Among the titanium alloy systems, β titanium alloy has the highest specific strength and good cold working performance. β titanium alloy was first used for aviation and military applications, and the current industrial β titanium alloy is more and more widely used in civil fields, such as chemical, medical, sports equipment and so on. A large number of expensive β-stabilizing elements are needed to be added to the existing β-titanium alloys.
The high cost of β-titanium alloy greatly limits the application of β-titanium alloy. Timetal62S(Ti-6Al-2Fe-0.ISi) is a low-cost alloy designed for Ti-6Al-4V. It completely replaces V with Fe, but its performance is better than Ti-6A1-4V. A small amount of Si is added to the alloy to improve the oxidation resistance and creep resistance. The yield strength in annealed state is 896 ~ 965MPa. The material belongs to α+β low cost titanium alloy, but the deformation rate of the material is poor, it is not suitable for cold machining forming.
In order to take advantage of the excellent properties of β-titanium alloy and make it widely used, it is necessary to develop β-titanium alloy containing little or no expensive alloying elements. B. The alloys Ti-4.3Fe-7.ICr, namely TFC alloy, and Ti-4.3Fe-7.lCr-3, namely TFCA alloy. The β-stable elements in the alloy used cheap Fe and Cr. The alloy is all β phase after quenching in β phase zone and has good cold working performance. The processing rate of Ti-4.3Fe-7.lCr-3. OAl (TFCA alloy) can reach 90%, and the alloy has a good matching of strength and toughness through mechanical thermal processing. However, the material has a great tendency of segregation, and the macro segregation causes a great change in the macro structure, which greatly increases the dispersion of the mechanical properties data. The macro segregation cannot be removed by heat treatment or plastic processing. In the process of preparing β titanium alloy such as Ti-4.3Fe-7.ICr, the forging process of three upsetting and three drawing is rarely reported at home and abroad.
The preparation method of β-titanium alloy material is as follows: the raw materials are prepared according to the mass percentage required by β-titanium alloy material, and then the raw materials are evenly mixed and melted in the vacuum induction furnace with a vacuum degree of 0_5Pa and a melting power of 200KW. After the smelting, the shrinkage cavity of the ingot is removed by wire cutting, and then the forging is carried out under the β-phase transformation temperature above 1000°C.
