WO2013012352A1

WO2013012352A1 - Ultrafine-grained aluminium alloys for electrical products and method for producing same (variants)

Info

Publication number: WO2013012352A1
Application number: PCT/RU2012/000005
Authority: WO
Inventors: Руслан Зуфарович ВАЛИЕВ; Максим Юрьевич МУРАШКИН; Елена Владимировна БОБРУК
Priority date: 2011-07-15
Filing date: 2012-01-13
Publication date: 2013-01-24
Also published as: RU2478136C2; RU2011129486A

Abstract

The invention relates to the production of aluminium alloys and is used for electrical products. In order to increase mechanical strength and electrical conductivity in Al-Mg-Si system aluminium alloys, two types of ultrafine-grained structures are formed with a grain size of from 400 to 1000 nm using methods that include water quenching at a temperature of 520-565°С and severe plastic deformation with a total true cumulative deformation of e≥8 and a deformation temperature not greater than 200°С according to a first variant and e≥4 and a temperature not greater than 300°С according to a second variant, according to which artificial aging is carried out after deformation. The alloys have a structure in which not less than 60% of the grains have high-angle boundaries which are disordered relative to adjacent grains by angles of 10 degrees or more, and an aluminium matrix that is depleted in the main alloying elements Mg and Si and contains nanosized precipitates of the strengthening phase Mg₂Si of the β variety equally distributed in the volume of the grains, or of the β variety situated in the boundary region of the grains, and the needle-shaped β", β' variety situated in the central region of the grains.

Description

Ultrafine-grained aluminum alloys for electrical products and methods for their production (options)

The invention relates to the field of UFG aluminum alloys with increased mechanical strength and conductivity, intended for the manufacture of billets for electrical purposes, for example, wire rod of round and square cross section, wire, wire for overhead power lines, conductive tires and profiles, as well as a method for processing said alloys.

It is known that in electrical engineering, the use of technically pure aluminum, which has the highest electrical conductivity among aluminum materials, is limited due to its low strength [IB Peshkov. Status and prospects of the use of aluminum in the cable industry // Cables and wires (2009) Nel. 314. C.7-9.]. An increase in the strength characteristics of aluminum is achieved through the introduction of certain alloying additives, such as, for example, magnesium (Mg) and silicon (Si), i.e. creation of alloys of the Al-Mg-Si system. Due to good processability and high corrosion resistance, Al-Mg-Si alloys are widely used as materials for electrical products [Aluminum and aluminum alloys in electrical products / L.A. Vorontsova, V.V. Maslov, I.B. Peshkov Publ. "Energy", Moscow 1971- 224 s; M.B. Altman, Yu.P. Arbuzov, B. I. Babichev et al. Aluminum alloys. The use of aluminum alloys. Help Guide. M.: Metallurgy, 1972-408]. Studies of the optimal content of Mg and Si, with the aim of increasing the mechanical properties, as well as minimizing the electrical conductivity, showed that the best combination of mechanical and electrical characteristics is demonstrated by alloys having a Mg and Si ratio corresponding to Mg ₂ Si. It was found that Mg and Si in aluminum form the hardening phase of Mg ₂ Si, and the solubility of this compound with increasing temperature allows us to apply thermal and thermomechanical treatment to such alloys.

Several methods are known for processing aluminum alloys of the Al-Mg-Si system, which make it possible to increase their mechanical strength and electrical conductivity due to the formation of special structures. For example, in [L. A. Vorontsova, V.V. Maslov, I.B. Peshkov Aluminum and aluminum alloys in electrical products. "Energy" 1971 - 224 s] describes a method of heat treatment (TH) of billets of aluminum alloys Al-Mg-Si, which consistently includes: quenching from 520 ... 550 ° C in water and artificial aging at 150 ... 160 ° With, within 12 ... 10 hours.

In the invention [US 3770151 148/1 1.5 MPKS22P / 04, published November 6, 1973] a method for thermomechanical processing (TMP) of an aluminum alloy Al-Mg-Si is described, including in series: quenching from a temperature of 621 ° C into water and cold rolling to a degree of deformation of 99.6%.

There is a method of TMT blanks from aluminum alloys Al-Mg-Si [M.B. Altman, Yu.P. Arbuzov, B. I. Babichev and other Aluminum alloys. The use of aluminum alloys. Reference guide. M.: Metallurgy, 1972 - 408 s], including successively: quenching from 525. ..565 ° С into water, drawing during natural aging with a degree of deformation of more than 85%, artificial aging at a temperature of 140 ... 180 ° С within 2 ... 12 hours. This method, as the closest, is selected as a prototype for the claimed technical solution.

