Effects of Grain Refinement by ECAP on the Deformation Resistance of Al Interpreted in Terms of Boundary-Mediated Processes

Wolfgang Blum, J. Dvořák, P. Král, P. Eisenlohr, V. Sklenička

    Research output: Contribution to journalArticle

    • 2 Citations

    Abstract

    Results of a large set of tensile and compressive creep tests on pure Al were reanalyzed for the influence of low- and high-angle grain boundaries on the deformation resistance at the temperature T = 473 K = 0.51Tm where Tm is the melting point. Thermomechanical treatment by equal channel angular pressing followed by heating to T led to strong increase of areal fraction of high-angle boundaries in a structure of subgrains of ≈10−6 m in size, accompanied by significant reduction of subgrain strengthening and of the stress sensitivity of the deformation rate. (Sub)grain strengthening by low-angle boundaries is most effective; the strengthening effect virtually disappears during creep as the boundary spacings coarsen toward their stress-dependent, quasi-stationary size wqs. The same type of coarsening is found for (sub)grain structures with large fraction of high-angle boundaries; in the quasi-stationary state they lead to softening at low and strengthening at high stresses, and a significant increase in tensile fracture strain to values up to 0.8. The results are analogous to former results for Cu and are explained in the same way by the influence of boundaries on storage and recovery of crystal defects and the homogenization of glide.

    Original languageEnglish (US)
    Pages (from-to)1309-1320
    Number of pages12
    JournalJournal of Materials Science and Technology
    Volume32
    Issue number12
    DOIs
    StatePublished - Dec 1 2016

    Profile

    Carbamyl Phosphate
    Addison Disease
    Creep
    Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)
    Acetanilides
    Erythrina
    Erwinia
    Hemothorax
    Thermomechanical treatment
    Crystal defects
    Cimetidine
    Dermatoglyphics
    Muscle Contraction
    Grain boundaries
    Motor Activity
    Heating
    Equal channel angular pressing
    Grain refinement
    Crystal microstructure
    Coarsening

    Keywords

    • Creep
    • Deformation
    • Dynamic recovery
    • Equal channel angular pressing (ECAP)
    • Fine grained microstructure
    • Grain boundaries

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Mechanics of Materials
    • Mechanical Engineering
    • Polymers and Plastics
    • Metals and Alloys
    • Materials Chemistry

    Cite this

    Effects of Grain Refinement by ECAP on the Deformation Resistance of Al Interpreted in Terms of Boundary-Mediated Processes. / Blum, Wolfgang; Dvořák, J.; Král, P.; Eisenlohr, P.; Sklenička, V.

    In: Journal of Materials Science and Technology, Vol. 32, No. 12, 01.12.2016, p. 1309-1320.

    Research output: Contribution to journalArticle

    Blum, Wolfgang; Dvořák, J.; Král, P.; Eisenlohr, P.; Sklenička, V. / Effects of Grain Refinement by ECAP on the Deformation Resistance of Al Interpreted in Terms of Boundary-Mediated Processes.

    In: Journal of Materials Science and Technology, Vol. 32, No. 12, 01.12.2016, p. 1309-1320.

    Research output: Contribution to journalArticle

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    abstract = "Results of a large set of tensile and compressive creep tests on pure Al were reanalyzed for the influence of low- and high-angle grain boundaries on the deformation resistance at the temperature T = 473 K = 0.51Tm where Tm is the melting point. Thermomechanical treatment by equal channel angular pressing followed by heating to T led to strong increase of areal fraction of high-angle boundaries in a structure of subgrains of ≈10−6 m in size, accompanied by significant reduction of subgrain strengthening and of the stress sensitivity of the deformation rate. (Sub)grain strengthening by low-angle boundaries is most effective; the strengthening effect virtually disappears during creep as the boundary spacings coarsen toward their stress-dependent, quasi-stationary size wqs. The same type of coarsening is found for (sub)grain structures with large fraction of high-angle boundaries; in the quasi-stationary state they lead to softening at low and strengthening at high stresses, and a significant increase in tensile fracture strain to values up to 0.8. The results are analogous to former results for Cu and are explained in the same way by the influence of boundaries on storage and recovery of crystal defects and the homogenization of glide.",
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