A high-strength, low-yield ratio near-α titanium alloy and its preparation method

Abstract

The present invention provides a near-α-type titanium alloy with high strength and low yield ratio and a preparation method thereof, which solves the technical problem that existing titanium alloys cannot achieve the synergy of high yield strength, high elongation and low yield ratio. The chemical composition of the titanium alloy consists of the following components by weight percentage: Zr: 10.0-15.0%; x: 0.5-10%; the balance is Ti and inevitable impurities; wherein x is one of the eutectoid β-stabilizing elements Fe, Mn, Cr, Ni or Cu, and the titanium alloy has a heterogeneous structural organizational feature of α′ martensite combined with primary α phase. The preparation method of the titanium alloy comprises: providing raw materials according to the composition of the titanium alloy, smelting and casting the raw materials into ingots, then subjecting the raw materials to grinding treatment, homogenization treatment, blanking forging, two-phase zone precision forging into blanks, and then subjecting the blanks to solid solution water quenching treatment. The titanium alloy can be widely used in the field of titanium alloy material technology.

Description

Technical Field

[0001] The present application relates to the technical field of titanium alloy materials, and in particular to a near-α-type titanium alloy with high strength and low yield ratio and a preparation method thereof. Background Art

[0002] At present, titanium alloys with light weight, high strength, excellent corrosion resistance and biocompatibility have been widely used in important fields such as aerospace, marine engineering, petrochemical industry, automobile industry and biomedicine. The yield strength ratio is an important mechanical index affecting the processing and engineering application of titanium alloys. However, the yield strength ratio (σ y / σ b ) is generally high, usually higher than 0.85, or even higher than 0.9, which is significantly higher than that of copper alloy (σ y / σ b =0.3~0.6)、aluminum alloy (σ y / σ b =0.5) and low and medium strength steel (σ y / σ b =0.6-0.8) and other traditional metal materials. A high yield ratio not only reduces the material's formability during cold working, but also reduces the material's deformation resistance from yield to plastic instability, resulting in a decrease in the safety margin of key titanium alloy structural components during service. Therefore, the yield ratio, a key mechanical parameter, must be considered when developing a new generation of titanium alloys with excellent cold working formability and high safety margins.

[0003] At present, the technology in this field usually uses alloy design to reduce the stability of the β phase in titanium alloys, thereby using stress-induced martensitic transformation or induced β twinning to reduce the yield ratio of titanium alloys. However, the above method is at the expense of the yield strength of the titanium alloy, so that the yield strength of the alloy is usually less than 600MPa, which is obviously insufficient for key structural devices. The lower yield strength not only fails to meet the design requirements of the component under certain working conditions, but also significantly reduces the utilization rate of the material, which is very unfavorable for the lightweighting of the component. Therefore, achieving the synergy of high yield strength, high elongation and low yield ratio in titanium alloys remains a problem that needs to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned technologies and to provide a near-α-type titanium alloy with high strength and low yield ratio and a preparation method thereof, so as to achieve the synergy of high yield strength, high elongation and low yield ratio.

[0005] To this end, the present invention provides a near-α-type titanium alloy with high strength and low yield ratio, wherein the chemical composition of the titanium alloy consists of the following components by weight percentage:

[0006] Zr: 10.0~15.0%;

[0007] x: 0.5~10%;

[0008] The balance is Ti and unavoidable impurities;

[0009] Wherein, x is one of the eutectoid β-stabilizing elements Fe, Mn, Cr, Ni or Cu, and the titanium alloy has a heterogeneous structure of α′ martensite combined with primary α phase.

[0010] Preferably, the size distribution of the heterogeneous structural phase of the titanium alloy is as follows: the size of the primary α phase is between 5 and 20 μm, and the size of the α′ martensite is between 0.5 and 1 μm.

[0011] Preferably, the titanium alloy has a yield strength of 900-1000 MPa, a yield strength ratio of not higher than 0.80, and an elongation of not lower than 11%.

