High-strength and high-plasticity Ti-15Zr alloy wire and preparation method thereof

Abstract

The invention provides a preparation method of a high-strength and high-plasticity Ti-15Zr alloy wire, which comprises the following steps: (1) weighing, mixing, pressing, welding and vacuum consumable smelting to obtain a cast ingot blank; (2) carrying out cogging forging and continuous rolling to obtain a wire blank; (3) heating to the alpha + beta two-phase region temperature for primary rounding and air cooling, cooling to the alpha-phase region temperature for secondary rounding, then heating to the alpha + beta two-phase region temperature for tertiary rounding and peeling to obtain a wire; and (4) multi-pass cold drawing and high-temperature short-time annealing are conducted, and the Ti-15Zr alloy wire is obtained. The invention further provides the high-strength and high-plasticity Ti-15Zr alloy wire, and the high-strength and high-plasticity Ti-15Zr alloy wire is prepared according to the preparation method of the high-strength and high-plasticity Ti-15Zr alloy wire. The machining process is simple, the production cost is low, the production efficiency is high, the performance of the titanium-zirconium alloy wire is good, and matching of high strength and good plasticity of the titanium-zirconium alloy wire in the cold machining process is achieved; belongs to the technical field of titanium-zirconium alloy wire preparation.

Description

Technical Field

[0001] The invention relates to the technical field of titanium-zirconium alloy wire preparation, in particular to a high-strength and high-plasticity Ti-15Zr alloy wire and a preparation method thereof. Background Art

[0002] Titanium-zirconium alloys are widely used in aerospace, medical equipment, chemical equipment, sports equipment and other fields due to their high strength, low density, good corrosion resistance and excellent biocompatibility. However, titanium alloys often face the problem of difficulty in simultaneously improving strength and plasticity during cold deformation.

[0003] The existing titanium alloy preparation technology mainly improves its cold deformation performance by adjusting the alloy composition and heat treatment process. The invention patent with publication number CN114657417B discloses a high-strength plastic titanium alloy suitable for cold deformation processing and a preparation method thereof, by adding strong β-stabilizing elements such as Mo, Cr, and Fe, without adding α-stabilizing elements, to improve the plastic deformation ability of the α phase at room temperature and high temperature. The method regulates the content and element distribution of the α and β phases through mechanical heat treatment, thereby improving the cold deformation processing performance of the titanium alloy and the matching of strength and plasticity. However, when preparing titanium alloy wire, this method may face technical problems such as difficult control of component uniformity, high processing cost, complex processing technology, and low production efficiency. The invention patent with publication number CN117107113A discloses a Ti-Al-V-Mo-Cr-Zr-Nb metastable β titanium alloy and a preparation method thereof, by adding elements such as Al, V, Mo, Cr, Fe, Nb, etc., and using different heat treatment systems to regulate mechanical properties in a wide range. This method can select different heat treatment conditions according to the different stages of the titanium alloy. For example, during the cold working process, the alloy strength is kept at a low level by heat treatment. After the finished product is obtained, the strength of the titanium alloy component is improved by heat treatment. However, when preparing titanium alloy wires, how to ensure that the wires maintain high strength and good plasticity during the cold working process is still a technical problem. Based on the above situation, it is urgent to study a method for preparing titanium alloy wires that can not only achieve high strength and good plasticity during the cold working process, but also reduce production costs and improve production efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a high-strength and high-plasticity Ti-15Zr alloy wire and a preparation method thereof, so as to solve the technical problems existing in the preparation method of the existing titanium alloy wire, that is, the inability to achieve the matching of high strength and good plasticity during cold working, the high production cost and the low production efficiency.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for preparing a high-strength and high-plasticity Ti-15Zr alloy wire, comprising the following steps:

[0006] (1) weighing raw materials in proportion, mixing, pressing into consumable electrode blocks, welding the consumable electrode blocks, and then performing vacuum consumable melting to obtain ingots;

[0007] (2) forging the ingot in the β single phase region, and then continuously rolling the ingot to obtain a wire billet;

[0008] (3) heating the wire blank to the temperature of the α+β two-phase region, performing the first rounding, air cooling, cooling to the temperature of the α phase region, performing the second rounding, and then heating to the temperature of the α+β two-phase region, performing the third rounding, and after rounding, peeling to obtain the wire;

[0009] (4) The wire is subjected to multiple cold drawing steps to obtain a coiled wire, which is then subjected to high temperature short-time annealing to obtain a Ti-15Zr alloy wire.

