Atomic structure of the Sigma 5 (310)/[001] symmetric tilt grain boundary in molybdenum

Atomistic simulations offer an important route towards understanding and mo deling materials behavior. Incorporating the essential physics into the mod els of interatomic interactions is increasingly difficult as materials with more complex electronic structures than f.c.c. transition metals are addre ssed. For b.c.c. metals, interatomic potentials have been developed that in corporate angularly dependent interactions to accommodate the physics of pa rtially filled d-bands. A good test of these new models is to predict the s tructure of crystal defects and compare them with experimentally observed d efect structures. To that end, the Sigma 5 (310)/[001] symmetric tilt grain boundary in Mo has been fabricated and characterized by HREM. The experime ntally observed structure is found to agree with predictions based on atomi stic simulations using angular-force interatomic potentials developed from model generalized pseudopotential theory (MGPT), but disagrees with predict ions based on radial-force potentials, such as those obtained from the Finn is-Sinclair method or the embedded atom method (EAM). (C) 1999 Acta Metallu rgica Inc. Published bl Elsevier Science Ltd. All rights reserved.