SYNERGIC MODEL OF THE SUPERPLASTIC DEFORMATION OF MATERIALS

A study is made of a synergic model of superplastic deformation of ult rafine-grained materials at high temperatures as a manifestation of co llective modes of motion and self-organization in a system of stimulat ed grain-boundary slip. The evolution of grain-boundary slip is accomp anied by the formation of a wavefront which separates two steady state s of the system and leads to the appearance of the experimentally obse rved ''running neck'' at the surface of the sample. The synergic model is used to explain the scaling effect of superplasticity. (C) 1998 Am erican Institute of Physics.