CPM Seminar

The Role of Obstacles in Diffusive Transport and Defect Mobility

Jeff Rickman

LeHigh University

The presence of obstacles, such as oversized solute and precipitates, can hinder the motion of extended defects and the diffusion of matter in solids, thereby altering mechanical and transport properties. In this talk we employ computer simulation, analytical methods and experiment to investigate two illustrative examples, namely the pinning of dislocation loops by impurities and the hindrance of grain-boundary diffusion in ceramic oxides by dopants. In the first example we describe the effects of impurities on dislocation mobility via level-set dislocation dynamics simulation, and in the second example we examine the impact of isovalent dopants on diffusion and diffusional creep in alumina via simulation and experiment. In both cases computer simulations provide useful insights into the underlying mechanisms governing defect motion and transport.