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Title: Phase Field Simulations of Microstructure Evolution in IN718 using a Surrogate Ni–Fe–Nb Alloy during Laser Powder Bed Fusion

Abstract

The solidification microstructure in IN718 during additive manufacturing was modeled using phase field simulations. The novelty of the research includes the use of a surrogate Ni–Fe–Nb alloy that has the same equilibrium solidification range as IN718 as the model system for phase field simulations, the integration of the model alloy thermodynamics with the phase field simulations, and the use of high-performance computing tools to perform the simulations with a high enough spatial resolution for realistically capturing the dendrite morphology and the level of microsegregation seen under additive manufacturing conditions. Heat transfer and fluid flow models were used to compute the steady state temperature gradient and an average value of the solid-liquid (s-l) interface velocity that were used as input for the phase field simulations. The simulations show that the solidification morphology is sensitive to the spacing between the columnar structures. Spacing narrower than a critical value results in continued growth of a columnar microstructure, while above a critical value the columnar structure evolves into a columnar dendritic structure through the formation of secondary arms. These results are discussed in terms of the existing columnar to dendritic transition (CDT) theories. The measured interdendritic Nb concentration, the primary and secondary arm spacingmore » is in reasonable agreement with experimental measurements performed on the nickel-base superalloy IN718.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [2];  [2];  [2];  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. United Technologies Research Center, East Hartford, CT (United States)
Publication Date:
Research Org.:
Oak Ridge National Laboratory, Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC); USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1560507
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Metals
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 2075-4701
Publisher:
MDPI
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; additive manufacturing; solidification; microstructure; phase field; columnar to dendritic transition

Citation Formats

Radhakrishnan, Balasubramaniam, Gorti, Sarma B., Turner, John A., Acharya, Ranadip, Sharon, John A., Staroselsky, Alexander, and El-Wardany, Tahany. Phase Field Simulations of Microstructure Evolution in IN718 using a Surrogate Ni–Fe–Nb Alloy during Laser Powder Bed Fusion. United States: N. p., 2018. Web. doi:10.3390/met9010014.
Radhakrishnan, Balasubramaniam, Gorti, Sarma B., Turner, John A., Acharya, Ranadip, Sharon, John A., Staroselsky, Alexander, & El-Wardany, Tahany. Phase Field Simulations of Microstructure Evolution in IN718 using a Surrogate Ni–Fe–Nb Alloy during Laser Powder Bed Fusion. United States. doi:10.3390/met9010014.
Radhakrishnan, Balasubramaniam, Gorti, Sarma B., Turner, John A., Acharya, Ranadip, Sharon, John A., Staroselsky, Alexander, and El-Wardany, Tahany. Fri . "Phase Field Simulations of Microstructure Evolution in IN718 using a Surrogate Ni–Fe–Nb Alloy during Laser Powder Bed Fusion". United States. doi:10.3390/met9010014. https://www.osti.gov/servlets/purl/1560507.
@article{osti_1560507,
title = {Phase Field Simulations of Microstructure Evolution in IN718 using a Surrogate Ni–Fe–Nb Alloy during Laser Powder Bed Fusion},
author = {Radhakrishnan, Balasubramaniam and Gorti, Sarma B. and Turner, John A. and Acharya, Ranadip and Sharon, John A. and Staroselsky, Alexander and El-Wardany, Tahany},
abstractNote = {The solidification microstructure in IN718 during additive manufacturing was modeled using phase field simulations. The novelty of the research includes the use of a surrogate Ni–Fe–Nb alloy that has the same equilibrium solidification range as IN718 as the model system for phase field simulations, the integration of the model alloy thermodynamics with the phase field simulations, and the use of high-performance computing tools to perform the simulations with a high enough spatial resolution for realistically capturing the dendrite morphology and the level of microsegregation seen under additive manufacturing conditions. Heat transfer and fluid flow models were used to compute the steady state temperature gradient and an average value of the solid-liquid (s-l) interface velocity that were used as input for the phase field simulations. The simulations show that the solidification morphology is sensitive to the spacing between the columnar structures. Spacing narrower than a critical value results in continued growth of a columnar microstructure, while above a critical value the columnar structure evolves into a columnar dendritic structure through the formation of secondary arms. These results are discussed in terms of the existing columnar to dendritic transition (CDT) theories. The measured interdendritic Nb concentration, the primary and secondary arm spacing is in reasonable agreement with experimental measurements performed on the nickel-base superalloy IN718.},
doi = {10.3390/met9010014},
journal = {Metals},
issn = {2075-4701},
number = 1,
volume = 9,
place = {United States},
year = {2018},
month = {12}
}

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Figures / Tables:

Table 1 Table 1: Laser track welding parameters used in the experiments.

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