Application of a profilometry method for the quantitative evaluation of fractures, secondary cracks and Palmqvistʹs cracks in sintered carbides

The paper presents the methodology and results of a quantitative description of fractures, secondary cracks and Palmqvistʹs cracks in sintered carbides by means of a profilometric method. It has been proved that the quantitative evaluation of decohesion mechanisms is possible thanks to a set of quantitative fractography parameters, which comprises fracture linear roughness, profile mean curvature, overlap coefficient and the WC phase dominance factor. res of coarse-grained sintered carbides are characterized by a large profile development, while the fractures of fine-grained grades form fractures of a weaker development. A mean profile curvature gives one a quantitative evaluation of the share of transcrystalline cracks in relation to intercrystalline ones; coarse-grained grades form mixed brittle fractures—trans- and intercrystalline ones—whereas the fine-grained grades form an intercrystalline fracture only. The overlap coefficient describes the number of secondary cracks on a profile. Large, compact WC phase grains are conducive to the formation of cracks, which is a characteristic of coarse-grained grades. The value of the WC phase dominance factor is higher than 1, which proves that the crack initiation and propagation within the sintered carbidesʹ structure is fostered by the WC phase. It was proved that the structural factor conducive to the propagation of Palmqvistʹs cracks is adjacent WC grains forming clusters.