A. Yamamoto et H. Tsubakino, CONVERGENT-BEAM DARK-FIELD IMAGING TECHNIQUE WITH ITS APPLICATION TO OBSERVATION OF MULTIPHASE MATERIALS, Materials transactions, JIM, 39(9), 1998, pp. 989-994
A new technique for the observation of multiphase materials has been p
roposed, which enables us to distinguish easily different phases by th
eir different contrasts. The technique is based on the broadening of d
iffraction spots and the overlapping of dark field images due to beam
convergence. Since contrasts are adjustable by changing the beam conve
rgence, the contrast of a weak diffraction phase can be made brighter
than a strong diffraction phase. An observation of the precipitates in
a Ti-10V-2Fe-3Al alloy by this technique showed that a stable oc phas
e precipitates nucleating at the metastable omega phase in the supersa
turated beta matrix.