Page 7 - MSAM-1-4

Materials Science in Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Influence of Y O reinforcement particles during
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heat treatment of IN718 composite produced by
laser powder bed fusion

Duy Nghia Luu , Wei Zhou *, Sharon Mui Ling Nai *
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1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang
Avenue, Singapore 639798, Singapore
2 Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang
Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
3 Singapore Institute of Manufacturing Technology (SIMTech), Agency for Science, Technology and
Research (A*STAR), Additive Manufacturing Division, 5 Cleantech Loop, CleanTech Two Block B,
Singapore 636732, Singapore

Abstract
A metal matrix composite with Inconel 718 as the base metal and yttrium oxide
(Y O ) as the reinforcement particles was fabricated by the laser powder bed
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fusion technology. This paper presents a comprehensive study on the influence
of the Y O reinforcement particles on the microstructures and mechanical
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properties of the heat-treated printed composite. Complex precipitates formation
between the Y O nanoparticles and the carbonitride precipitates were shown.
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The complex precipitates separated into individual Y O and titanium nitride (TiN)
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*Corresponding authors: nanoparticles after heat treatment. Nano-sized Y-Ti-O precipitates were observed
Wei Zhou
(mwzhou@ntu.edu.sg) after solutionization due to the release of supersaturated Y in the metal matrix.
Sharon Mui Ling Nai Grain refinement was also observed in the heat-treated composites due to the high
(mlnai@simtech.a-star.edu.sg) number of nano-sized precipitates. After solutionizing and aging, the grain size of
Citation: Luu DN, Zhou W, Nai SML, the Y O -reinforced sample is 28.2% and 33.9% smaller, respectively, than that of the
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2022, Influence of Y O reinforcement monolithic Inconel 718 sample. This effectively reduced the segregation of Nbat
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particles during heat treatment of
IN718 composite produced by laser the grain boundaries and thus, γ′ and γ′′ precipitates were distributed in the metal
powder bed fusion. Mater Sci Add matrix more homogeneously. Combined with the increased Orowan strengthening
Manuf, 1(4): 25. from a significantly higher number of nano-sized precipitates and grain boundary
https://doi.org/10.18063/msam.v1i4.25
strengthening, the composite achieved higher yield strength, and ultimate tensile
Received: October 10, 2022 strength (1099.3 MPa and 1385.5 MPa, respectively) than those of the monolithic
Accepted: December 7, 2022 Inconel 718 (1015.5 MPa and 1284.3 MPa, respectively).
Published Online: December 22,
2022 Keywords: Laser powder bed fusion; Additive manufacturing; Inconel 718; Y O
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Copyright: © 2022 Author(s). reinforcement; Heat treatment
This is an Open Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium, 1. Introduction
provided the original work is
properly cited. Fabricating metalmatrix composites (MMCs) with discontinuous reinforcements have
beensteadily gaining interest over the years to improve existing materials and tackle
Publisher’s Note: AccScience
Publishing remains neutral with new challenges. The MMCs usually have high modulus, strength, and stiffness, good
regard to jurisdictional claims in fatigue properties, and high-temperature performance [1,2] . This is made possible due to
published maps and institutional the exceptional ability of the MMCs to combine the ductile and tough characteristics of
affiliations.
Volume 1 Issue 4 (2022) 1 https://doi.org/10.18063/msam.v1i4.25