Franklin SV, Mertens F, Marder M
Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Dec;62(6 Pt B):8195-206. doi: 10.1103/physreve.62.8195.
Aluminum subjected to smooth mechanical loading does not often deform in a correspondingly smooth manner. Typically it deforms inhomogeneously through the propagation of deformation fronts that slowly traverse the sample. These are called Portevin-Le Chatelier fronts; what determines their velocity has been somewhat mysterious. We present a phenomenological theory for deformation fronts that centers on a nonlocal rate dependence of the flow stress. In a one-dimensional idealization the equations can be solved exactly, and compared directly with experiment. Many significant features of deformation fronts are captured, including a well-known transition from hopping to continuous front motion. The phenomenology's predictions are confirmed by our experiments.
