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Materials Science and Engineering A319321 (2001) 182187 A Peierls analysis of the critical stress for transmission of a screw

Summary: Materials Science and Engineering A319­321 (2001) 182­187
A Peierls analysis of the critical stress for transmission of a screw
dislocation across a coherent, sliding interface
Peter M. Anderson *, Zhiyong Li
Department of Materials Science and Engineering, The Ohio State Uni6ersity, 2041 College Road, Columbus, OH 43210-1179, USA
The resistance of interfaces and grain boundaries to dislocation transmission is a fundamental quantity that often serves to
control strength in plastically deforming polycrystals and multiphase materials. This manuscript extends the standard continuum
view of the transmission process, in which a Volterra or Peierls dislocation interacts with a non-slipping interface. The extensions
in this work are to use a modified Peierls description of the dislocation on the incoming and outgoing slip planes and to let the
interface slip according to a simple, periodic constitutive relation, so that the interface can store and emit dislocation content
during the transmission process. The analysis is restricted to a screw dislocation oriented parallel to the interface, with incoming
and outgoing slip planes that are normal to the interface, and with Burgers vectors that are the same on each side of the interface.
The last restriction is characteristic of coherent interfaces. The results show that the critical stress for transmission can be
increased dramatically by decreasing the elastic shear modulus and unstable stacking fault energy of the interface. In such cases,
a significant portion of the dislocation core can become stored in the interface during the transmission process, so that the critical
transmission step is to extract the core from the interface. The peak stress for dislocation transmission across interfaces is
contrasted for slipping and non-slipping cases. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Interface; Dislocation; Strength; Hall­Petch; Thin films; Peierls model


Source: Anderson, Peter M. - Department of Materials Science and Engineering, Ohio State University


Collections: Materials Science