Alloy close to beta-titanium for applications requiring high strength, and its manufacturing methods

FIELD: metallurgy.

SUBSTANCE: high-strength pseudo-beta titanium alloy contains the following, wt %: aluminium 5.3-5.7, vanadium 4.8-5.2, iron 0.7-0.9, molybdenum 4.6-5.3, chrome 2.0-2.5, oxygen 0.12-0.16, and titanium and impurities are the rest, and when necessary, one or more additional elements chosen from N, C, Nb, Sn, Zr, Ni, Co, Cu and Si; with that, each additional element is present in the amount of less than 0.1%, and total content of additional elements is less than 0.5 wt %. At production of alloy, after it is obtained, homogenisation is performed at the temperature below temperature of beta-conversion and its disperse strengthening. An aviation system component represents a landing gear or a fastening part, which is made using titanium alloy.

EFFECT: alloy has high strength,ductility and ability for deep hardening.

25 cl, 4 dwg, 3 tbl, 3 ex

 

Cross-reference to related applications

This application is claims priority claim US 61/182,619, filed may 29, 2009 and claims UK 0911684.9 filed July 06, 2009, which is in its entirety incorporated by reference as if fully set forth in the present description.

The technical field to which the invention relates.

This disclosure generally relates to high-strength titanium alloys and methods of its manufacture. Alloy mainly used in applications requiring a combination of high strength, the ability for deep hardening and excellent ductility.

Prior art

Traditionally, various titanium and steel alloys are used for the production of aircraft components. The use of titanium alloys is advantageous because it results in lighter components than are made from steel alloys.

An example of such a titanium alloy disclosed in US 7,332,043 ("patent' 043") (Tetyukhin and others), which describes the use of alloy Ti-555-3, consisting of 5% aluminum, 5% molybdenum, 5% vanadium, 3% chromium and 0.4% of iron in aeronautical engineering. However, the alloy Ti-555-3 does not provide the desired high strength, the capacity for deep hardening and excellent flexibility required for critical applications in the aviation industry (for example, the mechanisms of the landing). In addition, 043 patent does not disclose the use of oxygen in the alloy Ti-555-3, an important element in the composition of titanium alloys. The percentage of oxygen is often purposefully regulate to provide a significant impact on strength properties.

Another example is presented in US 2008/0011395 (hereinafter "the application' 395"), which describes titanium alloy that includes aluminum, molybdenum, vanadium, chromium, and iron. However, the ranges of the weight percentage of alloying elements presented in the publication, overly broad. For example, the alloys Ti-5Al-4.5V-2Mo-1Cr-0.6Fe (VT23) and Ti-5Al-5Mo-5V-1Cr-1Fe (VT22) easily fall within the specified ranges of weight percentages. These alloys have become public until 1976. In addition, the preferred weight percent ranges specified in the application 395 lead to unacceptable combinations of strength and ductility. Therefore, in alloys not achieved the required high strength, the capacity for deep hardening and excellent flexibility required for critical applications in the aviation industry, such as the mechanism for landing.

In this regard, there is a need in the alloy with improved strength, the ability to deep hardening and excellent ductility, the relevant requirements of the important applications in the aviation industry. Critical properties for tacos what about the product are high tensile strength (for example, the tensile strength ("TYS") and ultimate tensile strength ("UTS"), modulus of elasticity, elongation at break and the drawing ratio ("RA"). In addition, there is a need for improved methods of production and processing of this alloy to further improve its characteristics.

The invention

In accordance with the above-described problems, existing needs and goals, revealed high strength alloy is close to beta titanium. In one implementation of the titanium alloy includes, in wt.%: 5.3 to 5.7% aluminum, 4,8-5,2% vanadium, 0.7 to 0.9% iron, 4.6 to 5.3% molybdenum, 2.0 to 2.5% of chromium and 0.12 to 0.16% oxygen, the rest being titanium and inevitable impurities.

In another implementation, the ratio of beta isomorphous βISO) to beta eutectoid βEUT) stabilizers titanium alloy is 1,2-1,73, or more specifically 1,22-1,73, and the ratio of beta isomorphic to beta eutectoid stabilizers are defined as:

βISOβEUT=Mo+V1,5Cr0,65+Fe0,35

In the equations provided in this the m description Mo, V, Cr and Fe are respectively the weight percent of molybdenum, vanadium, chromium and iron in titanium alloy. In one implementation, the value of beta is isomorphic 7,80-8,77 and in particular about the implementation of 8.33. In another implementation, the value of beta eutectoid is 5,08-6.42 per and in particular about the implementation of 5.82. In a separate exercise ratio beta isomorphic to beta eutectoid the stabilizer is about 1.4 or more specifically, 1,43.

In another implementation of the equivalence of molybdenum (Moeq) titanium alloy is 12.8-15,2, and the equivalence of molybdenum is defined as:

Moeq=Mo+V1,5+Cr0,65+Fe0,35

In a separate implementation of the equivalence of molybdenum is about 14.2. In another implementation of the equivalence of titanium aluminum alloy (Aleq) is 8.5 to 10.0, and the equivalence of aluminum is defined as:

Aleq=Al+O

In this equation, Al and O are the weight percent of aluminum and oxygen, respectively, in the titanium alloy. The individual is the first implementation of the equivalence of aluminum is about 9.3. In another implementation, the temperature of transformation of beta phase titanium alloy (Tβ) is about 1557-1627°F (about 847-886°C), and the temperature of transformation to beta phase in °F is defined as:

Tβ=1594+39,3Al+330O+S+1020N-21,8V-32,5Fe-17,3Mo-70Si-27,3Cr.

