Interaction between lattice dislocations and grain boundaries in f.c.c. and ordered compounds: A computer simulation

Abstract

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. ABSTRACT The interaction of 1/2<110> screw-and 60°dislocations with symmetric [110] tilt boundaries was investigated by atomistic simulations using many-body potentials representing a pure f.c.c. metal and ordered intermetallic compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the structural unit model may help to predict the interaction mechanism for long period boundaries and that the interaction in ordered compounds shows similarities to the interaction in f.c.c.metals. Some comparisons with experimental observations have been made.

Interactions between lattice dislocations and grain boundaries in Ni3Al investigated by means of in situ TEM and computer modelling experiments

“…Our experimental observations of the interaction with the E = 3 coherent twin boundary can be compared to the computer modelling results, see also [4,5]. The dislocation-grain boundary system that was studied is exactly the same as the system that is studied here experimentally and therefore, a one-toone comparison is possible.…”

“…A possible explanation for the tendency to absorption could be found in a lower value of the energy of the ordering fault in the grain boundary plane between two 1[110] superpartial dislocations compared with the value of the APB between the superpartials in the bulk: i.e. in the order of 20 mJ/m 2 [4]. Thus regarding this energy difference absorption in the boundary might be expected, which of course is in contrast to f.c.c, materials since an ordering fault is not present, neither in the bulk nor grain boundary.…”

“…and other L12 materials like Cu3Au lies in the stress level at which transmission through the boundary occurs [4]. The two superpartial dislocations in L12 constituting the arriving dislocation will decrease their separation in response to the applied stress, when the leading superpartial dislocation is halted at the boundary.…”

Interactions between lattice dislocations and grain boundaries in L12 ordered compounds investigated by in situ transmission electron microscopy and computer modelling experiments

“…In general the results of computer modelling studies [11,12] indicate that grain boundaries in L12 ordered compounds hinder dislocation motion. This effect increases with higher ordering tendency.…”

Identification of planar defects in D019phases using high-resolution transmission electron microscopy

“…Introduction In the last two decades, extensive fundamental research has been made on structural intermetallics aiming at an implementation of these compounds in the ®eld of transportatio n and service at high temperature (Pestman et al 1991, Horton et al 1995, VeyssieÁ re and Saada 1996, Vitek et al 1996, Koch et al 1997, Yoo and Fu 1997, Liu and Maziasz 1998, Yamaguchi et al 2000. The high strength, good oxidation resistance and high melting point displayed by many non-cubic intermetallics make this class of materials potentially suitable for such applications.…”