A nonplanar Peierls–Nabarro model and its application to dislocation cross-slip

A novel semidiscrete Peierls–Nabarro model is introduced which can be used to study dislocation spreading at more than one slip plane, such as dislocation cross-slip and junctions. Within this essentially continuum model, the nonlinearity which arises from the atomic interaction across the slip plane is dealt with atomistic and/or ab initio calculations. As an example, we study the dislocation cross-slip and the constriction process in two contrasting fcc metals, Al and Ag. We find that the screw dislocation in Al can cross-slip spontaneously in contrast with the screw dislocation in Ag, which splits into two partials, and thus cannot cross-slip without first being constricted. The response of the dislocations to an external stress is examined in detail. The dislocation constriction energy and the critical stress for cross-slip are determined, and, from the latter, we estimate the cross-slip energy barrier for the straight screw dislocations.

[1]  Sidney Yip,et al.  Periodic image effects in dislocation modelling , 2003 .

[2]  E. Kaxiras,et al.  Hydrogen-enhanced local plasticity in aluminum: an ab initio study. , 2001, Physical review letters.

[3]  C. Woodward,et al.  Atomistic simulation of cross-slip processes in model fcc structures , 1999 .

[4]  E. Kaxiras,et al.  Generalized-stacking-fault energy surface and dislocation properties of aluminum , 1999, cond-mat/9903440.

[5]  Göran Wahnström,et al.  Peierls barriers and stresses for edge dislocations in Pd and Al calculated from first principles , 1998 .

[6]  V. Bulatov,et al.  Connecting atomistic and mesoscale simulations of crystal plasticity , 1998, Nature.

[7]  Hannes Jónsson,et al.  Atomistic Determination of Cross-Slip Pathway and Energetics , 1997 .

[8]  E. Kaxiras,et al.  SEMIDISCRETE VARIATIONAL PEIERLS FRAMEWORK FOR DISLOCATION CORE PROPERTIES , 1997 .

[9]  E. Kaxiras,et al.  Generalized Stacking Fault Energy Surfaces and Dislocation Properties of Silicon: A First-Principles Theoretical Study , 1996, mtrl-th/9604006.

[10]  Duesbery,et al.  Peierls-Nabarro model of dislocations in silicon with generalized stacking-fault restoring forces. , 1994, Physical review. B, Condensed matter.

[11]  T. Arias,et al.  Iterative minimization techniques for ab initio total energy calculations: molecular dynamics and co , 1992 .

[12]  A. Parasnis,et al.  Dislocations in solids , 1989 .

[13]  J. Hirth,et al.  Theory of Dislocations (2nd ed.) , 1983 .

[14]  D. Cockayne,et al.  The measurement of stacking-fault energies of pure face-centred cubic metals , 1971 .

[15]  J. E. Dorn,et al.  Dislocation dynamics , 1965 .

[16]  T. Broom.  Dislocations and mechanical properties of crystals: Edited by J.C. Fisher, W.G. Johnstone, R. Thomson and T. Vreeland Jr. John Wiley, New York; (Chapman and Hall, London), 1957. xiv + 634 pp., 120s. , 1959 .

[17]  R. M. Broudy,et al.  Dislocations and Mechanical Properties of Crystals. , 1958 .

[18]  A. Cottrell.  Dislocations and the Mechanical Properties of Crystals , 1956, Nature.

[19]  Frank Reginald Nunes Nabarro,et al.  Mathematical theory of stationary dislocations , 1952 .

[20]  Efthimios Kaxiras,et al.  Hydrogen-Enhanced Local Plasticity in Aluminum , 2001 .

[21]  M. Duesbery.  Dislocation motion, constriction and cross-slip in fcc metals , 1998 .

[22]  V. Vítek.  Structure of dislocation cores in metallic materials and its impact on their plastic behaviour , 1992 .

[23]  M. Duesbery,et al.  The dislocation core in crystalline materials , 1991 .

[24]  F. Nabarro,et al.  Dislocations in solids , 1979 .