The purpose of this paper is to describe an approximate mathematical model for studies of steady state, non-Newtonian flow regimes within friction welds. The complex flow patterns are described by a numerical solution of the Navier-Stokes equations which relies upon a heuristic model for viscosity. The results obtained predict many features observed in the micrographs of experimental samples. Three main topics are discussed in the paper. The first relates to a method of estimation for the parameters of a non-Newtonian viscosity model for the base material. The second concerns the retention of particles, and of the flow itself, with in the weld zone. The third illustrates that the theoretical framework predicts the existence of spiral defects.
Transactions of JWRI 25 (2), 171-184, 1996-12