RU2507289C1 - Titanium-based alloy and item made from it - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: titanium-based alloy contains the following, wt %: Al 5.0-6.6, Mo 1.5-2.5, Zr 1.0-2.8, V 0.4-1.4, Fe 0.08-0.40, Si 0.08-0.28, Sn 1.5-3.8, Nb 0.4-1.2, O 0.02-0.18, C 0.008-0.080, Ti is the rest.

EFFECT: alloy has high strength characteristics at high temperatures, increased processibility level at hot deformation.

2 cl, 3 tbl, 3 ex

Description

The invention relates to non-ferrous metallurgy, in particular to the production of titanium alloys, and can be used for highly loaded parts and assemblies operating at temperatures up to 550 ° C for a long time and at 600 ° C for a short time, for example, for compressor housings and parts, such as spacers and blades of gas turbine engines (GTE), as well as other parts of aerospace engineering and mechanical engineering.

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

Al 5.35-6.1 Mo 0.15-0.75 Zr 3.25-5.0 Si 0.2-0.6 Sn 3.5-4.5 Nb 0.5-1.5 C 0.03-0.1 Ti rest

(U.S. Patent No. 4,770,726).

The disks and blades of a high-pressure gas turbine compressor are made from a well-known titanium-based alloy.

The disadvantage of alloy and products made from it is the relatively low strength of the semi-finished products and parts in the annealed condition. Therefore, this alloy is used mainly after hardening heat treatment (quenching in oil and subsequent aging).

The alloy in a heat-strengthened state has reduced ductility characteristics (δ≥6%; ψ≥15%) and high sensitivity to stress concentrators, as well as a narrow temperature range of intense hot deformation, which is about 50 ° C.

Products made from this alloy require high surface quality after machining, have a high cost and therefore have limited use.

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

Al 5.5-6.5 Mo 0.3-0.5 Zr 3.5-4.5 Fe ≤0.03 Si 0.35-0.55 Sn 2.0-4.0 O ≤0.14 Ti rest

 (EP patent No. 0269196).

Disks of a high-pressure compressor of gas turbine engines are made from a known alloy.

The disadvantages of the known alloy is the low level of strength characteristics at temperatures up to 550 ° C, the increased sensitivity of the alloy to iron impurities, which limits the use of the alloy. Alloy and products made from it have low fatigue characteristics due to the coarse-grained structure.

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

Al 5.5-6.5 Mo 0.7-3.0 Zr 0.7-5.0 Si 0.04-0.13 Sn 1.7-2.3 Ti the rest (US Patent No. 3833363).

Cases, disks and blades of a high-pressure compressor of gas turbine engines, as well as blades and other details of turbines of power plants, which operate for a long time at temperatures up to 500 ° C, are made from a well-known alloy.

The disadvantages of the known alloy is the low level of strength and fatigue characteristics in the temperature range from 20 ° C to 500 ° C.

Products made from this alloy have a low working life.

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

Al 6.2-7.0 Mo 0.4-1.0 Zr 3.5-4.5 Si 0.1-0.22 Sn 2.2-3.5 Nb 0.5-1.5 O 0.05-0.12 C 0.02-0.1 Ti rest

(RF patent No. 2039112).

The disks and blades of a high-pressure compressor of gas turbine engines with an operating temperature of up to 600 ° C are made from a known alloy.

The disadvantages of the alloy are low strength characteristics, reduced thermal stability (δ≥3.5% after operation for 100 hours at 600 ° C), a narrow temperature range of intense deformation in the two-phase region (about 80 ° C) due to the high total aluminum content , tin and zirconium, which makes it impossible to manufacture thin sheets and body parts.

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

Al 5.8-6.6 Mo 0.8-1.5 Zr 2.0-4.0 Fe 0.06-0.13 Si 0.25-0.45 Sn 2.5-4.5 Nb 0.8-2.5 O 0.05-0.12 C 0.05-0.1 W 0.35-0.8 Ti rest

and a product made from it (RF Patent No. 2039112).

