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the matrix with Dla. This would impart high strength to
the alloy, and probably great stability as well.
6.5 Convergent Beam/X-ray Diffraction
The use of the convergent beam technique for lattice
parameter measurements must seem redundant in light of the
x-ray diffraction measurements that were made. The
convergent beam method is a powerful tool with which to
make these measurements since it can be used to make local
lattice parameter measurements, local strain measurements,
and perhaps measurements that would reflect subtle changes
in ordering, ternary ordering, for example. Ternary
ordering might change the symmetry of the convergent beam
FOLZ structure (Ecob et al., 1982).
Only lattice parameter measurements in the gamma
prime phase were practical. The gamma phase was in
general too fine with respect to the beam size to form a
pattern unique to the gamma phase. There was significant
interference between the gamma and gamma prime phases,
invariably resulting in unusuable diffraction patterns.
The same effect was observed in the gamma prime phase when
the beam was placed too close to the gamma phase, yet
still in the gamma prime phase.
It is not possible to quantitatively differentiate
alloying effects using lattice parameter measurements
unless numerous standards exist, and then generally, only