High-strength corrosion-resistant niobium-free zirconium alloy and method for manufacturing same

Abstract

The application relates to a high-strength corrosion-resistant niobium-free zirconium alloy and a manufacturing method thereof, and belongs to the field of nuclear engineering materials. The high-strength corrosion-resistant niobium-free zirconium alloy contains 0.7-1.5% of Sn, 0.1-0.4% of Fe, 0.15-0.35% of Cr, 0.02-0.08% of Ni, 0.1-0.18% of O, 0.001-0.1% of Ge and 0.001-0.15% of Cu in terms of weight percentage; the balance is Zr and inevitable impurities; in terms of atomic number ratio, 1<=Fe / Cr<=1.8 and 0.13<=Ni / Fe<=0.3. The alloy has good corrosion resistance, can prevent the occurrence of pimple-shaped corrosion, and has good resistance to uniform corrosion in a high-temperature water environment.

Description

Technical Field

[0001] This invention belongs to the field of nuclear engineering materials, specifically relating to a high-strength, corrosion-resistant niobium-zirconium-free alloy and its manufacturing method. Background Technology

[0002] Zirconium alloys possess excellent high-temperature mechanical properties and good corrosion resistance in aqueous environments, along with a very low thermal neutron absorption cross section. Therefore, they are widely used in the manufacture of fuel assembly structural components for pressurized water reactor nuclear power plants. Adding nitrogen (Nb) to zirconium alloys can effectively improve their mechanical properties; however, the addition of Nb significantly reduces the corrosion resistance of zirconium alloys in high dissolved oxygen environments. For example, ZIRLO alloys and M5 alloys fail to meet the design requirements of next-generation miniaturized reactors in aqueous environments due to their inability to withstand oxidation. Zr-4 and other Zr-Sn alloys do not contain Nb, but it is difficult to balance mechanical properties and corrosion resistance simultaneously, and high Sn content can also accelerate uniform corrosion of zirconium alloys.

[0003] Patent CN111254315A discloses a corrosion-resistant zirconium alloy. By adding elements such as Si, Ni, and V to the zirconium alloy, the resistance to knot corrosion is improved. However, this solution still cannot solve the problem of uniform corrosion resistance decay under high Sn content. The protective performance of the zirconium alloy oxide film provided by this solution will still show a significant decline when exposed to a long-term steam corrosion environment.

[0004] Patent CN111394617A adds trace amounts of Nb to improve the performance of zirconium alloys, but this still results in the risk of insufficient corrosion resistance in high dissolved oxygen environments. In addition, the zirconium alloys provided by this solution exhibit a decrease in the α-β phase transformation temperature, which increases the complexity of the heat treatment process for zirconium alloys.

[0005] Therefore, providing a niobium-free zirconium alloy with good comprehensive properties has high practical value. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength, corrosion-resistant niobium-free zirconium alloy, thereby improving the mechanical properties and corrosion resistance of zirconium alloys. This invention also provides a method for manufacturing this high-strength, corrosion-resistant niobium-free zirconium alloy.

[0007] According to one aspect of the present invention, a high-strength, corrosion-resistant niobium-zirconium-free alloy is provided, the alloy containing, by weight, 0.7%-1.5% Sn, 0.1%-0.4% Fe, 0.15%-0.35% Cr, 0.02%-0.08% Ni, 0.1%-0.18% O, and at least one of the following elements: 0.001%-0.1% Ge, 0.001%-0.15% Cu; wherein 0.27%≤Fe+Cr+Ni≤0.45%; the balance being Zr and unavoidable impurities; and by atomic ratio, 1≤Fe / Cr≤1.8, 0.13%≤Ni / Fe≤0.3.

[0008] In zirconium alloys, t-ZrO2 is the key phase for the protective zirconium alloy oxide film. Adding Ge can delay the phase transformation process of t-ZrO2 and improve the protective properties of the zirconium alloy oxide film. 4+ The ionic radius (53 pm) is greater than that of Zr. 4+ With a small ionic radius (72 pm), Cu particles, when dissolved in ZrO2, can delay the t-ZrO2 phase transformation, thereby inhibiting the accumulation of phase transformation stress, prolonging the corrosion transition period, and thus offsetting the negative impact of high tin content on zirconium alloy corrosion. Introducing Cu allows the presence of a nano-Cu second phase in the zirconium alloy, creating a hydrogen trapping effect to capture diffused hydrogen and reduce the risk of hydrogen-induced cracking during fuel rod cladding service. Simultaneously, Cu particles can also inhibit recrystallization and grain growth in the zirconium alloy matrix, improving the adhesion of the oxide film on the zirconium alloy surface.

