CN116497257B

CN116497257B - Light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility and preparation method thereof

Info

Publication number: CN116497257B
Application number: CN202310472768.8A
Authority: CN
Inventors: 李志明; 张炜; 严定舜; 甘科夫; 张勇
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2024-05-07
Anticipated expiration: 2043-04-27
Also published as: CN116497257A

Abstract

The invention discloses a light high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility and a preparation method thereof, wherein the alloy comprises, by atomic percentage, 22.0-38.0% of Nb, 26.0-36.0% of Ti, 23.0-32.0% of Zr, 5.0-10.0% of Al and 2.0-3.5% of Ta; the random state of the alloy is a BCC/B2 coherent structure, wherein the size of B2 is 0.5-2.5 nm. Compared with the existing multi-component refractory alloy, the light high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility, which is prepared by the invention, has lower mass density, higher room temperature tensile ductility and excellent high-temperature softening resistance, and has the potential of serving in high-temperature environments such as aerospace, national defense and military industry and the like.

Description

Light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility and preparation method thereof

Technical Field

The invention belongs to the technical field of metal material design and processing, and particularly relates to a light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility.

Background

The rapid development of high-precision fields such as aerospace, national defense, military industry, nuclear power and the like puts higher requirements on structural materials serving in high-temperature environments, such as aerospace aircrafts which are served in extreme conditions of ultrahigh temperature and high pressure, use temperatures of more than 1000 ℃, working temperatures of supersonic combustion ramjet engines of more than 2000 ℃ and the like. The service temperature of the existing single crystal nickel-based superalloy with the highest service temperature reaches the limit (1150 ℃), so that the service requirement of a higher temperature environment is difficult to meet, and a structural material capable of being used at a higher temperature is needed to be developed.

The new generation of high-performance structural materials are required to be light and have excellent toughness matching, and the traditional structural materials are often mainly made of one or two metals, so that the simultaneous matching of multiple excellent performances is difficult to achieve. As an innovative alloy design concept, the multi-component alloy breaks through the traditional alloy design category, and provides possibility for exploring ideal performance in a wide combination space. The multicomponent alloy tends to form FCC (face centered cubic) and BCC (body centered cubic) structural solid solution phases after component and process adjustment, but the multicomponent alloy of the FCC structure has better ductility and lower yield strength, while the multicomponent alloy of the BCC structure mainly comprises IV, V, IV subgroup elements Ti, cr, nb, mo, zr, hf, V, ta, W and the like has high yield strength at room temperature and high temperature due to the characteristics of the component elements, and has wide application value and research potential.

The multi-component alloy with the BCC structure has relatively fewer internal sliding systems and sliding directions, lower ductile-brittle transition temperature, larger lattice mismatch and higher stress fluctuation, so that the dislocation movement lattice resistance is higher, and the inherent brittleness is caused. Thus, it remains a challenge to design a multi-component refractory alloy that is lightweight, high strength, and ultra-high room temperature tensile ductility.

Disclosure of Invention

This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application.

The present invention has been made in view of the above and/or problems occurring in the prior art.

One of the objects of the present invention is to provide a lightweight high strength multi-component refractory alloy having ultra-high room temperature tensile ductility.

In order to solve the technical problems, the invention provides the following technical scheme: a light high-strength multi-component refractory alloy with ultrahigh room-temperature stretching ductility comprises,

The alloy comprises 22.0 to 38.0 percent of Nb, 26.0 to 36.0 percent of Ti, 23.0 to 32.0 percent of Zr23.0 to 10.0 percent of Al and 2.0 to 3.5 percent of Ta by atomic percentage;

Wherein the sum of the atomic percentages of Nb, ti and Zr is less than or equal to 93.0 percent and more than or equal to 87.5 percent; the sum of the atomic percentages of Al and Ta is less than or equal to 12.5 percent and more than or equal to 7.0 percent; the sum of the atomic percentages of the components is 100 percent;

The random state of the alloy is a BCC/B2 coherent structure, wherein the size of B2 is 0.5-2.5 nm.

