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dc.contributor.advisorPerkins, A.J. (Jeff)
dc.contributor.authorMayes, Larry Leroy
dc.dateMarch 1988
dc.descriptionApproved for public release; distribution is unlimited
dc.description.abstractThe evolution of tweed microstructure upon aging a 53Cu45Mn2Al alloy was studied in the transmission electron microscope (TEM). Characteristic (110) tweed contrast develops after the alloy is aged for 4 hours or longer at 400 C, which apparently is just within the miscibility gap, and is then cooled to room temperature. The microstructure evolved is proposed to consist of a small proportion of Mn-rich regions in a Cu-rich matrix. As the phase separation proceeds, the Neel temperature and the FCC-to-FCT transition temperature both rise within these Mn-rich domains, and as a result they begin to display incipient lattice instabilities when observed at room temperature. This takes the form of a 'flickering' effect in the TEM image. The flickering consists of consistent and repetitive contrast variations at specific locations in the microstructure. The significance of these microstructural features to damping is discussed.en_US
dc.publisherMonterey, California. Naval Postgraduate Schoolen_US
dc.rightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
dc.subject.lcshMechanical engineeringen_US
dc.titleAn electron microscopy study of tweed microstructures and premartensitic effects in high damping 53Cu45Mn2A1 alloyen_US
dc.contributor.corporateNaval Postgraduate School (U.S.)
dc.contributor.departmentMechanical Engineering
dc.subject.authorhigh damping
dc.subject.authorstrain-dependent damping
dc.subject.authorCu-Mn alloys
dc.subject.authorpremartensitic effects
dc.subject.authortweed microstructures
dc.description.serviceCommander, United States Navy
etd.thesisdegree.nameM.S. in Material Scienceen_US
etd.thesisdegree.disciplineMaterials Scienceen_US
etd.thesisdegree.grantorNaval Postgraduate Schoolen_US

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