The disks and blades of a high-pressure compressor of gas turbine engines are made from a known alloy.

The disadvantage of the alloy is the relatively low level of strength at temperatures of 20-550 ° C and the narrow temperature range of intense deformation in the two-phase region (about 100 ° C) due to the increased total content of elements stabilizing the alpha phase and neutral hardeners (aluminum, zirconium, tin ), which limits the use of the alloy.

The closest analogue to the purpose and set of essential features taken as a prototype is an alloy based on titanium having the following chemical composition, wt.%:

Al 5.5-7.0 Mo 0.5-2.0 Zr 1.5-2.5 V 0.8-2.5 Fe 0.03-0.3 W 0.001-0.10 Cu 0.001-0.08 Ni 0.001-0.02 Mn 0.001-0.10 H 0.003-0.3 Cr 0.001-0.10 Ti rest

and an article made therefrom (RF Patent No. 2308497).

Cases are made of the prototype alloy (including those made of sheets), rings, spacers and guide vanes of the gas turbine compressor for a long time operating at temperatures up to 450 ° C and for a short time up to 500 ° C.

The disadvantage of the alloy is the low level of strength characteristics in the range of operating temperatures, a sharp decrease in strength characteristics at temperatures above 500 ° C, which limits the use of the alloy. The alloy is used in the annealed state, while heat treatment is not hardened. Semi-finished alloy products have anisotropy in structure and mechanical properties due to the low annealing temperature.

The technical task of the invention is the creation of an alloy based on titanium having high strength characteristics at temperatures up to 600 ° C with an increased level of manufacturability during hot deformation.

The stated technical problem is achieved by the fact that the proposed alloy based on titanium containing aluminum, molybdenum, zirconium, vanadium, iron, characterized in that it additionally contains tin, niobium, silicon, oxygen, carbon in the following ratio of components, wt.%:

Al 5.0-6.6 Mo 1.5-2.5 Zr 1.0-2.8 V 0.4-1.4 Fe 0.08-0.40 Si 0.08-0.28 Sn 1,5-3,8 Nb 0.4-1.2 O 0.02-0.18 C 0.008-0.080 Ti rest

and an article made from it.

The proposed alloy can be used for the manufacture of bodies and rotor parts of a high-pressure compressor of gas turbine engines, as well as parts of power plants, including turbine blades.

The additional introduction of niobium, tin and silicon can improve the strength characteristics of the alloy in the range of operating temperatures at the declared content of other components.

The increase in the minimum total content of beta stabilizer elements (molybdenum, vanadium, iron), the additional introduction of niobium in the proposed alloy allows to improve the processability, including during hot deformation, of the alloy by increasing the amount of stable beta phase. Moreover, the alloy additionally contains interstitial elements (alpha stabilizers) - oxygen and carbon, which increase the polymorphic transformation temperature and compensate for the decrease in the aluminum content to increase the degree of solid solution hardening and expand the temperature range of deformation in the two-phase region. The above features of the chemical composition of the alloy provide an extension of the temperature range of intense hot deformation by 60 ° C. In the proposed alloy, the deformation temperature is in the range from 1000 ° C to 840 ° C, which is 160 ° C. For the prototype alloy, this range corresponds to temperatures of 980 ° C-880 ° C, which is 100 ° C. The presence in the proposed alloy of silicon allows you to combine both solid solution and dispersion hardening mechanisms, and also provides the opportunity to further increase the strength characteristics of the alloy and products made from it by varying the processing conditions.

The increase in the technological temperature range contributes to an increase in the degree of recrystallization of the alpha phase during heat treatment, which makes it possible to increase the degree of homogeneity of the structure and mechanical properties in the product, which leads to a reduction in the cost of manufacturing deformed semi-finished products and parts from them, including the method of sheet metal stamping with an increased level of strength characteristics at temperatures up to 600 ° C.