[0010] Preferably, in step (1), the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 13-18%, O: 0.14-0.20%, and the remainder is Ti and unavoidable impurities.

[0011] Preferably, in step (1), a hydraulic press is used to press the uniformly mixed raw materials into a consumable electrode block, and the density of the consumable electrode block is 3.4 to 3.6 g / cm 3 ; Use vacuum plasma welding box to weld the consumable electrode block, and fill argon gas to a vacuum degree of 4×10 4 Pa; the number of vacuum consumable melting is three times, and the current of the three vacuum consumable meltings is 200~20000A.

[0012] Preferably, in step (2), the ingot blank is forged in the β single-phase region at a temperature of 50 to 150°C.

[0013] Preferably, in step (2), continuous rolling is performed after forging is completed, the continuous rolling temperature is 900-950°C, the rolling speed is 1.5-2.5 m / s, the deformation amount per pass is 55-65%, and the cumulative deformation amount is more than 99.50%.

[0014] Preferably, in step (3), the wire blank is heated to the temperature of the α+β two-phase region for the first rounding, and the temperature of the first rounding is 780-830°C; the wire after the first rounding is air-cooled for 2-5 minutes, and then cooled to the temperature of the α phase region for the second rounding, and the temperature of the second rounding is 600-780°C; then the wire after the second rounding is heated to the temperature of the α+β two-phase region for the third rounding, and the temperature of the third rounding is 780-830°C.

[0015] Preferably, in step (3), after rounding three times, the wire is stripped using a centerless lathe.

[0016] Preferably, in step (4), the number of cold drawing is four times; during the cold drawing process, the surface of the wire is coated with a diamond-like structure coating; the drawing speed of the multi-pass cold drawing is 1.5 to 2.5 m / min, and the diameter reduction of each drawing pass is 0.15 to 0.20 mm.

[0017] Preferably, in step (4), the temperature of high temperature short-time annealing is 790-810° C., and the holding time is 10-25 min.

[0018] The present invention also provides a high-strength and high-plasticity Ti-15Zr alloy wire, which is prepared according to any of the above-mentioned methods for preparing the high-strength and high-plasticity Ti-15Zr alloy wire.

[0019] The present invention provides a high-strength and high-plasticity Ti-15Zr alloy wire and a preparation method thereof. Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention adopts a vacuum "lift-lift" heat treatment process in the rounding process. First, the temperature is raised to the temperature of the α+β two-phase region for a rounding process. As the temperature rises, the α phase will gradually dissolve in the β phase, and the β phase will nucleate and grow at the grain boundary of the α phase; then the temperature is lowered to the temperature of the α phase region for a second rounding process. The lattice distortion and dislocation generated during the phase change process will hinder the formation of slip bands, thereby improving the yield strength and tensile strength of the alloy. When the temperature drops to the α single-phase region, an undercooled β phase will be formed. These phases will be transformed into martensite during the subsequent heating process, thereby improving the strength; finally, the temperature is raised to the temperature of the α+β two-phase region again for a third rounding process. In this process, the alloy can be homogenized and recrystallized, thereby improving its plasticity and strength, and achieving a match between high strength and good plasticity of the titanium-zirconium alloy wire.

[0021] (2) The present invention adopts a multi-pass continuous cold drawing technology at room temperature, combined with a high-temperature short-time annealing process, to make the internal structure of the wire undergo fine grain strengthening while promoting taper surface slip, and successfully prepares ultrafine-grained Ti-15Zr alloy wire with a tensile strength greater than 1100MPa, a yield strength greater than or close to 1000MPa, and an elongation greater than or equal to 11%. The mechanical properties fully meet and exceed the standard requirements of GB / T13810-2017. Compared with the traditional process, the tensile strength is increased by more than 100MPa, the yield strength is increased by more than 50MPa, and the elongation is increased by more than 0.5%.