In this equation, N and Si represent wt.%. carbon, nitrogen and silicon, respectively, in the titanium alloy. In a separate exercise, the temperature of transformation of the beta phase is about 1590°F (about 865°C). In a separate implementation of the wt.%. aluminum is about 5.5%, % wt. vanadium is about 5.0%, % wt. iron is about 0.8%, % wt. molybdenum is approximately 5.0%, % wt. chromium is about 2.3% and/or % wt. oxygen is approximately 0.14%.

According to one implementation, the alloy can achieve excellent tensile strength. As an example, the alloy can achieve tensile strength ("TYS"), at least 170 Kropotov per square inch (ksi) and ultimate tensile strength ("UTS"), at least 180 ksi, a modulus of elasticity of at least 16.0 megafestov per square inch (Msi), an elongation at break of at least 10%, and/or and the drawing ratio ("RA"), at least 25%.

According to another implementation of the alloy can achieve excellent fatigue resistance. For example, the alloy can reach fatigue lifetime, Melsheimer, 200000 cycles, when tested in smooth fatigue specimen with axial load in accordance with ASTM E606 with variable deformation +0,6% and-0.6%.

According to the implementation of the composition of the alloy containing iron of 0.7-0.9 wt.%, reaches the desired high strength, the ability for deep hardening and excellent ductility required for critical applications in aircraft components, such as a mechanism for planting. This result is particularly unexpected, given the known prior art, which tells you about the benefits of using lower amounts of iron. For example, "patent '043 ' reveal that the use of iron concentrations below 0.5% wt. it is necessary to achieve a higher level of strength for large-size parts.

In accordance with another implementation of the invention proposed component of the aviation system, including high strength close to the beta form titanium alloy described in the invention. In a separate exercise component of the aviation system includes a mechanism for landing.

In accordance with another implementation of the invention, a method for manufacturing a titanium alloy for use in applications requiring high strength, the ability for deep hardening and excellent ductility. The method includes the original receipt is isotopolog close to the beta form of titanium alloy, comprising in wt.%, 5.3 to 5.7% aluminum, 4,8-5,2% vanadium, 0.7 to 0.9% iron, 4.6 to 5.3% molybdenum, 2.0 to 2.5% of chromium and 0.12-0.16% of oxygen, titanium and inevitable impurities else, performing the homogenization of titanium alloy at temperatures below the temperature of transformation of beta phase (for example, temperature of phase transformation and dispersion hardening a titanium alloy.

In some implementations, the method of manufacture also includes a vacuum arc remelting of the alloy and/or hot forging and rolling of titanium alloy below the temperature of transformation to beta phase. In a separate implementation of the open method of production of high strength, with the ability to deep hardening and excellent ductility of the alloy used for the manufacture of components of aircraft systems and more specifically for the manufacture of the mechanism for landing.

The accompanying figures, which are incorporated into and constitute part of this disclosure, illustrate a specific implementation of the disclosed subject matter of the invention and serve as an explanation of its principles.

Brief description of drawings

Figure 1 is a flowchart illustrating a method in accordance with the typical implementation disclosed in the present invention.

Figure 2 is microphotonics typical titanium alloy obtained according to the implementation of the present invention.

Figure 3 is the fast schedule, comparing the limit of tensile strength and elongation typical titanium alloys manufactured in accordance with implementations of the present invention, these characteristics of conventional titanium alloys.

Figure 4 is another graph comparing the tensile strength and elongation typical titanium alloys manufactured in accordance with implementations of the present invention, with the values obtained for conventional titanium alloys.

In all figures the same alphanumeric designation, unless otherwise indicated, used to denote like features, elements, components or parts illustrated accomplishments. In addition, although the subject invention will now be described in detail with reference to the figures, this disclosure is made in connection with an illustrative implementation.

The implementation of the invention

Disclosed high-strength titanium alloy with a capacity for deep hardening and excellent ductility. This alloy is ideal for use in the aviation industry or in other suitable applications where high strength, capacity for deep hardening and excellent ductility.

Also disclosed are methods of making the above-mentioned titanium alloy, which is suitable for use in about the svojstva aircraft components or any other suitable applications. Titanium alloy according to various implementations, disclosed in the invention, particularly well suited for the manufacture of machinery for planting, but there may be other suitable applications, such as fasteners and other aircraft components.

In one implementation of the proposed titanium alloy. A typical alloy includes, in wt.%, 5.3 to 5.7% aluminum, 4.8-5.2% vanadium, 0.7 to 0.9% iron, 4.6 to 5.3% molybdenum, 2.0 to 2.5% of chromium and 0.12 to 0.16% oxygen, the rest being titanium and inevitable impurities.

Aluminium as alloying element in titanium is alpha stabilizer, which increases the temperature at which a stable alpha phase. In one implementation of the alloy is present 5,3-5,7% wt. aluminum, In a separate exercise is about 5.5 wt.%. aluminum. If the aluminum content exceeds the upper limits disclosed in this description may appear excessive alpha stabilization and increased tendency to embrittlement due to the formation of Ti3Al. On the other hand, the presence of aluminum below the limits disclosed in this description, may adversely affect the kinetics of excretion of alpha phase during aging.

Vanadium as alloying element in titanium beta is isomorphic to the stabilizer, which lowers the temperature of transformation to beta phase. In one implementation of the alloy is present 4,8-5,2% wt. vanadium. In a separate assests the Institute is present in about 5.0 wt%, vanadium. If the vanadium content exceeds the upper limits disclosed in this description may be excessive beta stabilization, and will not reach the optimum of hardenability. On the other hand, the presence of vanadium lower limits disclosed in this description may lead to lack of beta stability.

