ATOMISTIC DETERMINATION OF CROSS-SLIP PATHWAY AND ENERGETICS

The mechanism for cross slip of a screw dislocation in Cu is determine d by atomistic simulations that only presume the initial and final sta tes of the process. The dissociated dislocation constricts in the prim ary plane and redissociates into the cross-slip plane while still part ly in the primary plane. The transition state and activation energy fo r cross slip as well as the energies of the involved dislocation const rictions are determined. One constriction has a negative energy compar ed to parallel partials. The energy vs splitting width for recombinati on of parallel partials into a perfect dislocation is determined. The breakdown of linear elasticity theory for small splitting widths is st udied. [S0031-9007(97)04444-X].