Page 60 - MSAM-3-1

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Role of customized scan strategies and dwell

time on microstructure and properties of
additively manufactured 316L stainless steel

Puskar Pathak 1,2,3 *, Goran Majkic 1,2,3 , and Venkat Selvamanickam 1,2,3

1 Advanced Manufacturing Institute, University of Houston, Houston, Texas, United States of America
2 Department of Mechanical Engineering, University of Houston, Houston, Texas, United States of
America
3 Texas Center for Superconductivity, University of Houston, Houston, Texas, United States of America

Abstract
Direct energy deposition (DED)-based additive manufacturing facilitates
fabrication of medium-to-large functional parts. This study assesses the role of
varying scan strategies and dwell time between each layer to control the cooling
rate of 316L stainless steel produced by the laser-engineered net shaping-DED
method. Customized print patterns were designed, keeping other optimized print
parameters constant to obtain printed parts with better dimensional tolerance. The
parts, which were >99% dense, were fabricated in a controlled argon environment.
A heterogeneous microstructure consisting of a cellular columnar and equiaxed
substructure was obtained. Two-dimensional X-ray diffraction revealed the presence
*Corresponding author: of a single-phase γ-austenitic FCC phase. A refined microstructure with less elemental
Puskar Pathak segregation was noticed with an increase in dwell time between the print layers.
(ppathak3@cougarnet.uh.edu)
Internal defect analysis using X-ray micro-computed tomography revealed low
Citation: Pathak P, Majkic lack-of-fusion voids along the build direction without any micro-cracks, which is
G, Selvamanickam V. Role of attributed to higher cooling rates between subsequent print layers. As demonstrated
customized scan strategies and
dwell time on microstructure in a mechanical performance evaluation of tensile and micro-hardness properties,
and properties of additively better performance can be achieved by controlling the cooling rate and customizing
manufactured 316L stainless deposition patterns.
steel. Mater Sci Add Manuf.
2024;3(1):2676.
doi: 10.36922/msam.2676
Keywords: Additive manufacturing; Scan strategy; Dwell time; LENS-DED; 316L stainless
Received: January 8, 2024 steel
Accepted: February 19, 2024
Published Online: March 8, 2024
Copyright: © 2024 Author(s). 1. Introduction
This is an Open-Access article
distributed under the terms of the Additive manufacturing (AM) has transitioned from its initial use in rapid prototyping
Creative Commons Attribution to becoming a significant player in high-value manufacturing sectors such as aerospace,
License, permitting distribution,
and reproduction in any medium, automotive, and medical industries. AM enables innovative geometries and delivers
provided the original work is advantages such as reduced weight, minimized material wastage, lower part expenses,
properly cited. component consolidation, and improved overall performance. Among various AM
1-4
Publisher’s Note: AccScience techniques, the direct energy deposition (DED) technique offering a high deposition
Publishing remains neutral with rate is the arc wire DED technique. Numerous studies have recently been conducted on
5,6
regard to jurisdictional claims in 7-12
published maps and institutional the applicability of this method to various structural alloys, such as stainless steels and
affiliations. Ni-based superalloys. 13-15 However, the surface quality of the products manufactured

Volume 3 Issue 1 (2024) 1 https://doi.org/10.36922/msam.2676