STP520: Effects of Grain Size and Temperature on the Cyclic Strength and Fracture of Iron

    Abdel-Raouf, H
    Research assistant professor, professor-chairman, and associate professor, University of Waterloo, Waterloo, Ont.

    Topper, TH
    Research assistant professor, professor-chairman, and associate professor, University of Waterloo, Waterloo, Ont.

    Plumtree, A
    Research assistant professor, professor-chairman, and associate professor, University of Waterloo, Waterloo, Ont.

    Pages: 11    Published: Jan 1973


    Abstract

    The influence of grain size on the cyclic deformation behavior and fracture of Ferrovac E iron under low-cycle fatigue conditions are studied at temperatures ranging from 23 to 540C and strain range of 0.010. The steady-state stress response and the related cell size are independent of the grain size. The cell size and the total dislocation density was found to depend markedly on the dynamic strain aging level. The inhomogenity of plastic deformation in the material was enhanced by dynamic strain aging. This inhomogeneity was observed by both surface damage studies and substructural investigations. The grain size has no effect on the redistribution of plastic strains. The fracture mechanism and fatigue life was dependent on the dynamic strain aging level through the degree of redistribution of plastic strains. The dependency of fatigue life on grain size is controlled by the fracture mechanism available at this temperature. At high dynamic strain aging levels, the material reveals brittle striations on the fracture surfaces. In this case, the fracture process is independent on the grain boundary resistance and life is independent of the grain size.

    Keywords:

    grain size, cracking (fracturing), fatigue (materials), plastic deformation, crack initiation, stress cycle, iron


    Paper ID: STP38848S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP38848S


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