MECHANISM OF THE Zr-V ALLOY NITRIDIZATION PROCESS

A sequence of structural transformations characterizing the high-temperature nitridization of a zirconium-vanadium bimetallic billet has been established. The mechanism of nitridization of zirconium-vanadium alloy ZrV, which is formed during the manufacture of a bimetallic workpiece by electric arc welding, has been established. During high-temperature interaction with nitrogen, the alloy disintegrates, the basis of which is ZrV intermetallic compound, with the formation of stoichiometric zirconium nitride ZrN, solid nitrogen solutions and compounds of the composition ZrVN with simultaneous segregation of vanadium at the grain boundaries of zirconium nitride. The released vanadium diffuses into the area of a solid solution of zirconium with nitrogen in the individual zirconium, forming a solid solution of the composition ZrVN. The final products of nitridization at the selected temperature are ZrN and ZrVN. Ceramics is a composite consisting of grains of stoichiometric zirconium nitride distributed in ZrVN with a limiting composition of ZrVN.