A Ti-15Mo/TiB metal matrix composite was produced by the spark plasma sintering process at 1400 °C using a Ti-14.25 wt.% Mo-5 wt.% TiB₂ powder mixture. The microstructure and mechanical properties of the composite were studied after non-isothermal rolling of specimens heated to 1000 °C to a thickness strain of ~0.7. Transmission and scanning electron microscopy, as well as X-ray analysis were used for microstructure examination; mechanical properties were evaluated using tensile testing and microhardness measurement. In the initial condition, the Ti-15Mo/TiB composite consisted of 8.5 vol.% of TiB needle-like particles heterogeneously distributed within the β matrix. A small volume of fractions of the α″ and ω phases was also found in the microstructure. Microstructure evolution of the composite during hot rolling was associated with dynamic recrystallization of the bcc titanium matrix and shortening of the TiB whiskers by a factor of ~2. The Ti-15Mo/TiB composite after hot rolling showed considerable improvement in ductility without substantial loss of strength and hardness. The hot rolled specimen was not fractured during the compression test even after 45% thickness reduction, while in the initial condition, the compression ductility was 22%. The yield strength for both conditions was quite similar (~1350 MPa). The hot rolled composite also showed some improvement in ductility to ~12% elongation at elevated temperature (500 °C) compared to the initial condition, the tensile elongation of which did not exceed 2%. The observed difference in the mechanical behavior was associated with the presence of the metastable α″ and isothermal ω phases in the initial condition and the more stable α phase in the hot rolled condition.

The structure and mechanical properties of as-cast and thermomechanicaly processed (cold rolling followed by annealing at 700 °C and 900 °C) Fe₄₀Mn₄₀Cr₁₀Co₁₀ (at.%) high-entropy alloys doped with different amounts (0, 0.5, and 2.0 at.%) of N were examined. The as-cast Fe₄₀Mn₄₀Cr₁₀Co₁₀ alloy (N0) contained σ-phase particles at the boundaries of the fcc grains. The addition of 0.5 (N0.5) and 2.0 (N2) at.% of nitrogen suppressed the formation of the σ-phase due to which the alloys consisted of only the fcc phase. Annealing after rolling resulted in the development of static recrystallization and precipitation of additional phases: the σ-phase was found in the N0 and N0.5 alloys, and hexagonal M₂N nitrides were found in the N2 alloy. The strength of the as-cast alloys at room temperature increased with increasing nitrogen concentration due to interstitial solid solution strengthening. Cold rolling and subsequent annealing resulted in considerable strengthening of the program alloys. The strength of the alloys increased with the N content and decreased with increasing annealing temperature. The best combination of mechanical properties at room temperature was attained in the N2 alloy after annealing at 700 °C, and at 77 K, was demonstrated by the N0.5 alloy after annealing at 900 °C.

A Ti-15Mo/TiB metal–matrix composite was produced by spark plasma sintering at 1400 °C. The fractions of the elements in the initial powder mixture were 80.75 wt.% Ti, 14.25 wt.% Mo, and 5 wt.% TiB₂. The initial structure of the synthesized composite was composed of bcc β titanium matrix and needle-like TiB reinforcements with an average thickness of 500 ± 300 nm. Microstructure and mechanical properties of the composite were studied after laser beam welding (LBW) was carried out at room temperature or various pre-heating temperatures: 200, 400, or 600 °C. The quality of laser beam welded joints was not found to be dependent noticeably on the pre-heating temperature; all welds consisted of pores the size of which reached 200–300 µm. In contrast to acicular individual particles in the base material, TiB whiskers in the weld zone were found to have a form of bunches. The maximum microhardness in the weld zone (~700 HV) was obtained after welding at room temperature or at 200 °C; this value was ~200 HV higher than that in the base material.

TiNbZr-(Ti,Nb)B composites were produced by vacuum arc melting; the weights of TiB₂ in the charge mixture were 0.7 wt. % (Alloy A) and 4.0 wt. % (Alloy B). In addition, unreinforced TiNbZr alloy specimens were fabricated without the addition of TiB₂. The microstructure of the TiNbZr-(Ti,Nb)B composites consisted of the TiNbZr β matrix and (Ti,Nb)B fibers. The (Ti,Nb)B fibers had a needle-like shape with an average diameter of ~0.4 and ~2.0 µm for Alloys A and B, respectively. The volume fraction of borides was found to be ~2.5 and ~12.4% for Alloys A and B, respectively. The presence of 12.4 vol.% of (Ti,Nb)B reduced the corrosion resistance of Alloy B in comparison with that of the TiNbZr alloy and Alloy A, which showed rather similar values of corrosion resistance. It was found that the addition of the TiB₂ to the TiNbZr alloy led to a decrease in the friction coefficient; when adding 0.7% TiB₂ to the alloy (Alloy A), the friction coefficient decreased from 1.15 to 1.13, and when the percentage of TiB₂ in the alloy increased to 4% (Alloy B), the friction coefficient decreased by ~2 times from 1.15 to 0.58. The full biocompatibility of TiNbZr-(Ti,Nb)B composites was demonstrated; no significant differences from the unreinforced state and alloy were found.