After the implementation of the indicated TMT method, the alloy structure is characterized by large elongated, mainly non-crystallized grains with a transverse size of more than 50 microns. The grains contain a developed cellular dislocation structure and nanoscale precipitates in the form of needles of reinforcing particles of Mg ₂ Si metastable modification β "and β '. The content of Mg and Si in the aluminum matrix is at least 0.2 and 0.3 am. %, respectively.

A drawback of the structure of aluminum alloys formed by the known TMT method is that it contains predominantly small-angle dislocation boundaries, and it contains nanosized particles of Mg ₂ Si phases of only metastable modification. Such a structural state and the method for its preparation do not provide sufficient strength and do not allow to achieve electrical conductivity in aluminum alloys close to that of technically pure aluminum. For example, if a wire made of electrotechnical aluminum of the AE grade (99.5A1) shows a level of temporary resistance (σ _Β ) of 100 ... .150 MPa with a specific electrical resistance (p) of 0.0283 Ohm * mm / m (about 61% IACS), then the wire made of an ABE grade Al-Mg-Si alloy, obtained by the known TMT method, has 280 ... 300 MPa, at which the p value is only 0.0325 ... 0.0335 Ohm * mm / m (53. .. 51.5% IACS) [GOST 839-80 Uninsulated wires for overhead power lines; M.B. Altman, Yu.P. Arbuzov, B. I. Babichev and others. Aluminum alloys. The use of aluminum alloys. Reference guide. M .: Metallurgy, 1972 - 408s].

The technical result of the invention is to increase the mechanical strength and electrical conductivity of aluminum alloys of the Al-Mg-Si system by creating an ultrafine-grained (UFG) structure in them obtained by the proposed processing methods.

The indicated technical result is achieved by an aluminum alloy of the Al-Mg-Si system, with an UFG structure, which is characterized by an average grain size of not more than 400 nm. No less than 60% of the grains have large-angle boundaries misoriented relative to neighboring grains by angles of 10 degrees or more. The aluminum matrix of the UFG alloy is significantly depleted in the main alloying elements Mg and Si, the content of which does not exceed contains 0.06 and 0.09 am%, respectively, and contains nanoscale precipitates of particles of the strengthening phase Mg ₂ Si of a stable modification (β) of globular shape uniformly distributed in the grain volume.

The indicated technical result is also achieved by an aluminum alloy of the Al-Mg-Si system, with an UFG structure, which is characterized by an average grain size in the range from 400 to 1000 nm. At least 60% of the grains have large-angle boundaries misoriented with respect to neighboring grains by angles of 10 degrees or more. The aluminum matrix of the UFG alloy is significantly depleted in the main alloying elements Mg and Si, the content of which does not exceed 0.08 and 0.10 at.%, Respectively, and contains nanoscale precipitates of particles of the reinforcing phase Mg ₂ Si of a stable modification (β) of a globular shape located in the boundary region of grains and metastable modification (β ", β ') in the form of needles located in the central region of grains.

The technical result is also achieved by the method of producing an aluminum alloy with an UFG structure with a grain size of not more than 400 nm, including quenching from a temperature of 520 ... 565 ° C in water and plastic deformation, in which, unlike the prototype, plastic The deformation is carried out with the true accumulated deformation e> 8 at a temperature not exceeding 200 ° С by the method of intensive plastic deformation (IPD).

The technical result is also achieved by the method of producing an aluminum alloy for electrical products with UFG structure with a grain size in the range from 400 to 1000 nm, including quenching from a temperature of 520 ... 565 ° C in water and plastic deformation, in which unlike the prototype, plastic deformation is carried out with a true accumulated deformation e> 4 at a temperature of no higher than 300 ° C using the IPD method and artificial aging at a temperature of 10 ... 180 ° C for 0.5 ... 24 hours. According to the invention, the SPD is carried out by torsion (IPDK), equal channel angular pressing (ECAP), equal channel angular pressing in parallel channels (ECAP-PC) and equal channel angular pressing according to the Conform (ECAP-K) scheme.

According to the invention, after the IPD, drawing is carried out.

According to the invention, after SPD rolling is carried out.

