Stable U-based metallic glasses

•A new metallic glass system based on uranium is achieved.•The glass-forming ability is the highest among U-based metallic glass systems.•The U-based glasses have good anti-corrosive and mechanical properties.•The deviation of elastic modulus from rule-of-mixture is revealed.

A series of U-based U-Co-Al metallic glasses with greatly improved glass-forming ability and thermal stability were obtained by the alloying addition of Al into U-Co alloys. The fragility of these glasses approached 28, indicating strong liquid behavior. The corrosion resistance and mechanical hardness of the glasses were substantially enhanced in comparison with crystalline uranium materials. The roles of delocalization of 5f electrons and their bonding states are stressed in the discussion of the glass formation, thermal stability and the deviation of elastic modulus from the rule of mixtures. The finding not only adds a new member to the family of metallic glasses, but also provides a category of potentially useful uranium materials.