title: Dynamic instability in intergranular fracture.
abstract: A molecular-dynamics model for crack propagation under steady-state conditions is used to study dynamic instabilities along a grain boundary in aluminum that occur when the crack speed approaches 1/3 of the material's Rayleigh wave speed. Instead of crack branching, as is characteristic for a crack propagating in a homogeneous environment, the instability of an intergranular crack results in a periodic series of dislocation bursts. These bursts limit the crack speed and produce velocity oscillations with a large increase in energy dissipation that increases the grain boundary toughness.
authors.affiliation: National Institute of Aerospace, Hampton, Virginia 23666, USA. yamakov@nianet.org
authors.forename: V
authors.initials: V
authors.lastname: Yamakov
authors.forename: E
authors.initials: E
authors.lastname: Saether
authors.forename: D R
authors.initials: DR
authors.lastname: Phillips
authors.forename: E H
authors.initials: EH
authors.lastname: Glaessgen