CRITICAL SHAPES AND ARRANGEMENTS OF CARBIDES IN HIGH-SPEED TOOL STEEL

High-speed tool steel can be regarded as a particle reinforced composi te consisting of carbides embedded in a martensitic matrix. The intern al stress distribution in such a material shows a significant dependen cy on various parameters such as geometry, material and arrangement of the inclusions as well as external loading conditions. Recent theoret ical results confirm the experimental observations that material failu re is initiated by cleavage fracture of the carbides rather than matri x rupture. Given a constant volume-fraction of particles in the compos ite material a Weibull approach is employed to estimate the fracture p robability of the carbides. Various inclusion shapes are examined for uniaxial loading conditions. The correlations between the probability of fracture of the inclusion and the parameters defining the geometry of the model will be demonstrated. Particular emphasis is put on the s ignificance of the Weibull modulus m. (C) 1997 Elsevier Science S.A.