Probing the cerium/cerium hydride interface using nanoindentation

•A disparity exists between the minimum energy and actual shape of a cerium hydride.•Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1.•A zone of material under compressive stress was identified surrounding the hydride.•No distribution of hardness was apparent within the hydride.

A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.