[0022] The invention has simple processing technology, low production cost, high production efficiency, good performance of the titanium-zirconium alloy wire, and achieves matching of high strength and good plasticity of the titanium-zirconium alloy wire during cold processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a metallographic diagram of the high-strength, high-plasticity, ultrafine-grained Ti-15Zr alloy wire prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. The methods used in the present invention are conventional methods unless otherwise specified; the raw materials and devices used are conventional commercial products unless otherwise specified.

[0026] In order to verify the reliability of the effect of the present invention, the present invention is described below in conjunction with Examples 1 to 4, and compared with Comparative Examples 1 to 4.

[0027] Example 1

[0028] This embodiment provides a method for preparing a high-strength and high-plasticity Ti-15Zr alloy wire, comprising the following steps:

[0029] (1) Ingot preparation: Raw materials are weighed and mixed according to the proportion; the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 13.1%, O: 0.14%, and the balance is Ti and unavoidable impurities;

[0030] The uniformly mixed raw materials are pressed into consumable electrode blocks using a hydraulic press. The density of the consumable electrode blocks is 3.4-3.6 g / cm 3 ;

[0031] Using vacuum plasma welding box, filled with argon gas 4×10 4 The consumable electrode block is welded in an inert gas environment of 1.5 Pa to obtain a consumable electrode;

[0032] The consumable electrode is subjected to three vacuum consumable arc melting, the current of the three vacuum consumable meltings is 200-20000A, and a titanium-zirconium alloy ingot blank with uniform composition is obtained.

[0033] (2) Forging and rolling: The Φ600.0 mm ingot is forged in the β single phase region at a temperature of 50 to 150°C;

[0034] After forging, continuous rolling is carried out at 930°C with a rolling speed of 1.5 m / s. The deformation amount of each pass in the billet rolling is 65%, and the cumulative deformation amount reaches more than 99.50%. After continuous rolling, a Ti-15Zr wire billet with a size of Φ11.0 mm is obtained.

[0035] (3) Rounding: The wire blank is rounded by using a vacuum "lift-lift" heat treatment process:

[0036] First, heat the Φ11.0 mm wire blank to 790°C in the α+β two-phase region for initial rounding, and then round it to a Φ10.8 mm wire.

[0037] Then, the Φ10.8 mm wire is air-cooled for 2 to 5 minutes, and then cooled to the α phase temperature of 760°C for secondary rounding, and the wire is rounded to Φ10.4 mm.

[0038] Then, the Φ10.4 mm wire is heated to the temperature of 790°C in the α+β two-phase region and rounded three times to a Φ10.2 mm wire;

[0039] After three roundings, the Φ10.2mm wire was stripped using a centerless lathe to obtain a Φ10mm Ti-15Zr wire.

[0040] (4) Cold drawing: The Φ10 mm wire is cold drawn four times. During the cold drawing process, a diamond-like structure coating is coated on the surface of the wire. The drawing speed of the multi-pass cold drawing is 2.5 m / min, and the diameter reduction of each drawing pass is 0.20 mm, thereby obtaining a Ti-15Zr coil wire;

[0041] The Ti-15Zr coil wire was subjected to high temperature short-time annealing at 810°C for 20 min, so that fine grain strengthening occurred inside the structure and the taper surface slip was promoted, and finally Φ6.0 mm ultrafine grain Ti-15Zr alloy wire was obtained.

