Topological analysis of {1 1 0} slip in an α-iron crystal from in situ atomic force microscopy Original Research Article

In situ tensile tests were performed inside an atomic force microscope on commercially pure α-iron single crystals to examine the process of emerging slip at a free surface during plastic straining. The reported study corresponds to a crystal orientation which favors slip on a {1 1 0} plane. Statistical analysis of periodically stored images during the test allowed the collection of information on the planar and heterogeneous nature of slip, as well as on the evolution of this heterogeneity with strain. The average slip and the slip dispersion were step-wise estimated separately in each of the slip bands in a representative crystal observation zone. An estimate of the related heterogeneous evolution of the mobile dislocation density was also obtained. For the advanced microstructure-based modeling of intra-crystalline plastic behavior actually used in multiscale computational approaches of metal plasticity it is of interest to describe the relevant intra-crystalline slip process, which is not homogeneous even in single slip mode, although it is frequently simplified as such. These results also are of particular importance in validating the dislocation collective behaviour predicted by dislocation dynamics simulations.