Zirconium alloy and method for producing the same

Abstract

This invention relates to the field of materials and discloses a zirconium alloy and its preparation method. The preparation method includes: sequentially melting, forging, hot rolling, and annealing zirconium alloy raw materials to obtain the zirconium alloy. The zirconium alloy raw materials include Zr, other metallic elements, and non-metallic elements. The other metallic elements mainly include Hf and Fe. Based on the total amount of the zirconium alloy, the total amount of other metallic elements does not exceed 1 wt.%, Hf does not exceed 0.6 wt.%, Fe content is 0.08-0.16 wt.%, and O content among the non-metallic elements is 0.12-0.16 wt.%. The hot rolling temperature does not exceed the phase transformation temperature of the zirconium alloy, and the total deformation of the hot rolling is not less than 60%. The zirconium alloy prepared by this invention has both excellent mechanical properties and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of materials, and more specifically to a zirconium alloy and its preparation method. Background Technology

[0002] Zirconium metal, due to its low thermal neutron absorption cross section, good radiation stability, excellent strength-ductility balance, and superior corrosion resistance, has become a key structural material in the nuclear and chemical industries. In recent years, zirconium and its alloys have seen increasingly wider applications in the chemical field, particularly in harsh corrosive environments, as materials for critical equipment components. Among them, R60702 zirconium alloy, with its excellent formability, weldability, and corrosion resistance, is widely used in the manufacture of heat exchangers, container linings, valves, agitators, and conduits in chemical equipment, demonstrating broad cross-domain application characteristics. With the iterative development of equipment technology, the requirements for the comprehensive performance (mechanical properties and corrosion resistance) of zirconium alloys continue to increase, necessitating the development of effective strategies to broaden its application boundaries.

[0003] Currently, the main approaches to improving the overall performance of zirconium alloys, besides heat treatment, include alloying, microstructure control, and surface coating technology. While alloying can enhance mechanical properties, it is detrimental to corrosion behavior in complex service environments. Adding alloying elements often results in precipitates, which are unfavorable for corrosion resistance. Microstructure control (such as grain refinement) is a relatively mature process and can improve mechanical properties, but its impact on corrosion resistance remains unknown. Surface coating technology can effectively isolate corrosive media, but the added complexity of the preparation process significantly increases manufacturing costs and process complexity. Furthermore, surface coating introduces additional interfaces, which is also detrimental to the overall mechanical properties of the material. Currently, there is no industrially viable method for preparing zirconium alloys that balances both mechanical properties and corrosion resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that existing technologies cannot simultaneously achieve both mechanical properties and corrosion resistance of zirconium alloys, and to provide a zirconium alloy and its preparation method. The high-alloy plates prepared by this method have excellent mechanical properties and also excellent corrosion resistance.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a zirconium alloy, wherein the method comprises: sequentially melting, forging, hot rolling and annealing a zirconium alloy raw material to obtain a zirconium alloy;

[0006] The zirconium alloy raw material includes Zr, other metallic elements and non-metallic elements, wherein the other metallic elements include Hf and Fe. Based on the total amount of the zirconium alloy, the total amount of the other metallic elements does not exceed 1 wt.%, Hf does not exceed 0.6 wt.%, Fe content is 0.08-0.16 wt.%, and the O content among the non-metallic elements is 0.12-0.16 wt.%.

[0007] The hot rolling temperature does not exceed the phase transformation temperature of the zirconium alloy, and the total deformation of the hot rolling is not less than 60%.

[0008] The second aspect of the present invention provides a zirconium alloy prepared by the preparation method described in the first aspect of the present invention, wherein the zirconium alloy has a tensile strength of not less than 410 MPa, a yield strength of not less than 290 MPa, an elongation of not less than 22%, and a strength-ductility product of not less than 10 GPa.

[0009] By controlling the content of metallic elements in the zirconium alloy raw materials to achieve a lower content of alloying elements, the corrosion resistance of the prepared zirconium alloy is improved. At the same time, by combining hot rolling at a temperature below the phase transformation temperature, controlling the total deformation of hot rolling, and introducing appropriate amounts of Fe and O elements, the mechanical properties of the zirconium alloy are improved, thus making the obtained zirconium alloy have both excellent mechanical properties and corrosion resistance. Attached Figure Description

[0010] Figure 1 The metallographic structure of the zirconium alloys obtained in Examples 1-3;

[0011] Figure 2 The grain size distribution of the zirconium alloys obtained in Examples 1-3 is shown.