According to the invention, after drawing or rolling, artificial aging is carried out at a temperature of 10 ... 180 ° C for 0.5 ... 24 hours.

The proposed UMP structures and methods for their preparation provide a higher level of mechanical strength and electrical conductivity of aluminum alloys of the Al-Mg-Si system used in electrical products.

The specified technical result is achieved due to the following.

It is known that the formation of the UFG structure, which contains mainly bolyno-angular boundaries, makes it possible to achieve unusually high strength in metallic materials [R.Z. Valiev, I.V. Aleksandrov. Bulk nanostructured metallic materials. - M.: IKC "Akademkniga", 2007 - 308 s]. It is also known that for the formation of UMP structures use such treatment as IPDK, ECAP, ECAP-PK and ECAP-K. In this case, the true accumulated deformation should reach a value of e> 4. Simultaneously with the formation of the UFG structure during SPD in alloys of the Al-Mg-Si system, a significant decrease in the concentration of alloying elements in the aluminum matrix occurs due to the development of deformation dynamic aging (DDS) , which is accompanied by the release of nanosized particles of hardening phases. The process of depletion of the aluminum matrix by the main alloying elements in the IPD process is much more intensive than in the implementation of traditional methods of TO and TMT [Y. Estrin, M. Murashkin and RZ Valiev Ultra-fme aluminum alloys: processes, structural features and properties pp. 468-503 in Fundamentals of aluminum metallurgy. Production, processing and applications. Ed. by Roger Lumley, Woodhead Publishing limited, 201 1, p. 843].

It is known that an increase in the strength of aluminum alloys subjected to SPD is caused, firstly, by a small average grain size (<1000 nm) and mainly by higher-angle grain boundaries, which ensures an increase in flow stress during plastic deformation, according to the Hall – Petch ratio [Hall E.O. // Proc. Phys. Soc. London 1951. V. 64B. 381. P.747-753; Fetch N.J. // J. Iron Steel Inst. 1953. V.174. 1. P.25-28; RZ Valiev, IV Aleksandrov Volume nanostructured metal materials: production, structure and properties. M .: Academic book, 2007-398 p]. Secondly, the regulated release in the UFG structure of the hardening nanoscale particles of phases stable (β) and, in particular, metastable modification (β ", β '), also provides the hardening effect from the implementation of the dispersion hardening mechanism [I. Fridlyander Aluminum deformable structural alloys. M: Metallurgy, 1979-208].

Simultaneously with hardening, the regulated release of nanosized particles leads to the depletion of the UFG of the aluminum matrix by the main alloying elements (Mg and Si), which ensures an increase in the electrical conductivity of alloys, since it is the alloying elements that are responsible for electron scattering [B. Livshits, Kraposhin BC, Lipetskiy Ya. L. Physical properties of metals and alloys. M.: Metallurgy, 1973-31 1 s; Aluminum and aluminum alloys in electrical products / L. A. Vorontsova, V. V. Maslov, I. B. Peshkov Publ. "Energy", Moscow 1971 - 224 s].

In general, the formation of the UFG structures described above in aluminum alloys of the Al-Mg-Si system in the proposed combination of features of the invention leads to a simultaneous increase in their mechanical strength and electrical conductivity. Structural changes of aluminum alloys are implemented by the proposed processing methods, subject to the indicated conditions for their implementation.

The invention is illustrated by illustrations, where in FIG. 1 shows an UFG structure with a grain size of less than 400 nm (a is an electron microscopic photograph of the structure, b is a schematic representation of the structure); in FIG. 2 - UFG structure with a grain size of more than 400 nm (a is an electron microscopic photograph of a general view of the structure, b is an electron microscopic photograph of a grain, c is an electron microscopic photograph of a fragment of the central region of the grain, d is a schematic image of the structure).

In FIG. Figure 1a shows that the structure consists of grains (1) with a size of less than 400 nm, and contains nanoscale precipitates of particles of the strengthening phase Mg ₂ Si (2) of stable modification (β), which have a globular shape and are uniformly distributed in the volume of grains.

In FIG. 2a, the structure consists of grains (3) with sizes greater than 400 nm, and in FIG. 2b it can be seen that in the boundary region of the grain there are precipitates of particles of the strengthening phase Mg ₂ Si (2) of stable modification (β), which have a globular shape. It is also seen that inside the grain (Fig. 2b) is located region (4), shown in enlarged view in Fig. 2c, containing nanoscale precipitates of particles of the hardening phase of the metastable modification (β ', β ") in the form of a needle (5).

