Secondary phase nature and fracture mechanism in niobium-zirconium-carbon alloy

To find out the nature of changing plasticity in the Nb+1% Zr+0.1% C alloy, regularities of phase transformations in the process of alloy heat treatment are investigated. It is shown that dispersion and solid solution hardening does not affect plasticity. A defective laminated structure of metastable niobium carbide in the alloy which is the result of epsilon-Nb3C2 transformation into Nb2C α-carbide taking place in the metastable phase during quenching and following heat treatments. Crystallographic peculiarities of this transformation are investigated. The correlation between plasticity level of the alloy and a fine structure of the metastable phase forming in the process of epsilon→α transformation is established