Generalized stacking-fault y energy surfaces

For accurately modeling bcc screw dislocation behavior, an even more important validation test concerns the generalized stacking-fault or y energy surfaces for the 

Complete [110] and [211] y surfaces calculated for bcc Ta at its equilibrium volume with the present MGPT potentials are displayed in Fig. 8. Super-cell size is not a hmitation in the MGPT calculations, and larger cells consisting of 32 planes (96 atoms) for the [110] surface and 96 atomic planes (96 atoms) for the 211 surface were used to ensure full convergence. Quahtatively, the calculated y surfaces display the well-known general features expected for bcc metals [33]. In particular, the 110 surface is fully symmetric, while the 211 surface reveals 

Dislocations and Plasticity in bcc Transition Metals at High Pressure 

Left panel the 110 surface right panel the 211) surface. 

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