As a preferable scheme of the light high-strength multi-component refractory alloy, the invention comprises the following steps: the alloy comprises 24.0-36.5% of Nb, 28.0-34.0% of Ti, 25.0-30.0% of Zr, 6.0-9.0% of Al and 2.5-3.0% of Ta by atomic percentage.

As a preferable scheme of the cast light high-strength multi-component refractory alloy, the invention comprises the following steps: the alloy has the following characteristics:

(a) The density of the alloy is 6.00-6.80 g/cm ³;

(b) The tensile yield strength of the multi-component refractory alloy at room temperature is 800-1100 MPa;

(c) The elongation percentage of the multi-component refractory alloy at room temperature is 6.5 to 35.0 percent.

Another object of the present invention is to provide a method for preparing a lightweight high strength multi-component refractory alloy having ultra-high room temperature tensile ductility, comprising,

The alloy is prepared by preparing the components according to the atomic percentage of the alloy, and smelting under the vacuum or inert gas protection condition.

As a preferable scheme of the preparation method of the light high-strength multi-component refractory alloy, the invention comprises the following steps: smelting under the vacuum condition, and maintaining the vacuum degree in the furnace at 1-0.0001 Pa; smelting under the protection of inert gas, charging inert gas and maintaining the gas pressure at 0.000001-0.05 MPa.

The invention also aims to provide a preparation method of the light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility, which comprises the steps of directly cold-rolling and annealing the as-cast light high-strength multi-component refractory alloy obtained by the preparation method to obtain the homogeneous alloy with compact structure.

As a preferable scheme of the preparation method of the light high-strength multi-component refractory alloy with the ultra-high room temperature tensile ductility, the invention comprises the following steps: the direct cold rolling is carried out, the multi-pass cold rolling is carried out, the single-pass rolling reduction is less than or equal to 25%, and the total rolling reduction is 40-100%.

As a preferable scheme of the preparation method of the light high-strength multi-component refractory alloy with the ultra-high room temperature tensile ductility, the invention comprises the following steps: and the annealing treatment is carried out under vacuum or inert gas atmosphere, the annealing temperature is 800-1200 ℃, the annealing time is 5-30 min, and then quenching is carried out immediately.

It is another object of the present invention to provide a lightweight high strength multi-component refractory alloy with ultra-high room temperature tensile ductility obtained by the above-described preparation method.

As a preferable scheme of the homogeneous light high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility, the invention comprises the following steps: the alloy has the following characteristics:

(a) The density of the alloy is 6.00-6.80 g/cm ³;

(b) The tensile yield strength of the multi-component refractory alloy at room temperature is 800-1200 MPa;

(c) The elongation percentage of the multi-component refractory alloy at room temperature is 15.0-50.0%.

Compared with the prior art, the invention has the following beneficial effects:

The light high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility prepared by the invention presents a BCC/B2 coherent structure, has tensile yield strength of 800-1200 MPa, and realizes tensile elongation of up to 6.5-50.0%; the density is 6.00-6.80 g/cm ³. Compared with the existing multi-component refractory alloy, the light high-strength multi-component refractory alloy has lower mass density and better toughness matching, and meanwhile, the light high-strength multi-component refractory alloy designed by the patent has excellent high-temperature softening resistance, has the potential of serving in high-temperature environments such as aerospace, national defense and military industry, and is simple in process flow and low in energy consumption and cost.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is a Scanning Electron Microscope (SEM) structure of an as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1.

FIG. 2 is an XRD pattern of the as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1.

FIG. 3 is a transmission electron microscope dark field image and selected area electron diffraction pattern of the as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1.

FIG. 4 is a graph of tensile engineering stress versus engineering strain for the as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1.

FIG. 5 is a Scanning Electron Microscope (SEM) structure chart of the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 2.

Fig. 6 shows a transmission electron diffraction pattern and a homogeneous transmission electron microscope dark field image embedded in a homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 2.

FIG. 7 is a graph of tensile engineering stress versus engineering strain for the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 2.

FIG. 8 is a Scanning Electron Microscope (SEM) structure chart of the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 3.

