Effect of additional carbon and boron alloying on the structure and mechanical properties of alloy VT22

Abstract

The creation of high-strength heat-resistant alloys based on titanium is of great scientific interest. Doublephase titanium (at + 13) alloys are widely used at present. The alloying sets for these alloys are mainly developed with the purpose of increasing their strength and heat resistance by solution strengthening of the phases with substitutional elements. However, the increasing strictness of the requirements on the level of their mechanical properties makes it necessary to create titanium alloys that can be strengthened by the segregation of an intermetallic phase or chemical compounds. An important problem in the development of such alloys is the choice of the optimum composition and the attainment of the requisite dispersity and uniformity of distribution of segregations of strengthening phases in the structure. In this connection, carbon and boron, poorly soluble in titanium and forming independent carbide and boride segregations, are of some interest as alloying additives to these alloys.

The effect of ageing on microstructure and mechanical properties of powder Ti–5Al–5Mo–5V–1Cr–1Fe alloy

“…In the present study no α" phase appears contrarily to the findings by Shevel'kov [22], because shorter ageing times used were not sufficient to produce large concentration gradients within β phase. The obtained microstructures are in good agreement with the existing literature [13,14,31,32].…”

“…3). The presence of similar white titanium carbide particles in β-Ti alloys is reported in the literature [20,32,34]. In another study [35], the effect of carbon content on structural changes in α phase in Ti-5Al-5Mo-5V-3Cr alloy has been discussed but they do not mention the presence of such particles.…”

“…The effect of the titanium carbide particles on the mechanical properties is mentioned in [20,32]. It has been shown that the addition of C reinforces the strength and reduces the elongation slightly due to the formation of titanium carbide compound.…”

“…On the other hand, the presence of titanium carbide can enhance the high temperature strength, i.e. creep properties of an alloy [20,32]. Since the melting temperature of titanium carbide particles is 3800 K and they remain stable at high temperature, thus they will render strength at high temperature application.…”

Microstructure and Tensile Properties of Boron-Doped Beta Titanium Alloy

“…Boron, unlike other interstitial elements such as oxygen and hydrogen, is almost insoluble in titanium in the solid state and, thus, does not embrittle the lattice. Recent studies suggested that a trace of boron addition to conventional titanium alloys such as Ti-64, Ti-6242s, Beta 21s and Ti-1024 etc., obtained obviously grain refinement in the as-cast structures [6][7][8][9][10][11][12]. The as-cast ingot with fine grains could avoid the breakdown process and reduce the process cost [13].…”