Date of Award

2024-05-01

Degree Name

Doctor of Philosophy

Department

Materials Science And Engineering

Advisor(s)

Stephen W. Stafford

Abstract

Promoted combustion testing is a vital tool for engineers to establish the combustion and flammability characteristics of materials (metallic or otherwise) in oxygen enriched environments. Historically, much of the established data for metallic promoted combustion has been with regards to materials in their cast and wrought forms. However, with the emergence of additive manufacturing as a preferred method of fabrication, the need exists to evaluate how metals in that form behave. Recent testing has demonstrated that even if a metal or alloy is nominally the same with regards to chemistry, flammability between samples in the wrought form can differ significantly from those which were additively manufactured. This has provided a rationale to evaluate what underlying principles and conditions may be driving such a variability in flammability response. This work will serve as an analysis and characterization of one specific alloy (the nickel-based superalloy Inconel 718), a material popular for aerospace applications such as liquid fueled rocket components and turbine engines. Promoted combustion testing (per the ASTM G124 standard) was conducted on samples of both wrought and selective laser melted (SLM) fabrication, to provide comparison of flammability response between materials produced by each manufacturing method. Additionally, post-build treatments were applied to test samples to identify any effects on performance provided by hot isostatic pressing (HIP), oxygen-getting wrapping during HIP, stress relieving, and solutionizing/aging heat treatments. This project will utilize optical and scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and metallography to identify the differences between flammability behavior of additively manufactured and wrought Inconel 718. This information is key for engineers to understand the safety and oxygen compatibility of this material while in use by an industry which will undoubtedly increase the adoption and use of additive manufacturing as a primary means for fabrication.

Language

en

Provenance

Received from ProQuest

File Size

218 p.

File Format

application/pdf

Rights Holder

Dominic George Dieguez

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