Dislocation structure and energy of high angle (001) twist boundaries: A computer simulation study

Journal Article · Mon Feb 29 23:00:00 EST 1988 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(88)90101-0· OSTI ID:6989413

Schwartz, D; Bristowe, P D; Vitek, V

High angle (001) twist boundaries have been frequently investigated experimentally and the presence of grain boundary dislocations (gbd's) and associated cusps in the dependence of the boundary energy on misorientation is in this case well established. However, in previous computer simulations of these boundaries neither localised gbd's nor distinct energy cusps have been identified. The principal aim of the present study is to clarify this discrepancy between observations and computer modelling. For this purpose the structure and energy of a number of long period (high ..sigma..) twist boundaries with misorientations very close to ..sigma.. = 5 have been calculated using empirical pair and n-body potentials to describe interatomic forces. Furthermore, an isolated gbd embedded into a ..sigma.. = 5 boundary has been modelled. Well defined cusps at ..sigma.. = 5 misorientation and localised gbd's have been found but the reference ..sigma.. = 5 structure is always the lowest energy structure which, in general, does not possess the symmetry of the coincidence site lattice. The misorientation dependence of the boundary energy is then discussed using a Read-Shockley type model. The cusps are always very shallow and may have an uncoventional shape which is related to the dependence of the elastic energy on misorientation that is not the same for twist and tilt boundaries, contrary to what is usually assumed. Finally, some remaining discrepancies between observed types of gbd's and those found in the present study are discussed in the light of the previously proposed multiplicities of boundary structures.

• Research Organization: Dept. of Materials Science and Engineering, Univ. of Pennsylvania, Philadelphia, PA (US)
• OSTI ID: 6989413
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 36:3; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

656000* -- Condensed Matter Physics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
99 GENERAL AND MISCELLANEOUS
990230 -- Mathematics & Mathematical Models-- (1987-1989)
COMPUTERIZED SIMULATION
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DATA
DISLOCATIONS
ENERGY SPECTRA
EXPERIMENTAL DATA
GRAIN BOUNDARIES
INFORMATION
LINE DEFECTS
MICROSTRUCTURE
NUMERICAL DATA
SIMULATION
SPECTRA
SYMMETRY