, recrystallization occurs, bringing forth new grains that degrade the high‐temperature creep properties. Here, a post‐3D printing recovery protocol is designed that eliminates the driving force for recrystallization, namely, the stored energy associated with the high retained dislocation density, prior to standard solution treatment and aging. The post‐electron‐beam‐melting, pre‐solutionizing recovery via sub‐solvus annealing is rendered possible by the rafting (i.e., directional coarsening) of γ ′ particles that facilitates dislocation rearrangement and annihilation. The rafted microstructure is removed in subsequent solution treatment, leaving behind a damage‐free and residual‐stress‐free single crystal with uniform γ ′ precipitates indistinguishable from the rest of the turbine blade. This discovery offers a practical means to keep 3D‐printed single crystals from cracking due to unrelieved residual stress, or stress‐relieved but recrystallizing into a polycrystalline microstructure, paving the way for additive manufacturing to repair, restore, and reshape any superalloy single‐crystal product.

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confidence: 99%

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

Chen

Huang

et al. 2020

Advanced Materials

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“…A problem during the SLM processing of Inconel 718 is the segregation of Nb and the formation of so-called Laves phase grains in the interdendritic region, which may considerably degrade mechanical properties. Nie et al [119] employed a numerical scheme based on a stochastic approach for studying the nucleation and growth of dendrites, the segregation of niobium (Nb) and the formation of Laves phase particles during the solidification. Additionally, a FEM-based discretization of the heat conduction equation has been employed for solving the thermal problem, which is required as input for the stochastic microstrucutre evolution model.…”

Section: Microscopic Simulation Modelsmentioning

confidence: 99%

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation, and Experimentation

Meier

Penny

Zou

et al. 2017

Annual Rev Heat Transfer

120

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Among the many additive manufacturing (AM) processes for metallic materials, selective laser melting (SLM) is arguably the most versatile in terms of its potential to realize complex geometries along with tailored microstructure. However, the complexity of the SLM process, and the need for predictive relation of powder and process parameters to the part properties, demands further development of computational and experimental methods. This review addresses the fundamental physical phenomena of SLM, with a special emphasis on the associated thermal behavior. Simulation and experimental methods are discussed according to three primary categories. First, macroscopic approaches aim to answer questions at the component level and consider for example the determination of residual stresses or dimensional distortion effects prevalent in SLM. Second, mesoscopic approaches focus on the detection of defects such as excessive surface roughness, residual porosity or inclusions that occur at the mesoscopic length scale of individual powder particles. Third, microscopic approaches investigate the metallurgical microstructure evolution resulting from the high temperature gradients and extreme heating and cooling rates induced by the SLM process. Consideration of physical phenomena on all of these three length scales is mandatory to establish the understanding needed to realize high part quality in many applications, and to fully exploit the potential of SLM and related metal AM processes. arXiv:1709.09510v1 [physics.app-ph] 4 Sep 2017 1.4. Differentiation of related additive manufacturing processes for metals References and comparisons to other powder-bed metal AM processes such as electron beam melting (EBM) and selective laser sintering (SLS) will be useful from time to time in the foregoing discussion [97,98,50,52,68]. Similar to SLM, the EBM process represents a powder bed-based additive manufacturing process where pre-defined contours are selectively melted in successively deposited powder layers. While SLM applies a laser beam as energy source, EBM is based on an electron beam. EBM is only applicable to electrically conductive materials and has to be

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“…Nie et al [19] predicted solidification microstructure during laser AM of a nickel-based superalloy using a multi-scale modeling approach that couples finite element (FE) method and stochastic analysis. The model was used to investigate the evolution of dendritic structure, niobium (Nb) segregation, and formation and morphology of the Laves phase.…”

Section: Introductionmentioning

confidence: 99%

Finite Interface Dissipation Phase Field Modeling of Ni-Nb Under Additive Manufacturing Conditions

et al. 2019

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During the laser powder bed fusion (L-PBF) process, the built part undergoes multiple rapid heating-cooling cycles, leading to complex microstructures with nonuniform properties. In the present work, a computational framework, which couples a finite element thermal model to a non-equilibrium phase field model was developed to investigate the rapid solidification microstructure of a Ni-Nb alloy during L-PBF. The framework is utilized to predict the spatial variation of the morphology and size of microstructure as well as the microsegregation in single-track melt pool microstructures obtained under different process conditions. A solidification map demonstrating the variation of microstructural features as a function of the temperature gradient and growth rate is presented. A planar to cellular transition is predicted in the majority of keyhole mode melt pools, while a planar interface is predominant in conduction mode melt pools. The predicted morphology and size of the solidification features agrees well with experimental measurements.

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Numerical modeling of microstructure evolution during laser additive manufacturing of a nickel-based superalloy

Cited by 330 publications

References 39 publications

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation, and Experimentation

Finite Interface Dissipation Phase Field Modeling of Ni-Nb Under Additive Manufacturing Conditions

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