Date of Award

2021-05-01

Degree Name

Master of Science

Department

Mechanical Engineering

Advisor(s)

Francisco Medina

Abstract

An extensive assortment of HIP parameters have been altered on EBM fabricated Ti-6Al-4V and have shown that cooling rates of 103 oC/min from temperatures above and below the beta transus produced acicular alpha-prime martensite characteristic elongations < 10 %. Optimum yield strength (0.9 GPa), UTS (1.0 GPa) and elongation (~14 %) were achieved for slow cooling (at 102 oC/min) from 850 oC HIP which produced a dense, Widmanstatten alpha structure within the retained, as-fabricated columnar grains by alpha-prime decomposition. These results suggest that manipulation of AM process parameters to produce a small-grain, equiaxed microstructure, HIPed below the beta transus and slow cooled, will have a wide range of superior, isotropic mechanical properties corresponding to a Widmanstatten alpha microstructure within the equiaxed grains. Also, Binder Jetting printing parameters for differing PSD's of low-cost water-atomized 17-4 Stainless Steel were optimized in order to produce high dense parts. Densities ranging from 94-97.5% were achieved, and issues of inhomogeneous porosity were addressed using a fumed silica flow additive.

Language

en

Provenance

Recieved from ProQuest

File Size

130 p.

File Format

application/pdf

Rights Holder

Ahmad Omar Abu-Issa

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