Embedded atom method simulation of 1/2{l_angle}110{r_angle} dislocation core structures
- NRC Research Associate, Wright-Patterson AFB, OH (United States)
- UES, Inc., Dayton, OH (United States)
- Wright Lab., Wright-Patterson AFB, OH (United States)
Atomistic simulations were performed to determine dislocation properties in L1{sub 0} structures. Using a set of EAM potentials that were fit to bulk properties of {gamma}-TiAl and that produced a mechanically stable L1{sub 0} structure, the authors simulated the core structures and friction stresses of 1/2{l_angle}110{r_angle} dislocations with the line orientations of pure screw, pure edge, 30{degree} mixed, and 60{degree} mixed orientations. It was found that all cores except the 60{degree} mixed orientation were planar in nature, being spread predominantly in the ({bar 1}11) close packed plane. The edge component of the 60{degree} mixed dislocation spread on the ({bar 1}11) primary glide plane, but the screw component spread on the (11{bar 1}) conjugate glide plane. The edge, 60{degree} mixed, and 30{degree} mixed orientations were found to dissociate into Shockley partials with separations of 0.9, 0.7, and 0.6 nm, respectively. The friction stresses of the screw and 60{degree} orientations were found to be the highest, being 4 {times} 10{sup {minus}3}{mu} and 2.5 {times} 10{sup {minus}3}{mu}, respectively, where {mu} is the shear modulus. The friction stresses for the edge and 30{degree} mixed orientations were found to be 0.8 {times} 10{sup {minus}3}{mu} and 0.5 {times} 10{sup {minus}3}g{mu}, respectively. These results are discussed in terms of the predictions of Greenberg, et al. regarding friction stresses in {gamma}-TiAl.
- OSTI ID:
- 72411
- Report Number(s):
- CONF-9310224-; ISBN 0-87339-249-3; TRN: IM9530%%23
- Resource Relation:
- Conference: Materials Week `93, Pittsburgh, PA (United States), 17-21 Oct 1993; Other Information: PBD: 1994; Related Information: Is Part Of Alloy modeling and design; Stocks, G.M. [ed.] [Oak Ridge National Lab., Oak Ridge, TN (United States). Metals and Ceramics Div.]; Turchi, P.E.A. [ed.] [Lawrence Livermore National Lab., Livermore, CA (United States)]; PB: 334 p.
- Country of Publication:
- United States
- Language:
- English
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