Summary: published in MRS Symp. Proc. on Interfacial Engineering for Optimized Properties (C.B. Carter, E.L. Hall, C.L.
Briant, and S Nutt, eds.), MRS Symp Proc 586, pp. 267-272, Materials Res Soc: Warrendale, PA (1999).
THE CRITICAL STRESS FOR TRANSMISSION OF A DISLOCATION ACROSS AN
INTERFACE: RESULTS FROM PEIERLS AND EMBEDDED ATOM MODELS
P.M. ANDERSON*, S. RAO**, Y. CHENG*, AND P.M. HAZZLEDINE**
*Dept. MSE, The Ohio State University, 2041 College Rd., Columbus, OH 43210-1179,
**Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson
Air Force Base, OH 45433. UES, Inc., 4401 Dayton-Xenia Rd., Dayton, OH 45432.
A continuum Peierls model of a screw dislocation being pushed through an interface and an
atomistic EAM study of dislocation transmission across a [0 0 1] Al-Ni interface suggest that
core spreading into the interface and misfit dislocations in the interface are both potent effects
that can significantly increase barrier strength of interfaces.
The critical resolved shear stress, t*, to push a dislocation past an obstacle is a fundamental
quantity that controls the onset of widespread plasticity in many materials. The familiar Hall-
Petch analysis of a pile-up of screw dislocations against an obstacle furnishes the critical
resolved shear stress, tH-P, to push the leading dislocation in the pile-up past the obstacle [1,2]
tH-P = to +