Date of Award

Spring 2023

Project Type

Thesis

Program or Major

Materials Science

Degree Name

Master of Science

First Advisor

Marko Knezevic

Second Advisor

Marko Knezevic

Third Advisor

Todd Gross

Abstract

This work presents two crystal plasticity finite element studies on magnesium alloys and an experimental characterization of a high entropy alloy. The first of two crystal plasticity studies presents a high strain rate deformation characterization via a split Hopkinson bar Taylor impact of a WE43 magnesium alloy. This study showed that crystal plasticity finite element modeling (CPFE) was able to model WE43 texture evolution, twin volume fraction along the length of the cylinder, and anisotropy with four different material orientations at high strain rates when compared to experimental data. The second study investigated the Taylor-type model homogenization response of the virtual polycrystal and how to best spread the crystal orientations over the finite element (FE) mesh for accurate modeling of Mg alloys specifically AZ31. It was found that 6 embedded crystals per integration point proved most optimal when compared to a full-field explicit grain mesh model. The third study investigated phase transformation hardness values and strain hardening characteristics for a four-phase high entropy alloy by nanoindentation. The material exhibited great strength based on phase transformation during plastic deformation upon compression.

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