[0042] Example 2

[0043] This embodiment provides a method for preparing a high-strength and high-plasticity Ti-15Zr alloy wire, comprising the following steps:

[0044] (1) Ingot preparation: weigh the raw materials in proportion and mix them; the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 15.4%, O: 0.20%, and the balance is Ti and inevitable impurities;

[0045] The uniformly mixed raw materials are pressed into consumable electrode blocks using a hydraulic press. The density of the consumable electrode blocks is 3.4-3.6 g / cm 3 ;

[0046] Using vacuum plasma welding box, filled with argon gas 4×10 4 The consumable electrode block is welded in an inert gas environment of 1.5 Pa to obtain a consumable electrode;

[0047] The consumable electrode is subjected to three vacuum consumable arc melting, the current of the three vacuum consumable meltings is 200-20000A, and a titanium-zirconium alloy ingot blank with uniform composition is obtained.

[0048] (2) Forging and rolling: The Φ600.0 mm ingot is forged in the β single phase region at a temperature of 50 to 150°C;

[0049] After forging, continuous rolling is carried out at 930°C with a rolling speed of 1.5 m / s. The deformation amount of each pass in the billet rolling is 65%, and the cumulative deformation amount reaches more than 99.50%. After continuous rolling, a Ti-15Zr wire billet with a size of Φ11.0 mm is obtained.

[0050] (3) Rounding: The wire blank is rounded by using a vacuum "lift-lift" heat treatment process:

[0051] First, heat the Φ11.0 mm wire blank to 820°C in the α+β two-phase region for initial rounding, and then round it to a Φ10.8 mm wire.

[0052] Then, the Φ10.8 mm wire is air-cooled for 2 to 5 minutes, and then cooled to the α phase temperature of 730°C for secondary rounding, and the wire is rounded to Φ10.4 mm.

[0053] Then, the Φ10.4 mm wire is heated to 820°C in the α+β two-phase region and rounded three times to a Φ10.2 mm wire;

[0054] After three roundings, the Φ10.2mm wire was stripped using a centerless lathe to obtain a Φ10mm Ti-15Zr wire.

[0055] (4) Cold drawing: The Φ10 mm wire is cold drawn four times. During the cold drawing process, a diamond-like structure coating is coated on the surface of the wire. The drawing speed of the multi-pass cold drawing is 2.5 m / min, and the diameter reduction of each drawing pass is 0.20 mm, thereby obtaining a Ti-15Zr coil wire;

[0056] The Ti-15Zr coil wire was subjected to high temperature short-time annealing at 810°C for 25 min, so that fine grain strengthening occurred inside the structure and the taper surface slip was promoted, and finally Φ5.5mm ultrafine grain Ti-15Zr alloy wire was obtained.

[0057] Example 3

[0058] This embodiment provides a method for preparing a high-strength and high-plasticity Ti-15Zr alloy wire, comprising the following steps:

[0059] (1) Ingot preparation: weigh the raw materials in proportion and mix them; the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 18.0%, O: 0.16%, and the balance is Ti and inevitable impurities;

[0060] The uniformly mixed raw materials are pressed into consumable electrode blocks using a hydraulic press. The density of the consumable electrode blocks is 3.4-3.6 g / cm 3 ;

[0061] Using vacuum plasma welding box, filled with argon gas 4×10 4 The consumable electrode block is welded in an inert gas environment of 1.5 Pa to obtain a consumable electrode;

[0062] The consumable electrode is subjected to three vacuum consumable arc melting, the current of the three vacuum consumable meltings is 200-20000A, and a titanium-zirconium alloy ingot blank with uniform composition is obtained.

[0063] (2) Forging and rolling: The Φ600.0 mm ingot is forged in the β single phase region at a temperature of 50 to 150°C;

[0064] After forging, continuous rolling is carried out at 930°C with a rolling speed of 1.5 m / s. The deformation amount of each pass in the billet rolling is 65%, and the cumulative deformation amount reaches more than 99.50%. After continuous rolling, a Ti-15Zr wire billet with a size of Φ11.0 mm is obtained.

[0065] (3) Rounding: The wire blank is rounded by using a vacuum "lift-lift" heat treatment process:

[0066] First, heat the Φ11.0 mm wire blank to 830°C in the α+β two-phase region for initial rounding, and then round it to a Φ10.8 mm wire.

