Date of Award

2013-01-01

Degree Name

Doctor of Philosophy

Department

Material Science and Engineering

Advisor(s)

Lawrence E. Murr

Abstract

Nickel-base superalloys have been used in cast and wrought, and powder metallurgy forms for nearly four decades for industrial and automotive applications. One drawback of cast alloys is that upon solidification, there is minimal microstructural control. Another issue to be improved is to eliminate the limitations of shapes and forms of fabricated alloys.

Rapid prototyping is a new technology of additive manufacturing that shows to be promising for the freeform fabrication of novel superalloys, including nickel-base alloys. New rapid manufacturing technologies allow us to produce parts in any shape that can be designed by computer-aided design (CAD) software. Additionally, the microstructure can be controlled by adjusting build parameters during fabrication.

Components made from Inconel 718 pre-alloyed powder have been fabricated by selective laser melting in two different orientations. These components, built in the transverse and longitudinal directions, parallel and perpendicular to the build direction, respectively, have been compared. Inconel 625 and has been fabricated by electron beam and selective laser melting. The two processes have been compared to each other as well as to their respective cast and wrought alloys. Microstructural characterization has been conducted using optical metallography, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Mechanical properties have been analyzed by Vickers microhardness, macrohardness, and tensile testing.

Language

en

Provenance

Received from ProQuest

File Size

100 pages

File Format

application/pdf

Rights Holder

Krista Amato

Download

Share

COinS