Iron as alloying element in titanium is a eutectoid beta stabilizer, which lowers the temperature of transformation of the beta phase, and iron is a hardening element in titanium at ambient temperatures. In one implementation of the alloy is 0.7 to 0.9 wt.%. iron. In a separate exercise is about 0.8% wt. iron. As indicated above, when using an iron content of 0.7-0.9 wt.%, can be achieved the required high strength, the capacity for deep hardening and excellent ductility, for example, in critical applications in aircraft components, such as a mechanism for planting. If, however, the iron content exceeds the upper limits disclosed in this description, during solidification of the ingot may be unnecessary segregation solution that will adversely affect mechanical properties. On the other hand, the use of iron content below the limits disclosed in this description may give the alloy, which does not reach the required high strength, JV is the ability to deep hardening and excellent ductility. This is shown, for example, on the properties of the alloy Ti-555-3 described in patent '043, and also test, performed in the examples described below.

Molybdenum as alloying element in titanium is isomorphic beta stabilizer, which lowers the temperature of transformation to beta phase. In one implementation of the alloy is present 4,6-5,3% wt. molybdenum. In a separate implementation is present in about 5.0 wt.%. molybdenum. If the molybdenum content exceeds the upper limits disclosed in this description may be excessive beta stabilization, and will not reach the optimum of hardenability. On the other hand, the presence of molybdenum below the limits disclosed in this description may lead to lack of beta stability.

Chromium is the eutectoid beta stabilizer, which reduces the temperature beta phase transformation in titanium. In one implementation of the alloy is 2.0 to 2.5% wt. chromium. In a separate exercise is about 2.3 wt.%. chromium. If the chromium content exceeds the upper limits disclosed in this description, may decrease the ductility due to the presence of eutectoid compounds. On the other hand, the chromium content below the limits disclosed in this description may lead to reduced hardenability.

Oxygen, as alloying element in titanium, is alpha stabilizer, and oxygen is the I effective hardening element in titanium alloys at ambient temperature. In one implementation of the alloy is present 0,12-0,16% wt. the oxygen. In a separate exercise is about 0.14 wt.%. the oxygen. If the oxygen content is too low, maybe too low strength, temperature beta phase transformation and the cost of the alloy can be increased, because for melting alloy will not go waste. On the other hand, if the oxygen content is too high, service life and resistance to damage can be degraded.

In accordance with some implementations of the present invention, the titanium alloy may also include impurities or other elements such as N, S, Nb, Sn, Zr, Ni, Co, Cu, Si, etc. to achieve the desired properties of the resulting alloy. In a separate implementation of these elements are present in a weight percent of less than 0.1% each, and the total content of these elements is less than 0.5% wt.

In accordance with another implementation of the invention the ratio of beta isomorphous βISO) to beta eutectoid βEUT) stabilizers titanium alloy is 1,2-1,73, or more specifically 1,22-1,73, and the ratio of beta isomorphic to beta eutectoid stabilizers defined by equation (I):

βISOβEUTmo> =Mo+V1,5Cr0,65+Fe0,35(1)

in the equations provided in this description, Mo, V, Cr and Fe are respectively the weight percent of molybdenum, vanadium, chromium and iron in titanium alloy. In one implementation, the value of beta is isomorphic 7,80-8,77 and in particular about the implementation of 8.33. In another implementation, the value of beta eutectoid is 5,08-6.42 per and in particular about the implementation of 5.82. In a separate exercise ratio beta isomorphic to beta eutectoid the stabilizer is about 1.4 or more specifically, 1,43.

The use of alloys with respect to beta isomorphic to beta eutectoid the stabilizer 1,2-1,73 is essential to achieve the required high strength, the ability for deep hardening and excellent ductility. If the ratio exceeds the upper limits disclosed in this description, the water will be reduced. On the other hand, when the ratio is below the limits disclosed in this description, will not be achieved the required high strength, the capacity for deep hardening and excellent ductility. This trademonster the Vano, for example, the properties of the alloys described in the application '395.

In accordance with another implementation of the equivalence of molybdenum (Moeq) titanium alloy is 12.8-15,2, and the equivalence of molybdenum defined in equation (2):

Moeq=Mo+V1,5+Cr0,65+Fe0,35.(2)

In a separate implementation of the equivalence of molybdenum is about 14.2. In another implementation of the equivalence of aluminum (Aleq) titanium alloy is 8.5 to 10.0, and the equivalence of aluminum determined by equation (3):

Aleq=Al+27OA(3)

In this equation, Al and O are the weight percent of aluminum and oxygen, respectively, in the alloy. In a separate implementation of the equivalence of aluminum is about 9.3. In another implementation, the temperature of transformation bet the phase titanium alloy (T β) is about 1557-1627°F (about 847-886°C), and the temperature of transformation to beta phase in °F defined by equation (4):

Tβ=1594+39,3Al+330O+1145C+1020N-21,8V-32,5Fe-17,3Mo-70Si-27,3Cr.(4)

In this equation, N and Si represent wt.%. carbon, nitrogen and silicon, respectively, in titanium alloy. In a separate exercise, the temperature of transformation of the beta phase is about 1590°F (about 865°C).

The alloy achieves excellent tensile property, such as tensile strength (TYS)of at least 170 ksi and ultimate tensile strength (UTS)of at least 180 ksi, a modulus of elasticity of at least 16,0 Msi, and elongation at break of at least 10%, and/or and drawing ratio ("RA"), at least 25%. Specific examples of tensile property achieved a typical alloys disclosed in this description, p is precisley in the examples presented next. The alloy also has excellent resistance to fatigue, capable of achieving, for example, the fatigue life of at least 200000 cycles, when tested in smooth fatigue specimen with axial load in accordance with ASTM E606 with variable deformation +0,6% and-0.6%.

In accordance with another implementation, a component of the aviation system, including the above-described high-strength titanium alloy is close to the beta form. In a separate implementation titanium alloy, presented in the description, is used for the manufacture of the mechanism for planting. However, other suitable applications of titanium alloy include, but are not limited to, fasteners and other aircraft components.

