Slip Line Growth as a Critical Phenomenon

We study the growth of a slip line in a plastically deforming crystal by numerical simulation of a double-ended pileup model with a dislocation source at one end, and an absorbing wall at the other end. In the presence of defects, the pileup undergoes a continuous nonequilibrium phase transition as a function of stress, which can be characterized by finite-size scaling. We obtain a complete set of critical exponents and scaling functions that describe the spatiotemporal dynamics of the slip line. Our findings allow us to reinterpret earlier experiments on slip line kinematography as evidence of a dynamic critical phenomenon.