[0009] By controlling the Fe / Cr atomic ratio (hereinafter referred to as Fe / Cr ratio), a Zr(Fe,Cr)2 Laves phase with stable composition and moderate volume expansion after oxidation can be formed in the alloy matrix. The alloy composition with this Fe / Cr ratio exhibits better corrosion resistance compared to Zr-4 alloys with a higher Fe / Cr ratio (approximately 2:1). NiO has high solid solubility in the ZrO2 matrix (approximately 5 mol%), significantly higher than Fe2O3 or Cr2O3 (approximately 2 mol%), thus improving the compatibility between the alloy matrix and the oxide film. Furthermore, the Pilling-Bedworth (PB) ratio of NiO is 1.65, much lower than Fe2O3 (2.09) and Cr2O3 (2.00), and closer to the PB ratio of ZrO2 (1.56). These characteristics collectively lead to a significant reduction in oxidation-induced stress, and since stress plays a crucial role in the initiation of knot corrosion, this alloy can effectively prevent knot corrosion. Controlling the Ni / Fe atomic ratio is to optimize the Ni content in the Zr2(Fe,Ni) type second phase, so that it can take advantage of the high solubility of NiO without excessively increasing hydrogen absorption.

[0010] Furthermore, in some embodiments, the matrix of the high-strength corrosion-resistant niobium-zirconium-free alloy is α-Zr, in which dispersed Zr2(Fe,Ni), Zr(Fe,Cr)2 and Cu and / or Ge particles are distributed; the total amount of solid dissolved elements in α-Zr, by weight ratio, is 0.27%≤Fe+Cr+Ni≤0.45%.

[0011] Solid solution of Fe, Cr, and Ni is crucial for inhibiting knot corrosion. Increasing the solid solubility of Fe, Cr, and Ni in the α-Zr matrix helps reduce the anisotropy of oxide film growth, thereby improving the alloy's resistance to knot corrosion. Controlling the total amount of solid solution elements ensures sufficient solid solution strengthening and inhibits knot corrosion nucleation while avoiding excessive matrix lattice distortion that could accelerate initial corrosion. The synergistic effect of increased Cr content and Ni addition enhances the stability of the oxidation front during zirconium alloy corrosion and inhibits knot corrosion nucleation and growth. This combination promotes a uniform oxidation process, thus completely preventing knot corrosion in zirconium alloys.

[0012] Furthermore, in some embodiments, the atomic ratio is 1.2 ≤ Fe / Cr ≤ 1.5.

[0013] According to another aspect of the present invention, a method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy is provided, for manufacturing the high-strength, corrosion-resistant niobium-zirconium-free alloy provided in any of the foregoing embodiments. The method includes the following steps:

[0014] Step a): According to the composition of the high-strength corrosion-resistant niobium-zirconium-free alloy, the raw materials are smelted to obtain an alloy ingot. The alloy ingot is then subjected to β-phase region homogenization heat treatment, hot rolling, and cold rolling to obtain an alloy billet.

[0015] Step b): The alloy billet is subjected to vacuum heating treatment at 450℃-500℃ for 5h-15h to obtain an aged billet with dispersed precipitates in its microstructure.

[0016] Step c): The aged billet is heat-treated at 530℃-590℃ for 2h-6h to obtain a high-strength, corrosion-resistant niobium-zirconium-free alloy finished product.

[0017] By performing medium-temperature aging treatment at 450℃-500℃, metastable nanophases (Cu and / or Ge second-phase particles) can be pre-precipitated, serving as nucleation sites for subsequent recrystallization of zirconium alloys and other second phases, thus improving the uniformity of the microstructure of the finished alloy. At the same time, medium-temperature aging treatment can also alleviate the diffusion of Sn to grain boundaries, reduce Sn segregation at grain boundaries, and suppress the weakening effect of Sn on grain boundaries.

