Page 47 - MSAM-1-2

Materials Science in Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Process study for directed energy deposition

of 316L stainless steel with TiB metal matrix
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composites

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2
Yao Ting Ang , Swee Leong Sing *, Joel Choon Wee Lim 1
1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
2 Department of Mechanical Engineering, National University of Singapore, Singapore

Abstract
In addition to laser powder bed fusion, directed energy deposition (DED) is also
gaining interest as an effective metal additive manufacturing technique. Due to its
system configuration, it is more efficient and flexible for materials development.
Therefore, it can be used for processing of metal matrix composites (MMCs) through
the use of powder mixture as feedstock. 316L stainless steel has high corrosion
resistance, biocompatibility, and ductility. Several studies have shown the feasibility
of using DED to process 316L stainless steel. The material properties of 316L stainless
steel can be improved using reinforcement particles such as TiB to form MMCs. In this
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study, the effects of process parameters on microstructure and mechanical properties
of 316L stainless steel reinforced with TiB 316L/TiB ) MMC were studied. The process
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2 (
parameters, including laser power, scanning speed, and hopper speed, were varied
and analyzed using Taguchi L9 array. It was found that the process parameters
*Corresponding author:
Swee Leong Sing have insignificant effect on the bulk density of the samples produced. Through this
(sweeleong.sing@nus.edu.sg) study, it is also found that tumble mixing was not suitable for the powder feedstock
preparation for MMCs to be processed by DED. The microstructure of DED 316L/TiB
Citation: Ang YT, Sing SL, 2
Lim JCW, 2022, Process study MMC samples consists of columnar and equiaxed grains. Columnar grains were
for directed energy deposition of located within the layers while equiaxed grains were located at the interlayer zones.
316L stainless steel with TiB metal Fine sub-grains were also observed within these grains and their boundaries were
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matrix composites. Mater Sci Add
Manuf. 1(2): 13. enriched with molybdenum and chromium segregations. Precipitates containing
https://doi.org/10.18063/msam.v1i2.13 titanium were also observed to segregate at the sub-grain boundaries. Finally, the
Received: April 29, 2022 Vickers microhardness of the DED 316L/TiB MMC was found to be similar to pure
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316L stainless steel produced by DED.
Accepted: June 10, 2022
Published Online: June 29, 2022
Keywords: Additive manufacturing; 3D printing; Directed energy deposition; Metal
Copyright: © 2022 Author(s). matrix composites; Steels
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. Additive manufacturing (AM) is a disruptive technology that has gain increasing traction
Publisher’s Note: Whioce in recent years. AM is a family of techniques and processes that involve the addition of
Publishing remains neutral with material layer-by-layer with the help of computer-aided designs and computer-aided
regard to jurisdictional claims in [1]
published maps and institutional manufacturing . Compared to traditional manufacturing that produces parts by
affiliations. removing material, AM is more flexible and efficient that can reduce manufacturing

Volume 1 Issue 2 (2022) 1 http://doi.org/10.18063/msam.v1i2.13