[0067] Then, the Φ10.8 mm wire is air-cooled for 2 to 5 minutes, and then cooled to the α phase temperature of 780°C for secondary rounding, and the wire is rounded to Φ10.4 mm.

[0068] Then, the Φ10.4 mm wire is heated to 830°C in the α+β two-phase region and rounded three times to a Φ10.2 mm wire;

[0069] After three roundings, the Φ10.2mm wire was stripped using a centerless lathe to obtain a Φ10mm Ti-15Zr wire.

[0070] (4) Cold drawing: The Φ10 mm wire is cold drawn four times. During the cold drawing process, a diamond-like structure coating is coated on the surface of the wire. The drawing speed of the multi-pass cold drawing is 2.5 m / min, and the diameter reduction of each drawing pass is 0.20 mm, thereby obtaining a Ti-15Zr coil wire;

[0071] The Ti-15Zr coil wire was subjected to high temperature short-time annealing at 810°C for 15 min, so that fine grain strengthening occurred inside the structure and the taper surface slip was promoted, and finally Φ5.0 mm ultrafine grain Ti-15Zr alloy wire was obtained.

[0072] Example 4

[0073] This embodiment provides a method for preparing a high-strength and high-plasticity Ti-15Zr alloy wire, comprising the following steps:

[0074] (1) Ingot preparation: weigh the raw materials in proportion and mix them; the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 16.3%, O: 0.19%, and the balance is Ti and unavoidable impurities;

[0075] The uniformly mixed raw materials are pressed into consumable electrode blocks using a hydraulic press. The density of the consumable electrode blocks is 3.4-3.6 g / cm 3 ;

[0076] Using vacuum plasma welding box, filled with argon gas 4×10 4 The consumable electrode block is welded in an inert gas environment of 1.5 Pa to obtain a consumable electrode;

[0077] The consumable electrode is subjected to three vacuum consumable arc melting, the current of the three vacuum consumable meltings is 200-20000A, and a titanium-zirconium alloy ingot blank with uniform composition is obtained.

[0078] (2) Forging and rolling: The Φ600.0 mm ingot is forged in the β single phase region at a temperature of 50 to 150°C;

[0079] After forging, continuous rolling is carried out at 930°C with a rolling speed of 1.5 m / s. The deformation amount of each pass in the billet rolling is 65%, and the cumulative deformation amount reaches more than 99.50%. After continuous rolling, a Ti-15Zr wire billet with a size of Φ11.0 mm is obtained.

[0080] (3) Rounding: The wire blank is rounded by using a vacuum "lift-lift" heat treatment process:

[0081] First, heat the Φ11.0 mm wire blank to 800°C in the α+β two-phase region for initial rounding, and then round it to a Φ10.8 mm wire;

[0082] Then, the Φ10.8 mm wire is air-cooled for 2 to 5 minutes, and then cooled to the α phase temperature of 750°C for secondary rounding, and the wire is rounded to Φ10.4 mm.

[0083] Then, the Φ10.4 mm wire is heated to 800°C in the α+β two-phase region and rounded three times to a Φ10.2 mm wire;

[0084] After three roundings, the Φ10.2mm wire was stripped using a centerless lathe to obtain a Φ10mm Ti-15Zr wire.

[0085] (4) Cold drawing: The Φ10 mm wire is cold drawn four times. During the cold drawing process, a diamond-like structure coating is coated on the surface of the wire. The drawing speed of the multi-pass cold drawing is 2.5 m / min, and the diameter reduction of each drawing pass is 0.20 mm, thereby obtaining a Ti-15Zr coil wire;

[0086] The Ti-15Zr coil wire was subjected to high temperature short-time annealing at 810°C for 10 min, so that fine grain strengthening occurred inside the structure and the taper surface slip was promoted, and finally Φ5.5mm ultrafine grain Ti-15Zr alloy wire was obtained.

[0087] Comparative Example 1

[0088] The difference between this embodiment and Example 3 is that in step (3), three roundings are not performed, and a Φ10 mm Ti-15Zr wire is obtained after two roundings. The remaining operations are the same, and an ultrafine-grained Ti-15Zr alloy wire is finally obtained.

