A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with a strain rate range of 0.01–10 s⁻¹ in this study. Electron backscatter diffraction (EBSD) was used to characterize the microstructure prior to and post hot deformation. The results show that the stress–strain curves have obvious yielding behavior at a high strain rate (>0.1 s⁻¹). As the deformation temperature increases and the strain rate decreases, the α phase content gradually decreases in the α + β phase region. Meanwhile, spheroidization and precipitation of α phase are prone to occur in the α + β phase region. From the EBSD analysis, the volume fraction of recrystallized grains was very low, so dynamic recovery (DRV) is the dominant deformation mechanism of Ti-35421 alloy. In addition to DRV, Ti-35421 alloy is more likely to occur in continuous dynamic recrystallization (CDRX) than discontinuous dynamic recrystallization (DDRX).

The aim of this study was to investigate the corrosion resistance of ultrafine-grained (UFG) Ti-6Al-7Nb fabricated by equal channel angular pressing (ECAP) and coarse-grained (CG) Ti- 6Al- 7Nb. The microstructure of each specimen was investigated by the electron backscattered diffraction (EBSD) method. The corrosion behavior of each specimen was determined by electrochemical measurement in Ringer’s solution. The surface corroded morphologies and oxide film formed on Ti-6Al-7Nb alloy after electrochemical measurement were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EBSD investigation shows that the grain size of UFG Ti-6Al-7Nb decreased to ~0.4 µm, accompanied by low angle grain boundaries (LAGBs) accounting for 39%. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicated that UFG Ti-6Al-7Nb alloy possessed a better corrosion resistance. The surface corroded morphologies revealed many small and shallow corrosion pits, which can be attributed to the good compactness of the oxide film and a rapid self- repairing ability of the UFG Ti-6Al-7Nb alloy.

In order to reduce the cost of titanium alloys, a novel low-cost Ti-3Al-5Mo-4Cr-2Zr-1Fe (Ti-35421) titanium alloy was developed. The influence of heat treatment on the microstructure characteristics and mechanical properties of the new alloy was investigated. The results showed that the microstructure of Ti-35421 alloy consists of a lamina primary α phase and a β phase after the solution treatment at the α + β region. After aging treatment, the secondary α phase precipitates in the β matrix. The precipitation of the secondary α phase is closely related to heat treatment parameters—the volume fraction and size of the secondary α phase increase when increasing the solution temperature or aging time. At the same solution temperature and aging time, the secondary α phase became coarser, and the fraction decreased with increasing aging temperature. When Ti-35421 alloy was solution-treated at the α + β region for 1 h with aging surpassing 8 h, the tensile strength, yield strength, elongation and reduction of the area were achieved in a range of 1172.7–1459.0 MPa, 1135.1–1355.5 MPa, 5.2–11.8%, and 7.5–32.5%, respectively. The novel low-cost Ti-35421 alloy maintains mechanical properties and reduces the cost of materials compared with Ti-3Al-5Mo-5V-4Cr-2Zr (Ti-B19) alloy.

Additive manufacturing, or 3D printing, is a process where a part is produced layer by layer, and represents a promising approach for designing components close to their final shape. Titanium alloys produced by additive manufacturing find application in various industries. This overview examines the features of the formation of the microstructure and properties in Ti alloys synthesized with the use of powder and wire laser additive technologies, as well as solid-phase methods of additive manufacturing such as friction stir additive manufacturing. Their main drawbacks and advantages are discussed, as applied to Ti alloys. The main approaches to solving the problem of increasing the strength properties of the synthesized Ti workpieces are considered. The authors of this overview propose a new area of research in the field of the application of additive technologies for producing ultrafine-grained Ti semi-products and parts with enhanced performance characteristics. Research in this area opens up prospects for designing heavily loaded complex-profile products for the aerospace, oil and gas, and biomedical industries.

In the present study, the unique bimodal grain size distribution microstructure with the ultrafine substrate and embedded macro grains was fabricated by a traditional hot-rolling process in a novel low-cost Ti-2Fe-0.1B titanium alloy, which possesses a good combination of strength (around 663 MPa) and ductility (around 30%) without any post heat treatment. Meanwhile, the mechanical behavior and corrosion resistance of hot-rolled Ti-2Fe-0.1B alloy after equal channel angular pressing (ECAP) deformation were studied. Results indicated that the average grain size decreased to 0.24 μm after 4 passes ECAP deformation, which led to the enhancement of tensile strength to around 854 MPa and good ductility to around 15%. In addition, corrosion resistance was also improved after ECAP due to the rapid self-repairing and thicker passivation film. Our study revealed that the novel low-cost titanium alloy after hot-rolling and ECAP could be used instead of Ti-6Al-4V in some industrial applications due to similar mechanical behavior and better corrosion resistance.