Mobility of Dislocations in Grain Boundaries

Abstract

B.&u& -Xous avons analyse la mobilite des dislocations dans les joints de By definition the SGBD, being part of the equilibrium structure of GB cannot be responsible for any dislocation-controlled GB processes. The changes in GB structure or any processes occurring at GB as the annihilation and generation of lattice dislocations, GB sliding, GB migration or cavitation etc. must therefore be related to the processes of creation, motion, rearrangements and annihilation of EGBDs, which because of the small, non lattice Burgers vectors, are constrained to remain in the boundary when they move.The EGBDs can be created in the pre-existing network of SGBDs by the Article published online by EDP Sciences and available at http://dx.

Non-uniform distribution of plastic strain in duplex steel during TEM in situ deformation

“…They restrict plastic deformation at room temperature, which leads to a build-up of internal stresses [1][2][3]. The ferritic-austenitic duplex steel possesses a specific microstructure, where the face centered cubic austenite (␥) and the body-centered cubic ferrite (␣) may create internal stresses during deformation due to their elastic and plastic incompatibilities.…”

Defect redistribution within a continuum grain boundary plasticity model

“…Finally, in general, the (coupled) processes of grain boundary sliding, grain boundary migration and grain rotation are accompanied with the defect redistribution and the change of the grain boundary structure (Grabski, 1988;Priester, 1997;Valiev et al, 1986). It is expected that these phenomena have a significant influence on the macroscopic behaviour.…”

“…Climb is a thermally activated process and is controlled by grain boundary diffusion. In general, due to the rather special conditions for glide, it has been concluded in Grabski (1988) that, from the experimental point of view, independently of the orientation of the Burgers vector with respect to the grain boundary plane, the mobility of dislocations is controlled by grain boundary diffusion. In our work, at the continuum scale, no distinction is made between glissile and sessile dislocations in the redistribution of the net defect.…”

“…The mobility of dislocations in the grain boundary η is proportional to D gb b kT (Grabski, 1988), where D gb is the grain boundary self-diffusion, k is the Boltzmann constant, T is the absolute temperature and b is, as before, the magnitude of the Burgers vector. The grain boundary selfdiffusion follows an Arrhenius form (Sutton and Balluffi, 1995) …”

The model of grain-boundary sliding stimulated by intragranular slip

“…Sources may be analogous to Frank± Read sources or, as Grabski (1988) suggested, be of Bardeen± Herring type. The question inevitably arises concerning the nature and sources of intrinsic GBDs with the Burgers vector lying in the boundary plane.…”