[0012] A preparation method of a high-strength, low-yield ratio, near-α-type titanium alloy comprises the following steps: providing raw materials according to the composition of the high-strength, low-yield ratio, near-α-type titanium alloy described in any one of the above items, fully smelting the raw materials to obtain an ingot, grinding the ingot, homogenizing it, forging it, and fine-forging it in a two-phase zone to obtain a billet, and then subjecting it to a solution quenching treatment to obtain the titanium alloy.

[0013] Preferably, after the ingot is homogenized, it is subjected to blanking and drawing deformation. After solution treatment, it is kept warm in the single-phase region for a period of time and then subjected to drawing deformation with a total deformation of not less than 50%. Then, after keeping warm in the two-phase region for a period of time, it is subjected to drawing deformation with a total deformation of not more than 40%. Then, it is hot rolled and then subjected to solution quenching treatment to obtain a titanium alloy.

[0014] Preferably, the homogenization treatment temperature of the ingot is 1100-1300°C.

[0015] Preferably, when heat preservation is carried out in the single-phase region, the heat preservation temperature is: the β phase transformation temperature T of the titanium alloy β +40℃, the holding time depends on the actual situation, usually 120min.

[0016] Preferably, when the dual phase region is kept warm, the holding temperature is: the β phase transition temperature T of the titanium alloy β -40℃, the holding time depends on the actual situation, usually 120min.

[0017] Preferably, the hot rolling temperature is T β -40℃.

[0018] Preferably, rapid drawing deformation is performed in the single-phase region, with a deformation rate ranging from 40 to 50 mm / s; and slow drawing deformation is performed in the dual-phase region, with a deformation rate ranging from 5 to 10 mm / s.

[0019] Preferably, the solution temperature after blanking and drawing is T β -40℃.

[0020] Preferably, the solution temperature after hot rolling deformation is T β -40℃.

[0021] Preferably, the quenching medium is water.

[0022] Preferably, the raw materials are smelted three times to obtain ingots, and the raw material smelting device usually adopts a vacuum consumable furnace.

[0023] Preferably, the ingot is subjected to a homogenization treatment at 1100-1300° C. and then subjected to a first drawing deformation, a third drawing deformation after being kept in a single-phase region for a period of time, and a third drawing deformation after being kept in a dual-phase region for a period of time.

[0024] Preferably, the ingot after homogenization treatment at 1150°C is subjected to a blanking and drawing deformation, then subjected to solution treatment, and then subjected to three drawing deformations in the single-phase region and three drawing deformations in the dual-phase region. β The plate of a certain thickness is prepared by hot rolling at -40℃, and finally subjected to solid solution quenching treatment to obtain an α-type titanium alloy plate with α′ martensite combined with primary α phase.

[0025] The design concept of the present invention is:

[0026] The present invention adds zirconium and one of the appropriate eutectoid β-stabilizing elements Fe, Mn, Cr, Ni or Cu to the titanium alloy, so that the alloy forms a heterogeneous structure consisting of an α′ martensite phase and a primary α phase after solution treatment and water quenching, while simultaneously increasing the axial ratio of the α phase. While increasing the strength of the alloy, the alloy's work hardening ability and plastic deformation ability are enhanced, thereby achieving a combination of high strength and low yield ratio.

[0027] The present invention provides a high-strength, low-yield ratio near-α-type titanium alloy and a preparation method thereof, which has the following beneficial effects:

[0028] (1) Different from the microstructure of existing engineering titanium alloys, the titanium alloy provided by the present invention has a unique heterogeneous structure of α′ martensite combined with primary α phase. The size of the primary α phase is between 5 and 20 μm, and the size of the α′ martensite is between 0.5 and 1 μm.

[0029] (2) The method of the present invention can significantly reduce the yield strength ratio of the alloy while ensuring the yield strength and tensile strength of the alloy, thereby further increasing the service safety and reliability of the alloy while meeting the lightweight requirements of the components.

[0030] (3) The method of the present invention can be used to prepare titanium alloy rods, wires, plates, etc., which can be widely used in many important fields such as aerospace, marine engineering, petrochemical industry, automobile industry and biomedicine.