In accordance with another implementation, a method of manufacturing a titanium alloy for use in applications requiring high strength, the ability for deep hardening and excellent ductility. The method includes obtaining a high-strength close to the beta form of titanium alloy consisting essentially of, in wt.%, 5.3 to 5.7% aluminum, 4,8-5,2% vanadium, 0.7 to 0.9% iron, 4.6 to 5.3% molybdenum, 2.0 to 2.5% of chromium and 0.12-0.16% of oxygen, titanium and inevitable impurities else, performing the homogenization of titanium alloy at temperatures below the temperature of transformation of beta phase (e.g., below t is mperature conversion of beta phase), and execution of the dispersion hardening of titanium alloy. Used titanium alloy can have all the above in the application properties.

In some implementations, the method of manufacture also includes a vacuum arc remelting of the alloy and/or hot forging and rolling of titanium alloy below the temperature of transformation to beta phase. In a separate implementation of the open method of production of high strength, with the ability to deep hardening and excellent ductility of the alloy used for the manufacture of components of aircraft systems and more specifically for the manufacture of the mechanism for landing.

Figure 1, which presents the purpose of illustration, and not limitation, is a block diagram representing a typical method of manufacturing titanium alloys. At the stage 100 prepare the required amount of raw materials. Raw materials may include, for example, primary raw materials, including titanium sponge and any of the alloying elements disclosed in this description. Alternatively, the feedstock can include a return into circulation titanium alloys, such as machining chips or solid parts made of titanium alloys of the respective composition. Primary and returned in the turnover of raw materials can be mixed in any combination of the prior art.

After preparation of raw materials to the stage 100 is melted at the stage 110 for polycriamide. The melting may be performed by such methods as vacuum arc remelting, electron beam melting, plasma arc melting, melting consumable electrode under the slag or any combinations thereof. In a separate implementation of the final melting stage 110 hold vacuum arc remelting. Then the ingot is subjected to hot forging and rolling on the stage 120. Hot stamping and rolling perform below the temperature of transformation of beta phase (beta transition). This is followed by a homogenization of the ingot at the stage 130, which is in a separate exercise performed at a temperature below the transition temperature. Homogenization in this exercise performed at a temperature lower by at least about 65°F temperature conversion of beta phase. Finally, samples bullion dispersion strengthen at the stage 140.

In some implementations stage hot stamping and rolling (120), homogenization (130) and dispersion hardening (140) is adjusted to obtain a microstructure consisting of fine alpha particles. Additional details of a typical method of manufacturing titanium alloys are described in the following examples.

Examples

Vacuum arc remelting (VAR) is used for the manufacture of ingot in accordance with implementations, disclosed in this description, as well as for ingots normal titans the x alloys, Ti-10-2-3 Ti-555-3 for comparison. The diameter of each strand is about eight inches and the weight of the ingot about 60 pounds. The chemical composition of the alloys in the weight percentages given in table 1 below:

Table 1
Chemical composition (% wt.) alloy sample
AlloyThe type of alloyAlVFeMoCrONNiMOeq
Ti-10-2-3Ti-10V-2Fe-3Al2,97to 10.091,7990,010,0130,1440,0090,00911,9
Ti-555-3Ti-5Al-5V-5Mo-3Cr5,494,94,3724,882,950,142 0,0050,00813,8
The alloy of example No. 1Ti-5.5Al-5V-0.8Fe-2.3Cr-0.1405,34,770,7324,792,270,1280,0050,00813,6

The final hot forging and rolling ingots perform below the temperature of transformation of beta phase (beta transition). Then the samples bullion homogenized at a temperature below the transition temperature. Finally spend dispersion strengthening samples bullion. The test results presented in table 2 below:

As shown in table 2, two of the ingot is manufactured according to the examples of methods # 1 and # 2, show higher performance than conventional alloys, including higher strength than conventional bars. Optical microphotonic representing the microstructure typical of Ti alloys of examples obtained according to implementations, disclosed in the following description, given in figure 2. Microphotonic shows a large number of primary particles of the alpha phase, which are essentially equiaxial with dimensions of about 0.5-5 Mick is metrov. μm) in diameter. The primary alpha particle phase are seen mostly as white particles dispersed in the dispersion hardened matrix (i.e., a dark background). Certain alloy Ti, shown in figure 2, homogenized at 1500°F for 1 hour and then chilled air to room temperature. This is followed by dispersion strengthening in T for 8 hours and then cooled to room temperature at ambient conditions.

Figure 3 is a graph comparing the tensile strength of the tensile and elongation titanium alloys manufactured in accordance with implementations of the present invention, with similar characteristics Ti alloys of the prior art. Data presented in figure 3 show that most of the titanium alloys of example, manufactured according to the methods # 1 and # 2 examples, higher strength (for example, TYS and UTS) and plasticity (e.g., elongation) compared with conventional titanium alloys. This is due to a unique combination of content elements in the weight percents disclosed in this description. The graph presented on figure 4, is similar to figure 3, but with additional data representing Ti alloys of the prior art (for example, alloys Ti-10-2-3 Ti-555-3). In figure 4 the data obtained for Ti alloys of examples of this image is etenia, marked as Ti18.