[0012] Figure 3 These are the electrochemical performance test results of the zirconium alloys in Example 3 and Comparative Example 2. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The terms “first”, “second”, etc. are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. The objects distinguished by “first”, “second”, etc. are usually of the same class and the number of objects is not limited. For example, the first object can be one or more.

[0015] Furthermore, the term "and / or" in the specification and claims is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0016] In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0017] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0018] In this application, the phase transition temperature refers to the temperature at which the phase changes from the α phase to the β phase.

[0019] Recrystallized grains refer to new grains that re-form after the final annealing.

[0020] Other metallic elements refer to metallic elements other than Zr.

[0021] The first aspect of the present invention provides a method for preparing a zirconium alloy, wherein the method comprises: sequentially melting, forging, hot rolling and annealing a zirconium alloy raw material to obtain a zirconium alloy;

[0022] The zirconium alloy raw material includes Zr, other metallic elements and non-metallic elements, wherein the other metallic elements include Hf and Fe. Based on the total amount of the zirconium alloy, the total amount of the other metallic elements does not exceed 1 wt.%, Hf does not exceed 0.6 wt.%, Fe content is 0.08-0.16 wt.%, and the O content among the non-metallic elements is 0.12-0.16 wt.%.

[0023] The hot rolling temperature does not exceed the phase transformation temperature of the zirconium alloy, and the total deformation is not less than 60%.

[0024] In the prior art, the mechanical properties of zirconium alloys are often improved by adding other metal elements. However, the content of other metal elements in this application is low. If the alloy sheet is prepared by conventional methods, its mechanical properties will be insufficient. In this application, by introducing appropriate amounts of Fe and O elements and controlling thermomechanical processing technology, such as hot rolling deformation, the mechanical properties of the obtained zirconium alloy are excellent.

[0025] Other metallic elements in this application include Hf, Fe, Al, Nb, Ti, etc., and non-metallic elements include C, O, N, H, etc. Based on the total amount of the zirconium alloy, the total amount of non-metallic elements does not exceed 0.3 wt.%, such as not exceeding 0.3 wt.%, or not exceeding 0.2 wt.%.

[0026] To introduce appropriate amounts of Fe and O elements and control the content of other metallic elements, different types of sponge zirconium, including high-Hf sponge zirconium (Hf content not less than 2.5 wt.%) and low-Hf sponge zirconium (Hf content less than 1 wt.%), can be selected and combined with appropriate amounts of iron wire and zirconium dioxide to regulate the Fe and O element content, thereby controlling the mechanical properties.

[0027] Preferably, the melting is vacuum consumable electrode arc melting, and the melting is performed three times. The diameter of the consumable electrode increases with each melting attempt. Gradually increasing the diameter of the consumable electrode promotes a more uniform distribution of the chemical composition within the material.

[0028] After preparing the required zirconium alloy raw materials as required, they are made into consumable electrodes. The consumable electrodes are then subjected to three vacuum consumable electrode arc melting (VAR melting) processes to obtain zirconium alloy ingots. The risers and ingot bottoms are removed from the ingots, and the outer skin is peeled off before the forging process is carried out.

[0029] Preferably, the forging temperature is 900-1050℃. The forging can be performed 2-3 times, generally 2 times, and the thickness of the plate after forging can be 75-100mm.

[0030] By fully forging the β region at this temperature, the as-cast structure can be significantly broken down, and the grain size can be refined. The forging temperature can be 900℃, 950℃, 1000℃, 1050℃, or any value between any two of these.

[0031] Preferably, the hot rolling includes 1-3 hot rolling passes.

