Structural, microstructural and thermal analysis of U−(6-x)Zr−xNb alloys (x = 0, 2, 4, 6)

Uranium-rich U-Zr-Nb alloy is considered as a good alternative fuel for fast reactors from the perspective of excellent dimensional stability and desired thermo-physical properties to achieve higher burnup. Detailed investigations related to the structural and microstructural characterization, thermal expansion, phase transformation, microhardness were carried out on U−6Zr, U−4Zr−2Nb, U−2Zr−4Nb and U−6Nb alloys (composition in wt%) where the total amount of alloying elements was restricted to 6 wt%. Structural, microstructural and thermal analysis studies revealed that these alloys undergo a series of transformations from high temperature bcc γ-phase to a variety of equilibrium and intermediate phases depending upon alloy composition, cooling rate and quenching. The structural analysis was carried out by Rietveld refinement. The data of U−Nb and U−Zr−Nb alloys have been highlighted and compared with binary U−Zr alloy.