The invention is implemented as follows:

To form an UFG structure with an average grain size of no more than 400 nm, the initial billet of an Al – Mg – Si alloy with a standard chemical composition is used. At the first stage, the billet is subjected to heat treatment-hardening, including heating the billet to a temperature of 520 ... 565 ° C, exposure under these temperature conditions is continued up to 2 hours and subsequent cooling in water at room temperature.

At the second stage, the hardened billet is subjected to SPD processing at a temperature not exceeding 200 ° C, with a true accumulated deformation of e> 8. This treatment can be carried out with SPDK or ECAP or ECAP-PK or ECAP-K. At this stage, the microstructure is crushed in the bulk of the workpiece without changing its size. Due to the evolution of the structure during the SPD process under specified conditions, an UFG structure with an average grain size of not more than 400 nm is formed in aluminum alloys. At least 60% of the grains have large-angle boundaries misoriented with respect to neighboring grains by angles of 10 degrees or more. Simultaneously with the formation of the UFG structure during the SPD, DDS occurs in the aluminum matrix, as a result of which nanodimensional precipitates of particles of the hardening β phase (Mg ₂ Si) of stable modification are formed in it, having a globular shape uniformly located in the grain volume. The separation of β phase particles leads to a significant depletion of the aluminum matrix by the main alloying components (Mg and Si), which ensures an increase in the electrical conductivity of the material.

To form an UFG structure with a grain size in the range from 400 to 1000 nm, an initial billet of an alloy of the Al-Mg-Si system with a standard chemical composition is used. At the first stage, the billet is subjected to heat treatment — quenching, which includes heating the billet to a temperature of 520 ... 565 ° C, holding it under given temperature conditions for up to 2 hours and then cooling it in room temperature water.

At the second stage, the hardened billet is subjected to SPD processing at a temperature not exceeding 300 ° C, with a true accumulated deformation of e> 4. This treatment can be carried out using the IPDK or ECAP or ECAP-PK or ECAP-K method. After processing the SDI with true accumulated by the formation e = 1 in the alloy preform, the initial structure is transformed into a subgrain one with a clearly defined orientation with respect to the shear plane. The transverse size of the formed subgrains is 600 nm, and the longitudinal size is 1200 nm, respectively. The resulting structural state is characterized by a high density of lattice dislocations.

As a result of processing the SPD with the true accumulated deformation e = 2-3 in the subgrains, fragmentation develops due to the formation of transverse subboundaries in them. Along with fragmentation, separate sections are formed in the alloy (the volume fraction of which in the structure is ~ 30%) of equiaxed grains with an average size of 500 nm. Achieving during the IPD e> 4 leads to the formation in the alloy billet of a uniform UFG structure with a grain size in the range from 400 to 1000 nm.

Thus, as a result of the evolution of the structure during the SPD, an UFG structure is formed in an aluminum alloy with a grain size in the range of 400 ... 1000 nm, of which more than 60% of the grains have large-angle boundaries, misoriented relative to neighboring grains by angles of 10 degrees or more . Simultaneously with the formation of the UFG structure during the SPD according to the proposed method, DDS passes in the aluminum matrix, as a result of which nanoscale precipitates of particles of the strengthening phase (Mg ₂ Si) of a stable modification (β) of globular shape are formed. After completion of the SPD, the formed β phase particles are predominantly located in regions adjacent to the grain boundaries.

At the third stage of the UFG, the billet is subjected to artificial aging at a temperature of 10 ... 180 ° C with a holding time of 0.5 ... 24 hours. Artificial aging according to the indicated regime leads to further evolution of the structure obtained after SPD, which consists in the formation in the central region of grains of nanoscale precipitates of particles of strengthening phases of Mg ₂ Si metastable modification (β ', β "), having the shape of a needle, which ensures additional increase in material strength. The depletion of the aluminum matrix by the main alloying elements (Mg and Si) at the second stage of processing — during the DDS, and at the third stage of processing — during artificial aging, ensures an increase in the electrical conductivity of the material.

To obtain UFG billets in the form of a wire rod, wire or profile after SPD, additional plastic deformation is carried out by drawing or rolling.