Fig. 9 is a tensile engineering stress-engineering strain curve of the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 3.

FIG. 10 is a Scanning Electron Microscope (SEM) structure chart of the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 4.

FIG. 11 is a graph of tensile engineering stress versus engineering strain for the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 4.

FIG. 12 is a Scanning Electron Microscope (SEM) structure chart of the Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy in homogeneous form of example 5.

Fig. 13 is a tensile engineering stress-engineering strain plot for the example 5 homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy.

Fig. 14 is an XRD pattern of the as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy obtained in example 6.

Fig. 15 is a tensile engineering stress-engineering strain plot of the as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy obtained in example 6.

FIG. 16 is a Scanning Electron Microscope (SEM) structure chart of a homogeneous Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy obtained in example 7.

FIG. 17 is a graph showing the tensile engineering stress-engineering strain curve of the homogeneous Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy obtained in example 7.

Fig. 18 is an XRD pattern of the as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy obtained in example 8.

Fig. 19 is a tensile engineering stress-engineering strain plot of the as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy obtained in example 8.

FIG. 20 is a Scanning Electron Microscope (SEM) structure chart of a homogeneous Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy obtained in example 9.

FIG. 21 is a graph of tensile engineering stress versus engineering strain for the homogeneous Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy obtained in example 9.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will become more apparent, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.

Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Unless otherwise indicated, all starting materials used in the examples were commercially available.

Example 1

The embodiment designs a multi-component refractory alloy with light weight, high strength and ultra-high room temperature tensile ductility, wherein the chemical formula is Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 (atomic percent), and the preparation steps are as follows:

(1) Pretreatment of raw materials: nb, zr and Ta particles with the purity of more than or equal to 99.90 weight percent and Ti and Al particles with the purity of 99.95 weight percent are put into a beaker of absolute ethyl alcohol to be ultrasonically cleaned for 20 minutes at room temperature so as to remove surface dirt and impurities, and finally are put into a drying box to be dried for standby.

(2) The raw materials are as follows: by converting the mole percentage and the mass percentage of the light high-strength multi-component refractory alloy, 38.752g, 17.473g, 35.071g, 2.812g and 5.912g of each metal raw material are respectively weighed according to Nb, ti, zr, al g of alloy as a basis.

(3) Smelting: sequentially placing the raw materials weighed in the step (2) into a water-cooled copper crucible of a vacuum arc furnace according to the melting point, paying attention to the fact that Al particles with low melting point are placed at the bottom, vacuumizing to 5X 10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; melting additional Ti ingots preset in a hearth for 2min before smelting to consume residual oxygen, nitrogen and the like in a smelting furnace, wherein the smelting current is 320A, and the smelting time is 90 seconds; and (3) starting to smelt the alloy ingot, repeatedly smelting for 6 times, controlling the smelting current to be 380A, and keeping the electric arc for 6 minutes each time and assisting an electromagnetic stirring technology, wherein the current frequency is 8Hz, so that the alloy is fully and uniformly mixed.

(4) Casting: placing the alloy which is uniformly smelted into a water-cooled copper mold with the thickness of 80 multiplied by 30 multiplied by 10mm in a vacuum arc furnace for remelting molding, and taking out a sample after the sample is cooled, wherein the specific operation is as follows: vacuumizing to 5×10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; melting additional Ti ingots preset in a hearth for 2min before smelting, wherein the smelting current is 320A, and the smelting time is 90 seconds; and starting to smelt the alloy ingot, repeatedly smelting for 4 times, controlling the smelting current to be 380A, and keeping the electric arc for 8 minutes each time. The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy is obtained.

The scanning electron microscope structure diagram of the obtained as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy is shown in figure 1, and it can be seen that the as-cast alloy is of a typical dendritic morphology.

Fig. 2 is an XRD pattern of the as-cast alloy obtained in example 1, and fig. 3 is a transmission electron microscope dark field image and a selected area electron diffraction pattern of the as-cast alloy obtained in example 1, and it can be seen that the alloy has a BCC/B2 coherent structure, in which B2 is uniformly dispersed in the alloy, and the size of B2 is 1.2±0.36nm.

