Effects of ultrasonic surface rolling processing on the corrosion properties of uranium metal

Highlights: • This paper provides an effective processing method (ultrasonic surface rolling) for improving the corrosion resistance of uranium materials. • Gradient twin structure of uranium materials has been obtained. • Compared with turning, the oxide layer of surface rolling process has better stability. Ultrasonic rolling processing is adopted to realize severe plastic deformation on uranium metal surfaces, and the microstructure near the surface is reconstructed. The results show that after rolling, the surface roughness of uranium samples can be reduced below Ra0.4, a gradient twin structure can be produced on the surface layer of uranium metal, and a U(002) basal texture can be formed. The results of corrosion resistance tests performed after ultrasonic rolling surface processing indicate that the oxidation rate of the material is reduced significantly after rolling. Due to the formation of a dense and continuous oxide layer with high stability after rolling, the further expansion of oxygen can be hindered. The electrochemical performance tests show that the corrosion current of the ultrasonic rolled sample is basically the same as that of the turned sample, but the rolled sample has a lower corrosion voltage. The increase in the free energy produced by the refinement of the structure can reduce the potential of the electrode, leading to the electrochemical dissolution of uranium metal more easily in a specific corrosion environment, but the local corrosion behavior is restrained.