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Date of Award

2016

Document Type

Campus Access Master's Report

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Ibrahim Miskioglu

Committee Member 1

Carl R. Vilmann

Committee Member 2

Gregory Odegard

Abstract

The Zn-9%Al-3%Cu (ZCA-9) alloy was subjected to equal channel extrusion at various temperatures to obtain the lowest temperature possible for which extrusion is possible without any change in the microstructure of the alloy. The extrusions failed for the various temperatures and two different cross sections. Data obtained from nanoindentation tests by Serkan Ates, a visiting scholar, was then used to analyze the creep and wear strength properties of the alloy. The effect of the number of passes and the route of ECAE on the creep and wear properties was done. To study and analyze the creep in the ECAE processed ZCA-9 the creep stress exponents were calculated and the values for the routes A and BC were compared. The values of stress exponents were found to be decreasing. Similar observations were made by calculating the stress exponents for the tensile creep strength test data carried out by Akshay Patil. Patil concluded in his dissertation that the creep strength decreases with increase in number of passes. However, stress exponents alone cannot be used as a measure to compare the creep strengths of the alloys.

The wear strength of the alloy was analyzed using the data obtained from nanoindentation for the samples prepared by Serkan. From the data wear track deformation for all the samples was calculated. The wear strength of the alloys was found to be constant and almost same as the as cast alloys. The number of passes and the routes used for ECAE didn’t affect the wear properties of the ZCA-9 alloy.

Microstructural study was conducted for the ECAE processed ZCA-9 alloys. The areas for the grains, anisotropy in the material and the volume fraction of the Al grains found in the Zn matrix for the samples were calculated. A very well refined structure is found to be obtained by the ECAE processes. The sample produced by route A was found to have elongated grain structures and the samples produced by the route BC were found to have equi-axed grain structures. The volume fraction increased with increase in the number of grains.

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