Quantitative grain growth and rotation probed by in-situ TEM straining and orientation mapping in small grained Al thin films

Despite abundant literature claims of mechanisms involving grain boundaries (GB) mechanisms in the deformation of nanocrystalline metals and alloys, few are actually evidencing them. Experimentally sorting and quantifying these mechanisms adds complexity and remains a challenge. Here we report evidence and quantitative measurements of both grain growth and rotation in response to a tensile strain, in sub-micron grained aluminium thin films. The behavior of several grains was monitored during in-situ transmission electron microscopy (TEM) experiments combining tensile test and crystal orientation mapping. A custom routine was created to discriminate relative GB movements from the rigid body motion of the sample. We also provide evidence that grain rotation results from the motion of intergranular dislocations.