RU2192493C2 - Titanium-based alloy and article made from such alloy - Google Patents

Abstract

FIELD: non-ferrous metallurgy; manufacture of titanium alloys used for high-strength structural materials for airframe members. SUBSTANCE: titanium-based high-strength alloy contains, mass-%: aluminum, 2.0 to 4.0; molybdenum, 5.5 to 8.0; iron, 0.4 to 0.8; vanadium, 8.5 to 10.5; chromium, 0.4 to 0.8; niobium, 2.1 to 3.0; silicon, 0.11 to 0.35 and titanium being the remainder. EFFECT: enhanced ultimate strength, relative elongation and high-temperature strength of alloy. 3 cl, 2 tbl

Description

 The invention relates to non-ferrous metallurgy, and in particular to the creation of titanium alloys intended for use as high-strength materials for aircraft glider structures.

Known alloy based on titanium composition, wt.%:
Aluminum - 3-7
Molybdenum - 0.2-5
Iron - ≤0.3
Niobium - 0.2-4
Nickel - 0.5-5
Tungsten - 0.06-2
Molybdenum and Nickel (amount) - ≤5
Titanium - the rest [1]
This alloy has low characteristics of tensile strength, elongation and heat resistance.

 Products made from this alloy (such as ribs and stringers of the internal set, etc.), due to the low values of tensile strength and elongation cannot be used in critical power structures.

The closest analogue taken as a prototype is an alloy based on titanium of the following composition, wt.%:
Aluminum - 2.0-6.0
Molybdenum - 5.0-10.0
Iron - 0.1-4.0
Nickel - 0.3-4.0
Vanadium - 0.1-10.0
Chrome - 2.0-12.0
Titanium - the rest [2]
The prototype alloy also has insufficiently high values of tensile strength, elongation and heat resistance. Products made from this alloy (such as fuselage skin, glider plumage, etc.) cannot be used for a long time at temperatures above 250 ^o C due to embrittlement of the alloy.

 An object of the invention is to increase the tensile strength, elongation and heat resistance characteristics of the alloy.

The technical problem is achieved by the fact that the proposed alloy based on titanium containing aluminum, molybdenum, iron, vanadium, chromium, which additionally contains niobium, silicon in the following ratios of components, wt.%:
Aluminum - 2.0-4.0
Molybdenum - 5.5-8.0
Iron - 0.4-0.8
Vanadium - 8.5-10.5
Chrome - 0.4-0.8
Niobium - 2.1-3.0
Silicon - 0.11-0.25
Titanium - the rest
and an article (such as slat structures, engine ducts, torsion bars, etc.) made from it.

 The authors found that the combined introduction of niobium and silicon at the proposed content of components in the titanium-based alloy contributes to the hardening of the alloy by modifying the structure and hardening grain boundaries, and also increases the heat resistance due to the formation of intermetallic compounds in the alloy structure.

 Ingots of the proposed alloy and prototype alloy were prepared by the double remelting method in vacuum arc furnaces within the composition of the proposed alloy and the prototype alloy (1,2, 3, and 4, respectively, see Table 1).

 The ingots were forged into slabs, and then hot in the α + β region, they were rolled onto sheets with a thickness of 3.5 mm. Then, in the cold state, the sheets were rolled to a final thickness of 1.5 mm with intermediate annealing.

 Samples were made from sheets with a thickness of 1.5 mm, which were then subjected to hardening heat treatment. In accordance with GOSTs, the ultimate strength, elongation, and long-term tensile strength (heat resistance, see Table 2) were determined on the samples.

 As can be seen from table 2, the mechanical properties of the proposed alloy exceed the mechanical properties of the prototype alloy: tensile strength by 8.5%, elongation by 30%, long-term strength by 10.5%.

 The use of the proposed alloy based on titanium and products made from it will provide a reduction in the mass of structures by 20–25%, a 1.3-fold reduction in energy costs, and an improvement in the ecology of production through heat treatment in a protective atmosphere.

Literature
1. Application 1-55350, Japan
2. Patent 1479855, Great Britain.

Claims (1)

1. An alloy based on titanium containing aluminum, molybdenum, iron, vanadium, chromium, characterized in that it additionally contains niobium and silicon in the following ratio, wt. %:
Aluminum - 2.0-4.0
Molybdenum - 5.5-8.0
Iron - 0.4-0.8
Vanadium - 8.5-10.5
Chrome - 0.4-0.8
Niobium - 2.1-3.0
Silicon - 0.11-0.25
Titanium - Else
2. The product of an alloy based on titanium, characterized in that it is made of an alloy of the following chemical composition, wt. %:
Aluminum - 2.0-4.0
Molybdenum - 5.5-8.0
Iron - 0.4-0.8
Vanadium - 8.5-10.5
Chrome - 0.4-0.8
Niobium - 2.1-3.0
Silicon - 0.11-0.25
Titanium - Else

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