Atomistic study of tilt grain boundaries with substitutional impurities

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(82)90105-5· OSTI ID:6267575

Sutton, A P; Vitek, V

An atomistic study of symmetrical (001) tilt boundaries in f.c.c. metals with a nonequilibrium distribution of substitutional impurities in the boundaries has been carried out. Bismuth and silver as solute atoms in copper, and silver as a solute in gold have been studied. The relaxations associated with widely spaced solute atoms in otherwise ideal crystals of the two hosts are examined first. The grain boundaries studied are ..sigma.. = 5 (210), 36.87/sup 0/ and ..sigma.. = 17 (530), 28.07/sup 0/. In both hosts the (530) boundary consists of two units of the (210) boundary and one octahedron from the ideal crystal orientation. Impurity atoms were then introduced successively at two sites in (210) boundaries and five sites in the (530) boundaries. For each case the energy of segregation, E/sub s/, to the sites selected, the concomitant relaxation of the host boundary structure and the change in grain boundary energy, ..delta gamma../sub b/, have been found, E/sub s/ is found to be very sensitive to the local atomic environment of the solute atom in the host boundary and there is not a substantial difference in the overall segregation propensity to the two boundaries selected. Bismuth atoms cause larger distortion and expansion of the host copper boundaries than does silver. E/sub s/ for the former is governed principally by the size effect while this can only partially explain the variation of E/sub s/ for silver atoms at the various sites of the boundaries in copper. Segregation is energetically favorable for silver atoms at all sites considered in the boundaries in gold. E/sub s/ value is dominated in any specific case by the strong effect of the local atomic environment. This leads to a strong selectivity of segregation sites. Implications of the results for understanding of the propensity for segregation, effects of impurities on faceting and embrittlement are discussed. 60 references, 10 figures, 3 tables.

• Research Organization: Univ. of Pennsylvania, Philadelphia
• DOE Contract Number: AC02-79ER10429
• OSTI ID: 6267575
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 30; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
BISMUTH ADDITIONS
BISMUTH ALLOYS
COPPER ALLOYS
COPPER BASE ALLOYS
CRYSTAL STRUCTURE
GOLD ALLOYS
GOLD BASE ALLOYS
GRAIN BOUNDARIES
MICROSTRUCTURE
SEGREGATION
SILVER ADDITIONS
SILVER ALLOYS