Examples of specific implementations of the invention:

JVsl example

A hot pressed rod of alloy 6060 of the Al – Mg – Si system with a standard chemical composition with a diameter of 20 mm was used as the initial billet. From this rod, a billet in the form of a disk with a diameter of 20 mm and a thickness of 1.5 mm was made by machining. This preparation was subjected to heat treatment — quenching, which included heating to a temperature of 540 ° C, holding at a given temperature for 1 hour, and subsequent cooling to room temperature in water. The time interval between the heat treatment operation and the IPD was no more than 1 hour.

After quenching, the workpiece was subjected to IPDK at a temperature of 180 ° C, at an applied pressure of 6 GPa, with a true accumulated deformation of e = 10. Then the workpiece was removed from the tool / tool, cooled in air to room temperature.

Samples for studying the microstructure, mechanical properties, and electrical conductivity were made from the obtained preform.

The microstructure was analyzed by transmission electron microscopy (TEM) using a Jeol 2100 EX microscope.

Using X-ray diffraction analysis (XRD) on a Rigaku diffractometer, and spatial atomic tomography on a company installation Sates analyzed the change in concentration in the aluminum matrix of the main alloying elements.

Mechanical testing of the samples was carried out in accordance with the requirements of GOST 1497-84.

The obtained UFG structure in the alloy preform (Fig. 1 a), which was formed during the implementation of the proposed processing method, has an average grain size (1) of 350 nm. Inside the grains, one can see precipitates of the globular form of the secondary hardening β phase (Mg ₂ Si) (2) with an average size of 30 nm, uniformly distributed in the aluminum matrix.

Table 1 presents the results of structural studies, mechanical tests and measurements of the electrical conductivity of the obtained samples. As a comparison, the results of studies of alloy samples subjected to the TMT method according to the prototype are given.

Table 1

Parameter Content

Alloying method σ _Β , δ, P, IACS

The type of structure of the crystal- MP% Ohm * *%

boots a mm /

aluminum grilles - m

(), howl matrix

A (am.%)

UMP structure

with grain size less than 400

According to the nm. Inside - 0.052Mg

Ren located 4.0498 ± 347 8 0.029 58.1 Nom 0.088Si

Allocations 0.0002 67 to the method of O.OOBS

globular

99.837A1

forms of the secondary hardening β phase

(Mg ₂ Si) stable modification uniformly distributed in aluminum

matrix

Elongated, non-recrystallized grains,

0.400Mg

TMW containing 4.051 1 ± 250 7 0.032 53.6 developed cell - 0.427Si

0.0002 15 empty structure 0.01 l Cu

with discharges 99.1 19A1

reinforcing

metastable phases β "and β '

(MfeSi)

* - the electrical conductivity of the material at a temperature of 20 ° C relative to the reference value of the electrical conductivity of annealed copper, which is taken as 100% according to IACS (International Annealed Copper Standart)

From table 1, it is seen that the content of alloying elements in the aluminum matrix after processing by the proposed method decreased by almost an order of magnitude. The achieved decrease in the concentration of alloying elements in the aluminum matrix in combination with the UFG structure made it possible to significantly increase the value of temporary resistance (σ _Β ), lower the specific electrical resistance (p) and, accordingly, increase the electrical conductivity of the 6060 aluminum alloy in comparison with the corresponding values, achieved in the material subjected to the standard method of TMT.

JV22 example

A hot-pressed rod of alloy ADZ 1 of the Al-Mg-Si system of standard chemical composition with a diameter of 12 mm and a length of 500 mm was used as the initial billet. . This billet was subjected to heat treatment — quenching, including heating to a temperature of 540 ° C, holding at a given temperature for 1 hour, and subsequent cooling to room temperature in water. The interval between the heat treatment operation and the IPD was no more than 1 hour. After hardening, the billet was subjected to ECAP-K processing to the true accumulated strain e – 4.8 under isothermal conditions at a temperature of 100 ° С. The angle of conjugation of the channels in the instrument was P O degrees. Then the workpiece was removed from the tool / tool, cooled in air to room temperature, and then subjected to drawing at room temperature with a total degree of deformation of 50%. As a result of such processing, a bar with a diameter of 6 mm and a length of more than 1 m was obtained. After drawing, the billet was subjected to heat treatment — artificial aging at a temperature of 130 ° C and a holding time of 12 hours.

Using X-ray diffraction analysis (XRD) on a Rigaku diffractometer and spatial atomic tomography on a Sates installation, an analysis was made of the change in concentration in the aluminum matrix of the main alloying elements.