[0089] Comparative Example 2

[0090] The present embodiment differs from Example 3 in that in step (3), no secondary rounding and tertiary rounding are performed, and a Φ10 mm Ti-15Zr wire is obtained after the initial rounding. The remaining operations are the same, and an ultrafine-grained Ti-15Zr alloy wire is finally obtained.

[0091] Comparative Example 3

[0092] The present embodiment differs from Example 3 in that in step (4), high temperature short-time annealing is not performed, and a Φ6.0 mm Ti-15Zr wire is obtained after multiple cold drawing passes. The remaining operations are the same, and finally a Ti-15Zr alloy wire is obtained.

[0093] Comparative Example 4

[0094] The present embodiment differs from Example 3 in that in step (4), multiple cold drawing passes are not performed, and after rounding and peeling three times, high temperature short-time annealing is directly performed, and the remaining operations are the same, and finally Ti-15Zr alloy wire is obtained.

[0095] It should be noted that: in the above-mentioned embodiments 1 to 4 and comparative examples 1 to 4, in step (2), after forging, continuous rolling is performed at 930°C, the rolling speed is 1.5m / s, the deformation amount per pass in the billet rolling is 65%, and the cumulative deformation amount reaches more than 99.50%. It is only used as a preferred embodiment. In actual production, the temperature of continuous rolling can be 900-950°C, the rolling speed can be 1.5-2.5m / s, the deformation amount per pass can be 55-65%, and the cumulative deformation amount is more than 99.50%, which can be adaptively adjusted according to specific circumstances. In step (3), in actual production, the temperature of the first return to roundness can be 780-830°C, the temperature of the second return to roundness can be 600-780°C, and the temperature of the third return to roundness can be 780-830°C, which can be adaptively adjusted according to specific circumstances. In step (4), the diamond-like structural coating coated on the surface of the wire can be a diamond-like carbon coating or other types of diamond-like structural coatings, which can be adaptively adjusted according to specific circumstances. In step (4), the drawing speed of the multi-pass cold drawing is 2.5m / min, and the diameter reduction of each drawing is 0.20mm. This is only a preferred embodiment. In actual production, the drawing speed of the multi-pass cold drawing is 1.5-2.5m / min, and the diameter reduction of each drawing is 0.15-0.20mm, which can be adaptively adjusted according to specific circumstances. In step (4), the temperature of high-temperature short-time annealing can be 790-810°C, and the holding time can be 10-25min, which can be adaptively adjusted according to specific circumstances.

[0096] The ultrafine-grained Ti-15Zr alloy wire prepared in Example 3 was tested, and its metallographic image was measured as follows: Figure 1 As shown. Figure 1 It can be seen that the grain size of Ti-15Zr alloy wire is extremely small, which makes the material have a large number of grain boundaries. The existence of grain boundaries can effectively hinder the movement of dislocations, thereby improving the strength of the material. In addition, the orientation of the grains can be highly random. When external forces act, grains with different orientations can jointly bear the deformation, thereby avoiding premature fracture of the material in a certain direction, and thus helping to improve the plasticity of the material. Although the atomic arrangement at the grain boundary is different from that inside the grain, there may be defects such as vacancies and impurity atoms. However, in ultrafine-grained Ti-15Zr alloy wire, due to the extremely small grain size, the defects at the grain boundary can be suppressed to a certain extent, thereby maintaining high strength and toughness.

[0097] Depend on Figure 1 It can be seen that the ultrafine-grained Ti-15Zr alloy wire prepared in Example 3 can maintain high strength and good plasticity at the same time, that is, the preparation method of the present invention achieves the matching of high strength and good plasticity of the titanium-zirconium alloy wire during cold working.

[0098] In order to verify the effect of the present invention, the mechanical properties of the ultrafine-grained Ti-15Zr alloy wires of Examples 1 to 4 and the ultrafine-grained Ti-15Zr alloy wires and Ti-15Zr alloy wires of Comparative Examples 1 to 4 were tested respectively. The testing method was carried out in accordance with the provisions of GB / T13810-2017 "Titanium and Titanium Alloy Processing Materials for Surgical Implants". The results are shown in Table 1.