[0031] (4) The method of the present invention can produce a series of duplex titanium alloys with different yield strengths and yield ratios, wherein the yield strength is not less than 900 MPa, the yield ratio is not higher than 0.80, and the elongation is not less than 11%. This satisfies the different requirements of titanium alloys in cold forming and safe service. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application.

[0033] Figure 1 A typical engineering stress-strain curve diagram of the titanium alloy according to the embodiment of the present application;

[0034] Figure 2 This is a scanning electron microscope photograph of the titanium alloy according to the embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0036] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "above", "the", and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0037] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0038] Unless otherwise specified, the methods used in the present invention are all conventional methods; the raw materials and devices used are all conventional commercially available products unless otherwise specified.

[0039] At present, the design of key titanium alloy structural components in important fields such as aerospace, marine engineering, petrochemical industry, automobile industry and biomedicine, on the one hand, expects to have low yield strength and low yield ratio and excellent elongation during cold working to improve the cold deformation ability of the alloy; on the other hand, it is expected that the titanium alloy has high yield strength, high elongation and low yield ratio to ensure better service performance and safety margin of the alloy. However, the titanium alloy technology in this field sacrifices the yield strength of the titanium alloy at the expense of stress-induced martensitic phase transformation or induced β twinning to reduce the yield ratio of the titanium alloy, making the yield strength of the alloy less than 600MPa. Therefore, the current titanium alloy cannot meet the use requirements of key titanium alloy structural components.

[0040] To solve the above technical problems, the present application provides a near-α-type titanium alloy with high strength and low yield ratio. The chemical composition of the titanium alloy consists of the following components by weight percentage:

[0041] Zr: 10.0~15.0%;

[0042] x: 0.5~10%;

[0043] The balance is Ti and unavoidable impurities; wherein, x is one of the eutectoid β-stabilizing elements Fe, Mn, Cr, Ni or Cu, and the titanium alloy has a heterogeneous structure of α′ martensite combined with primary α phase.

[0044] The titanium alloy preferably contains 15.0% Zr by weight. Zr is an α-phase neutral element in the titanium alloy and plays a role in solid solution strengthening and increasing the strength of the alloy.

[0045] In the titanium alloy, the content of x is preferably 5.0% by weight. Element x is one of Fe, Mn, Cr, Ni or Cu, and is a β-stabilizing element in the titanium alloy to strengthen the β-transformed structure, such as α′ martensite. In addition, the content of each x element in the titanium alloy is different, and its β-phase transformation temperature T β The metallographic method is usually used to determine the T content in titanium alloys. β .

[0046] It should be noted that the titanium alloy in the embodiment of the present application, in addition to the above-mentioned Zr and x elements, inevitably contains Ti and other inevitable impurities, wherein the inevitable impurities may include C, O and N, for example.

[0047] In one embodiment of the present application, the yield strength of the titanium alloy may be no less than 900 MPa, the yield strength ratio may be no more than 0.80, and the elongation may be no less than 11%.

[0048] Based on the above composition of the titanium alloy, the present application also provides a method for preparing a near-α-type titanium alloy with high strength and low yield ratio, which may include the following steps:

[0049] S1. Provide raw materials according to the following titanium alloy composition:

[0050] In terms of weight percentage, Zr is 10.0-15.0%, x is 0.5-10%; the balance is Ti; wherein x is selected from one of Fe, Mn, Cr, Ni or Cu;

[0051] The raw materials of the above components can be selected from existing elemental metal raw materials or alloy raw materials, and can also be selected from existing recycled cutting materials or solid block materials.

[0052] S2. The raw materials are fully melted to obtain an ingot, and the ingot is ground to remove burrs.

[0053] In one embodiment of the present application, in step S2, the raw material is smelted at least three times to obtain an ingot. The smelting equipment may include an existing vacuum consumable furnace or other device.

