Determination of Omega phase volume fraction in single crystals of beta titanium alloys

Single crystals of metastable bcc Ti--6.5 at. percent Mo alloy have been aged at 3500C for varying times to precipitate the omega phase. The variation in volume fraction of precipitate was determined by a quantitative x-ray diffraction technique and correlated with transmission electron microscopy from thin foils. For Ti--Mo alloys the lattice misfit between omega and beta phases is small; reflections from parallel planes of both phases overlap necessitating the use of reflections from nonparallel planes. The 310 beta reflection and 3141 and 3032 omega reflections were selected. These two omega reflections occurred at 960 and 1050 2 theta angles with CuKα radiation and required a 140 reorientation of the crystal