Kinetics of Grain Boundary Sliding and Rotational Deformation in Nanocrystalline Materials

摘要

Kinetics of combined grain boundary (GB) sliding and rotational deformation processes in nanocrystalline materials is examined using computer simulations of GB dislocation slip and climb. We consider the situation where GB sliding and rotational deformation (plastic deformation accompanied by crystal lattice rotations) serve as dominant deformationmodes in a nanocrystalline specimen and thereby crucially influence its deformation behavior. Based on the results of the computer simulations, the dependences of the flow stress on plastic strain in nanocrystalline Ni and Al₂O₃ are calculated, and their strain rate sensitivity parameters are estimated. It was found that combined actions of GB sliding and rotational deformation modes enhance ductility of nanocrystalline specimens.