The ingot with a diameter of 32 inches (12 Kropotov) are preparing a triple vacuum arc remelting (TVAR) in accordance with typical implementations, disclosed in this description, and the homogeneity of the composition is determined by the length of the ingot. The composition of the ingot is determined in five places along the strand, including the top, middle top, middle, middle, lower part and the bottom, and the results are presented in table 3 below:

Table 3
The homogeneity of the standard ingot
Element (% wt.) or propertyTopMid topThe middleThe middle bottomBottomAverage
Al5,56the 5.655,55the ceiling of 5.605,50to 5.57
C0,0120,0140,0120,0120,011 0,012
Cr2,302,352,332,362,382,34
Fe0,7110,7220,7310,7490,7870,740
Mo5,125,175,075,084,945,08
N0,0070,0060,0060,0060,0050,006
Ni0,00350,00350,00350,00360,00390,004
O0,1460,1480,1460,1480,1420,146
to 0.0320,0310,0300,0300,0330,031
Sn0,0100,0150,0140,0150,0130,013
V5,035,105,035,095,03of 5.06
The sum of the rest [S, N, Ni, Si, Sn]0,061of 0.0660,0620,0630,0620,063
Tβthat calculation. (°F)159515961593159315861593
Tβthat calculation. (C)868869867867863867
MOeq14,014,214,114,214,214,2
βISOof 8.478,578,428,488,308,45
βEUT5,56of 5.685,675,775,915,72
βISOEUT1,521,511,481,471,401,48
Aleq9,59,69,59,69,39,5

The results presented in table 3, show excellent uniformity along the entire length of the ingot, with deviations from the average content of less than or equal to about 2.8% for all defined elements is impressive. The values of βISOEUTMoeq, Aleqand Tβprovided in table 3, calculated using equations 1-4, respectively. The values of βISOand βEUTcalculated using the expressions presented in the numerator and denominator of equation 1, respectively.

For clarity in the description of implementations of the present invention, the following terms are defined as follows:

The tensile strength: Conventional tensile stress at which a material shows a certain limit deviation (0.2 percent) from proportionality of stress and strain.

Tensile strength tensile: conditional Maximum tensile stress that a material can withstand is calculated from the maximum load during testing of tensile stress to rupture and the original cross-sectional sample.

Modulus of elasticity: When tested for tensile strength, the ratio of stress to corresponding strain below the limit of elastic deformation.

Elongation: test tensile strength, increase the working length of the sample (expressed in percent of the initial sample length) after the break.

The drawing ratio: test tensile strength, reduction of the cross-section tie rod sample (expressed as a percentage of IP is one of the cross-section) after the break.

Fatigue resource: Number of cycles a given deformation or strain, which is resistant to the sample before the appearance of detectable cracks.

ASTM E606: standard method of fatigue testing of controlled deformation.

Alpha stabilizer: an element that, when dissolved in titanium, causes an increase in the temperature of transformation to beta phase.

Beta stabilizer: an element that, when dissolved in titanium, causes a decrease in the temperature of transformation to beta phase.

Temperature conversion of beta phase: the lowest temperature at which the titanium alloy ends allotropic transformation of the crystal structure of α+β in β.

Eutectoid connection: intermetallic compound of titanium and a transition metal, which is formed by decomposition rich in titanium β phase.

Isomorphous beta stabilizer: Element stabilizing the β phase, in which the phase relations of such β titanium and which does not form intermetallic compounds with titanium.

Eutectoid beta stabilizer: Element stabilizing the β phase can form intermetallic compounds with titanium.

Other embodiment of the invention will be obvious to a person skilled in the art upon consideration of the description and the implementation of the invention disclosed in the description. The description and examples should RA is considered only as illustrative, with the scope and essence of the invention presented in the annexed claims.

Experts in the art should understand that the present invention is not limited to that specifically shown and described in the description. The amount of the claims of the present invention is defined in accordance with the attached claims. In addition, it should be understood that the above description is only illustrative examples of accomplishments. For the convenience of the reader, the above description is focused on representative examples of possible implementations, examples, which disclose the principles of the present invention. Other implementation may be the result of different combinations of the various parts of the implementation.

The description does not attempt to exhaustively enumerate all possible modifications. Should not be construed as a waiver of rights to additional implement such additional implementation, which cannot be represented as a specific part of the invention, and may be the result of various combinations of the described parts, or when other undescribed additional implementation can be partially available. It should be understood that many of those undescribed realizations fully included in the scope of the claims appended claims, and the others who may be equivalent. In addition, all references, publications, US the US patents and applications cited in the present description, is included by reference as if they were fully set forth in the present description.

All percentages are weight percent (% wt.) and in the description and in the claims.

1. High strength pseudo-beta titanium alloy comprising, by wt.%: 5,3-5,7 aluminum, 4,8-5,2 vanadium, 0.7 to 0.9 iron, 4.6 to 5.3 molybdenum, 2.0 to 2.5 chromium, 0.12 to 0.16 oxygen, the remainder ti and impurities, optionally, one or more additional elements selected from N, S, Nb, Sn, Zr, Ni, Co, Cu and Si, and each additional element is present in an amount of less than 0.1%, and the total content of the additional elements is less than 0.5 wt.%.

2. Titanium alloy according to claim 1, with the ratio of beta isomorphic to beta eutectoid stabilizers about 1.4, and the ratio of beta isomorphic to beta eutectoid stabilizers are defined as:
βISOβEUT=Mo+V1,5Cr0,65+Fe0,35.

