Initiation of cleavage in polycrystalline iron

Material grain size and crack size influences on cleavage fracturing

“…McMahon & Cohen [47] were pioneers in investigating the initiation of cleavage caused by cracking of carbide plates at grain boundaries. In a later publication dedicated to Orowan, Cohen and Vukcevik reported a model analysis for such carbide-initiated cleavage of ferrite in which the H-P yield stress was equated to the Griffith stress for carbide cracking, expressed in …”

Statistical analysis of cleavage fracture ahead of sharp cracks and rounded notches

“…The process of cleavage fracture is envisioned in terms of the s 1 i p-i nduced cracking of predominate 1 y grain boundary part i c 1 es, followed by propagation of the resultant cracks into the surrounding matrix (12,13). Ahead of a rounded notch (with root radius large compared to microstructural dimensions), this process has been considered to occur when the maximum value of the local tensile stress exceeds a critical fracture stress (14), generally regarded as a quantity independent of temperature and strain rate (14,15).…”

Design of duplex low carbon steels for improved strength: weight applications

“…n e other hand, in the extreme case where the particles are continuous and unidirectionally aligned in the direction of applied stress, which is the case in a fiber reinforced composite, the resulting flow stress of the system is governed by Eq. (1). The derivation of Eq.…”

“…(1) and (2) In such two phase materials containing the second phase constituent of 1-50 ym in size, the major microstructural barriers which are more likely to be surfaces can not be bypassed by dislocations. Nor can they be treated simply on the bais of fiber strengthening models.…”