Grain refinement effects on the strain rate sensitivity and grain boundary sliding in partially solidified Al-5 wt%Mg alloy

R. Takai, S. Kimura, R. Kashiuchi, H. Kotaki, Makoto Yoshida

    Research output: Contribution to journalArticle

    14 Citations (Scopus)

    Abstract

    This study investigated a mechanism of reducing solidification cracking susceptibility by grain refinement. Previously, the occurrence of grain boundary sliding (GBS) is implied as one mechanism, which is known for the characteristics of superplastic deformation.To verify GBS occurrence during solidification of an Al-5 wt%Mg alloy, the effects of refinement on the true stress-true strain curve and the effective power-law coefficient neff (the reciprocal of the strain rate sensitivity) were investigated in a partially solidified state. Furthermore, the contribution of GBS to deformation was examined using the index ξGBS defined in the research field of superplasticity. The results are following.(1) The grain refined structure elongation is greater than that in the coarse grain structure regardless of the solid fraction. Greater elongation is expected to result from both lower value of the coefficient neff and the higher contribution of the GBS, which provide more uniform deformation.(2) Maximum elongation of up to 20% was found at 480 °C (fs: 0.939) in the grain refined structure. Based on the knowledge of superplastic behavior, the values of both neff≈2 and ξGBS≈70% at the temperature indicates superplastic-like deformation during the solidification, reducing solidification cracking susceptibility by grain refinement.

    Original languageEnglish
    Pages (from-to)417-425
    Number of pages9
    JournalMaterials Science and Engineering A
    Volume667
    DOIs
    Publication statusPublished - 2016 Jun 14

    Fingerprint

    Grain boundary sliding
    Grain refinement
    strain rate
    sliding
    Strain rate
    grain boundaries
    solidification
    Solidification
    Crystal microstructure
    elongation
    Elongation
    occurrences
    superplasticity
    magnetic permeability
    Superplastic deformation
    Superplasticity
    coefficients
    Stress-strain curves
    curves
    Temperature

    Keywords

    • Al-Mg alloy
    • Grain refinement
    • Hot tearing
    • Semi-solid state
    • The strain rate sensitivity

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanical Engineering
    • Mechanics of Materials

    Cite this

    Grain refinement effects on the strain rate sensitivity and grain boundary sliding in partially solidified Al-5 wt%Mg alloy. / Takai, R.; Kimura, S.; Kashiuchi, R.; Kotaki, H.; Yoshida, Makoto.

    In: Materials Science and Engineering A, Vol. 667, 14.06.2016, p. 417-425.

    Research output: Contribution to journalArticle

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    AU - Yoshida, Makoto

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