[0018] Furthermore, in some embodiments, in step c), by weight ratio, when the Sn content in the high-strength corrosion-resistant niobium-zirconium-free alloy does not exceed 1.2%, the heat treatment temperature is 530℃-550℃, and the holding time is 2h-4h; when the Sn content in the high-strength corrosion-resistant niobium-zirconium-free alloy is >1.2%, the heat treatment temperature is 570℃-590℃, and the holding time is 3h-6h.

[0019] When the Sn content is low, low-temperature annealing inhibits grain growth, resulting in fine equiaxed grains (approximately 5μm-10μm) + high-density nano-second phase, maximizing corrosion resistance. When the Sn content is high, higher annealing temperatures promote complete recrystallization of the alloy structure and ensure sufficient Sn dissolution, enhancing the overall strength of the alloy. The second phase particles in the alloy are moderately coarsened (approximately 80nm-150nm), balancing the strength and oxidation resistance of the alloy.

[0020] Furthermore, in some embodiments, in step a), the alloy ingot is manufactured by a vacuum consumable arc melting process.

[0021] Furthermore, in some embodiments, in step a), the process of homogenizing the β phase region heat treatment is as follows: heating the alloy ingot to 1000℃-1050℃ and holding it for 30min-60min, followed by water quenching.

[0022] Furthermore, in some embodiments, in step a), the hot rolling temperature is 650°C-750°C.

[0023] Furthermore, in some embodiments, in step a), the total deformation of the cold rolling process is 70%-90%. Attached Figure Description

[0024] Figure 1 This is a transmission electron microscope image of the microstructure of an annealed billet in one embodiment;

[0025] Figure 2 The image shows the microstructure of the high-strength, corrosion-resistant, niobium-zirconium-free alloy product from Example 1.

[0026] Figure 3 The image shows the microstructure of the high-strength, corrosion-resistant, niobium-zirconium-free alloy product from Example 2.

[0027] Figure 4 Corrosion kinetic curves in steam environments are shown for both examples and comparative examples.

[0028] The purpose of the above figures is to provide a detailed description of the invention so that those skilled in the art can understand the technical concept of the invention, and not to limit the invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0030] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment herein. The phrase appearing in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without causing structural conflicts.

[0031] In this article, "multiple" means at least two.

[0032] Zirconium alloys exhibit excellent mechanical properties, corrosion resistance, and neutron permeability within the normal operating temperature range of pressurized water reactors, making them widely used in the manufacture of fuel rod cladding, fuel assembly grids, and strips. Among the zirconium alloys commonly used in civilian nuclear power plants, niobium-containing zirconium alloys possess high mechanical properties, but they are prone to significant corrosion in high dissolved oxygen environments. Conversely, it is difficult to achieve a balance between mechanical properties and corrosion resistance in niobium-free zirconium alloys.

[0033] The embodiments of the present invention provide a niobium-free zirconium alloy that simultaneously possesses good resistance to nodular corrosion and excellent long-term resistance to uniform corrosion, as well as mechanical properties and creep resistance that meet the design requirements of high burnup reactors.

[0034] Specifically, the alloy contains, by weight, 0.7%-1.5% Sn, 0.1%-0.4% Fe, 0.15%-0.35% Cr, 0.02%-0.08% Ni, 0.1%-0.18% O, and at least one of the following elements: 0.001%-0.1% Ge, 0.001%-0.15% Cu; wherein 0.27%≤Fe+Cr+Ni≤0.45%; the balance is Zr and unavoidable impurities; by atomic ratio, 1≤Fe / Cr≤1.8, 0.13≤Ni / Fe≤0.3. The alloy matrix is ​​α-Zr, in which dispersed Zr2(Fe,Ni), Zr(Fe,Cr)2, and Cu and / or Ge particles are distributed; the total amount of solid dissolved elements in α-Zr, by weight, is 0.27%≤Fe+Cr+Ni≤0.45%.

