RU2405849C1 - Intermetallic titanium-based alloy - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: invention refers to intermetallic alloys on the basis of titanium, which are intended for manufacture of compressor parts of gas-turbine engine, for example such as blades, discs, inserts, housings, which work at increased temperatures. There proposed is intermetallic titanium-based alloy having the following chemical composition, wt %: Al 10.5-12.5, Nb 38-42, Mo 0.3-0.6, Zr 1.5-2.5, Si 0.1-0.25, C 0.03-0.08, W 0.5-1.0, Ta 0.7-1.5, and Ti is the rest. Alloy is characterised with increased fire resistance at temperature of up to 700C. ^ EFFECT: service life of parts increases and reliable operation of the construction is provided. ^ 2 tbl, 3 ex

Description

The invention relates to the field of non-ferrous metallurgy, in particular to titanium-based intermetallic alloys intended for the manufacture of compressor parts of a gas turbine engine, for example, such as vanes, discs, spacers, housings operating at elevated temperatures.

Known intermetallic alloy based on titanium having the following chemical composition, wt.%:

Al 9.3-14.0 Nb 32.0-60.5 V 0.24-6.2 Ti the rest (US Patent No. 5205984)

Elements of engine structures operating at temperatures of 550-650 ° C in a non-oxidizing environment are made from a known alloy.

The disadvantage of the alloy is its low heat resistance - long-term strength in 100 hours at temperatures up to 650 ° C. Products made from a well-known alloy have a limited service life at operating temperatures.

Known intermetallic alloy based on titanium having the following chemical composition, wt.%:

Al 8.2-11.81 Nb 31.7-43.8 Mo 0-3,2 Ta 0-6.1 Zr 0-3.0 Si 0-0.38 Ti the rest (Patent EP No. 0924308)

The alloy has not sufficiently high values of specific strength at room temperature and specific short-term and long-term strength for 100 hours at temperatures up to 650 ° C due to the increased density. Structural elements made of a known alloy have a limited resource due to increased oxidation.

The closest analogue, taken as a prototype, is an intermetallic alloy based on titanium having the following chemical composition, wt.%:

Al 10-12 Nb 38-42 Mo 0.5-1.0 V 1-1.5 Zr 1-1.5 Si 0.1-0.25 C 0.03-0.08 Ti the rest (RF Patent 2210612)

The prototype alloy has insufficient heat resistance to oxidation in air at operating temperatures of 600 ° C and above.

An object of the invention is the development of an intermetallic alloy based on titanium having high heat resistance at temperatures up to 700 ° C.

To achieve the technical task, an intermetallic alloy based on titanium is proposed, containing aluminum, niobium, molybdenum, zirconium, silicon and carbon, which additionally contains tungsten and tantalum in the following ratio of components, wt.%:

Al 10.5-12.5 Nb 38-42 Mo 0.3-0.6 Zr 1.5-2.5 Si 0.1-0.25 C 0.03-0.08 W 0.5-1.0 Ta 0.7-1.5 Ti rest

Products from the proposed alloy are able to work for a long time at temperatures up to 700 ° C in air.

The authors found that the additional introduction of tungsten and tantalum to an intermetallic alloy based on the stated ratio and content of components increases the heat resistance of the alloy due to the formation of dense oxide compounds [(Ti ₂ O ₃ , Al ₂ O ₃ , (Nb, Ta) ₂ O _5], hampering the oxygen permeability of the interfaces to the gaseous medium - metal, and the formation of a surface layer of titanium metal doped solid solution with Nb, Mo, W, Ta and Si, reduce the diffusion coefficients of oxygen in the matrix at elevated temp tures.

Examples of implementation

The ingots of the proposed alloys were manufactured using the production technology of intermetallic titanium alloys, including the use of charge materials - titanium sponges and alloys, the manufacture of a consumable electrode by continuous pressing, and the ingot smelting by multiple vacuum-arc remelting to obtain a uniform chemical composition.

For heat resistance tests, 15 × 20 mm cylindrical samples were used.

The compositions of the proposed alloy (No. 1-3) and alloy prototype No. 4 are shown in table 1.

The heat resistance of the alloys was evaluated by the weight gain of the samples in g / m ² when they were held in air at temperatures of 600, 650, 700 ° C for 100 hours.

As can be seen from table 2, the proposed alloy surpasses the prototype alloy in heat resistance at a temperature of 600 ° C by 29.3-34.6%, at a temperature of 650 ° C by 14.5-18.7% and at 700 ° C by 24 -25%.

Using the proposed alloy as a heat-resistant material will increase the resource of parts and ensure reliable operation of the structure.

Table No. The content of components in wt.% Al Nb Mo Zr Si C W Ta V Ti one 10.5 38,0 0.3 1,5 0.10 0,03 0.5 0.7 - The basis 2 11.1 39.0 0.5 2.0 0.12 0.04 0.7 0.9 - - | - 3 12.5 42.0 0.6 2.5 0.25 0.08 1,0 1,5 - - | - four 10.5 39.0 0.6 1,2 0.18 0.06 - - 1.3 - | -

table 2 No. The weight gain by oxidation, g / m ² for 100 hours Test temperature ° C 600 650 700 one 0.53 0.78 0.96 2 0.51 0.81 0.95 3 0.49 0.82 0.91 four 0.75 0.96 1,2

Claims (1)

An intermetallic alloy based on titanium, including aluminum, niobium, molybdenum, zirconium, silicon and carbon, characterized in that it additionally contains tungsten and tantalum in the following ratio of components, wt.%:
Al 10.5-12.5 Nb 38-42 Mo 0.3-0.6 Zr 1.5-2.5 Si 0.1-0.25 FROM 0.03-0.08 W 0.5-1.0 That 0.7-1.5 Ti rest