The resulting as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy was tested for tensile properties and fig. 4 is a plot of tensile engineering stress versus engineering strain for the as-cast alloy of example 1, which can be seen to have a yield strength of 891MPa and a tensile elongation of 6.9% at room temperature.

The density measurement is carried out on the obtained as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, the measurement is carried out by an Archimedes drainage method, firstly, a 5 multiplied by 5mm block sample is uniformly cut off from the as-cast alloy sample, ultrasonic cleaning is carried out for 20 minutes at room temperature before the measurement, so as to remove surface dirt and impurities, and finally, the as-cast alloy sample is placed in a drying box for drying; weighing each sample dry weight M ₁, and weighing each sample 3 times to reduce measurement errors; weighing the mass M ₂ of each sample in water, and weighing each sample for 3 times; finally, the density calculation is performed according to the following formula:

Where ρ ₀ is the temperature of the water, 0.9982g/cm ³(20℃);ρ₁ is the air density, 0.0012g/cm ³. The average value obtained by three measurements was ρ= 6.498g/cm ³.

Example 2

The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1 was subjected to a cold rolling annealing treatment: cutting the cast alloy into a strip-shaped sample with the thickness of 9.5mm, wherein the rolling amount of a single pass is 10 percent, and the total rolling amount is 80 percent; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being subjected to heat preservation at 850 ℃ for 5min, so as to obtain the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy.

The homogeneous alloy was cut into 1.5X7.5X121 mm dog bone tensile specimens by wire cutting, polished on # 180, # 400, # 800, # 1200, # 2000, # 3000, # 5000 sandpaper, ultrasonically cleaned for 15min, dried and stretched at a strain rate of 1X 10 ^-3s^-1.

Experiments show that the light high-strength multi-component refractory alloy of the Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 in the embodiment 1 can be subjected to large deformation structure regulation and control in an as-cast state, the cold rolling deformation amount is up to 80% at room temperature, and then the uniform structure is obtained after heat preservation for 5min at 850 ℃.

FIG. 5 is a Scanning Electron Microscope (SEM) tissue map of the resulting homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy; it can be seen that after the cold rolling annealing treatment, the alloy structure is compact and the grain size distribution is uniform.

FIG. 6 shows a transmission electron diffraction pattern embedded in a bright field image of a homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy and a dark field image of a homogeneous transmission electron microscope; the alloy can be seen to be a BCC/B2 coherent structure, wherein B2 is uniformly dispersed and distributed in the alloy.

Fig. 7 is a drawing engineering stress-engineering strain plot of the resulting homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, which after a drawing anneal treatment, exhibited an ultra-high room temperature tensile elongation of 47.4% and a tensile yield strength of 1021 MPa.

Example 3

The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1 was subjected to a cold rolling annealing treatment: cutting the as-cast alloy into a strip-shaped sample with the thickness of 9mm, wherein the rolling amount of a single pass is 8%, and the total rolling amount is 60%; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being kept at 1000 ℃ for 15min, and the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy is obtained.

The test pieces were cut into dog bone-shaped tensile test pieces of 1.5X7.5X121 mm by wire cutting, polished on abrasive paper of 180#, 400#, 800#, 1200#, 2000#, 3000#, 5000# and ultrasonically cleaned for 20 minutes after polishing, and stretched at a strain rate of 1X 10 ^-3s^-1 after drying.

Fig. 8 is a scanning electron microscope structure diagram of the obtained homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, and it can be seen that the alloy structure is dense, the crystal grains are relatively large and the distribution is uniform after the cold rolling annealing treatment.

Fig. 9 is a drawing stress-engineering strain plot of the resulting homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, which after a drawing anneal treatment exhibited a tensile yield strength of 931MPa and a tensile elongation of 25.2%.

Example 4

The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1 was subjected to a cold rolling annealing treatment: cutting the as-cast alloy into a strip-shaped sample with the thickness of 10.0mm, wherein the rolling amount of a single pass is 10% and the total rolling amount is 90%; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being subjected to heat preservation at 800 ℃ for 5min, so as to obtain the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy.

