Single-crystal Cu micro-pillars were self-ion irradiated up to 190 displacements per atom

a level commensurate with damage expected after long exposure in a reactor environment. Compression experiments performed along the ⟨ 110 ⟩ to 10% strain were compared against un-irradiated Cu. Two specimen configurations were explored: large 10 μm tall and small 4 μm tall pillars. Compared to un-irradiated Cu

the small irradiated pillars exhibited a flow stress increase of more than 500 MPa and were able to attain peak stresses approaching 1 GPa. These results are discussed in the context of an end of range effect

a damage gradient effect

and size effects.