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Ti–15(wt.%)Mo alloy is produced with a conventional cast and wrought approach using double electron-beam cold hearth melting, 3D hot pressing, and subsequent rolling. Three batches of specimens are subjected to microstructure study and quasi-static tensile testing in the following states: (1) as-rolled, (2) partially recrystallized via annealing at 800 ºC for 40 minutes, (3) annealed at 800 ºC for 3 hours followed by water quenching to fix the β-phase. The specimens in the second state (2) are chosen for a more detailed study of mechanical behaviour upon both quasi-static and high strain-rate compressions. The obtained data on the mechanical behaviour are analysed from the standpoint of the effect of initial microstructure and crystallographic texture in three mutually perpendicular planes on the strain energy and the critical strain rate that results in the fracture. A detailed microstructural study of the tested specimens reveals the influence of microstructure and texture on the deformation mechanisms at different strain rates. A strong effect of microstructural inhomogeneity and crystallographic texture formed during rolling is noted. The results are compared with those obtained earlier for other titanium alloys and some important structural materials tested under the same conditions. As shown, the Ti–15Mo alloy has a rather high mechanical characteristic. At high strain rates, this material corresponds to other single-phase titanium alloys in terms of strain energy; however, it is inferior to the two-phase alloys with a fine and homogeneous microstructure, e.g., Ti-6-4 or T110 (see list of acronyms in Appendix). Taking into account the specific weight of materials, the Ti–15Mo alloy is not inferior to such high-strength materials as the heat-hardened alloy B95, steels ARMOX 600T and Docol 1500M, and, in addition, is cheaper compared to other titanium β-alloys.

The structure and mechanical properties of high-entropy CoCrFeMnNi (equiatomic) and Co20Cr26Fe20Mn20Ni14 alloys, which differ significantly in the stacking-fault energy, are studied. The structure of the alloys was investigated in three states – as-cast, after homogenizing annealing at T = 1000 °C for 24h and after annealing at T = 850 °C. It was found that in the cast state and after homogenizing annealing at 1000 °C both alloys are single-phase solid solutions with a FCC lattice. Annealing at 850 °C preserves the single-phase state in the equiatomic CoCrFeMnNi alloy, but leads to the appearance of a σ-phase in the Co20Cr26Fe20Mn20Ni14 alloy. The mechanical properties of these alloys were studied in a single-phase state by uniaxial compression tests and hardness measurements. It was discovered, that both alloys in a single-phase state had high plasticity and tendency to force strain hardening. The behavior of hardening coefficients in the area of true strains e = 0.05 – 0.17 vary considerably. This may be due to a significant difference in the stacking-fault energy of the investigated alloys. As a result, in Co20Cr26Fe20Mn20Ni14 alloy along with dislocation deformation mechanism there is a high probability of implementation the twinning mechanism.