[0032] Preferably, the hot rolling includes one rolling pass with a total deformation of 65-70%; or the hot rolling includes two rolling passes with a total deformation of 85-90%; or the hot rolling includes three rolling passes with a total deformation of 90-95%. In this application, different hot rolling cycles can be selected according to actual needs. When only one hot rolling is performed, the total deformation is 65-70% (e.g., 65%, 66%, 67%, 68%, 69%, 70%) to ensure the improvement of the mechanical properties of the final zirconium alloy. When two hot rolling cycles are used, the total deformation is 85-90% (e.g., 85%, 86%, 87%, 88%, 89%, 90%), which can further ensure the improvement of the mechanical properties of the final zirconium alloy. When three hot rolling cycles are used, the total deformation is 90-95% (e.g., 90%, 91%, 92%, 93%, 94%, 95%), which can further improve the mechanical properties of the final zirconium alloy.

[0033] Preferably, the hot rolling includes two rolling processes, wherein the deformation of the first rolling process is 65-70%, and the deformation of the second rolling process is 60-65%.

[0034] Preferably, the hot rolling includes three rolling passes, wherein the deformation amount of the first rolling pass is 65-70%, the deformation amount of the second rolling pass is 60-65%, and the deformation amount of the third rolling pass is not less than 50%. Through multiple rolling passes with large deformation amounts, the microstructure can be sufficiently refined, which is beneficial for further improving the morphology of the microstructure. The deformation amount of the first rolling pass can be 65%, 66%, 67%, 68%, 69%, 70%, or any value between any two of these numbers; the deformation amount of the second rolling pass can be 60%, 61%, 62%, 63%, 64%, 65%, or any value between any two of these numbers; the deformation amount of the third rolling pass can be 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, or any value between any two of these numbers.

[0035] Preferably, before the first rolling, the material is placed at a temperature not exceeding the phase transformation temperature for heat preservation treatment for 100-150 minutes.

[0036] Preferably, before the second rolling, the material is placed at a temperature not exceeding the phase transformation temperature for heat preservation treatment for 50-80 minutes.

[0037] Preferably, before the third rolling, the material is placed at a temperature not exceeding the phase transformation temperature for heat preservation treatment for 30-50 minutes.

[0038] Preferably, each hot rolling process includes 2-5 passes, with a deformation of 20-40% per pass, and the rolling direction is the same for all passes. The deformation of each pass affects the grain size, and thus the mechanical properties of the sheet. The deformation of each pass can be 20%, 22%, 25%, 28%, 30%, 33%, 35%, 37%, 40%, or any value between any two of these values.

[0039] Preferably, the hot rolling temperature is 700-800℃.

[0040] Preferably, the hot rolling temperature is 730-770°C.

[0041] The hot rolling temperature needs to be lower than the phase transformation temperature. If it is higher than the phase transformation temperature, the microstructure cannot be refined. The phase transformation temperature of the zirconium alloy raw material in this application is about 920-930℃. The hot rolling temperature can be 700℃, 720℃, 730℃, 740℃, 760℃, 770℃, 780℃, 800℃ and any value between any two of them.

[0042] Preferably, the annealing includes a first annealing, which is performed after hot rolling; the annealing also includes a second annealing, which is performed after the first annealing, followed by cold rolling and the second annealing, wherein the total deformation of the cold rolling is 30-35%.

[0043] Preferably, the temperatures for the first and second annealing are independently set to 550-600℃, and the times are independently set to 40-60 minutes. High annealing temperatures and long annealing times can cause excessive grain growth, while low temperatures and short annealing times cannot guarantee complete grain recrystallization, which is detrimental to mechanical properties. The temperatures for the two annealing processes can be independently set to 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, or any value between any two of these values.

[0044] The second aspect of the present invention provides a zirconium alloy prepared by the preparation method described in the first aspect of the present invention, wherein the zirconium alloy has a tensile strength of not less than 410 MPa, a yield strength of not less than 290 MPa, an elongation of not less than 22%, and a strength-ductility product of not less than 10 GPa.

[0045] Preferably, the zirconium alloy comprises recrystallized grains with a grain size of 5-15 μm.

[0046] Preferably, the size of the recrystallized crystals is 7-10 μm. The grain size can be 5 μm, 7 μm, 9 μm, 10 μm, 12 μm, 14 μm, 15 μm, or any value between any two of these numbers.