3. Titanium alloy of claim 1, wherein the wt.% aluminum is about 5.5.

4. Titanium alloy according to claim 2, in which the wt.% aluminum is about 5.5.

5. Titanium alloy according to any one of claims 1 to 4, in which the wt.% vanadium is about 5.0.

6. Titanium alloy according to any one of claims 1 to 4, in which the wt.% iron is about 0.8.

7. Titanium alloy according to claim 5, in which the wt.% iron is about 0.8.

8. Titanium alloy according to any one of claims 1 to 4 or 7, in which the molybdenum is about 5.0 wt.%.

9. Titanium alloy according to claim 5, in which the molybdenum is about 5.0 wt.%.

10. Titanium alloy according to claim 6, in which the molybdenum is about 5.0 wt.%.

11. Titanium alloy according to any one of claims 1 to 4, 7, 9, or 10, in which chromium is about 2.3 wt.%.

12. Titanium alloy according to claim 5, in which chromium is about 2.3 wt.%.

13. Titanium alloy according to claim 6, in which chromium is about 2.3 wt.%.

14. Titanium alloy of claim 8, in which chromium is about 2.3 wt.%.

15. Titanium alloy according to any one of claims 1 to 4, 7, 9, 10, 12-14 in which the oxygen is about 0.14 wt.%.

16. Titanium alloy according to claim 5, in which the oxygen is about 0.14 wt.%.

17. Titanium alloy according to claim 6, in which the oxygen is about 0.14 wt.%.

18. Titanium alloy of claim 8 in which the oxygen is approximately 0.14% of the mass.

19. Titanium alloy according to claim 11, in which the oxygen is about 0.14 wt.%.

20. Component of the aviation system, which is the chassis or mounting on the hoist, manufactured using alloy according to any one of claims 1 to 19.

21. A method of manufacturing a high-strength pseudo-beta titanium alloy, including:
obtaining alloy according to any one of claims 1 to 19,
the homogenization of the titanium alloy at a temperature below the beta transformations and
dispersion strengthening titanium alloy.

22. The method according to item 21, in which the alloy receive the vacuum-arc remelting.

23. The method according to item 21 or 22, which additionally comprises hot pressing and rolling the titanium alloy is lower than the temperature of the beta transformation.

24. A method of manufacturing a component of the aviation system, which is a chassis or fastener, comprising forming a high-strength pseudo-beta titanium alloy manufactured by the method according to any of PP-23.

25. The use of high-strength pseudo-beta titanium alloy according to any one of claims 1 to 19 for manufacturing a component of the aviation system, which is a chassis or fastener.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: method of processing the titanium alloy consisting of, at least, the following components, in wt %: iron - 0.2-0.5, oxygen - 0.02-0.12, silicon - 0.15-0.6, titanium and unavoidable impurities making the rest, comprises executing the first thermal treatment at first temperature to form the structure containing 50% of beta-phase, and, then, cold rolling. Second thermal treatment at second temperature is executed to produce second-phase precipitation while third thermal treatment is performed at third temperature for alloy recrystallisation without dissolution of precipitation.

EFFECT: high-strength titanium alloy with high resistance to oxidation and pliability at low temperatures.

18 cl, 6 dwg

FIELD: metallurgy.

SUBSTANCE: proposed method comprises hot forming of slab, hot rolling and teat treatment of plate, whereat hot forming if carried out in one step. Immediately after reaching required thickness in slab forming it is quickly cooled to the depth of 20-30 mm at the rate of at least 50°C/min. Subsequent hot lengthwise rolling at performed at first step in α+β-area by partial reduction with deformation degree εi varying from 3% to 5% to total deformation ε=25…30% with breaks between passes of 8 to 12 s. At second step, it is performed in β-area from heating temperature determined by definite formula. At the next step rolling is performed in α+β-are with breaks and heating in lengthwise or transverse directions with total degree of deformation e after every break to 60%.

EFFECT: homogeneous fine-grain microstructure, high and stable mechanical properties, high precision, no surface defects.

FIELD: metallurgy.

SUBSTANCE: soaking is done at heating temperature for 10-15 minutes, and cooling is done in a coolant with speed of 300°C/s, afterwards ageing is done under load at 18-25°C, stress not exceeding yield point at ageing temperature, and time required to achieve stable speed of relaxation process.

EFFECT: increased strength of titanium of BT1-0 grade in combination and higher plasticity during treatment of items from titanium BT1-0, including heating, is carried out to temperature exceeding temperature of polymorphous transformation.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to nanostructured materials with ultra-fine grain structure, and namely two-phase alpha-beta titanium alloys which can be used for manufacture of semi-finished products and products in different branches of engineering, machine-building industry and medicine. Proposed alloy has microstructure consisting of ultra-fine grains of alpha-phase and beta-phase with the size of less than 0.5 mcm. In alloy microstructure the amount of grains with grain shape coefficient of not more than 2 is not less than 90%; at that, more than 40% of grains have wide-angle borders, and average density of dislocation is not more than 1014 m-2. the method for obtaining ultra-fine grain two-phase alpha-beta titanium alloy involves heat treatment with heating of a billet at the temperature of not more than 0.6 T"пп", further multicycle intense plastic deformation with achievement of accumulated true deformation degree e≥4. Then, plastic deformation is performed so that the billet shape is changed at the rate of less than 10-1 s-1 in several cycles to provide deformation degree ε≥50%.

EFFECT: improving strength and fatigue properties and preserving high ductility.

5 cl, 2 dwg, 1 tbl, 1 ex

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy and may be used at making rods with heads from titanium alloys. Billets are subjected to thermal treatment to perform hot heading. After heading thread is cut and head fillet is hardened. Thread is cut in two steps. First, preliminary incomplete knurling is performed after tempering of billets with deformation. Said deformation is defined by percentage between formed tooth thread depth to required depth to make 85-98%. Then workpiece is age-hardened to perform final thread cutting.

EFFECT: high strength bolts from titanium alloys with flaw-free thread, lower production costs.

3 cl, 1 tbl, 6 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to production of thin sheets from ingot of pseudo-alpha titanium alloy. Proposed method comprises forming ingot of alloy Ti-6.5Al-2.5Sn-4Zr-1Nb-0.7Mo-0.15Si into slab and machining of the latter. Then, said slab is heated to temperature exceeding that of polymorphic transition, deformation and multistep rolling to semi-finished rolled stock with regulated total degree of deformation and degree of deformation in a pass. Sheets are stacked, stacks are rolled to finished size and subjected to multipass rolling with regulated total deformation, sheets are extracted from the stack and subjected to finishing.

