Grain refinement and mechanical response of U-5.5 wt%Nb alloy produced by cold rolling and heat treatment

Cold rolling was coupled with annealing and water quenching to manipulate the grain size of U-5.5 wt%Nb (U-5.5Nb) alloy. X-ray diffraction analysis and optical microscopy were used to study the microstructure evolution of the U-5.5Nb alloy. Specimens with fine and homogeneous equiaxed grains were obtained with an average grain size of 4.3 μm for the fine-grained sample. Tensile testing and micro-indentation testing were employed to investigate the mechanical properties of the samples. The strength of the fine-grained alloy decreased by ∼5.6% compared with that of the coarse-grained sample, and the ductility increased by more than 30%. The mean hardness and elastic modulus of the fine-grained alloy decreased by 11.8% and 21.8%, respectively. Overall, this cold-rolling and annealing/quenching process is an attractive method to control the grain size of U-5.5Nb alloy, and thus its properties.