Plasticity of Micrometer-Scale Single Crystals in Compression

Abstract

This review examines the recent literature that has focused on uniaxial compression experiments of single crystals at the micrometer scale. Collectively, the studies discovered new regimes of plastic flow that are size-scale dependent and that occur in the absence of strong strain gradients. However, the quantitative comparison of the flow curves between independent studies is hampered by differences in the particular implementations of the testing methodology. Modeling of microcompression experiments using 3-D discrete dislocation simulations has provided valuable insight into the mechanisms that control plastic flow in FCC metals. These efforts identified the importance of the initial dislocation density and distribution of mobile dislocation segments, the influence of free surfaces on that distribution, as well as altered multiplication and hardening responses due to the finite source statistics. Microcrystal experiments also provide a new pathway to characterize the global system dynamics of dislocation ensembles and associated stochastic processes.