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Thermal behavior of copper processed by ECAP with and without back pressure
journal contribution
posted on 2015-03-01, 00:00 authored by Y L Wang, Rimma LapovokRimma Lapovok, J T Wang, Y S Qi, Y EstrinSamples of electrolytic tough pitch (ETP) pure copper were subjected to 12 passes of Equal-Channel Angular Pressing (ECAP) at room temperature with and without back pressure. Subsequent annealing was performed to evaluate the influence of back pressure during ECAP on the thermal behavior of ultrafine-grained copper. The microstructural and hardness changes caused by annealing were characterized by orientation imaging microscopy (OIM) and microhardness measurements. The application of back pressure resulted in an earlier drop in hardness upon annealing, which is believed to be associated with a lower critical temperature for the initiation of recrystallization and a rapid coarsening of microstructure. Regardless of whether back pressure was applied or not, structure coarsening during short-time annealing of ECAP-processed copper was governed by discontinuous static recrystallization. This is seen as a result of microstructure heterogeneity. Analysis of recrystallization kinetics was carried out based on observations of the microstructure after annealing in terms of the Avrami equation. The magnitude of the apparent activation energies for recrystallization in the absence of back pressure and in the case of back pressure of 100 MPa was estimated to be ~99 kJ/mol and ~91 kJ/mol, respectively. The reasons for reduced activation energy in the case of processing with back pressure are discussed.
History
Journal
Materials science and engineering: aVolume
628Pagination
21 - 29Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0921-5093Language
engPublication classification
C Journal article; C1.1 Refereed article in a scholarly journalCopyright notice
2015, ElsevierUsage metrics
Keywords
Science & TechnologyTechnologyNanoscience & NanotechnologyMaterials Science, MultidisciplinaryMetallurgy & Metallurgical EngineeringScience & Technology - Other TopicsMaterials ScienceThermal stabilityEqual Channel Angular Pressing (ECAP)Back pressureCopperRecrystallizationCHANNEL ANGULAR EXTRUSIONMECHANICAL-PROPERTIESMICROSTRUCTURAL STABILITYPLASTIC-DEFORMATIONSTRAINALLOYEVOLUTIONNICKELCUMechanical Engineering
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