Examples of implementation

The proposed alloy in the form of ingots was smelted by a double vacuum-arc remelting method. Then the ingots were subjected to multi-transition forging. The resulting product (deformed semi-finished product - precision stamping with a cross section thickness of 25 mm, a sheet with a thickness of 1.2 mm) was thermally processed by the annealing mode and hardening heat treatment (quenching in water or oil, followed by aging and cooling in air).

The compositions of the proposed alloy (No. 1-3) and alloy prototype No. 4 are given in table. 1. The mechanical properties of the proposed alloy and prototype alloy are given in table. 2 (stamping), in table. 3 (sheets). As can be seen from the table. 2 and 3, the proposed alloy has a working temperature increased by 50-100 ° C, the strength level is 10.5-15.5% in the annealed state while maintaining high ductility (relative elongation, narrowing). The alloy allows you to further increase the level of strength characteristics in the range of operating temperatures by at least 20% compared with the prototype alloy.

The use of the proposed alloy based on titanium and products made of it, including aircraft compressor components for gas turbine engines - housings, rings, spacers, vanes, etc., as well as turbine parts of power engineering, such as turbine vanes, will increase the operating temperature to 600 ° C, reduce the cost of products by increasing the level of manufacturability during hot deformation will increase the service life.

Table 1 No. p / p Al Mo Zr V Fe Si Sn Nb O C Cu Ni Mn H Cr W Ti one 5,0 1,5 1,0 0.4 0.08 0.08 1,5 0.4 0.02 0.008 - - - - - - rest 2 5.8 2.0 1.9 1,0 0.24 0.18 2.7 0.8 0.12 0,035 - - - - - - “-“ 3 6.6 2,5 2,8 1.4 0.40 0.28 3.8 1,2 0.18 0,080 - - - - - - “-“ Prototype 6.7 1,5 2.2 1.8 0.2 - - - - - 0.05 0.01 0.05 0.15 0.05 0.05 “-“

table 2 No. p / p Type of heat treatment Strength at 20 ° C, MPa Elongation at 20 ° C,% Relative narrowing at 20 ° C,% Strength at 500 ° C, MPa Strength at 550 ° C, MPa Strength at 600 ° C, MPa one annealing 1055 25.5 41.0 700 665 580 hardening and aging 1145 14.5 22.5 785 755 650 2 annealing 1125 16.5 29.5 725 690 635 hardening and aging 1215 7.4 15,5 810 765 660 3 annealing 1210 8.8 18.5 785 760 675 hardening and aging 1360 6.7 15,5 850 790 705 four Prototype annealing 955 14.5 31.5 635 590 515

Table number 3 No. p / p Type of heat treatment Strength at 20 ° C, MPa Elongation at 20 ° C,% Strength at 500 ° C, MPa Strength at 550 ° C, MPa Strength at 600 ° C, MPa one annealing 1105 16.5 725 645 545 hardening and aging 1195 12.5 790 760 600 2 annealing 1125 14.5 755 695 575 hardening and aging 1205 10.5 830 785 615 3 annealing 1275 12.0 795 780 590 hardening and aging 1330 6.5 865 825 630 four Prototype annealing 995 11.5 645 595 470

Claims (2)

1. An alloy based on titanium containing aluminum, molybdenum, zirconium, vanadium, iron, characterized in that it additionally contains tin, niobium, silicon, oxygen, carbon in the following ratio, wt.%:
Al 5.0-6.6 Mo 1.5-2.5 Zr 1.0-2.8 V 0.4-1.4 Fe 0.08-0.40 Si 0.08-0.28 Sn 1,5-3,8 Nb 0.4-1.2 O 0.02-0.18 C 0.008-0.080 Ti rest 2. The product is made of an alloy based on titanium, characterized in that it is made of an alloy according to claim 1.