A study on the evolution of carbide phases in Nb-1Zr-0.1C alloy under the influence of neutron and Ne ion irradiation

In the present work, stability of Nb2C and (Nb,Zr)C phases, encountered in the Nb-1Zr-0.1 C alloy, is being assessed under the influence of fast neutron and 250 keV Ne ion irradiation, respectively. Microstructural investigations revealed a reduction in the volume fraction of the Nb2C phase in as-solidified alloy as a function of irradiation dose when irradiated with neutrons to a dose of-0.65 dpa. On the other hand, (Nb,Zr)C phase in the recrystallized alloy was also observed to dissolve during in situ assessment as a function of irradiation dose when irradiated with Ne ions to a dose of-32 dpa. With the help of DFT, SPECTER and SRIM simulations, it is rationalized that out of the various possible mechanisms of dissolution, the dissolution of these carbide phases proceeds through ejection of atoms from the precipitates to the matrix phase. Dissolution of Nb2C phase proceeds through the ejection of carbon atoms from the precipitate to the matrix phase, which is envisaged by segregation of carbon at the grain boundaries in the form of Nb2C phase and nucleation of (Nb,Zr)C precipitates within the matrix phase observed in neutron irradiated specimens. Dissolution of (Nb,Zr)C precipitates, on the other hand, is rationalized in terms of ejection of C/ Zr/Nb atoms from the precipitate to the matrix phase. & COPY; 2023 Elsevier B.V. All rights reserved.