Date of Award

Winter 2014

Project Type

Thesis

Program or Major

Mechanical Engineering

Degree Name

Master of Science

First Advisor

IOANNIS Korkolis

Second Advisor

Todd S Gross

Third Advisor

Yaning Li

Abstract

The mechanical behavior and material properties of a Stainless Steel SS-304L microtube, with an OD of 2.40 mm and wall thickness of 160 µm, was investigated through uniaxial, isothermal, biaxial, and metallographic testing. The grain structure, microhardness, and tube eccentricity were investigated using optical microscopy. The rate- and temperature-dependence of the material was characterized by isothermal uniaxial tension experiments. A biaxial experimental setup, consisting of a 2 kN electromechanical tensile stage and a 1.4 kbar hydraulic pump, was created to internally pressurize and axially load the microtube in biaxial stress states. Fourteen radial nominal stress path tests were conducted to determine the formability, failure mode, and anisotropy during biaxial stress states. The Yld2000-2D and Yld2004-3D yield functions were fit to the data at the initial yield surface and higher levels of plastic work. The path-dependence of failure stresses and strains was investigated by comparing radial path results to corner paths.

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