[0035] NiO exhibits high solid solubility and good microstructure compatibility in the oxide layer of zirconium alloys. Introducing Ni effectively reduces oxidation-induced stress on the alloy surface and improves oxide adhesion. However, Ni is prone to transmutation and gas generation under neutron irradiation, necessitating control of the Fe / Ni atomic ratio to manage hydrogen absorption in the zirconium alloy. This alloy, by effectively controlling the Fe / Cr atomic ratio, promotes the formation of a stable Laves phase with a Zr(Fe,Cr)₂ composition in the alloy matrix. The volume change of this Laves phase after oxidation matches the α-Zr matrix phase, contributing to improved bonding strength and structural integrity of the oxide film on the zirconium alloy surface. In a further preferred embodiment, while ensuring the Ni / Fe atomic ratio, the Fe / Cr atomic ratio is further limited to 1.2-1.5 to achieve better corrosion resistance.

[0036] Solid solution of Fe, Cr, and Ni is key to inhibiting knot corrosion. Increasing the solid solubility of Fe, Cr, and Ni in the α-Zr matrix helps reduce the anisotropy of oxide film growth, thereby improving the alloy's resistance to knot corrosion. Controlling the total amount of solid solution elements ensures sufficient solid solution strengthening and inhibits knot corrosion nucleation while avoiding excessive matrix lattice distortion that could accelerate initial corrosion. The synergistic effect of increased Cr content and Ni addition enhances the stability of the oxidation front during zirconium alloy corrosion and inhibits knot corrosion nucleation and growth. This combination promotes a uniform oxidation process, thus completely preventing knot corrosion in zirconium alloys.

[0037] The high-strength, corrosion-resistant niobium-free zirconium alloy provided in the above embodiments can be manufactured by a method for manufacturing a high-strength, corrosion-resistant niobium-free zirconium alloy provided in another aspect of the present invention. The specific steps are as follows:

[0038] Step a): Raw materials are provided according to the composition of the high-strength, corrosion-resistant niobium-zirconium-free alloy, and the raw materials are smelted to obtain alloy ingots. In a preferred embodiment, the smelting adopts a vacuum consumable arc melting process. The alloy ingot is subjected to β-phase region homogenization heat treatment, specifically, held at 1000℃-1050℃ for 30min-60min, followed by water quenching; after quenching, it is heated to 650℃-750℃ for hot rolling, followed by cold rolling with a total deformation of 70%-90% to obtain alloy billets.

[0039] Step b): The alloy billet is subjected to a medium-temperature aging treatment at 450℃-500℃ for 5h-15h to obtain an aged billet. The medium-temperature aging treatment can promote the precipitation of second-phase particles in the alloy and regulate the balance between solid solution and precipitation of alloying elements, thereby adjusting the total amount of Fe, Cr, and Ni elements dissolved in the α-Zr matrix.

[0040] Step c): The aged billet is heat-treated at 530℃-590℃ for 2h-6h to obtain a high-strength, corrosion-resistant niobium-free zirconium alloy product. In a further preferred embodiment, different heat treatment regimes are used for the final heat treatment based on the Sn content in the zirconium alloy: when the Sn content by weight does not exceed 1.2%, the heat treatment temperature is 530℃-550℃, and the holding time is 2h-4h; when Sn>1.2%, the heat treatment temperature is 570℃-590℃, and the holding time is 3h-6h.

[0041] When the Sn content is low, low-temperature annealing inhibits grain growth, resulting in fine equiaxed grains (approximately 5μm-10μm) + high-density nano-second phase, maximizing corrosion resistance. When the Sn content is high, higher annealing temperatures promote complete recrystallization of the alloy structure and ensure sufficient Sn dissolution, enhancing the overall strength of the alloy. The second phase particles in the alloy are moderately coarsened (approximately 80nm-150nm), balancing the strength and oxidation resistance of the alloy.