[0047] Preferably, the zirconium alloy has a tensile strength of not less than 460 MPa, a yield strength of not less than 340 MPa, an elongation of not less than 28%, and a strength-ductility product of not less than 13 GPa.

[0048] In the prior art, the mechanical properties of zirconium alloys are often improved by adding other metal elements. In this application, the content of other metal elements is low. If the alloy sheet is prepared by conventional methods, its mechanical properties will be insufficient. However, in this application, by introducing appropriate amounts of Fe and O elements and controlling the thermomechanical processing technology, such as hot rolling deformation and hot rolling temperature, the mechanical properties of the obtained zirconium alloy are excellent.

[0049] The present invention will be described in detail below through examples. Unless otherwise specified, all reagents or instruments used in the following examples are commercially available conventional products. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0050] The metallographic structure of the prepared material was obtained using a metallographic microscope;

[0051] The average grain size was determined using Nano Measurer software according to ASTM E112 standard.

[0052] Mechanical property tests, including tensile strength, yield strength, and elongation, were conducted according to GBT 228.1-2010. The strength-ductility product = tensile strength × elongation. Corrosion resistance testing methods were as follows: Electrochemical measurements were performed using an electrochemical workstation (VersaSTAT3F). A three-electrode method was used, with the experimental material as the working electrode (10 mm × 10 mm surface area), Pt as the auxiliary electrode (10 mm × 10 mm × 0.5 mm, 99.997%), and a saturated calomel electrode as the reference electrode. After stabilizing the working electrode at an open-circuit potential (OCP) in solution for 3600 s, its potentiodynamic polarization curve was measured from -0.8 V to 1 V at a scan rate of 0.5 mV / s. The experimental material was then potentiostatically polarized at 0 V for 4 h to form a stable passivation film. Electrochemical impedance spectroscopy (EIS) measurements were performed using an excitation potential method, with frequencies selected from 10 kHz to 10 mHz and amplitudes of 10 mV. After the electrochemical impedance spectroscopy experiment was completed, the polarization curves were fitted and analyzed using Cview software, and Bode and Nyquist plots were drawn.

[0053] Unless otherwise specified, the specific composition of the zirconium alloy raw materials in the following examples and comparative examples is shown in Table 1.

[0054] Table 1

[0055] Content (wt.%) 0.6 0.12 <0.08 <0.01 <0.005 <0.03 0.14 <0.01 <0.003

[0056] Example 1

[0057] S1, the zirconium alloy raw material is subjected to three VAR melting processes. The diameters of the consumable electrodes for each melting process are 160mm, 220mm, and 300mm, respectively, to obtain an ingot. The riser and bottom of the ingot are removed, and the oxide scale and impurities are removed by peeling.

[0058] S2 involves forging the ingot obtained in S1 twice at a forging temperature of 900℃. The forging method is a combination of free forging techniques such as upsetting, drawing, and octagonal forging. The cooling method is air cooling. The resulting zirconium slab has a thickness of 80mm, a width of 265mm, and a length of 605mm.

[0059] S3. The zirconium slab is heated until it reaches 750℃±15℃, at which point timing begins and the holding time is 120 minutes. After the holding time is completed, the slab is rolled. The total deformation during rolling is 68%, and the rolling is performed in three passes in the same direction. The deformation of each pass is 30%, 35%, and 30%, respectively, resulting in a 25.5mm thick slab.

[0060] S4. The sheet material obtained in S3 is annealed at 600℃ for 60 minutes, and then the finished product is ground, sheared and shot-blasted and pickled to obtain a zirconium alloy sheet material with a thickness of 25mm.

[0061] Example 2

[0062] S1 is the same as S1 in Example 1.

[0063] S2 involves forging the ingot obtained in S1 twice at a forging temperature of 1000℃. The forging method is a combination of free forging techniques such as upsetting, drawing, and octagonal forging. The cooling method is air cooling. The resulting zirconium slab has a thickness of 75mm, a width of 280mm, and a length of 600mm.

[0064] S3. The zirconium slab is heated until the temperature reaches 750℃±15℃, and the holding time is started for 120 minutes. After the holding time is completed, the first rolling is performed, with a total deformation of 65.9%, which is divided into 3 passes in the same direction. The deformation of each pass is 30%, 35%, and 25%, respectively, to obtain the first plate with a thickness of 25.6 mm.

