Effect of the substrate structure on the characteristics of a TiB <sub>2</sub>-containg mesocomposite
In the work, we studied the effect of the substrate of a mesostructural composite on its mechanical properties. A mesostructural composite or a mesocomposite is taken to mean a composite material with a submicrocrystalline substrate in which the hardening phase is Cu–TiB <sub>2</sub> nanocomposite particles-agglomerates. Two types of mesocomposite are examined: with a pure copper substrate and with an internally oxidized copper substrate of composition Cu + 3.5 vol.% Al <sub>2</sub>O <sub>3</sub>. The nanocomposite in them is agglomerates of size 1–5 mm consisting of 28 vol. % Cu and 72 vol. % TiB <sub>2</sub> and titanium diboride (TiB <sub>2</sub>) is contained in the form of particles of size »100 nm. It is shown that the properties of the formed mesocomposites are strongly affected by the structure and mechanical properties of the substrate. It is found that as the mesocomposite substrate material is changed from pure copper to internally oxidized copper, the initial microstructure of the mesocomposite is changed involving a considerable change its mechanical properties and dependence on the hardening phase amount. Comparison of the mechanical test results and the microstructural changes in the examined mesocomposites allowed us to disclose the nature of the processes responsible for the properties of the mesocomposites under loading of different types.