Mechanical testing of the samples was carried out in accordance with the requirements of GOST 1497-84. The electrical resistivity of the samples was determined in accordance with GOST 7229-76 and GOST 12177-79.

The obtained UFG structure in the alloy preform (Fig. 2a), which was formed during the implementation of the proposed processing method, has an average grain size (3) of 600 nm. Inside the grain (Fig. 2b), there are visible precipitates of globular particles of the secondary reinforcing β phase (Mg ₂ Si) (2) of stable modification with an average size of 20 nm located in the border region, and precipitates of particles of the reinforcing phases (β ', β ") of metastable modification in the form of needles (5) (Fig. 2c) with a diameter of 2 nm and a length of up to 40 nm, located in the central region of grains (4) (Fig. 2b). Table 2 presents the results of structural studies, mechanical tests, and measurements of the electrical resistivity of the obtained samples. As a comparison, the results of studies of alloy samples subjected to the TMT method according to the prototype are given.

table 2

From table 2, it is seen that the content of alloying elements in the aluminum matrix after processing by the proposed method decreased by ty an order of magnitude. The decrease in the concentration of alloying elements achieved in the aluminum matrix in combination with the UFG structure achieved by the proposed method made it possible to significantly increase the value of the temporary resistance (<^ c), the conditional yield strength (σ ₀ .2), and lower the electrical resistivity (p) and, accordingly, to increase the electrical conductivity of the ADZ 1 aluminum alloy, in comparison with the corresponding values achieved in the material subjected to the TMT method.

Thus, the proposed invention allows the formation in the UFG aluminum alloys of a structure providing the material with enhanced mechanical strength and electrical conductivity.

Claims

Claim

1. An ultrafine-grained aluminum alloy of the Al-Mg-Si system, characterized by an average grain size of not more than 400 nm, in which not less than 60% of the grains have high-angle boundaries misoriented with respect to neighboring grains by angles of 10 degrees or more, moreover, the aluminum matrix contains alloying elements Mg and Si at a level that does not exceed 0.06 and 0.09 am. %, respectively, and nanoscale precipitates of particles of the hardening phase Mg ₂ Si of a stable modification (β) of globular shape uniformly distributed in the volume of grains.

2. An ultrafine-grained aluminum alloy of the Al-Mg-Si system, characterized by an average grain size in the range from 400 to 1000 nm, in which at least 60% of the grains have high-angle boundaries, misoriented from neighboring grains by angles of 10 degrees or more moreover, the aluminum alloy matrix contains alloying elements Mg and Si at a level that does not exceed 0.08 and 0.10 am. %, respectively, and nanoscale precipitates of particles of the hardening phase Mg ₂ Si of stable modification (β) of globular shape located in the boundary region of grains and metastable modification (β ", β ') in the shape of a needle located in the central region of grains .

3. A method of obtaining UFG of an aluminum alloy Al-Mg-Si with an average grain size of not more than 400 nm, including quenching from 520. ..565 ° C into water and plastic deformation, characterized in that the plastic deformation is carried out with true accumulated deformation e> 8 by the method of intense plastic deformation at a temperature of no higher than 200 ° C.

4. The method of obtaining UFG aluminum alloy Al-Mg-Si with an average grain size of 400 ... 1000 nm, including quenching from 520 ... 565 ° C in water, plastic deformation and artificial aging, characterized in that plastic deformation is carried out with a true accumulated deformation e> 4 by the method of intense plastic deformation at a temperature of no higher than 300 ° C and artificial aging at a temperature of 100 ... 180 ° C with a holding time of 0.5 ... 24 hours

5. The method according to any one of p. 3, 4, characterized in that the intense plastic deformation is carried out by torsion, or equal-channel angular pressing, or equal-channel angular pressing in parallel channels, or equal-channel angular pressing according to the conform form.

6. The method according to claim 5, characterized in that after intensive plastic deformation, drawing is carried out.

7. The method according to claim 5, characterized in that rolling is carried out after intensive plastic deformation.

8. The method according to claim 6, characterized in that after the drawing, the workpiece is artificially aged at a temperature of 10 ... 180 ° C with a holding time of 0.5 ... 12 hours.

9. The method according to claim 7, characterized in that after rolling, the workpiece is artificially aged at a temperature of 10 ... 180 ° C with a holding time of 0.5 ... 12 hours.