Creating Heterostructures via Laser Powder Bed Fusion Using Titanium and Stainless Steel Mixtures

Date
2024-09-16
Authors
Xu, Dingmeng
Yang, Wuxin
Behera, Malaya Prasad
Singamneni, Sarat
Hodgson, Michael A
Cao, Peng
Supervisor
Item type
Journal Article
Degree name
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier BV
Abstract

This study addresses the challenge of breaking the trade-off dilemma between strength and ductility in additively manufactured Titanium (Ti) products. By leveraging concentration non-uniformity and controlled diffusion during in-situ alloying of unalloyed titanium (CP-Ti) and 316L stainless steel (SS316) powders via laser powder bed fusion (LPBF), we formulated a novel Fe-containing alloy with improved printability and enhanced mechanical performance. The microstructure of the as-built Ti alloy comprises a heterostructure of nano-scaled martensitic α′ within the micro-scaled equiaxed prior-β grains, resulting from rapid solidification inherent in LPBF. Since the modified laser-powder bed fusion in this work lacks a pre-heating function, a stress-relief annealing process was conducted to enhance the mechanical properties of the as-built parts. The annealed in-situ alloyed Ti-Fe achieves a superb balance between strength and ductility, with an ultimate tensile strength (UTS) of approximately 1118.0 MPa and an elongation of ∼9.0 %. This study provides insights for designing high-performance Ti alloys with heterostructures using a mixture of elemental powder and alloyed powders via LPBF. The significance of concentration non-uniformity and diffusion during solidification is highlighted, demonstrating how these factors contribute to the formation of superior heterostructures through additive manufacturing.

Description
Keywords
4014 Manufacturing Engineering , 40 Engineering , 0910 Manufacturing Engineering , 0912 Materials Engineering , 0913 Mechanical Engineering , Materials , 4016 Materials engineering , 4017 Mechanical engineering
Source
Materials Science and Engineering: A, ISSN: 0921-5093 (Print), Elsevier BV, 147260-147260. doi: 10.1016/j.msea.2024.147260
Rights statement
© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).