The [001] antiphase boundaries at the order-disorder transition of cu3au

Kinetic features of alloy ordering with many types of ordered domain: D03-type orderings

“…As was repeatedly noted in sections 5-7, many results of our simulations, including those mentioned in points (i)-(vii), agree well with the experimental observations of multivariant orderings described in references [1][2][3][4][5][6][7]34,39]. This agreement can illustrate the opportunities to use the master equation approach of references [17][18][19][20] for the microscopical studies of most of the various problems of microstructural evolution in alloys.…”

“…and D in equations (33) and (34) in our models are positive at T = T s (c) (which probably follows from considerations of the thermodynamic stability). Therefore, these equations show that both the local order parameter η i and the local mean concentration c i have either a pit or a hump at the ζ -APB depending on the sign of the difference c + − 1/2.…”

“…Moreover, simulation of a 2D version of the D0 3 ordering allows us to study also a kinetic behaviour of the so-called 'conservative' APBs which are often observed under multivariant orderings, e.g. under the L1 2 and L1 0 orderings [6,34]. For geometrical reasons discussed below, the conservative APBs are not formed in realistic 3D models of D0 3 ordering, such as our models 1 and 2, but such APBs can arise in a 2D version of model 2.…”

“…Let us also note that the APDs formed under In later stages of evolution, when the D0 3 order parameter has virtually reached its equilibrium value (figures 6(b)-6(f )), a large proportion of sufficiently long η-APBs become very thin and aligned along the (10) directions parallel to their vector of displacement b d = (1, 0)a or b d = (0, 1)a. In our 2D model 2, such boundaries present an example of the so-called conservative APBs, which can be viewed as a half-space of the ordered domain shifted along the displacement vector parallel to the APB [34]. Without relaxation, the average concentration in each plane parallel to a conservative APB is the same as in the bulk of the ordered phase.…”