High-strength cubic texture composite strip and preparation method thereof

Abstract

The invention discloses a high-strength strong-cube-texture metal strip and a preparation method thereof, through alloy component design, proper amounts of Cr, Cu, Mo, Fe and W are added into Ni alloy to serve as surface alloy, proper amounts of Al, Ti, C, Mo and other alloy elements are added into high-W Ni alloy to serve as intermediate alloy, and the high-strength strong-cube-texture metal strip is prepared by utilizing the idea of a multi-layer composite material. The strong cubic texture can be obtained through cold rolling and three-step heat treatment, and the high-strength composite strip with the strong cubic texture can be finally obtained by combining aging treatment subsequently and utilizing the precipitation strengthening principle.

Description

Technical Field

[0001] This invention belongs to the field of high-strength metal substrate preparation technology for second-generation high-temperature coated superconducting tapes, specifically relating to a high-strength cubic textured composite tape and its preparation method. Background Technology

[0002] Second-generation high-temperature coated superconducting materials, represented by YBCO, have potential applications in fields such as power and transportation. Currently, China can mass-produce these coated superconducting tapes. However, the application areas are significantly limited due to the low strength and ferromagnetic properties of the metal tapes supporting the YBCO superconducting films. High-performance coated superconducting tapes place high demands on the metal substrate material, requiring high yield strength, ferromagnetism under liquid nitrogen, and a strong cubic texture. Ni-W binary alloys have simple compositions and are widely studied metal substrate materials. High-W nickel-based alloys possess high strength and ferromagnetism, showing great application potential. However, it is difficult to form a strong cubic texture during recrystallization, making it challenging to simultaneously achieve superior mechanical properties, ferromagnetism, and a strong cubic texture. Designing new alloy compositions and novel reinforced texture metal tapes is key to simultaneously achieving ferromagnetism, high strength, and a strong cubic texture in metal tapes.

[0003] Patent document CN202511002818.1 discloses a high-strength metal composite strip and its preparation method. The composite strip is composed of a first outer layer alloy, an intermediate layer alloy, and a second outer layer alloy stacked sequentially. Both the first and second outer layer alloys are Ni-9wt.%W alloys, and the intermediate layer alloy is Ni-12wt.%W-3wt.%Mo alloy. The cubic texture content of the composite strip is not less than 90%, and the yield strength is not less than 480MPa. This patent document does not involve obtaining a strong cubic texture on the surface through rolling composite combined with a special heat treatment process. The core is a supersaturated solid solution, and finally, a large number of dispersed precipitates are formed in the core by low-temperature aging treatment to improve the core strength without reducing the content of strong cubic texture on the surface. Patent document CN202510032389.6 discloses a high-strength / strong cubic textured metal strip and its preparation method. Through alloy composition design, appropriate amounts of W, C, Cr, Mo, Cu, and V are added to a Ni alloy. While improving ferromagnetism, the rolling and heat treatment processes are controlled, and the heat treatment atmosphere is appropriately matched, ultimately resulting in a strip with a strong cubic texture and high strength. This patent document only focuses on the composition design of a single-layer alloy and the improvement of strip performance through processing. It does not involve multi-layer alloy composites, nor does it involve obtaining a strong cubic texture on the surface through rolling composite combined with a special heat treatment regime, with the core being a supersaturated solid solution, and finally using low-temperature aging treatment to form a large number of dispersed precipitates in the core, increasing the core strength without reducing the content of the strong cubic texture on the surface. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a high-strength cubic textured composite strip and its preparation method.

[0005] This invention is achieved through the following technical solution: a high-strength cubic textured composite strip, wherein the initial ingot for preparing the composite strip consists of three metal layers, wherein the chemical composition of the upper and lower outer layers is: 10wt%~15wt% Cu, 10wt%~16wt% Fe, 10wt%~15wt% Cr, 2wt%~3wt% Mo, 2wt%~3wt% W, with the remainder being Ni; the chemical composition of the middle layer is: 12wt% W, 1.5wt%~1.8wt% Al, 2wt%~3wt% Mo, 0.7wt%~1.2wt% Ti, 0.1wt%~0.15wt% C, with the remainder being Ni.

[0006] A method for preparing the above-mentioned high-strength cubic textured composite tape, comprising the following steps:

[0007] Step S1: Obtain an alloy ingot with the composition of the central layer through vacuum induction melting, and then obtain the initial billet of the central layer for composite use through forging and hot rolling, with a final rolling temperature of 950°C or higher.

[0008] Step S2: Obtain alloy ingots with upper and lower outer layer compositions through vacuum induction melting, and then obtain initial billets for composite upper and lower outer layers through forging and hot rolling. The final rolling temperature is 550-600℃, and the deformation amount in the last pass is 40%-45%.

[0009] Step S3: The initial billet of the central layer and the initial billets of the upper and lower outer layers are rolled into a layered composite billet by cold rolling. The cold rolling deformation is 60% to 70%, and the process is repeated in one pass.