[0054] S3. The ingot is homogenized and forged;

[0055] In one embodiment of the present application, after the ingot is homogenized, it is subjected to one or more blanking and drawing deformations. The number of blanking and drawing deformations is determined according to the actual situation. After the blanking and forging is completed, it is preferably subjected to solution treatment. The solution temperature is preferably T β -40℃, so that the excess phase is fully dissolved. The homogenization temperature of the ingot is preferably 1100~1300℃, and the homogenization time is determined according to the actual situation. S4. Two-phase region precision forging into billet. Wherein:

[0056] In one embodiment of the present application, when heat preservation is carried out in the single-phase region, the heat preservation temperature is preferably: the β phase transformation temperature T of the titanium alloy β +40°C, holding time can be set to 120 minutes depending on actual conditions. Rapid pull-out deformation is preferred in the single-phase region, with a deformation rate ranging from 40 to 50 mm / s. The number of pull-out deformations is preferably at least three, with the specific number depending on actual conditions. The total deformation during the pull-out deformation is preferably no less than 50%.

[0057] In one embodiment of the present application, when the dual phase region is kept warm, the holding temperature is: the β phase transformation temperature T of the titanium alloy βThe holding temperature is -40°C, and the holding time can be set to 120 minutes depending on the actual situation. Slow drawing deformation is preferably performed in the two-phase region, with a deformation rate ranging from 5 to 10 mm / s. The drawing deformation is preferably repeated at least three times, with the specific number depending on the actual situation. The total deformation of the drawing deformation is preferably no less than 40%.

[0058] In one embodiment of the present application, the hot rolling temperature is preferably T β -40℃, and obtain slabs of suitable shape and size.

[0059] S5. Solution quenching treatment to obtain titanium alloy.

[0060] In one embodiment of the present application, the solution temperature after hot rolling deformation is preferably T β -40℃, the quenching medium is preferably water.

[0061] Figure 1 This is a typical engineering stress-strain curve diagram of a titanium alloy according to an embodiment of the present application, as shown in FIG. Figure 1 As shown in the figure, after the material yields in the elastic deformation stage, it enters the plastic deformation stage and reaches the maximum stress, that is, the tensile strength is about 1300MPa. After that, the stress gradually decreases with the increase of strain. When the plastic strain reaches about 10%, the material breaks.

[0062] Figure 2 This is a scanning electron microscope photo of a titanium alloy according to an embodiment of the present application. Figure 2 As shown in the figure, according to the contrast of the scanning electron microscope image, the alloy has two different phases, the darker phase area corresponds to the primary α phase structure, and the brighter phase area with needle-like structure inside corresponds to the β transformation structure, that is, the α′ martensite phase structure. It can be seen that the titanium alloy has a heterogeneous structure of α′ martensite combined with primary α phase; the size of the primary α phase is between 5 and 20 μm, and the size of α′ martensite is between 0.5 and 1 μm.

[0063] The present application will be described and explained below through several groups of specific embodiments, but they should not be used to limit the scope of the present application.

[0064] Example 1

[0065] This embodiment is a near-α-type titanium alloy with high strength and low yield ratio. The chemical composition of the titanium alloy is specifically composed of the following components by weight percentage:

[0066] Zr: 10.0%;

[0067] x is Fe: 0.5%;

[0068] The balance is Ti and inevitable impurities.

[0069] The specific preparation method of the titanium alloy is as follows:

[0070] S1. Provide raw materials according to the following titanium alloy composition:

[0071] In terms of weight percentage, Zr is 10.0%, Fe is 0.5%; and the balance is Ti.

[0072] S2. A vacuum consumable furnace is used to perform three smelting operations to obtain a raw material ingot with uniform composition, and the ingot is then ground.

[0073] S3. The ingot is homogenized at 1300℃ for 0.5h and then subjected to a blanking and drawing deformation. After the blanking and forging is completed, it is solution treated at a solution temperature of 740℃.

[0074] S4. Two-phase zone precision forging into billet.

[0075] When the single-phase region is kept warm, the holding temperature is 820°C and the holding time is 120 minutes. Three rapid pull-out deformations are carried out in the single-phase region, with a deformation rate ranging from 40 to 50 mm / s, and the total deformation of the pull-out deformation is not less than 50%.

[0076] When holding in the dual phase region, the holding temperature is 740°C and the holding time is 120 minutes. Three slow pull-out deformations are performed in the dual phase region, with a deformation rate ranging from 5 to 10 mm / s, and the total deformation of the pull-out deformation is not less than 40%.

