Study of Boundary Structures.
Abstract
Continuing the previous three-year project, atomic properties of boundaries between two solid phases are studied theoretically, using the cluster variation method (CVM). The 90 deg-rotational boundary in the binary Cu-Au ordered alloy phase is calculated using a four-point tetrahedron as the basic cluster of the CVM. The layers on the left of the boundary are perpendicular to the layers on the right-hand side. By calculating the excess free energy and the amount of adsorbed Au atoms, a first-order phase transition is derived within the boundary; there is a discontinuous change in the Au absorption as the overall composition of the system changes across the stoichiometric state. Also there is a switch-over from the low temperature phase to the high-temperature phase; the difference of the two phases is in the behavior of the layer parallel to the boundary. The ABC-CBA stacking boundary in the fcc lattice in the (110) direction is also studied. A reference hexagonal lattice with three times as many lattice points as the original fcc lattice is considered by supplementing the latter by interstitial points; atoms are assumed to move on the reference hexagonal lattice.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1982
- Accession Number
- ADA120452
Entities
People
- Ryoichi Kikuchi
Organizations
- HRL Laboratories