[0042] In Example 1, the high-strength, corrosion-resistant niobium-zirconium-free alloy, by weight, comprises 1% Sn, 0.2% Fe, 0.18% Cr, 0.03% Ni, 0.005% Ge, 0.06% Cu, and 0.12% O, with the balance being Zr; wherein, by atomic ratio, Fe / Cr is 1.035 and Ni / Fe is 0.1427. This alloy is manufactured by the following method: First, raw materials are provided and alloy ingots are obtained by vacuum arc remelting. The ingots are held at 1030°C for 45 minutes, followed by water quenching. After quenching, the ingots are heated to 700°C for hot rolling, followed by cold rolling with a total deformation of 70%-90%, yielding alloy billets. Subsequently, the alloy billets are subjected to medium-temperature aging treatment at 495°C for 8 hours to obtain aged billets. After aging treatment, as shown... Figure 1 As shown, the microstructure of the aged billet contains uniformly dispersed second-phase particles, including nano-sized Cu / Ge particles 1 and Zr(Fe,Cr)2 / Zr2(Fe,Ni) particles 2. The aging treatment simultaneously adjusted the ratio of Fe, Cr, and Ni particles dissolved in solid solution to their precipitation. Energy dispersive spectroscopy (EDS) analysis revealed that the total amount of Fe, Cr, and Ni dissolved in α-Zr satisfies the weight ratio of 0.27% ≤ Fe + Cr + Ni ≤ 0.45%. Finally, after holding at 540℃ for 3 hours, a high-strength, corrosion-resistant niobium-free zirconium alloy was obtained, with the microstructure shown below. Figure 2 As shown, its morphology consists of fine equiaxed crystals and dispersed, fine second-phase particles. The α-Zr equiaxed crystal grain size is about 5 μm, and the second-phase particle size is usually below 100 nm.

[0043] In Example 2, the high-strength, corrosion-resistant niobium-zirconium-free alloy, by weight, comprises 1.35% Sn, 0.21% Fe, 0.18% Cr, 0.03% Ni, 0.005% Ge, 0.06% Cu, and 0.14% O, with the balance being Zr; the atomic ratios are Fe / Cr = 1.086 and Ni / Fe = 0.1359. This alloy is manufactured using the following method: First, raw materials are provided and melted using a vacuum arc remelting process to obtain an alloy ingot, which is held at 1030°C for 45 minutes, followed by water quenching. After quenching, the ingot is heated to 700°C for hot rolling, followed by cold rolling with 80% total deformation to obtain an alloy billet. Subsequently, the alloy billet is subjected to a medium-temperature aging treatment at 495°C for 8 hours to obtain an aged billet. Finally, after holding at 570℃ for 4 hours, a high-strength, corrosion-resistant niobium-zirconium-free alloy product was obtained, with a microstructure as follows: Figure 3 As shown, its morphology consists of fully recrystallized equiaxed crystals and dispersed second-phase particles. The α-Zr equiaxed crystal grain size is about 10 μm. The second-phase particles are coarsened to a certain extent under higher final heat treatment temperature and longer holding time, and their particle size is between 80 nm and 150 nm.

[0044] The zirconium alloy in Comparative Example 1, by weight, comprises 1.33% Sn, 0.21% Fe, 0.18% Cr, 0.028% Ni, 0.0102% Si, 0.12% O, with Zr as the balance; the Fe / Cr ratio is 1.086 and the Ni / Fe ratio is 0.1269 by atomic number. This alloy was manufactured using the following method: the alloy ingot was preheated at 700℃ for 30 min and hot-pressed, then heated at 1030℃ for 40 min, followed by multiple hot rollings at 700℃, then reheated to 1030℃ and held for 40 min, and then subjected to multiple cold rollings. Between cold rollings, a vacuum heating treatment was performed at 550℃ for 4 h. After the final cold rolling, the alloy was held at 580℃ for 5 h and cooled to obtain the comparative alloy.

[0045] The zirconium alloy used in Comparative Example 2 is a commercially available Zr-4 alloy product.

[0046] The corrosion kinetic curves of Examples 1 and 2 and Comparative Examples 1 and 2 in water vapor at 500℃ and 10.3MPa are shown below. Figure 4 As shown in the figure. By comparison, it can be seen that the corrosion weight gain rate of Comparative Example 1 increases rapidly after 400 hours, reaching 567.98 mg / dm³ at 1000 hours. 2 Comparative Example 2 showed boil-like corrosion after 7 hours, with a rapid increase in corrosion weight. Example 1, however, exhibited the best corrosion resistance, with a corrosion weight gain of only 384.03 mg / dm³ after 1000 hours. 2In Example 2, when the Sn content exceeded that of Comparative Example 1, the corrosion weight gain after 1000 hours was only 450.62 mg / dm³. 2 .