[0077] Hot rolling is performed at 740°C to obtain a slab with a thickness of 30 mm. It should be noted that in actual production, the thickness of the slab can be determined according to actual conditions to ensure hardenability.

[0078] S5. Solution quenching treatment, wherein the solution temperature is 740°C, the holding time is 0.5h, and then water quenching is performed to obtain a near-α-type titanium alloy plate with high strength and low yield ratio.

[0079] Example 2

[0080] Example 2 is a near-α-type titanium alloy with high strength and low yield ratio, which differs from Example 1 in that:

[0081] (1) The composition of titanium alloys is different. The composition of specific titanium alloys is listed in Table 1.

[0082] (2) The solution temperature in step S3 is 770°C; in step S4, the holding temperature of the single-phase region is 850°C, the holding temperature of the dual-phase region is 770°C, and the hot rolling temperature is 770°C; the solution temperature in step S5 is 770°C.

[0083] The other contents are the same as those in Example 1 and will not be repeated here.

[0084] Example 3

[0085] Example 3 is a near-α-type titanium alloy with high strength and low yield ratio, which differs from Example 1 in that:

[0086] (1) The composition of titanium alloys is different. The composition of specific titanium alloys is listed in Table 1.

[0087] (2) In step S3, the homogenization treatment temperature of the ingot is 1250°C and the solid solution temperature is 770°C; in step S4, the holding temperature of the single-phase region is 850°C, the holding temperature of the dual-phase region is 770°C, and the hot rolling temperature is 770°C; in step S5, the solid solution temperature is 770°C.

[0088] The other contents are the same as those in Example 1 and will not be repeated here.

[0089] Example 4

[0090] Example 4 is a near-α-type titanium alloy with high strength and low yield ratio, which differs from Example 1 in that:

[0091] (1) The composition of titanium alloys is different. The composition of specific titanium alloys is listed in Table 1.

[0092] (2) In step S3, the homogenization treatment temperature of the ingot is 1200°C and the solid solution temperature is 750°C; in step S4, the holding temperature of the single-phase region is 830°C, the holding temperature of the dual-phase region is 750°C, and the hot rolling temperature is 750°C; in step S5, the solid solution temperature is 750°C.

[0093] The other contents are the same as those in Example 1 and will not be repeated here.

[0094] Example 5

[0095] Example 5 is a near-α-type titanium alloy with high strength and low yield ratio, which differs from Example 1 in that:

[0096] (1) The composition of titanium alloys is different. The composition of specific titanium alloys is listed in Table 1.

[0097] (2) In step S3, the homogenization treatment temperature of the ingot is 1150°C and the solid solution temperature is 730°C; in step S4, the holding temperature of the single-phase region is 810°C, the holding temperature of the dual-phase region is 730°C, and the hot rolling temperature is 730°C; in step S5, the solid solution temperature is 730°C.

[0098] The other contents are the same as those in Example 1 and will not be repeated here.

[0099] Example 6

[0100] Example 6 is a near-α-type titanium alloy with high strength and low yield ratio, which differs from Example 1 in that:

[0101] (1) The composition of titanium alloys is different. The composition of specific titanium alloys is listed in Table 1.

[0102] (2) In step S3, the homogenization treatment temperature of the ingot is 1100°C and the solid solution temperature is 700°C; in step S4, the holding temperature of the single-phase region is 780°C, the holding temperature of the dual-phase region is 700°C, and the hot rolling temperature is 700°C; in step S5, the solid solution temperature is 700°C.

[0103] The other contents are the same as those in Example 1 and will not be repeated here.

[0104] Table 1 Raw material composition of titanium alloys in Examples 1 to 6

[0105]

[0106] Tensile properties test

[0107] The room temperature tensile mechanical properties of the titanium alloy plates (i.e., test specimens) prepared in Examples 1 to 6 were tested using a Zwick Z150 tensile testing machine in accordance with GB / T 228.1-2021 at a tensile rate of 0.3 mm / min. Three replicates were taken for each test specimen, and the test results were averaged. The mechanical properties obtained from the experiments, including yield strength, tensile strength, and elongation, are shown in Table 2.