The test pieces were cut into dog bone-shaped tensile test pieces of 1.0x7.5x21 mm by wire cutting, polished on abrasive paper of 180#, 400#, 800#, 1200#, 2000#, 3000#, 5000# and ultrasonically cleaned in a beaker for 20 minutes after polishing, and stretched at a strain rate of 1 x 10 ^-3s^-1 after drying.

FIG. 10 is a scanning electron microscope structure diagram of the obtained homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, and it can be seen that the alloy has a remarkable band structure and is elongated in the rolling direction after the cold rolling annealing treatment.

FIG. 11 is a graph of tensile engineering stress-engineering strain for the resulting homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, which after a tensile annealing treatment exhibited a tensile yield strength of 993MPa and a room temperature tensile elongation of 36.3%.

Example 5

The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1 was subjected to a cold rolling annealing treatment: cutting the as-cast alloy into a lath-shaped sample with the thickness of 11.0mm, wherein the rolling amount of a single pass is 10 percent, and the total rolling amount is 100 percent; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being subjected to heat preservation at 800 ℃ for 5min, so as to obtain the homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy.

The test pieces were cut into 0.8X7.5X121 mm dog bone tensile test pieces by wire cutting, polished on # 180, # 400, # 800, # 1200, # 2000, # 3000, # 5000 sandpaper, ultrasonically cleaned in a beaker for 20 minutes after polishing, and stretched at a strain rate of 1X 10 ^-3s^-1 after drying.

FIG. 12 is a scanning electron microscope structure diagram of the obtained homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, and it can be seen that after the cold rolling annealing treatment, the alloy has a large-area obvious band structure and is elongated along the rolling direction.

Fig. 13 is a drawing stress-engineering strain plot of the resulting homogeneous Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy, which after a drawing anneal treatment exhibited a tensile yield strength of 1091MPa and a room temperature tensile elongation of 30.6%.

Example 6

The embodiment designs a multi-component refractory alloy with light weight, high strength and ultra-high room temperature tensile ductility, and the chemical formula is Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 (atomic percent), and the preparation steps are as follows:

(1) Pretreatment of raw materials: nb, zr and Ta particles with the purity of more than or equal to 99.90 weight percent and Ti and Al particles with the purity of 99.95 weight percent are put into a beaker of absolute ethyl alcohol to be ultrasonically cleaned for 15 minutes at room temperature so as to remove surface dirt and impurities, and finally are put into a drying box to be dried for standby.

(2) The raw materials are as follows: by converting the mole percentage and the mass percentage of the light high-strength multi-component refractory alloy, 43.911g, 18.599g, 29.528g, 2.097g and 5.863g of each metal raw material are respectively weighed according to Nb, ti, zr, al g of alloy as a basis.

(3) Smelting: sequentially placing the raw materials weighed in the step (2) into a water-cooled copper crucible of a vacuum arc furnace according to the melting point, paying attention to the fact that Al particles with low melting point are placed at the bottom, vacuumizing to 5X 10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; additional Ti ingots preset in a hearth are melted for 2min before smelting to further consume free oxygen in the furnace, the smelting current is 330A, and the smelting time is 80 seconds; and (3) starting to smelt the alloy ingot, repeatedly smelting for 6 times, controlling the smelting current to be 380A, and keeping the electric arc for 6 minutes each time and assisting an electromagnetic stirring technology, wherein the current frequency is 8Hz, so that the alloy is fully and uniformly mixed.

(4) Casting: placing the alloy which is uniformly smelted into a water-cooled copper mold with the thickness of 80 multiplied by 30 multiplied by 10mm in a vacuum arc furnace for remelting molding, and taking out a sample after the sample is cooled, wherein the specific operation is as follows: vacuumizing to 5×10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; melting additional Ti ingots preset in a hearth for 2min before smelting, wherein the smelting current is 320A, and the smelting time is 80 seconds; and starting to smelt the alloy ingot, repeatedly smelting for 4 times, controlling the smelting current to be 380A, and keeping the electric arc for 8 minutes each time. The as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy is obtained.

