Phase composition of niobium alloys alloyed with zirconium, hafnium, carbon, and nitrogen

The structure and phase composition of the Nb-Zr(Hf)-C and Nb-Zr(Hf)-N cast alloys have been studied. Studied has been the morphology of the disperse phase, being precipitated depending on the alloy composition. The type and structure of the precipitated phase have been determined by the methods of the local X-ray micro spectral and X-ray analysis. THe influence of the annealing on the phase composition of the researched alloys has been investigated. The Nb2C niobium carbides and (Nb,Zr)C or (Nb,Hf)C complexely alloyed carbides are formed during the crystallization of the Nb-Zr(Hf)-C alloys. Annealing causes an increase in the zirconium (or hafnium) content in the complexely alloyed carbides. The disperse nitrides of zirconium (ZrN) or hafnium (HfN) and niobium (NbN) are present in the Nb-Zr(Hf)N cast alloys. Annealing causes a more complete decomposition of a solid solution as compared with the cast condition