[0099] Table 1 Mechanical properties of Ti-15Zr alloy wires of Examples 1 to 4 and Comparative Examples 1 to 4

[0100]

[0101] From Table 1 we can see that:

[0102] By comparing Examples 1 to 4 and Comparative Examples 1 to 2, it can be seen that the tensile strength, yield strength and elongation of the ultrafine-grained Ti-15Zr alloy wire of Comparative Examples 1 to 2 are all lower than those of Examples 1 to 4; thus, it can be seen that the present invention adopts a vacuum "lift-lift" heat treatment process in the rounding process, which can improve the plasticity and strength of the Ti-15Zr alloy wire and achieve a match between high strength and good plasticity of the titanium-zirconium alloy wire.

[0103] By comparing Examples 1 to 4 and Comparative Examples 3 to 4, it can be seen that the tensile strength, yield strength and elongation of the Ti-15Zr alloy wire of Comparative Examples 3 to 4 are all lower than those of Examples 1 to 4; thus, it can be seen that the present invention adopts a multi-pass continuous cold drawing technology combined with a high-temperature short-time annealing process to strengthen the internal structure of the wire while promoting conical surface slip, and successfully prepares ultrafine-grained Ti-15Zr alloy wire, which significantly improves the tensile strength, yield strength and elongation of the titanium-zirconium alloy wire.

[0104] As can be seen from Table 1, the present invention can effectively ensure the surface grain size and roughness of the wire through the vacuum "lift-lift" heat treatment process of the rounding process and the multi-pass cold drawing process combined with the "high temperature short time annealing" process, and successfully prepares high-strength and high-plastic ultrafine-grained Ti-15Zr alloy wire, whose tensile strength is greater than 1100MPa, yield strength is greater than or close to 1000MPa, and elongation is greater than or equal to 11%. The mechanical properties fully meet and exceed the standard requirements of GB / T13810-2017. Compared with the traditional process, the tensile strength is increased by more than 100MPa, the yield strength is increased by more than 50MPa, and the elongation is increased by more than 0.5%.

[0105] In summary, the present invention provides a high-strength and high-plasticity Ti-15Zr alloy wire and a preparation method thereof. (1) The present invention adopts a vacuum "lift-lift" heat treatment process in the rounding process. First, the temperature is raised to the temperature of the α+β two-phase region for a rounding process. As the temperature rises, the α phase will gradually dissolve in the β phase, and the β phase will nucleate and grow at the grain boundary of the α phase; then the temperature is lowered to the temperature of the α phase region for a second rounding process. The lattice distortion and dislocation generated during the phase change process will hinder the formation of slip bands, thereby improving the yield strength and tensile strength of the alloy. When the temperature drops to the α single-phase region, an undercooled β phase will be formed. These phases will transform into martensite during the subsequent heating process, thereby improving the strength; finally, the temperature is raised to the temperature of the α+β two-phase region again for a third rounding process. In this process, the alloy can be homogenized and recrystallized, thereby improving its plasticity and strength, and achieving a match between high strength and good plasticity of the titanium-zirconium alloy wire. (2) The present invention adopts a multi-pass continuous cold drawing technology at room temperature, and combines it with a high-temperature short-time annealing process to strengthen the internal structure of the wire while promoting the sliding of the cone surface, and successfully prepares an ultrafine-grained Ti-15Zr alloy wire, whose tensile strength is greater than 1100MPa, yield strength is greater than or close to 1000MPa, and elongation is greater than or equal to 11%. The mechanical properties fully meet and exceed the standard requirements of GB / T13810-2017. Compared with the traditional process, the tensile strength is increased by more than 100MPa, the yield strength is increased by more than 50MPa, and the elongation is increased by more than 0.5%. The processing technology of the present invention is simple, the production cost is low, the production efficiency is high, the performance of the titanium-zirconium alloy wire is good, and the matching of high strength and good plasticity of the titanium-zirconium alloy wire during cold processing is achieved. The present invention can be widely used in the field of titanium-zirconium alloy wire preparation technology.

