Author ORCID Identifier
https://orcid.org/0000-0001-6555-8070
Date of Award
3-10-2024
Document Type
Thesis
School
School of Mechanical Engineering
Programme
Ph.D.-Doctoral of Philosophy
First Advisor
Dr.P.Dinesh Babu
Keywords
Metal Additive Manufacturing, 17-4 PH Stainless Steel, Material Characterization, Heat Treatment, Wear Behaviour
Abstract
The surface and microstructural characteristics of additively manufactured parts play a significant role under mechanical loading. Due to its high strength, tailorable mechanical properties by heat treatment, and ease of printability, the 17-4 precipitation hardened (PH) stainless steel is gaining attention in the additive manufacturing (AM) field.
Selective Laser Melting (SLM), one of the laser-based powder bed fusion (L-PBF) processes, is capable of making fully dense metallic parts with high geometrical fidelity and greater design flexibility at high resolution. The main factors limiting the adoption of SLM are poor surface roughness, anisotropic microstructure, and the formation of micro-pores in the components. These issues lead to poor mechanical properties and eventual component failure.
In recent research, alongside heat treatment, peening technology is increasingly utilized to mitigate the adverse effects of SLM. This research presents an experimental investigation into the fabrication, characterization, and property enhancement of 17-4 PH SS fabricated by the SLM process.
The samples were printed at various laser energy densities (LEDs) in order to identify the optimum SLM process parameter combination, which results in superior mechanical properties. Mechanical tests, along with density measurements and surface morphology tests, were conducted to evaluate the performance of the as-printed (AP) samples. The results of the mechanical tests were then compared with those of the wrought sample.
In the final phase, the AP sample underwent a specific heat treatment (HT) process to introduce Cu-rich precipitates in its grain morphology, thereby enhancing its mechanical properties, including hardness and tensile strength.
LSP, considered one of the advanced surface modification techniques, was performed on both as-printed and heat-treated sample surfaces, and the combined effect of HT and LSP on the surface morphology, microstructure, residual stress, mechanical and high-temperature wear behaviour on the selective laser melted 17-4 PH stainless steel was evaluated.
Recommended Citation
S, Pradeep Kumar Mr, "Synergistic Approaches For Microstructural Refinement, Enhanced Mechanical And Wear Behaviour In Additively Manufactured 17-4 PH Stainless Steel" (2024). Theses and Dissertations. 72.
https://knowledgeconnect.sastra.edu/theses/72