A Criterion for Plastically Induced Cleavage After General Yield in Notched Bend Specimens.

Abstract : Charpy V-notch specimens of mild steel with varying root radii were fractured in slow three point bending over a temperature range -196 to 20C. An analysis of the fracture data is presented based upon the relationship between the macroscopic deformation represented by the bend angle at fracture and the local plastic strains around the notch root. This analysis predicts that the critical bend angle at fracture should vary as the square of the root radius at a given temperature and is in agreement with the experimental observations. The physical significance of these micro- and macroscopic criteria are discussed. (Author)