“…Most of the mentioned above research papers were focused on the development of the methods of the surface modification of the titanium alloys, or the approaches to form desirable intermetallic phases in Ti-Al system. For the initial characterization of the microstructure, metallography, scanning electron microscopy, and X-ray diffraction methods have been successfully used [7][8][9][10]13,17,30,31,33,35,36,42,51]. However, detailed study of the microstructure in gradient materials requires the application of analytical methods with high resolution, such as transmission electron microscopy, which was successfully used previously [14,22,32,34,42,46,54,58].…”