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Four origins are possible for each orientation. Thus,
3x4 = 12 variants exist. TAPB and PT interfaces can
result (Ruedl et al., 1968).
2.2.3.3 Nipx (Pt?Mo)
Eighteen different variants can exist. The
orthorhombic cell can have six relationships with respect
to the FCC unit cell. Each domain may have three
different origins. There are thus 6x3 = 18 variants
possible. TAPB, ATB, and PT boundaries have been reported
for the Pt2Mo superlattice N2V (Tanner, 1972).
2.2.4 SRO in Ni-x Binaries
The Nix binary alloys can also exhibit short range
order (SRO). Briefly, SRO in binary alloys is a local
arrangement of atoms in which an A atom has a greater
preference for another unlike atom, say a B atom, than for
another A atom. The presence of diffuse (1, 1/2, 0)
maxima in both x-ray and electron diffraction patterns has
been offered as evidence for the existence of short range
order in Ni-Mo and Ni-W alloys.
Considerable controversy exists over the explanation
of this diffuse (1, 1/2, 0) scattering. These scattered
intensities can be calculated from a model of statistical
arrangements of atoms in which statistical short range
order is maintained, that is, a model in which there is a