Date of Award

2021-12-01

Degree Name

Master of Science

Department

Metallurgical and Materials Engineering

Advisor(s)

Francisco Medina

Abstract

The optimization of mechanical properties with thermal postprocessing treatments was investigated in this study across a wide variety of variants. The relationship between heat treatments and the impacts on the mechanical properties and microstructure of printed materials is a crucial part of additive manufacturing. As a result, the current paper provides a comprehensive overview of postprocess heat treatments for Laser Powder Bed Fusion fabricated AlSi10Mg alloy, including stress relief anneals at 190 and 285 degrees Celsius for 2 hours, hot isostatic pressing at 515 degrees Celsius for 3 hours, hot isostatic pressing + T6 treatment for 6 hours, and final aging at 177 degrees Celsius for up to 1000 hours. This resulted in 40 experimental variants: 20 in the vertical tensile direction and 20 in the horizontal. The resulting mechanical properties (ultimate tensile strength, yield strength, and elongation) as well as stress–strain curves are examined after tensile testing to compare all variants. The as built and stress relief anneal conditions were dominated by ultra-fine cellular, micro dendritic structures (0.6–1.2 μm) and melt-band structures. In contrast, 10 μm, equiaxed, recrystallized grain structures and pseudo-eutectic silicon particles with varied sizes and size distributions dominated the hot isostatic pressing and hot isostatic pressing + T6 conditions. The results of microhardness and fractography matched their respective heat treatment and microstructure. Heat treatment comparisons and correlations are offered to facilitate the selection of design solutions for high-performance applications.

Language

en

Provenance

Received from ProQuest

File Size

103 p.

File Format

application/pdf

Rights Holder

Jorge Merino-Gomez

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