Electronic Theses and Dissertations

Identifier

993

Date

2013

Document Type

Thesis

Degree Name

Master of Science

Major

Mechanical Engineering

Committee Chair

Gang Qi

Committee Member

Steven F. Wayne

Committee Member

Gladius Lewis

Committee Member

John Hochstein

Abstract

There is a lack of knowledge concerning the evolution of stress-induced damage in cast iron on the microstructural scale. This study addresses this need by investigating the continuous failure of gray cast iron (GCI) and nodular cast iron (NCI) microstructures using acoustic emissions (AE). Microstructural damage evolution is characterized by grouping into three distinct ensembles (stress ranges) for GCI and four for NCI. The amplitude of the AE damage events was interpreted as being proportional to the failure mechanism, with lower amplitude events attributed to graphite failure. Microstructural and failure analysis revealed the following failure mechanisms: graphite fracture and debonding and transgraular fracture of the iron matrix for GCI and graphite fracture and debonding and ductile fracture of the iron matrix for NCI. The AE results bring light to the controversy in the literature on NCI failure by identifying ductile fracture of the iron matrix as the dominant failure mechanism.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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