Interfacial Diffusion Induced Giant Plasticity in Sub-Micron Sized Aluminum Pillars

The plastic deformation of a solid generally conserves the local sample mass/volume. Here, we show that this may not hold for the widely-adopted compression test geometry, with self-supported submicron-sized pillars. Plastic flow can instead proceed with continuous shortening while keeping constant overall diameter and shape. This apparent non-conservation results from a rarely-reported interfacial-diffusion-mediated deformation, when interface diffusion between the metal and the native oxide layer is rejuvenated to mediate mass relocation spreading over an area far exceeding the dimensions of the self-supported pillar, thus providing large continuous plastic strain.