[0065] S4. After grinding the first plate, heat it until the temperature reaches 750℃±15℃, then start timing and hold for 60 minutes. After holding, perform a second rolling process with a total deformation of 64%. The rolling direction is the same, and it is divided into 3 passes with deformations of 25%, 35%, and 26% for each pass, resulting in a second plate with a thickness of 9.2mm.

[0066] S5, the second plate is annealed at 580℃ for 50 minutes, and then polished, sheared and pickled to obtain a zirconium alloy plate with a thickness of 9mm.

[0067] Example 3

[0068] S1 is the same as S1 in Example 1.

[0069] S2 involves forging the ingot obtained in S1 twice at a forging temperature of 1050℃. The forging method is a combination of free forging techniques, including upsetting, drawing, and octagonal forging. The cooling method is air cooling. The resulting zirconium slab has a thickness of 82mm, a width of 300mm, and a length of 650mm.

[0070] S3. The zirconium slab is heated until the temperature reaches 750℃±15℃, at which point timing begins and the holding time is 120 minutes. After the holding time is completed, the first rolling is performed, with a total deformation of 70%, divided into 3 passes in the same direction. The deformation of each pass is 35%, 35%, and 30%, respectively, to obtain a first slab with a thickness of 24.8 mm.

[0071] S4. After grinding the first plate, heat it until the temperature reaches 750℃±15℃, then start timing for 60 minutes. After the heat preservation is completed, perform a second rolling process with a total deformation of 61.3%. The rolling direction is the same, and it is divided into 3 passes, with deformations of 25%, 35%, and 20% for each pass, respectively, to obtain a second plate with a thickness of 9.6mm.

[0072] S5. After grinding the second plate, heat it until the temperature reaches 750℃±15℃, then start timing for 45 minutes. After the heat preservation is completed, perform the third rolling, with a total rolling deformation of 52.1%, divided into 3 passes in the same rolling direction. The deformation of each pass is 20%, 25%, and 20%, respectively, to obtain a second plate with a thickness of 4.6mm.

[0073] S6. Anneal the second sheet at 580°C for 30 minutes, then air-cool it to room temperature to obtain the third sheet.

[0074] S7, the third sheet is subjected to three cold rolling passes, with corresponding deformations of 13%, 12.5%, and 14.3% respectively, and a total deformation of 34.7%, to obtain the fourth sheet.

[0075] S8. The fourth plate is annealed at 550°C for 45 minutes, and then polished, sheared and pickled in sequence to obtain a zirconium alloy plate with a thickness of 3 mm.

[0076] Example 4

[0077] The procedure is the same as in Example 1, with the only difference being:

[0078] In step S3, the total deformation of the first rolling pass is 60%, which is divided into 3 passes, with deformations of 25%, 30%, and 24% for each pass, respectively.

[0079] Example 5

[0080] The procedure is the same as in Example 2, with the only difference being:

[0081] In step S4, the total deformation of the second rolling pass is 70%, which is divided into 3 passes, with deformations of 25%, 35%, and 35% for each pass, respectively.

[0082] Example 6

[0083] The procedure is the same as in Example 3, with the only difference being:

[0084] In step S4, the total deformation of the third rolling pass is 40%, which is divided into 3 passes, with deformations of 20%, 20%, and 30% for each pass, respectively.

[0085] Example 7

[0086] The process is carried out in accordance with Example 3, except that only one hot rolling is performed. Specifically, the first hot rolling in step S3 of Example 3 is divided into 9 passes, with the deformation of the first 8 passes being 10% and the deformation of the 9th pass being 15% (the total deformation is the same as in Example 3). The second and third hot rolling steps S4 and S5 are not performed.

[0087] Example 8

[0088] The procedure is the same as in Example 3, with the only difference being:

[0089] In steps S3-S5, each heat treatment is performed at 800℃ for the same duration before rolling.

[0090] Comparative Example 1

[0091] The main components of the raw materials are shown in Table 2, and the preparation method is carried out in accordance with the method in Example 3.

