Effect of grain size on phase stability of monoclinic U–Nb alloy during low-temperature aging

Abstract Two U-5.8wt.%Nb alloys with different grain size were prepared and analyzed by X-ray diffraction line profile analysis. The experimental results indicate that the phase transformation in the coarse-grained sample is faster than that in the fine-grained sample during aging at 200 °C due to more microstrains in the coarse-grained sample after quenching. The maximum microstrain appears in plane (−111), which can be used to illuminate the conversion between α″ and γ° during aging.