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Title: Solidification-driven orientation gradients in additively manufactured stainless steel

Abstract

A sample of 304L stainless steel manufactured by Laser Engineered Net Shaping (LENS) was characterized in 3D using TriBeam tomography. The crystallographic, structural, and chemical properties of the as-deposited microstructure have been studied in detail. 3D characterization reveals complex grain morphologies and large orientation gradients, in excess of 10°, that are not easily interpreted from 2D cross-sections alone. Misorientations were calculated via a methodology that locates the initial location and orientation of grains that grow during the build process. For larger grains, misorientation increased along the direction of solidification. For grains with complex morphologies, K-means clustering in orientation space is demonstrated as a useful approach for determining the initial growth orientation. The gradients in misorientation directly tracked with gradients in chemistry predicted by a Scheil analysis. Finally, the accumulation of misorientation is linked to the solutal and thermal solidification path, offering potential design pathways for novel alloys more suited for additive manufacturing.

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [2]; ORCiD logo [2];  [1]
  1. Univ. of California, Santa Barbara, CA (United States). Materials Dept.
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Univ. of California, Santa Barbara, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1575110
Alternate Identifier(s):
OSTI ID: 1576080
Grant/Contract Number:  
NA0002910; NA 0002910
Resource Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 183; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; additive manufacturing; stainless steel; tomography; solidification; TriBeam

Citation Formats

Polonsky, Andrew T., Lenthe, William C., Echlin, McLean P., Livescu, Veronica, Gray, George T., and Pollock, Tresa M. Solidification-driven orientation gradients in additively manufactured stainless steel. United States: N. p., 2020. Web. doi:10.1016/j.actamat.2019.10.047.
Polonsky, Andrew T., Lenthe, William C., Echlin, McLean P., Livescu, Veronica, Gray, George T., & Pollock, Tresa M. Solidification-driven orientation gradients in additively manufactured stainless steel. United States. doi:10.1016/j.actamat.2019.10.047.
Polonsky, Andrew T., Lenthe, William C., Echlin, McLean P., Livescu, Veronica, Gray, George T., and Pollock, Tresa M. Wed . "Solidification-driven orientation gradients in additively manufactured stainless steel". United States. doi:10.1016/j.actamat.2019.10.047.
@article{osti_1575110,
title = {Solidification-driven orientation gradients in additively manufactured stainless steel},
author = {Polonsky, Andrew T. and Lenthe, William C. and Echlin, McLean P. and Livescu, Veronica and Gray, George T. and Pollock, Tresa M.},
abstractNote = {A sample of 304L stainless steel manufactured by Laser Engineered Net Shaping (LENS) was characterized in 3D using TriBeam tomography. The crystallographic, structural, and chemical properties of the as-deposited microstructure have been studied in detail. 3D characterization reveals complex grain morphologies and large orientation gradients, in excess of 10°, that are not easily interpreted from 2D cross-sections alone. Misorientations were calculated via a methodology that locates the initial location and orientation of grains that grow during the build process. For larger grains, misorientation increased along the direction of solidification. For grains with complex morphologies, K-means clustering in orientation space is demonstrated as a useful approach for determining the initial growth orientation. The gradients in misorientation directly tracked with gradients in chemistry predicted by a Scheil analysis. Finally, the accumulation of misorientation is linked to the solutal and thermal solidification path, offering potential design pathways for novel alloys more suited for additive manufacturing.},
doi = {10.1016/j.actamat.2019.10.047},
journal = {Acta Materialia},
number = C,
volume = 183,
place = {United States},
year = {2020},
month = {1}
}

Journal Article:
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This content will become publicly available on January 15, 2021
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