FIG. 14 is an XRD pattern of the resulting as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy, illustrating that the alloy is BCC/B2 in structure.

Fig. 15 is a plot of tensile engineering stress versus engineering strain for the resulting as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy, it can be seen that the as-cast alloy has a tensile yield strength of 891MPa and a room temperature tensile elongation of 28.9%.

The resulting as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy was density measured as in example 1, and the average value was found to be ρ= 6.683g/cm ³ three times.

Example 7

The as-cast Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy obtained in example 6 was subjected to cold rolling annealing: cutting the as-cast alloy into a lath-shaped sample with the thickness of 8mm, wherein the rolling amount of a single pass is 10 percent, and the total rolling amount is 80 percent; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being subjected to heat preservation at 900 ℃ for 10min, so as to obtain the homogeneous Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy.

Fig. 16 is a scanning electron microscope structure diagram of the obtained homogeneous Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy, and it can be seen that the alloy structure is dense and the grain size distribution is uniform after the cold rolling annealing treatment.

Fig. 17 is a drawing stress-engineering strain plot of the resulting homogeneous Nb _36.5Zr₂₅Ti₃₀Al₆Ta_2.5 alloy, exhibiting a room temperature tensile elongation of 31.3% and a tensile yield strength of 1085MPa after a recrystallization annealing treatment.

Example 8

The embodiment designs a multi-component refractory alloy with light weight, high strength and ultra-high room temperature tensile ductility, and the chemical formula is Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ (atomic percent), and the preparation steps are as follows:

(1) Pretreatment of raw materials: nb, zr and Ta particles with the purity of more than or equal to 99.90 weight percent and Ti and Al particles with the purity of 99.95 weight percent are put into a beaker of absolute ethyl alcohol to be ultrasonically cleaned for 20 to 25 minutes at room temperature so as to remove surface dirt and impurities, and finally are put into a drying box to be dried for standby.

(2) The raw materials are as follows: by converting the mole percentage and the mass percentage of the light high-strength multi-component refractory alloy, 30.208g, 22.066g, 37.078g, 3.293g and 7.361g of each metal raw material are respectively weighed according to Nb, ti, zr, al g of alloy as a basis.

(3) Smelting: sequentially placing the raw materials weighed in the step (2) into a water-cooled copper crucible of a vacuum arc furnace according to the melting point, paying attention to the fact that Al particles with low melting point are placed at the bottom, vacuumizing to 5X 10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; melting additional Ti ingots preset in a hearth for 2min before smelting to consume residual oxygen, nitrogen and the like in a smelting furnace, wherein the smelting current is 320A, and the smelting time is 80 seconds; and (3) starting to smelt the alloy ingot, repeatedly smelting for 6 times, controlling the smelting current to be 380A, and keeping the electric arc for 6 minutes each time and assisting an electromagnetic stirring technology, wherein the current frequency is 8Hz, so that the alloy is fully and uniformly mixed.

(4) Casting: placing the alloy which is uniformly smelted into a water-cooled copper mold with the thickness of 80 multiplied by 30 multiplied by 10mm in a vacuum arc furnace for remelting molding, and taking out a sample after the sample is cooled, wherein the specific operation is as follows: vacuumizing to 5×10 ^-3 Pa, and repeating for three times; argon is filled to 0.05MPa as a protective atmosphere; melting additional Ti ingots preset in a hearth for 2min before smelting, wherein the smelting current is 320A, and the smelting time is 80 seconds; and starting to smelt the alloy ingot, repeatedly smelting for 4 times, controlling the smelting current to be 380A, and keeping the electric arc for 8 minutes each time. The as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy is obtained.

FIG. 18 is an XRD pattern of the resulting as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy, illustrating that the alloy is BCC/B2 in structure.

Fig. 19 is a plot of tensile engineering stress versus engineering strain for the resulting as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy having a tensile yield strength of 1011MPa and a room temperature tensile elongation of 31.3%.

The resulting as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy was density measured as in example 1, and the average value was found to be ρ= 6.330g/cm ³ three times.

