Dislocation transport and intermittency in the plasticity of crystalline solids

When envisioned at the relevant length scale, plasticity of crystalline solids consists in the transport of dislocations through the lattice. In this paper, transport of dislocations is evidenced by experimental data gathered from high-resolution extensometry carried out on copper single crystals in tension. Spatiotemporal kinematic fields display spatial correlation through characteristic lines intermittently covered by plastic activity. Intermittency shows temporal correlation and power-law distribution of avalanche size. Interpretation of this phenomenon is proposed within the framework of a field dislocation theory attacking the combined problem of dislocation transport and long-range internal stress field development. Intermittency and transport properties show remarkable independence from sample size, aspect ratio, loading rate, and strain-rate sensitivity of the flow stress.