INVESTIGATION OF ATOMIC-STRUCTURE OF OMEGA-PHASE CRYSTALS IN TI-MO ALLOYS USING HIGH-RESOLUTION ELECTRON-MICROSCOPY

High-resolution electron microscope (HREM) images of omega-phase cryst als in Ti-11.1at%Mo alloy single crystals formed by aging are discusse d by comparing with the calculated images. The calculation was carried out using the multi-slice method at different defocus values for omeg a-phase crystals at three different positions in the matrix. It is fou nd that bright spots of HREM images of omega-phase crystals appear at the positions of atoms, which are displaced in the opposite direction and make atom pairs in the model, as was proposed by de Fontaine et al . This fact was previously predicted in 1987. It is also found that br ight spots of HREM images appear at the position of atoms, which are n ot displaced in the model. These results suggest that the proposed mod el is satisfactory.