Ultrahigh strength of dislocation-free Ni₃Al nanocubes

Individual Ni₃Al nanocubes under pressure are investigated by comparing the compressive strength of both dislocation-free and irradiated Ni₃Al nanocubes. The results are dicussed in light of the size-dependent and size-independent strength of face-centered cubic (fcc) nanocrystals in the framework of dislocation nucleation at free surfaces. This study sheds more light on the understanding of fundamental deformation mechanisms and size-affected strength in dislocation-free metallic nanocrystals.