title: Stress-gradient plasticity.
abstract: A new model, stress-gradient plasticity, is presented that provides unique mechanistic insight into size-dependent phenomena in plasticity. This dislocation-based model predicts strengthening of materials when a gradient in stress acts over dislocation source-obstacle configurations. The model has a physical length scale, the spacing of dislocation obstacles, and is validated by several levels of discrete-dislocation simulations. When incorporated into a continuum viscoplastic model, predictions for bending and torsion in polycrystalline metals show excellent agreement with experiments in the initial strengthening and subsequent hardening as a function of both sample-size dependence and grain size, when the operative obstacle spacing is proportional to the grain size.
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912, USA. srinath_chakravarthy@brown.edu
authors.forename: Srinath S
authors.initials: SS
authors.lastname: Chakravarthy
authors.forename: W A
authors.initials: WA
authors.lastname: Curtin
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004548:Elasticity; D008422:Materials Testing / Q000379:methods*; D008962:Models, Theoretical; D055585:Physical Phenomena; D015203:Reproducibility of Results; D013314:Stress, Mechanical