Structure, phase composition, and mechanical and tribological properties of two-layer cermet composites based on TiB obtained by free SHS compression

In this work, two-layer cermet composites based on TiB–(20, 30 and 40 wt%)Ti were obtained from the initial powder components of titanium and boron using the free Self-Propagating High-Temperature Synthesis (SHS) compression method, which combines combustion in the mode of self-propagating high-temperature synthesis and shear deformation of combustion products. The combustion characteristics of selected compositions and the temperature profiles arising at the interface between the cermet layer and the titanium layer were studied. The general rules of the effect of the initial composition of cermet composites and technological parameters of free SHS compression on the phase composition, structure, and mechanical properties were established. Tribological tests of the surface and cross-section of the obtained cermet composites of the studied compositions were carried out depending on the orientation of titanium monoboride whiskers in the volume of the sample. Dependence of the friction coefficient on the travel length of the counterbody and 3D images of wear grooves are provided. The interface between cermet and Ti layers was studied. It was shown that this interface is formed due to diffusion and convective mixing of synthesis products and melt of the surface of the titanium layer. Bending tests of the resulting two-layer cermet composites showed that fracture does not occur at the cermet/Ti interface, which qualitatively indicates good adhesive strength between the layers. It was established that after melting and crystallization, the titanium layer consists of two modifications: α-Ti and a small amount of β-Ti, the presence of which leads to an increase in the hardness of the layer up to 1.5 times. © 2024