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3D non-isothermal phase-field simulation of microstructure evolution during selective laser sintering

Yang, Yangyiwei and Ragnvaldsen, Olav and Bai, Yang and Yi, Min and Xu, Bai-Xiang (2019):
3D non-isothermal phase-field simulation of microstructure evolution during selective laser sintering.
In: npj Computational Materials, Springer Nature, 5, (1), ISSN 2057-3960,
DOI: 10.1038/s41524-019-0219-7,
[Online-Edition: https://doi.org/10.1038/s41524-019-0219-7],
[Article]

Abstract

During selective laser sintering (SLS), the microstructure evolution and local temperature variation interact mutually. Application of conventional isothermal sintering model is thereby insufficient to describe SLS. In this work, we construct our model from entropy level, and derive the non-isothermal kinetics for order parameters along with the heat transfer equation coupled with microstructure evolution. Influences from partial melting and laser-powder interaction are also addressed. We then perform 3D finite element non-isothermal phase-field simulations of the SLS single scan. To confront the high computation cost, we propose a novel algorithm analogy to minimum coloring problem and manage to simulate a system of 200 grains with grain tracking algorithm using as low as 8 non-conserved order parameters. Specifically, applying the model to SLS of the stainless steel 316L powder, we identify the influences of laser power and scan speed on microstructural features, including the porosity, surface morphology, temperature profile, grain geometry, and densification. We further validate the first-order kinetics of the transient porosity during densification, and demonstrate the applicability of the developed model in predicting the linkage of densification factor to the specific energy input during SLS.

Item Type: Article
Erschienen: 2019
Creators: Yang, Yangyiwei and Ragnvaldsen, Olav and Bai, Yang and Yi, Min and Xu, Bai-Xiang
Title: 3D non-isothermal phase-field simulation of microstructure evolution during selective laser sintering
Language: English
Abstract:

During selective laser sintering (SLS), the microstructure evolution and local temperature variation interact mutually. Application of conventional isothermal sintering model is thereby insufficient to describe SLS. In this work, we construct our model from entropy level, and derive the non-isothermal kinetics for order parameters along with the heat transfer equation coupled with microstructure evolution. Influences from partial melting and laser-powder interaction are also addressed. We then perform 3D finite element non-isothermal phase-field simulations of the SLS single scan. To confront the high computation cost, we propose a novel algorithm analogy to minimum coloring problem and manage to simulate a system of 200 grains with grain tracking algorithm using as low as 8 non-conserved order parameters. Specifically, applying the model to SLS of the stainless steel 316L powder, we identify the influences of laser power and scan speed on microstructural features, including the porosity, surface morphology, temperature profile, grain geometry, and densification. We further validate the first-order kinetics of the transient porosity during densification, and demonstrate the applicability of the developed model in predicting the linkage of densification factor to the specific energy input during SLS.

Journal or Publication Title: npj Computational Materials
Volume: 5
Number: 1
Publisher: Springer Nature
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Functional Materials
Date Deposited: 15 Sep 2019 19:55
DOI: 10.1038/s41524-019-0219-7
Official URL: https://doi.org/10.1038/s41524-019-0219-7
URN: urn:nbn:de:tuda-tuprints-90873
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