[0108] Table 2 Mechanical properties test results of titanium alloy products of Examples 1 to 6

[0109]

[0110]

[0111] From the test data of Examples 1 to 6 in Table 2, it can be seen that the yield strength of the titanium alloy of the present invention is 900 to 1000 MPa, the tensile strength is not less than 1200 MPa, the yield strength ratio is not higher than 0.80, and the elongation is not less than 11%.

[0112] It can be seen that while improving the strength of titanium alloy, the alloy's work hardening ability and plastic deformation ability are improved, thereby obtaining a combination of high strength and low yield ratio, achieving the synergy of high yield strength, high elongation and low yield ratio, and obtaining a near-α titanium alloy with both high strength and low yield ratio and an α′ martensite combined with primary α phase heterogeneous structure, which can be widely used in important fields such as aerospace, marine engineering, petrochemical industry, automotive industry and biomedicine.

[0113] It should be noted that, in addition to being able to prepare titanium alloy plates, the method of the present invention can also be used to prepare titanium alloy bars, wires and other products.

[0114] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A near-α-type titanium alloy with high strength and low yield ratio, characterized in that: The chemical composition of the titanium alloy consists of the following components by weight percentage: Zr：10.0～15.0%； x：0.5～10%； The balance is Ti and unavoidable impurities; Wherein, the x is one of the eutectoid β-stabilizing elements Fe, Mn, Cr, Ni or Cu, and the titanium alloy has a heterogeneous structure of α´ martensite combined with a primary α phase; the size distribution of the heterogeneous structure phase of the titanium alloy is: the size of the primary α phase is between 5 and 20 μm, and the size of the α´ martensite is between 0.5 and 1 μm; The method for preparing the high-strength, low-yield ratio near-α-type titanium alloy comprises the following steps: Raw materials are provided according to the composition of the high-strength, low-yield-ratio near-α-type titanium alloy, the raw materials are fully smelted to obtain an ingot, the ingot is subjected to a grinding treatment, homogenization treatment, open forging, two-phase zone precision forging to form a billet, and then solution quenching treatment to obtain the titanium alloy; wherein: After homogenization treatment is completed, the ingot is subjected to blanking and drawing deformation, and after solution treatment, it is kept in a single-phase region for a period of time and then subjected to drawing deformation with a total deformation of not less than 50%, and then kept in a dual-phase region for a period of time and then subjected to drawing deformation with a total deformation of not more than 40%, and then hot rolled, and then subjected to solution quenching treatment to obtain the titanium alloy; The homogenization treatment temperature of the ingot is 1100-1300°C; When heat preservation is carried out in the single-phase region, the heat preservation temperature is T β +40℃; when keeping warm in the two-phase region, the holding temperature is T β -40 ℃; hot rolling temperature is T β -40 ℃; In the single-phase region, rapid pier pulling deformation is carried out with a deformation rate ranging from 40 to 50 mm / s; in the dual-phase region, slow pier pulling deformation is carried out with a deformation rate ranging from 5 to 10 mm / s; The solution temperature after blanking and drawing is T β -40 ℃, the solution temperature after hot rolling deformation is T β -40 ℃.

2. The high-strength, low-yield-ratio near-α titanium alloy according to claim 1, characterized in that: The titanium alloy has a yield strength of 900 to 1000 MPa, a yield strength ratio of not higher than 0.80, and an elongation of not lower than 11%.

3. A near-α-type titanium alloy with high strength and low yield ratio according to claim 1 or 2, characterized in that: The quenching medium is water.

4. A near-α-type titanium alloy with high strength and low yield ratio according to claim 1 or 2, characterized in that: A vacuum consumable furnace is used for three smelting to obtain a raw material ingot with uniform composition. The ingot is homogenized at 1100-1300°C and then subjected to one blanking and drawing deformation. After keeping the ingot in a single-phase region for a period of time, the ingot is subjected to three drawing deformations. After keeping the ingot in a two-phase region for a period of time, the ingot is subjected to three drawing deformations.

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