Example 9

The as-cast Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy obtained in example 8 was subjected to cold rolling annealing: cutting the as-cast alloy into a lath-shaped sample with the thickness of 8mm, wherein the rolling amount of a single pass is 10 percent, and the total rolling amount is 80 percent; and placing the rolled sample into a quartz tube for sealing, vacuumizing the quartz tube to 2.5 multiplied by 10 ^-3 Pa, and then filling argon gas, and keeping the air pressure in the tube to be 0.025MPa. And after sealing, the sample is immediately water quenched after being subjected to heat preservation at 850 ℃ for 10min, so as to obtain the homogeneous Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy.

The test pieces were cut into dog bone-shaped tensile test pieces of 1.5X7.5X121 mm by wire cutting, polished on abrasive paper of 180#, 400#, 800#, 1200#, 2000#, 3000#, 5000# and ultrasonically cleaned for 15 minutes, dried and stretched at a strain rate of 1X 10 ^-3s^-1.

FIG. 20 is a Scanning Electron Microscope (SEM) structure diagram of the obtained homogeneous Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy, which shows that after cold rolling annealing treatment, the alloy structure is compact and the grain size distribution is uniform;

FIG. 21 is a drawing of the tensile engineering stress-engineering strain curve of the resulting homogeneous Nb ₂₄Zr₃₀Ti₃₄Al₉Ta₃ alloy, after recrystallization annealing, with room temperature tensile yield strength up to 1088MPa, and with a tensile elongation of 34.4%.

Comparative example 1

The as-cast Nb ₃₂Zr_29.5Ti₂₈Al₈Ta_2.5 alloy obtained in example 1 was subjected to hot rolling deformation treatment: the as-cast alloy was cut into 8mm thick lath-shaped specimens, and the hot rolling temperature was 1050 ℃, the holding time was 30min, the single pass rolling reduction was 10%, and when the hot rolling deformation of the alloy was about 40%, the alloy appeared to crack, so the as-cast alloy of example 1 was not suitable for hot rolling structure control under the condition that the hot rolling temperature was 1050 ℃, and the rolling deformation was 40% when the holding time was 30 min.

The invention realizes that the room temperature tensile elongation of the light high-strength multi-component refractory alloy reaches 30.0-50.0%, has room temperature tensile yield strength of 900-1200 MPa, can realize direct cold rolling-annealing treatment at room temperature to realize tissue regulation, is beneficial to deformation processing, and can realize large-size sample preparation.

The near equimolar ratio of Nb, ti and Zr ensures that the alloy has high solid solubility and improves the yield strength of the alloy; compared with other elements in the alloy system, ta element has higher Young's modulus which is about 3.5 times of Ti element and 7 times of Al, nb and Zr elements, and the solid solution strengthening effect of the alloy is obviously enhanced while the weight is kept to be light by a small amount of addition. Meanwhile, ta has excellent plasticity, corrosion resistance and high-temperature performance, and is beneficial to improving the strength, plasticity and thermal stability of the alloy.

According to the invention, a light element Al is introduced into the multi-component refractory alloy, and the proportion of the Al element is reasonably selected on the premise of ensuring that the alloy structure is a single-phase solid solution, so that the low-density multi-component refractory alloy is obtained, wherein the alloy density rho=6.20-6.70 g/cm ³; meanwhile, the addition of Al element induces the formation of a large amount of ordered phases, and a BCC/B2 structure similar to the gamma/gamma' of the commercial nickel-based superalloy is formed, so that the nickel-based superalloy has great commercial potential.

The invention provides a light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility, which takes Nb, ti and Zr refractory elements as main materials, and simultaneously adds oxidizing element Al, so that a compact oxide film or passivation protection layer is easily formed on the surface of the alloy, the diffusion rate of oxygen atoms is blocked preferentially, the high-temperature corrosion resistance of the alloy is obviously improved, and the alloy is expected to become a new generation of high-temperature structural material.

The invention provides a light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility, which has uniform structure, can directly carry out large deformation cold rolling to regulate and control the structure without intermediate annealing treatment, has simple process flow and obviously reduces energy consumption and cost.

