Nickel and molybdenum influence on the structure and chemical composition of surface destruction of iron with spherical graphite

The results of the study of the influence of nickel and molybdenum on the structure and chemical composition of the fracture surface of cast iron with spherical graphite are presented in the paper. It is shown that the fracture of cast iron with spherical graphite occurs along the boundaries of the distribution of graphite balls with matrix, and the fracture of the matrix occurs both by the mechanism of intergranular and transgranular fractures. Molybdenum and nickel alloying changes the mechanism of transgranular fracture of the matrix from brittle for ordinary cast iron to viscous for molybdenum and nickel alloying. It is established that the fracture surfaces of cast iron, depending on the analysis places there are elements such as O, C, P, N, Cu, Ni, Si, Mg. Studies of the distribution of impurities in the near-surface layers of the destroyed samples have shown that the quantity of elements such as oxygen, phosphorus and nitrogen decreases with increasing distance from the fracture surface. The phosphorus quantity is reduced by 40 - 45% in the places of the cast iron matrix, where the graphite balls were located during the alloying of cast iron by molybdenum and nickel. Keywords: cast iron, nickel, molybdenum, alloying, Auger spectroscopy, chemical composition, structure, fracture, surface.