[0092] Table 2

[0093] Content (wt.%) 2.5 0.05 <0.08 <0.01 <0.005 <0.03 0.08 <0.01 <0.003

[0094] Comparative Example 2

[0095] The main components are chemical components as shown in Table 3, and the preparation method is carried out in accordance with the method of Example 3.

[0096] Table 3

[0097] Content (wt.%) 0.6 0.2 <0.08 <0.01 <0.005 <0.03 0.2 <0.01 <0.003

[0098] Comparative Example 3

[0099] The procedure was carried out in accordance with Example 1, with the only difference being that the total variable of the hot-rolled shape was 50%.

[0100] The microstructure and grain size of the finally obtained zirconium alloys were analyzed using Examples 1-3 as examples.

[0101] Metallographic results as follows Figure 1 As shown, where Figure 1 (a) shows the metallographic structure of the zirconium alloy prepared in Example 1. Figure 1 (b) shows the metallographic structure of the zirconium alloy obtained in Example 2. Figure 1 (c) shows the metallographic structure of the zirconium alloy prepared in Example 3. As can be seen from the figure, the zirconium alloys prepared in the three examples all have fine recrystallized grains and uniform structure.

[0102] Grain size results are as follows Figure 2 As shown, where Figure 2 (a) The grain size statistics of the zirconium alloy prepared in Example 1 are shown, with an average grain size of 14.60 μm; Figure 2 (b) The grain size statistics of the zirconium alloy prepared in Example 2 are shown, with an average grain size of 10.60 μm; Figure 3 (c) The grain size statistics of the zirconium alloy prepared in Example 3 show that the average grain size is 9.18 μm. In particular, the minimum grain size of the plate prepared in Example 3 is only 2.78 μm, indicating that the grains are significantly refined.

[0103] The mechanical properties and corrosion resistance of the zirconium alloys prepared in Examples 1-8 and Comparative Examples 1-3 were further analyzed. The mechanical property results are shown in Table 4 (the results are the average values ​​after multiple tests).

[0104] Table 4

[0105]

[0106]

[0107] In the table, RD represents the rolling direction, and TD represents the direction perpendicular to the rolling direction, i.e., the transverse direction.

[0108] As shown in Table 4, the alloy prepared in Comparative Example 1 is a traditional high-Hf zirconium alloy. By increasing the Hf content, the alloy exhibits good mechanical properties (the drawback being insufficient corrosion resistance, which will be explained in subsequent experiments). Reducing the Hf content significantly decreases its mechanical properties (e.g., in Comparative Example 1, when the Hf content is reduced to approximately 0.6 wt.%, the tensile strength decreases by approximately 29 MPa (RD) and 24 MPa (TD), the yield strength decreases by approximately 32 MPa (RD) and 35 MPa (TD), and the elongation decreases by approximately 3% (RD) and...). The Hf content of the zirconium alloy prepared by this invention is 4.5% (TD). Compared with Comparative Example 1, the Hf content of the zirconium alloy prepared by this invention is relatively low, but the mechanical properties of the zirconium alloy prepared by this invention are excellent. This is mainly because appropriate amounts of Fe and O elements are introduced in this application and the rolling deformation is optimized, so that the mechanical properties of the zirconium alloy prepared by this invention are comparable to those of traditional high Hf zirconium alloys. In particular, the mechanical properties of the zirconium alloy prepared by Example 3 are significantly better than those of traditional high Hf zirconium alloys. It can be seen that the method provided by this application can greatly improve the mechanical properties of zirconium alloy plates by adjusting the chemical element content and combining it with the control of thermomechanical process parameters.

