Cellular dislocation patterning during plastic deformation

Abstract

A simulation of dislocation patterning in a two-dimensional multislip configuration is carried out by means of coarse graining in the presence of plastic strain. In order to study the influence of climb on the dislocation cell pattern formation, fatigue simulations with and without climb mobility are performed and compared. The main result is that, in the presence of climb, cellular structures with well-defined characteristic length emerge, in contrast to the self-similar dislocation patterns developing under similar deformation conditions in the absence of climb. Despite the simplicity of our model, the fractal dimension of the self-similar dislocation patterns emerging without climb confirms the previous results for fcc crystals deformed in a multislip configuration. The cell structures emerging when climb is not negligible ͑in our simulations a climb mobility 1000 times smaller than the glide mobility was considered͒ resemble the dislocation patterns seen in thermal recovery or melt-grown experiments.

Dislocation dynamics simulations with climb: kinetics of dislocation loop coarsening controlled by bulk diffusion

“…The nodal velocities are obtained by solving the set of equations that link the nodal forces to the nodal velocities [19,20], using mobility laws such as the one given by Eq. (8). This is more easily done if the velocity varies linearly with the applied force.…”

Continuum model of irradiation-induced spinodal decomposition in the presence of dislocations

“…whereη has been defined above. The dislocation model described above has also been used (albeit without the composition effect) in a study of two-dimensional melting by Nelson and co-workers 32,33 and more recently by Bako and Hoffelner 34 (see also Ref. 35) in a theoretical study of dislocation patterning during plastic deformation.…”

Influence of Size on the Fractal Dimension of Dislocation Microstructure

“…2D-DDD reproduces the fractal dislocation structures in multiple slip [15]. It is also found that self-similar dislocation patterns form without dislocation climb, but cellular structures with well-defined characteristic lengths are observed with dislocation climb [26]. To our knowledge, 3D-DDD is not used to investigate the fractal nature of dislocation structures yet due to the significant computational expense when simulating highly tangled dislocation cells.…”