International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Titanium Ti-6-4 alloy coated with Ni-base material was obtained via Blended Elemental Powder Metallurgy approach by sintering a mixture of laminated powders. Microstructure and phase composition of obtained laminated material were studied, and formation of Ti2Ni phase and multicomponent phase (Ti, Ni, Al, V, C) with E93 crystal cell of space group 227: Fd-3m was established. The intermetallic melt deeply permeated into the Ti-6-4 material at sintering temperature (1250°C) higher than Ti2Ni melting point (942°C), and a dense gradient structure formed. The microstructure, phase composition and properties of obtained gradient material are discussed in detail.

The high specific strength of Ti-based alloys and composites makes them highly requested materials in various structural applications. However, reinforcement of the alloys with hard particles generally lowers the values of toughness and plasticity of material. A satisfactory combination of plastic and strength can be achieved by formation of layered structures comprising of two and more layers of different materials with different chemical compositions within individual layers. The multi-layer materials allow controlling the mechanical properties of the individual layers by changing microstructure and chemical composition within each layer specifically. In the present study, a cost-efficient process of fabrication of Ti-based multi-layer composites using blended elemental powder metallurgy (BEPM) and TiH2 powder is proposed. Two and three-layered composites based on titanium or Ti-6Al-4V alloy and their metal-matrix composites (MMC) with TiC and TiB were fabricated. Multi-layered samples reinforced by TiC were successfully sintered due to very close shrinkage of adjacent layers. Shrinkage values of layers reinforced by TiB were lower than those for the Ti-alloy, which led to delamination of layered structures, distortion of shape, and cracking. We can control shrinkage in individual layers by means of optimizing the powder size, that allows to obtain multi-layer titanium matrix composites reinforced by TiB with well-balanced mechanical properties.