[0010] Step S4: Cold roll the layered composite billet to 0.07-0.09 mm, and then perform a three-step heat treatment to obtain a composite strip with a strong cubic texture on the surface and a supersaturated solid solution in the core. The first heat treatment process is: heat the strip at 500-550℃ for 2-3 hours by furnace heating and then cool it to room temperature. The second heat treatment process is: heat the strip at 850-900℃ for 2-5 minutes by furnace heating and then cool it to room temperature. The third heat treatment process is: heat the strip at 1200-1230℃ for 5-10 minutes by furnace heating and then cool it to room temperature.

[0011] Step S5: The composite strip is subjected to low-temperature annealing again to obtain a high-strength cubic textured composite strip. The specific process of low-temperature annealing is as follows: the temperature is kept at 680-720℃ for 2 hours. Through the low-temperature annealing process, a large number of dispersed precipitates are formed in the core to improve the strength of the core, while not reducing the content of strong cubic texture on the surface.

[0012] Furthermore, in step S1, the initial thickness of the central layer of the billet is 8–8.6 mm.

[0013] Furthermore, in step S2, the thickness of the initial billet of the upper and lower outer layers after hot rolling is 5 to 5.8 mm.

[0014] Furthermore, in step S3, the initial billet of the central layer and the initial billets of the upper and lower outer layers before cold rolling composite need to have their surface oxide scale removed by grinding.

[0015] Furthermore, in step S4, the atmosphere for the three heat treatment steps is a mixture of nitrogen and hydrogen, with a nitrogen to hydrogen volume ratio of 2:1.

[0016] Compared with existing technologies, this invention has the following advantages and beneficial technical effects: By adding appropriate amounts of Cr, Cu, Mo, and W to Ni alloys, this invention can significantly reduce the ferromagnetism of the alloy while achieving a higher yield strength. Through a rolling composite approach combined with a special heat treatment process, a strong cubic texture can be obtained on the surface, while the core is a supersaturated solid solution. Finally, low-temperature aging treatment forms a large number of dispersed precipitates in the core, improving the core strength without reducing the content of the strong cubic texture on the surface, thus enabling industrial production. Attached Figure Description

[0017] Figure 1 This is a microscopic image of the tissue after low-temperature treatment in Example 1.

[0018] Figure 2 This is a microscopic image of the tissue after low-temperature treatment in Example 2.

[0019] Figure 3 This is a microscopic image of the tissue after low-temperature treatment in Example 3. Detailed Implementation

[0020] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0021] Example 1

[0022] The initial ingot for composite materials was prepared by vacuum induction melting. The chemical composition of the upper and lower outer layers was: 10 wt% Cu, 10 wt% Fe, 10 wt% Cr, 2 wt% Mo, 2 wt% W, with the remainder being Ni. The chemical composition of the middle layer was: 12 wt% W, 1.8 wt% Al, 3 wt% Mo, 1.2 wt% Ti, 0.15 wt% C, with the remainder being Ni. Subsequently, the central layer is forged and hot-rolled to obtain the initial ingot for the composite central layer. The final rolling temperature is 970℃, and the thickness of the hot-rolled central layer initial ingot is 8.6mm. Alloy ingots of the upper and lower outer layers are cast, and subsequently forged and hot-rolled to obtain the initial ingots for the composite upper and lower outer layers. The final rolling temperature is 550℃, with a final deformation of 40%, and the thickness of the hot-rolled upper and lower outer layer initial ingots is 5.8mm. The above three initial ingots are then stacked and rolled into a layered composite ingot using a cold rolling method. The cold rolling deformation is 70%, and it is done in one pass. The resulting layered composite ingot is cold-rolled to 0.09mm, and then subjected to a three-step heat treatment to obtain a surface layer with strong cubic properties. The composite strip with a textured structure and a supersaturated solid solution core undergoes the following heat treatment processes: First, a furnace heating process is performed, holding at 500℃ for 2 hours and then cooling to room temperature; second, a furnace heating process is performed, holding at 900℃ for 2 minutes and then cooling to room temperature; third, a furnace heating process is performed, holding at 1230℃ for 5 minutes and then cooling to room temperature. All three heat treatments are conducted in a nitrogen and hydrogen mixture with a nitrogen to hydrogen volume ratio of 2:1. The resulting strip is then subjected to low-temperature annealing, specifically, holding at 680℃ for 2 hours. The microstructure of the composite strip is as follows: Figure 1 As shown, a dispersed nano-precipitated phase was formed; ultimately, a high-strength, strongly cubic textured, and non-ferromagnetic composite tape was obtained.

