Experimental decoding of grain boundary-based plastic deformation

Here, we apply the electron backscatter diffraction (EBSD) technique to identify grain boundaries (GBs) in a metal sheet surface, and the metal sheet is subsequently deformed via contact with a hard nanomold. Quantified by the length of molded nanorods, combining with molecular dynamics (MD) simulations and transmission electron microscopy (TEM) characterization, the microstructure evolution and the important influence of individual GBs on plastic deformation during nanomolding of crystalline Ag at different temperatures and stresses are revealed. Diffusion-based mechanisms become dominant once the temperature is above a critical value (Ttran∼0.54Tm), and the GB-affected zone in this temperature range is measured as several micrometers, approximately 3-4 orders of magnitude larger than the structural width of GBs. Finally, benefiting from the decoded GB-based deformation mechanism, we demonstrate that the prevalent deformation mechanism map can be experimentally constructed with high efficiency based on the proposed method. Our findings provide new insights into the individual GB-based deformation mechanism at high temperature and show the importance of developing new methods for constructing deformation mechanism maps to experimentally quantify specific deformation mechanisms.