The effect of severe plastic deformation on the brittle-ductile transition in low carbon steel

Masaki Tanaka, Kenji Higashida, Tomotsugu Shimokawa

    Research output: Chapter in Book/Report/Conference proceedingChapter

    2 Citations (Scopus)


    Brittle-ductile transition (BDT) behaviour was investigated in low carbon steel deformed by an accumulative roll-bonding (ARB) process. The temperature dependence of its fracture toughness was measured by conducting four-point bending tests at various temperatures and strain rates. The fracture toughness increased while the BDT temperature decreased in the specimens deformed by the ARB process. Arrhenius plots between the BDT temperatures and the strain rates indicated that the activation energy for the controlling process of the BDT was not changed by the deformation with the ARB process. It was deduced that the decrease in the BDT temperature by grain refining was not due to the increase in the dislocation mobility controlled by short-range barriers. Quasi-three-dimensional simulations of dislocation dynamics, taking into account of crack tip shielding due to dislocations, were performed to investigate the effect of a dislocation source spacing along a crack front on the BDT. The simulation indicated that the BDT temperature is decreased with decreasing in the dislocation source spacing. Molecular dynamics simulations revealed that moving dislocations were impinged against grain boundaries and were reemitted from there with increasing strain. It indicates that grain boundaries can be new sources in ultra-fine grained materials, which increases toughness at low temperatures.

    Original languageEnglish
    Title of host publicationDuctility of Bulk Nanostructured Materials
    PublisherTrans Tech Publications Ltd
    Number of pages10
    ISBN (Print)0878493050, 9780878493050
    Publication statusPublished - Jan 1 2010

    Publication series

    NameMaterials Science Forum
    ISSN (Print)0255-5476

    All Science Journal Classification (ASJC) codes

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


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