The effect of work-hardening and thermal annealing on the early stages of the uranium-hydrogen corrosion reaction

• Distinct differences in (early) H 2 corrosion of U due to differences in the level of induced strain in the metal. • Mass of hydride decreases from the work-hardened to an as-cast and then a thermally annealed metal surface. • Damage per hydride growth decreases from the work-hardened to the as-cast and finally the thermally annealed surface. • Vacuum annealing of uranium resulted in a reduction of UH 3 nucleation per unit area. • Cold work-hardening significantly altered the (early) H 2 corrosion behaviour. The characteristics of hydride formation on metallic U at the early stages were investigated for three differently treated samples. The first sample reacted in its as-received state, the second was thermally annealed and the third sample underwent cold work-hardening prior to reaction with deuterium. From the analysis, the vacuum heat-treated sample was found to be more resilient to hydriding at the nucleation and growth stage, exhibiting a reduced number of nucleation points when compared to the as-cast uranium. The work-hardened sample was observed to be more susceptible to H 2 corrosion, displaying very dissimilar hydriding behaviour when compared to the other.