[001] Twist boundaries in Cu3Au for T ? 0 K

Abstract

Four different [001] twist boundaries in Cu3Au spanning a wide range of the rotation angle are investigated for temperatures below the bulk order-disorder transition temperature. All the boundaries show almost identical behavior for the plane averaged stoichiometry and the order parameter at a given temperature. Within the accuracy of the calculations no segregation of either Cu or Au is observed to the boundary. At the boundary and below the transition temperature there is a layer which is more disordered than the rest of the crystal, and its width increases as the bulk order-disorder transition temperature is approached. This indicates wetting phenomena, which are in agreement with the experimental and theoretical results on other boundaries.

Temperature dependencies of the relaxation, order and segregation at a tilt grain boundary in

“…At 0.25 T c , these planes are 90% gold. This contrasts with the case of the = 5 (100) (reference [25]) and the = 3 (111) (reference [26]) boundaries for which neither significant segregation nor relaxation is found.…”

“…In what follows, the temperatures are scaled to T c for convenience, according to the procedure used in [25]. For each simulation, a first series of two hundred thousand Monte Carlo steps (including each of the three elementary steps described by equations ( 7) and ( 8)) is necessary to reach equilibrium.…”