[0106] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for preparing high-strength and high-plasticity Ti-15Zr alloy wire, characterized in that: The following steps are involved: (1) weighing raw materials in proportion, mixing, pressing into consumable electrode blocks, welding the consumable electrode blocks, and then performing vacuum consumable melting to obtain ingots; (2) forging the ingot in the β single phase region, and then continuously rolling the ingot to obtain a wire billet; (3) heating the wire blank to the temperature of the α+β two-phase region, performing the first rounding, air cooling, cooling to the temperature of the α phase region, performing the second rounding, and then heating to the temperature of the α+β two-phase region, performing the third rounding, and after rounding, peeling to obtain the wire; (4) The wire is subjected to multiple cold drawing steps to obtain a coiled wire, which is then subjected to high temperature short-time annealing to obtain a Ti-15Zr alloy wire.

2. The method for preparing the high-strength and high-plasticity Ti-15Zr alloy wire according to claim 1, characterized in that: In step (1), the weight percentage content of each element in the Ti-15Zr alloy wire is: Zr: 13-18%, O: 0.14-0.20%, and the remainder is Ti and unavoidable impurities.

3. The method for preparing the high-strength and high-plasticity Ti-15Zr alloy wire according to claim 1, characterized in that: In step (1), a hydraulic press is used to press the uniformly mixed raw materials into a consumable electrode block, and the density of the consumable electrode block is 3.4 to 3.6 g / cm 3 ; Use vacuum plasma welding box to weld the consumable electrode block, and fill argon gas to a vacuum degree of 4×10 4 Pa; the number of vacuum consumable melting is three times, and the current of the three vacuum consumable meltings is 200~20000A.

4. The method for preparing the high-strength and high-plasticity Ti-15Zr alloy wire according to claim 1, characterized in that: In step (2), the ingot is forged in the β single phase region at a temperature of 50 to 150°C.

5. The method for preparing the high-strength and high-plasticity Ti-15Zr alloy wire according to claim 4, characterized in that: In step (2), continuous rolling is performed after forging is completed, the continuous rolling temperature is 900-950° C., the rolling speed is 1.5-2.5 m / s, the deformation amount per pass is 55-65%, and the cumulative deformation amount is more than 99.50%.

6. The method for preparing high-strength and high-plasticity Ti-15Zr alloy wire according to claim 1, characterized in that: In step (3), the wire blank is heated to the temperature of the α+β two-phase region for the first rounding, and the temperature of the first rounding is 780-830°C; the wire after the first rounding is air-cooled for 2-5 minutes, and then cooled to the temperature of the α phase region for the second rounding, and the temperature of the second rounding is 600-780°C; then the wire after the second rounding is heated to the temperature of the α+β two-phase region for the third rounding, and the temperature of the third rounding is 780-830°C.

7. The method for preparing the high-strength and high-plasticity Ti-15Zr alloy wire according to claim 6, characterized in that: In step (3), after three roundings, the wire is stripped using a centerless lathe.

8. The method for preparing high-strength and high-plasticity Ti-15Zr alloy wire according to claim 1, characterized in that: In step (4), the number of cold drawing is four times; during the cold drawing process, the surface of the wire is coated with a diamond-like structure coating; the drawing speed of the multi-pass cold drawing is 1.5-2.5 m / min, and the diameter reduction of each drawing pass is 0.15-0.20 mm.

9. The method for preparing high-strength and high-plasticity Ti-15Zr alloy wire according to claim 8, characterized in that: In step (4), the temperature of high temperature short-time annealing is 790-810° C., and the holding time is 10-25 min.

10. A high-strength and high-plasticity Ti-15Zr alloy wire, characterized in that: The high-strength and high-plasticity Ti-15Zr alloy wire is prepared according to the preparation method of any one of claims 1 to 9.

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