EFFECT: high and uniform strength and plastic properties.

1 dwg, 2 tbl

FIELD: metallurgy.

SUBSTANCE: sheet is made from pure titanium and contains titanium and unavoidable impurities. It features yield point of 215 MPa or higher, mead size d of the grain making 25 mcm of larger and 75 mcm or smaller, and hexagonal crystalline structure. Appropriate grains in hexagonal crystalline structure feature means Schmidt factors (SF) of twins 11-22 with rolling direction oriented along their axes. Means Schmidt factor (SF) and grain means size d satisfy the following relationship: 0.055≤[SF/√d]≤0.084. Heat exchanger plate comprises sheet of pure titanium and as integral component.

EFFECT: high ductility and strength, heat exchange plate with such sheet.

2 cl, 6 dwg, 3 tbl

FIELD: metallurgy.

SUBSTANCE: method to produce a blank of a blade of gas turbine engines (GTE) with ultra-fine grain structure from titanium alloys includes preliminary heating of the blank to temperature below temperature of polymorphous conversion and treatment by means of multiple intensive plastic deformation with changing of deformation directions in several cycles. Treatment is carried out under isothermic conditions at identical temperature of the blank and the punch. In each cycle deformation is carried out at temperature of alloy annealing according to stages, which include setting of the cylindrical blank in the closed punch, open setting with production of the blank in the form of a disc, flattening to the disc rib in the closed punch for production of the blank with the square section, its setting in the closed punch to the cylindrical blank. Number of treatment cycles is determined based on achievement of the extent of accumulated deformation of at least five. Then closed setting of the blank is carried out at the temperature of 50-100°C below the alloy annealing temperature, squeezing into the cylindrical blank, having two different diameters of cross section for a blade foot and airfoil, and flat stamping of the blade blank.

EFFECT: homogeneous ultra-fine grain structure is produced in a blade blank, providing for high physical and mechanical and operating properties of a blade.

2 dwg

FIELD: metallurgy.

SUBSTANCE: thermomechanical device includes a working member made in the form of one pre-deformed element or several pre-deformed and parallel and/or in-series connected elements from alloy based on titanium with shape memory effect. The working member is made in the form of a rod with working part of cylindrical or rectangular shape and fixing parts in the form of expansions on the rod ends, the sectional area of which is at least by five times more than the sectional area of its working part.

EFFECT: achieving maximum possible translational relative movements of the member at variation of its temperature at the temperature interval of reverse martensitic transformation of material.

6 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises smelting of alloy, making slab, machining its surface, hot, warm, and cold rolling, sintering and ageing. Smelted is pseudo-beta-titanium alloy with aluminium content not higher than 5.0 wt % and molybdenum equivalent No eq. ≥ 12 wt %, calculated by the following formula: Mo eq. wt % = %Mo + %Ta/4 + %Nb/3.3 + %W/2 + %V/1.4 + %Cr/0.6 + +%Fe/0.5 + %Ni/0.8 + %Mn/0.6 + %Co/0.9. Semi-finished 8-2 mm-thick rolled stock produced in hot and cold rolling is subjected, prior to cold rolling, to quenching at Tpt+(20-50°C) for 0.1-0.5 h with cooling. Cold rolling is performed to sheet thickness of 6-1 mm in signal-phase beta-state in two and more steps in several passes with 1-6%-reduction in one pass and total reduction at every step of 30-50%. Note here that intermediate quenching is carried out between said steps in conditions identical to quenching of semi-finished rolled stock before cold rolling.

EFFECT: high-quality rolled thin sheets.

5 dwg, 2 tbl

FIELD: metallurgy.

SUBSTANCE: proposed composite comprises matrix of pure titanium ≤250 nm age-hardened by thermally and chemically stable nano-sized particles of titanium carbide, boride or nitride with particle size of 2-10 nm. Hardening particles are uniformly distributed in composite volume while their fraction therein makes 0.05-0.50 wt %. Composite is obtained by mechanical alloying of pure titanium with particle size of 40-200 mcm in ball triple-action mill in atmosphere of protective gas and after-hot isostatic pressing.

EFFECT: higher strength due to higher yield point, extension limit, fatigue strength and biological compatibility.

13 cl, 1 dwg, 3 tbl, 3 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to nanostructured materials with ultra-fine grain structure, and namely two-phase alpha-beta titanium alloys which can be used for manufacture of semi-finished products and products in different branches of engineering, machine-building industry and medicine. Proposed alloy has microstructure consisting of ultra-fine grains of alpha-phase and beta-phase with the size of less than 0.5 mcm. In alloy microstructure the amount of grains with grain shape coefficient of not more than 2 is not less than 90%; at that, more than 40% of grains have wide-angle borders, and average density of dislocation is not more than 1014 m-2. the method for obtaining ultra-fine grain two-phase alpha-beta titanium alloy involves heat treatment with heating of a billet at the temperature of not more than 0.6 T"пп", further multicycle intense plastic deformation with achievement of accumulated true deformation degree e≥4. Then, plastic deformation is performed so that the billet shape is changed at the rate of less than 10-1 s-1 in several cycles to provide deformation degree ε≥50%.

EFFECT: improving strength and fatigue properties and preserving high ductility.

5 cl, 2 dwg, 1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: method involves the following stages: formation of a basic consumable electrode by melting with the help of at least one stage of vacuum arc melting of common primary γ-TiAl-alloy containing titanium and/or at least one β-stabilising element in the amount that is not enough in comparison to the obtained basic β-γ-TiAl-alloy, arrangement on the above basic consumable electrode of titanium and/or p-stabilising element in the amount corresponding to the above insufficient amount of titanium and/or β-stabilising element, with uniform distribution as to length and periphery of the basic consumable electrode, addition to the basic consumable electrode of the above arranged amount of titanium and/or β-stabilising element so that homogeneous basic β-γ-TiAl-alloy is obtained at final stage of vacuum arc melting process.