According to the invention, through designing the proportion of Nb, ti, zr, ta and Al elements, the room temperature elongation rate is up to 30.0-50.0% in the light high-strength multi-component refractory alloy, and the room temperature yield strength has the strong plastic matching combination of 900-1200 MPa, and the structure regulation and control can be realized through direct cold rolling-short-time annealing treatment at room temperature, so that the deformation processing is facilitated, and the preparation of large-size samples can be realized; the Al element proportion is reasonably selected to obtain the light high-strength multi-component refractory alloy with density rho=6.20-6.70 g/cm ³; meanwhile, addition of Al induces formation of a large amount of ordered phases to form a BCC/B2 structure, so that the method has great commercial potential; the addition of near-equal atomic ratios of Nb, ti and Zr ensures that the alloy has high solid solubility and improves the yield strength of the alloy; ta has excellent plasticity, corrosion resistance and high temperature performance, and the addition of Ta is beneficial to improving the strength, plasticity and thermal stability of the alloy; at high temperature, the Al element is very easy to form a compact oxide film or passivation protection layer on the surface of the alloy, so that the diffusion rate of oxygen atoms is preferentially blocked, the high-temperature corrosion resistance of the alloy is remarkably improved, and the Al element is expected to become a new generation high-temperature structural material.

It should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered in the scope of the claims of the present invention.

Claims

1. A light high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility is characterized in that:

The random state of the alloy is a BCC/B2 coherent structure, wherein the size of B2 is 0.5-2.5 nm;

the alloy comprises, in atom percent, 32% of Nb, 29.5% of Zr, 28% of Ti, 8% of Al and 2.5% of Ta, 36.5% of Nb, 25% of Zr, 30% of Ti, 6% of Al and 2.5% of Ta, or 24% of Nb, 30% of Zr, 34% of Ti, 9% of Al and 3% of Ta; preparing each component according to the atomic percentage, smelting under the protection of vacuum or inert gas to obtain an as-cast alloy, and performing direct cold rolling and annealing treatment on the as-cast alloy to obtain a homogeneous alloy with compact structure;

Wherein, the direct cold rolling is carried out, the multi-pass cold rolling is carried out, the single-pass rolling reduction is less than or equal to 25%, and the total rolling reduction is 80-100%;

and the annealing treatment is carried out under vacuum or inert gas atmosphere, the annealing temperature is 800-1200 ℃, the annealing time is 5-30 min, and then quenching is carried out immediately.

2. The lightweight high strength multi-component refractory alloy having ultra-high room temperature tensile ductility according to claim 1, wherein: smelting under a vacuum condition, and maintaining the vacuum degree in the furnace at 1-0.0001 Pa; smelting under the protection of inert gas, charging inert gas and maintaining the gas pressure at 0.000001~0.05 MPa.

3. A preparation method of a light high-strength multi-component refractory alloy with ultrahigh room temperature tensile ductility is characterized by comprising the following steps of: comprises the steps of preparing each component according to the atomic percentage of the alloy in claim 1, smelting under the protection of vacuum or inert gas to obtain an as-cast alloy, and carrying out direct cold rolling and annealing treatment on the as-cast alloy to obtain the homogeneous alloy with compact structure.

4. A method of making a lightweight high strength multi-component refractory alloy having ultra-high room temperature tensile ductility as defined in claim 3, wherein: the direct cold rolling is carried out, the multi-pass cold rolling is carried out, the single-pass rolling reduction is less than or equal to 25%, and the total rolling reduction is 80-100%.

5. The method for preparing a lightweight high strength multi-component refractory alloy having ultra-high room temperature tensile ductility as claimed in claim 3 or 4, wherein: and carrying out annealing treatment, wherein the annealing treatment is carried out under vacuum or inert gas atmosphere, the annealing temperature is 800-1200 ℃, the annealing time is 5-30 min, and then quenching is carried out immediately.

6. The homogeneous light-weight high-strength multi-component refractory alloy with ultra-high room temperature tensile ductility obtained by the preparation method according to any one of claims 3 to 5.