[0109] Taking the zirconium alloy (named R60702) from Example 3 and Comparative Example 1 as examples, its corrosion resistance was analyzed by electrochemical tests. The impedance value Rp of the zirconium alloy obtained in Example 3 was 557950±66350 Ω·cm. 2 The impedance value Rp of the zirconium alloy in Comparative Example 1 is 307100±6400 Ω·cm. 2 The potentiodynamic polarization test curves of the two are as follows: Figure 3 As shown in (a) and 3(b), Figure 3 (a) is a graph showing the results of the potentiodynamic polarization test. Figure 3 (b) is an enlarged view of the passivation region of the potentiodynamic polarization curve. The figure shows that the alloy exhibits typical surface passivation behavior in solution, namely, the active dissolution region, the passivation transition region, and the passivation region. Based on the self-corrosion current density of each alloy determined by fitting the potentiodynamic polarization curve using the Tafel extrapolation method, Example 3 has a lower self-corrosion current density and a lower corrosion rate, meaning that the corrosion resistance of Example 3 is superior to that of Comparative Example 1. Both materials exhibit typical passivation regions at anodes with passivation current densities around 10... -5 -10 -6 Order of magnitude.

[0110] The passivation film formed on the electrode surface plays a crucial role in the alloy's resistance to corrosion. Electrochemical impedance spectroscopy (EIS) is used to characterize the protective ability of the passivation film formed in solution. EIS test results are as follows: Figure 3 As shown in (c) and 3(d), where, Figure 3 (c) is the Nyquist plot of the EIS test. Figure 3 (d) shows the Bode plot from the EIS test. In the Nyquist curves, both alloys exhibit only a single capacitance loop, indicating that the corrosion reaction of each alloy in solution is kinetically controlled by the charge transfer process. Figure 3 (c) It can be seen that the alloy prepared in Example 3 has a larger arc diameter, indicating that its passivation film has stronger corrosion resistance and the material exhibits better corrosion resistance. Figure 3 (d) Bode plot shows that the low Hf alloy prepared in Example 3 has a higher absolute value of θ peak and its passivation film is more stable. The film resistance value |Z| in the 100mHz low frequency region also indicates that the zirconium alloy of Example 3 has stronger corrosion resistance than the zirconium alloy of Comparative Example 1.

[0111] In summary, the results of multi-faceted electrochemical experiments show that the corrosion resistance of the zirconium alloy prepared by this invention is superior to that of commercially available zirconium alloys.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing a zirconium alloy, characterized by, The preparation method includes: sequentially melting, forging, hot rolling and annealing zirconium alloy raw materials to obtain zirconium alloy; The zirconium alloy raw material includes Zr, other metallic elements, and non-metallic elements. The other metallic elements include Hf and Fe. Based on the total amount of the zirconium alloy, the total amount of the other metallic elements does not exceed 1 wt.%, Hf does not exceed 0.6 wt.%, the Fe content is 0.08-0.16 wt.%, and the O content among the non-metallic elements is 0.12-0.16 wt.%. The hot rolling temperature does not exceed the phase transformation temperature of the zirconium alloy, and the total deformation of the hot rolling is not less than 60%; the hot rolling includes three rolling processes, wherein the deformation of the first rolling process is 65-70%, the deformation of the second rolling process is 60-65%, and the deformation of the third rolling process is not less than 50%. The hot rolling temperature is 730-770℃.

2. The production method according to claim 1, wherein Each hot rolling process includes 2-5 passes, with a deformation of 20-40% per pass, and the rolling direction is the same for each pass.

3. The production method according to claim 2, wherein, The forging temperature is 900-1050℃.

4. The production method according to claim 2, wherein, The annealing includes a first annealing, which is performed after hot rolling; The annealing also includes a second annealing, after which cold rolling and the second annealing are performed in sequence, wherein the total deformation of the cold rolling is 30-35%.

5. The production method according to claim 4, wherein, The temperatures for the first and second annealing processes are each independently set at 550-600℃, and the times are each independently set at 40-60 minutes.

6. A zirconium alloy produced by the production method according to any one of claims 1 to 5, characterized by, The zirconium alloy has a tensile strength of not less than 410 MPa, a yield strength of not less than 290 MPa, an elongation of not less than 22%, and a strength-ductility product of not less than 10 GPa.

7. The zirconium alloy of claim 6, wherein, The zirconium alloy comprises recrystallized grains with a grain size of 5-15 μm.

8. The zirconium alloy of claim 7, wherein, The size of the recrystallized grains is 7-10 μm; And / or, the zirconium alloy has a tensile strength of not less than 460 MPa, a yield strength of not less than 340 MPa, an elongation of not less than 28%, and a strength-ductility product of not less than 13 GPa.

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