Title: Understanding process-microstructure-property relationships in laser powder bed fusion of non-spherical Ti-6Al-4V powder

Abstract

Powder feedstock is a major cost driver in metal additive manufacturing (AM). Replacing the spherical powder with the cost-efficient non-spherical one can reduce the feedstock cost up to 50% and attract more interest to adopt AM in production and new alloy development. Here, for this paper, a comprehensive study was conducted to understand process-microstructure-property relationships in laser powder bed fusion of hydride-dehydride Ti-6Al-4V powder. We demonstrated that variation of laser scan speed had a significant impact on the grain structure, pore evolution and properties compared to laser power. Dynamic X-ray radiography showed that with decreasing scan speed at a constant laser power, a transition from conduction to keyhole mode laser processing occurred, in which a deeper melt pool at lower scan speed intensified texture. In other words, an increase in laser scan speed resulted in formation of the refined prior β grains with shape factor of ~5, lowering the anisotropy. Furthermore, the degree of variant selection was evaluated based on the analyzed texture as a function of laser power and scan speed. With increasing laser scan speed, the dominant α/α boundary type was altered from type 2 to 4 and the degree of variant selection was noticeably decreased. On themore » other hand, increasing laser power left the morphology of prior β grains, their size, and the dominant α/α boundary (type 4) unchanged, while the texture and anisotropy were intensified, and the degree of variant selection was slightly decreased. Finally, dependency of surface roughness and microhardness were discussed as a function of laser processing parameters.« less

Authors:

Asherloo, Mohammadreza ^[1]; Hwang, Junghyun ^[1]; Leroux, Ryan ^[2]; Wu, Ziheng ^[3]; Fezzaa, Kamel ^[4]; Paliwal, Muktesh ^[5]; Rollett, Anthony D. ^[6]; Mostafaei, Amir ^[1]

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+ Show Author Affiliations

1. Illinois Institute of Technology, Chicago, IL (United States)
2. University of California, Los Angeles, CA (United States)
3. Carnegie Mellon University, Pittsburgh, PA (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States). Materials Engineering Division
4. Argonne National Laboratory (ANL), Argonne, IL (United States). X-ray Science Division
5. Kymera International, Robesonia, PA (United States)
6. Carnegie Mellon University, Pittsburgh, PA (United States)

Publication Date:

Sun Feb 26 00:00:00 EST 2023

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); USDOE Office of Science (SC)

OSTI Identifier:

2281002

Alternate Identifier(s):

OSTI ID: 1959854; OSTI ID: 1983730

Report Number(s):

LLNL-JRNL-844166
Journal ID: ISSN 1044-5803; 185718

Grant/Contract Number:  

AC02-06CH11357; AC52-07NA27344; DMR-2050916

Resource Type:

Accepted Manuscript

Journal Name:

Materials Characterization

Additional Journal Information:

Journal Volume: 198; Journal ID: ISSN 1044-5803

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Additive manufacturing; Texture analysis; Synchrotron X-ray high-speed imaging; variant selection; Hardness; Hydride-dehydride powder; additive manufacturing; texture analysis; synchrotron x-ray high-speed imaging; hardness