Effect of High–Temperature Annealing on the Structure and Properties of TiB/TiAl/Ti Layered Composite Material Obtained by Free SHS Compression

In this work, a layered composite material was obtained by the method of free SHS compression, which combines the processes of self-propagating high-temperature synthesis and high-temperature shear deformation, using initial powder components of titanium, boron, and aluminum, as well as a VT1-0 titanium substrate. It is shown that the resulting composite consists of a TiB-based ceramic layer, a Ti-Al-based intermetallic layer, and an α-Ti titanium layer, with the interfaces between them having a wavy and diffuse character. The influence of high-temperature annealing in an oxidizing atmosphere at a temperature of 1000°C for 1 h on the structure, phase composition, and mechanical properties of each layer in the obtained composite was determined. The results of SEM, powder X-ray diffraction, and EDS analysis of the studied layered composite materials before and after annealing are presented. It was found that during annealing, the intermetallic layer, which initially consists primarily of the TiAl3 phase, undergoes transformation into the main phases TiAl and Ti3Al due to diffusion processes, while free titanium reacts with nitrogen to form up to 10 wt. % of the TiN nitride phase. It is shown that high-temperature annealing leads to structural and phase transformations in the studied layers, which result in improved mechanical properties: hardness increases up to 2.1 times, and the elastic modulus increases up to 1.7 times.