[0047] The room temperature tensile strengths of Examples 1 and 2 were 398 MPa and 425 MPa, respectively; the room temperature tensile strengths of Comparative Examples 1 and 2 were 381 MPa and 368 MPa, respectively. The comparison shows that the room temperature tensile strengths of Examples 1 and 2 were increased by 4.5% and 11.5% respectively compared to Comparative Example 1.

[0048] As can be seen, the high-strength, corrosion-resistant niobium-free zirconium alloy provided in this application achieves excellent corrosion resistance without introducing niobium, effectively preventing the occurrence of knot corrosion through reasonable optimization of alloy composition and manufacturing process. Using the high-strength, corrosion-resistant niobium-free zirconium alloy provided in this embodiment of the invention as a structural component of pressurized water reactor nuclear power plant fuel assemblies can effectively improve the service life and reliability of the fuel assemblies.

[0049] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimization or equivalent substitution of the technical features involved, as well as combination of implementation methods in different embodiments without causing a conflict of principles, all fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy, characterized in that, And includes the following steps: Step a): Melting to obtain an alloy ingot, the alloy ingot containing, by weight, 0.7%-1.5% Sn, 0.1%-0.4% Fe, 0.15%-0.35% Cr, 0.02%-0.08% Ni, 0.1%-0.18% O, 0.001%-0.1% Ge, and 0.001%-0.15% Cu; the balance being Zr and unavoidable impurities; by atomic ratio, 1≤Fe / Cr≤1.8, 0.13≤Ni / Fe≤0.3; the alloy ingot is then subjected to β-phase region homogenization heat treatment, hot rolling, and cold rolling to obtain an alloy billet; Step b): The alloy billet is subjected to vacuum heating treatment at 450℃-500℃ for 5h-15h to obtain an aged billet with dispersed precipitates in its microstructure. Step c): The aged billet is heat-treated at 530℃-590℃ for 2h-6h to obtain a high-strength, corrosion-resistant niobium-zirconium-free alloy finished product.

2. The method for manufacturing the high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 1, characterized in that, In step c), by weight ratio, When the Sn content in the high-strength, corrosion-resistant, niobium-zirconium-free alloy does not exceed 1.2%, the heat treatment temperature is 530℃-550℃, and the holding time is 2h-4h. When Sn > 1.2% in the high-strength, corrosion-resistant niobium-zirconium-free alloy, the heat treatment temperature is 570℃-590℃ and the holding time is 3h-6h.

3. The method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 1 or 2, characterized in that, In step a), the alloy ingot is manufactured by a vacuum consumable arc melting process.

4. The method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 1 or 2, characterized in that, In step a), the homogenization heat treatment process of the β phase region is as follows: the alloy ingot is heated to 1000℃-1050℃ and held for 30min-60min, followed by water quenching.

5. The method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 1 or 2, characterized in that, In step a), the hot rolling temperature is 650℃-750℃.

6. The method for manufacturing a high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 1 or 2, characterized in that, In step a), the total deformation during cold rolling is 70%-90%.

7. A high-strength, corrosion-resistant niobium-zirconium-free alloy, characterized in that, It is manufactured using the manufacturing method of the high-strength, corrosion-resistant, niobium-zirconium-free alloy as described in any one of claims 1 to 6.

8. The high-strength, corrosion-resistant niobium-zirconium-free alloy according to claim 7, characterized in that, The matrix of the high-strength, corrosion-resistant niobium-zirconium-free alloy is α-Zr, in which dispersed Zr2(Fe,Ni), Zr(Fe,Cr)2, Cu and Ge particles are distributed; the total amount of solid dissolved elements in α-Zr, by weight ratio, is 0.27%≤Fe+Cr+Ni≤0.45%.

9. The high-strength, corrosion-resistant, niobium-zirconium-free alloy according to claim 7 or 8, characterized in that, Based on the atomic ratio, 1.2 ≤ Fe / Cr ≤ 1.5.

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