EFFECT: invention allows creating homogeneous basic β-γ-TiAl-alloy without formation of any cracks.

10 cl, 5 ex, 4 dwg

FIELD: metallurgy.

SUBSTANCE: sheet is made from pure titanium and contains titanium and unavoidable impurities. It features yield point of 215 MPa or higher, mead size d of the grain making 25 mcm of larger and 75 mcm or smaller, and hexagonal crystalline structure. Appropriate grains in hexagonal crystalline structure feature means Schmidt factors (SF) of twins 11-22 with rolling direction oriented along their axes. Means Schmidt factor (SF) and grain means size d satisfy the following relationship: 0.055≤[SF/√d]≤0.084. Heat exchanger plate comprises sheet of pure titanium and as integral component.

EFFECT: high ductility and strength, heat exchange plate with such sheet.

2 cl, 6 dwg, 3 tbl

FIELD: metallurgy.

SUBSTANCE: thermomechanical device includes a working member made in the form of one pre-deformed element or several pre-deformed and parallel and/or in-series connected elements from alloy based on titanium with shape memory effect. The working member is made in the form of a rod with working part of cylindrical or rectangular shape and fixing parts in the form of expansions on the rod ends, the sectional area of which is at least by five times more than the sectional area of its working part.

EFFECT: achieving maximum possible translational relative movements of the member at variation of its temperature at the temperature interval of reverse martensitic transformation of material.

6 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: alloy based on titanium with shape memory effect for bone implants and method for its treatment are proposed. Alloy contains the following, wt %: Ti 71.0-74.0, Nb 19.0-23.0, Ta and/or Zr 4.0-9.0. At room temperature the alloy has nano-sized structure consisting of cubic metastable β-phase, orthorhombic α"-martensite, hexagonal ω-phase and hexagonal α'-martensite, and alloy elasticity modulus does not exceed 25 GPa. Alloy treatment method involves hot pressure shaping of an alloy ingot based on titanium at initial temperature of 900-950°C and final temperature of 700-750°C, thermomechanical treatment by multi-pass cold deformation with total degree of reduction of 31 to 99%, annealing after deformation at the temperature of 500-600°C and final quenching in water. Then, mechanical pseudoelastic cycling of the obtained workpiece is performed under conditions of single-axis tension till 2% of deformation is achieved during 50-100 cycles and removal of load.

EFFECT: alloy has long-term service life of bone implants due to low elasticity modulus close as to the value to bone tissue and pseudoelasticity effect.

5 cl, 1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention may be used in structures operated at up to 650°C, for example, parts of gas turbine engine high-pressure compressor housing and blades Proposed titanium-based alloy comprises the following components in wt %: Al - 5.7-6.7, Sn - 3.0-4.5, Zr - 3.0-4.5, Mo - 0.5-1.4, Nb - 0.2-0.6, W - 0.01-0.3, V - 0.3-0.9, Fe - 0.01-0.07, Si - 0.3-0.52, C - 0.03-0.10, O - 0.03-0.14, Ti making the rest. Note here that (V+Nb)≤1.1 wt %. Proposed alloy features higher strength at temperatures exceed 600°C.

EFFECT: higher operating temperatures of parts.

2 tbl, 5 ex

FIELD: metallurgy.

SUBSTANCE: proposed alloy comprises the following elements, in wt %: carbon - 0.03-0.07, iron - 0.15-0.25, silicon - 0.05-0.10, nitrogen - 0.010-0.030, aluminium - 0.05-0.50, boron - 1.5-3.5, titanium and impurities making the rest.

EFFECT: higher efficiency of absorption, better working properties.

3 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: proposed alloy contains the following components, wt %: aluminium 0.3÷0.7, zirconium 7.0÷15.0, niobium 1.0÷2.0, oxygen 0.2÷0.3, carbon 0.05÷0.15, silicon 0.10÷0.35, iron 0.1÷0.6, hafnium of not more than 1.0, titanium is the rest; at that, sum of iron and aluminium is not more than 1.0 wt %.

EFFECT: creation of alloy with optimum ratio of alloying elements, which has high mechanical properties, including the value of elasticity modulus and having no adverse effect on a living organism.

1 tbl

FIELD: metallurgy.

SUBSTANCE: beta-titanium alloy with ultrafine-grained structure consists of beta-phase gains with mean size not exceeding 0.5 mcm, precipitations of secondary alpha-phase particles of spherical shape and mean size not exceeding 0.5 mcm and volume fraction in the structure making at least 40%. Proposed method comprises intensive plastic deformation and thermal treatment. Thermal treatment is carried out before deformation by heating to temperature exceeding that of polymorphic conversion by 5-15°C for, at least, one minute for 1 mm of diameter cross-section and quenching in water. Intensive plastic deformation is performed by equal-channel angular pressing with changing deformation direction through 90 degrees after every deformation cycle at (T"пп"-200…T"пп"-150)°C with total accumulated deformation e≥3.5 and subsequent quenching in water.

EFFECT: higher strength and fatigue characteristics of alloys.

2 cl, 1 tbl, 1 ex

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering, particularly, to reduction of aerodynamic noise produced by aircraft undercarriage in takeoff and landing. Aircraft undercarriage extended in landing and/or takeoff comprises two end covers and buckle. Two end covers are designed to close every end of undercarriage hollow axle, say, articulated axle of undercarriage two links. Crossbar can enter said hollow axle to connected end covers so that they are retained thrusted against ends of this axle.

EFFECT: reduced noise at takeoff an landing.

9 cl, 1 dwg

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