Show simple item record

dc.contributor.advisorZhang, Xinghang
dc.creatorLiu, Yue
dc.date.accessioned2015-01-09T20:26:32Z
dc.date.available2016-05-01T05:30:49Z
dc.date.created2014-05
dc.date.issued2014-04-28
dc.date.submittedMay 2014
dc.identifier.urihttp://hdl.handle.net/1969.1/152621
dc.description.abstractLow energy planar defects such as twin boundaries have been employed to strengthen materials effectively with insignificant loss of the conductivity and ductility. High density growth twins can be formed in low stacking fault energy (SFE) metals, such as copper (Cu) and silver (Ag). However, low SFE metal cobalt (Co) received little attention due to the complex coexistence of hexagonal close-packed (HCP) and face-centered cubic (FCC) structure. The focus of this research is to identify the strengthening mechanisms of planar defects such as twin boundaries, stacking faults, and layer interfaces in epitaxial FCC/HCP Co, and Cu/Co multilayers. Our studies show that epitaxial Cu/Co multilayers with different texture have drastic different mechanical properties, dictated by the transmission of partial vs. full dislocations across layer interfaces. Furthermore the mechanical properties of epitaxial Co are dominated by high density stacking faults. Moreover, by applying advanced nanoindentation techniques, such as thermal-drift corrected strain-rate sensitivity measurement, the mechanical properties including strain-rate sensitivity is accurately determined. By using in situ nanoindentation under transmission electron microscope (TEM), we determined deformation physics of nanotwinned Cu, including detwinning, dislocation-twin interactions and work hardening. This project provides an important new perspective to investigate mechanical behavior of nanostructured metals with high density stacking faults.en
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.subjectnanoindentationen
dc.subjectTransmission electron microscopyen
dc.subjectMagnetron sputteringen
dc.subjectThin filmen
dc.subjectX-ray diffractionen
dc.titleStrengthening Mechanisms of Sputtered Copper, Cobalt and Their Nanocompositesen
dc.typeThesisen
thesis.degree.departmentMaterials Science and Engineeringen
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.grantorTexas A & M Universityen
thesis.degree.nameDoctor of Philosophyen
thesis.degree.levelDoctoralen
dc.contributor.committeeMemberHartwig, Karl T
dc.contributor.committeeMemberKaraman, Ibrahim
dc.contributor.committeeMemberWang, Haiyan
dc.type.materialtexten
dc.date.updated2015-01-09T20:26:32Z
local.embargo.terms2016-05-01
local.etdauthor.orcid0000-0001-8518-5734


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record