Theses and Dissertations

Date of Award

8-2021

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Manufacturing Engineering

First Advisor

Dr. Jianzhi Li

Second Advisor

Dr. Rajiv Nambiar

Third Advisor

Dr. Richard Crawford

Abstract

This study investigated the synthesis of CuCrFeNiTiAl high entropy alloy (HEA) from pure elements using selective laser melting (SLM). The objectives are to validate the feasibility of the HEA fabrication from elemental powder materials, and to examine the effect of various hatch strategies and energy densities on the microstructures and other materials properties. 3D samples of CuCrFeNiTiAl alloy were fabricated under different energy densities and with different scan vector lengths. The as-built samples were characterized by X-ray diffraction (XRD), and the microstructures were observed using scanning electron microscopy (SEM). The XRD results showed that face centered cubic, and body centered cubic structures were mostly present in all samples. Analysis of SEM pictures revealed that laser energy density has a correlation with size, shape and area of grains formed. Four types of grain microstructures observed from SEM pictures are dendrites, rosette, petals, and branches type structures. The morphologies of the grain structures were greatly affected by laser scan vector length. Shorter scan vectors facilitated development of more dendritic structures, and larger grains. As the number of grains decreased due to shorter scan lengths, the micro-hardness of the as-built samples was also reduced. Moreover, shorter scan vectors improved the surface quality of the printed samples.

Comments

Copyright 2021 Joni Chandra Dhar. All Rights Reserved.

https://go.openathens.net/redirector/utrgv.edu?url=https://www.proquest.com/dissertations-theses/investigation-different-hatch-strategies-on-high/docview/2596044625/se-2?accountid=7119

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