Annealing Behavior of Nanostructured Aluminum Produced by Cold Rolling to Ultrahigh Strains

W.Q. Cao, A. Godfrey, Niels Hansen, Q. Liu

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    The isochronal annealing behavior of nanostructured commercial purity aluminum (AA1100 and AA1200) produced by either cold rolling (CR) or accumulative roll bonding (ARB) up to ultrahigh strains of about 99.5 pct reduction in thickness has been studied in the temperature range from 200 degrees C to 420 degrees C. Microstructural and texture measurements were made using data from electron backscatter diffraction (EBSD) investigations, and the change in mechanical strength was followed using hardness measurements. A large effect of the rolling strain is observed on recovery at temperatures below 200 degrees C to 220 degrees C. This effect is exemplified by samples deformed to the largest strain, where a rapid decrease in the stored energy from approximately 2 MJ/m(3) in the deformed state to less than 0.5 MJ/m(3) is seen, accompanied by a large decrease in the hardness. A new method for analyzing the uniformity of the structural coarsening, based on analysis of the crystallite size distribution with respect to the mode, is described. The analysis demonstrates that annealing leads to locally nonuniform changes in the microstructure, and to a description of the annealing process at temperatures greater than 220 degrees C as one of conventional recrystallization.
    Original languageEnglish
    JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
    Volume40
    Issue number1
    Pages (from-to)204-214
    ISSN1073-5623
    DOIs
    Publication statusPublished - 2009

    Keywords

    • Materials research
    • Light strong materials for wind turbines and for transportation

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