In-Situ Full-Field Strain Measurement at the Sub-grain Scale Using the Scanning Electron Microscope Grid Method

Full-field measurement techniques are invaluable tools for investigating material behavior across length-scales. In the current work, a full-field measurement technique, the Grid Method, is implemented within a scanning electron microscope to demonstrate its ability to capture deformation heterogeneities at sub-grain length-scales. Microgrids, fabricated using focused ion beam platinum deposition are positioned on multiple areas with different underlying microstructure of an aluminum 1100 oligo-crystal. In-situ scanning electron microscope tensile testing is then conducted while capturing micrographs of the deposited grids after individual loading increments. Strain maps are generated through localized spectral analysis of a reference (non-deformed) and deformed micrographs. The strain maps exhibit intragranular and transgranular heterogeneities. The current work demonstrates the successful implementation and promise of the SEM grid method for extracting strain maps at reduced length-scales.