Stochastic modeling of the independent roles of particle size and grain size in transgranular cleavage fracture

The independent roles of grain size and particle size on sharp crack and rounded notch toughness are investigated over a range of temperatures from the lower shelf into the early ductile/brittle transition region. The results are interpreted in terms of a weakest link statistical model wherein the onset of failure coincides with the critical propagation of a particle microcrack into the matrix. It is shown that, for a fixed particle size distribution, both sharp-crack and rounded-notch toughness decrease with increasing grain size. However, at fixed grain size, the sharp-crack toughness increases, while the rounded-notch toughness decreases with increasing particle size. Such effects result primarily from the difference in the number of activated particles in the plastic zone.

[1]  D. Shetty,et al.  Fractographic observations of cleavage initiation in the ductile-brittle transition region of a reactor-pressure-vessel steel , 1983 .

[2]  C. Turner,et al.  Method for Laboratory Determination of J c , 1976 .

[3]  A. N. Stroh.  The formation of cracks as a result of plastic flow , 1954, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[4]  W. Gerberich,et al.  New contributions to the effective surface energy of cleavage , 1985 .

[5]  John W. Hutchinson,et al.  Singular behaviour at the end of a tensile crack in a hardening material , 1968 .

[6]  A. Pineau,et al.  A local criterion for cleavage fracture of a nuclear pressure vessel steel , 1983 .

[7]  C. J. McMahon,et al.  Initiation of cleavage in polycrystalline iron , 1965 .

[8]  Kim Wallin,et al.  Statistical model for carbide induced brittle fracture in steel , 1984 .

[9]  K. Sieradzki,et al.  The effect of a partially dissociated nitrogen environment on the fracture toughness of 4340 steel , 1978 .

[10]  R. Hill.  The mathematical theory of plasticity , 1950 .

[11]  F. Marino,et al.  Electrical resistivity and structural relaxation in Fe75TM5B20 amorphous alloys (TM = Ti, V, Cr, Mn, Co, Ni) , 1984 .

[12]  A. Argon,et al.  Physics of Strength and Plasticity , 1969 .

[13]  Anthony G. Evans,et al.  A statistical model of brittle fracture by transgranular cleavage , 1986 .

[14]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[15]  J. Rice,et al.  Plane strain deformation near a crack tip in a power-law hardening material , 1967 .

[16]  J. F. Knott,et al.  Effect of microstructure on cleavage fracture toughness of quenched and tempered steels , 1979 .

[17]  R. Ritchie,et al.  Statistical analysis of cleavage fracture ahead of sharp cracks and rounded notches , 1986 .

[18]  Anthony G. Evans,et al.  Statistical aspects of cleavage fracture in steel , 1983 .

[19]  J. Im,et al.  Cavity formation from inclusions in ductile fracture , 1975 .

[20]  David R. Owen,et al.  An elastic-plastic stress analysis for a notched bar in plane strain bending , 1971 .

[21]  John W. Hutchinson,et al.  High strain-rate crack growth in rate-dependent plastic solids , 1985 .

[22]  C. A. Rau,et al.  A general model to predict the elastic-plastic stress distribution and fracture strength of notched bars in plane strain bending☆ , 1968 .

[23]  J. F. Knott,et al.  Effects of microstructure on cleavage fracture stress in steel , 1978 .

[24]  J. Rice,et al.  Physics of Strength and Plasticity , 1969 .

[25]  F. Mcclintock,et al.  Statistical Determination of Surface Flaw Density in Brittle Materials , 1976 .

[26]  J. Knott,et al.  Fundamentals of Fracture Mechanics , 2008 .

[27]  John R. Rice,et al.  ON THE RELATIONSHIP BETWEEN CRITICAL TENSILE STRESS AND FRACTURE TOUGHNESS IN MILD STEEL , 1973 .

[28]  E. Hall,et al.  The Deformation and Ageing of Mild Steel: III Discussion of Results , 1951 .