Dislocation structure and energy of high angle (001) twist boundaries: A computer simulation study
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 localized gbd's nor distinct energy cusps have been identified. 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 ) twist boundaries with misorientations very close to = 5 have been calculated using empirical pair and n-body potentials to describe interatomic forces. Furthermore, an isolated gbd embedded into an = 5 boundary has been modeled. Well-defined cusps at = 5 misorientation and localized gbd's have been found but the reference = 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 unconventional 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:
- Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Materials Science and Engineering; Pennsylvania Univ., Philadelphia (USA). Dept. of Materials Science and Engineering
- DOE Contract Number:
- FG02-84ER45116; FG02-87ER45310
- OSTI ID:
- 6298811
- Report Number(s):
- DOE/ER/45310-1; ON: DE87012745
- Resource Relation:
- Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
Similar Records
Study of energy versus misorientation for grain boundaries in gold by crystallite rotation method. I. (001) twist boundaries
Study of energy vs misorientation for grain boundaries in gold by crystallite rotation method - I. (001) twist boundaries
Related Subjects
DISLOCATIONS
METALS
COMPUTERIZED SIMULATION
COPPER
FCC LATTICES
GOLD
GRAIN BOUNDARIES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELEMENTS
LINE DEFECTS
MICROSTRUCTURE
SIMULATION
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies