Analytical and numerical determination of the elastic interaction energy between glissile dislocations and stacking fault tetrahedra in FCC metals

Understanding flow localization in materials containing high concentrations of Stacking Fault Tetrahedra (SFT's) depends on delineation of the mechani sms by which they are destroyed as effective dislocation obstacles. The ela stic interaction between glissile dislocations and SFT's in FCC metals is e xamined, both analytically and numerically. Numerical calculations are perf ormed for both full and truncated tetrahedra interacting with edge dislocat ions, while a new analytical formula is derived for the elastic energy of a full tetrahedron-dislocation system. Calculations confirm that the stress field of glissile dislocations is not sufficient to re-configure SFT's into faulted Frank loops by reverse glide of stair-rod dislocations. This mecha nism of SFT destruction by shear unfaulting of Frank loops seems to be unli kely. It is proposed that the destruction of SFT's in irradiated materials is enabled by dislocation drag of interstitial clusters, followed by subseq uent recombination and melting of the SFT core. (C) 2001 Elsevier Science B .V. All rights reserved.