Review of hydrogen-induced mechanical degradation in uranium and uranium alloys

In this review, we examine the hydrogen corrosion behavior of uranium and its alloys, with a focus on its impact on their mechanical performance, including hydrogen embrittlement and hydrogen-induced stress corrosion cracking (HISCC). Alloying with elements such as Nb and Mo has been shown to improve hydrogen corrosion resistance of uranium alloys, thereby reducing susceptibility to hydrogen embrittlement and hydrogen-induced stress corrosion cracking. Although studies about uranium hydrogen embrittlement under high strain deformation remain limited, existing evidence suggests that increasing strain rate can alleviate hydrogen embrittlement. The mechanisms underlying hydrogen embrittlement and hydrogen-induced stress corrosion cracking in uranium are still under debate, particularly regarding whether uranium hydrides formation or solid-solution hydrogen plays the dominant role in the embrittlement process. Future research should integrate advanced characterization techniques with multiscale modelling, spanning from atomic scale to continuum scale, to elucidate these mechanisms.