[0023] Example 2

[0024] The initial ingot for composite materials was prepared by vacuum induction melting. The chemical composition of the upper and lower outer layers was 15 wt% Cu, 16 wt% Fe, 15 wt% Cr, 3 wt% Mo, 3 wt% W, with the remainder being Ni. The chemical composition of the middle layer was 12 wt% W, 1.5 wt% Al, 3 wt% Mo, 0.7 wt% Ti, 0.1 wt% C, with the remainder being Ni. Subsequently, the central layer is forged and hot-rolled to obtain the initial ingot for the composite central layer. The final rolling temperature is 960℃, and the thickness of the hot-rolled central layer initial ingot is 8mm. The alloy ingots of the upper and lower outer layers are cast, and then forged and hot-rolled to obtain the initial ingots for the composite upper and lower outer layers. The final rolling temperature is 600℃, and the deformation in the last pass is 45%. The thickness of the hot-rolled upper and lower outer layer initial ingots is 5.8mm. The above three initial ingots are stacked and rolled into a layered composite ingot using a cold rolling method. The cold rolling deformation is 60%, and it is done in one pass. The resulting layered composite ingot is cold-rolled to 0.07mm, and then subjected to three-step heat treatment to obtain a surface layer with a strong cubic texture. The composite strip with a core of supersaturated solid solution undergoes the following heat treatment processes: First, a furnace heating process is performed, holding at 550℃ for 2 hours and then cooling to room temperature. Second, a furnace heating process is performed, holding at 850℃ for 5 minutes and then cooling to room temperature. Third, a furnace heating process is performed, holding at 1200℃ for 10 minutes and then cooling to room temperature. All three heat treatments are conducted in a nitrogen and hydrogen mixture with a nitrogen to hydrogen volume ratio of 2:1. The resulting composite strip is then subjected to low-temperature annealing, specifically holding at 720℃ for 2 hours. The microstructure of the composite strip is as follows... Figure 2 As shown, a dispersed nano-precipitated phase was formed; ultimately, a high-strength, strongly cubic textured, and non-ferromagnetic composite tape was obtained.

[0025] Example 3

[0026] The initial ingot for composite materials was prepared by vacuum induction melting. The chemical composition of the upper and lower outer layers was 12 wt% Cu, 14 wt% Fe, 13 wt% Cr, 2.5 wt% Mo, 2.6 wt% W, with the remainder being Ni. The chemical composition of the middle layer was 12 wt% W, 1.7 wt% Al, 2.5 wt% Mo, 0.9 wt% Ti, 0.12 wt% C, with the remainder being Ni. Subsequently, the central layer is forged and hot-rolled to obtain the initial ingot for the composite central layer. The final rolling temperature is 980℃, and the thickness of the hot-rolled central layer initial ingot is 8.3mm. The alloy ingots of the upper and lower outer layers are cast, and then forged and hot-rolled to obtain the initial ingots for the composite upper and lower outer layers. The final rolling temperature is 580℃, and the deformation in the last pass is 43%. The thickness of the hot-rolled upper and lower outer layer initial ingots is 5.5mm. The above three initial ingots are stacked and rolled into a layered composite ingot using a cold rolling method. The cold rolling deformation is 65%, and it is done in one pass. The resulting layered composite ingot is cold-rolled to 0.08mm, and then subjected to a three-step heat treatment to obtain a surface layer with a strong cubic texture. The composite strip with a core of supersaturated solid solution undergoes the following heat treatment processes: First, a furnace heating process is performed, holding at 520℃ for 3 hours and then cooling to room temperature. Second, a furnace heating process is performed, holding at 870℃ for 4 minutes and then cooling to room temperature. Third, a furnace heating process is performed, holding at 1220℃ for 8 minutes and then cooling to room temperature. All three heat treatments are conducted in a nitrogen and hydrogen mixture with a nitrogen to hydrogen volume ratio of 2:1. The resulting composite strip is then subjected to low-temperature annealing, specifically holding at 700℃ for 2 hours. The microstructure of the composite strip is as follows: Figure 3 As shown, a dispersed nano-precipitated phase was formed; ultimately, a high-strength, strongly cubic textured, and non-ferromagnetic composite tape was obtained.

[0027] Table 1. Yield strength and cubic texture content of composite strips in Examples 1-3

[0028]

[0029]

[0030] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A high-strength cubic textured composite strip, characterized in that: The initial ingot for preparing this composite strip consists of three metal layers. The outermost and innermost layers have the following chemical compositions: 10wt%~15wt% Cu, 10wt%~16wt% Fe, 10wt%~15wt% Cr, 2wt%~3wt% Mo, 2wt%~3wt% W, with the remainder being Ni. The middle layer has the following chemical composition: 12wt% W, 1.5wt%~1.8wt% Al, 2wt%~3wt% Mo, 0.7wt%~1.2wt% Ti, 0.1wt%~0.15wt% C, with the remainder being Ni.

2. A method for preparing the high-strength cubic textured composite tape according to claim 1, characterized in that... The preparation steps are as follows: Step S1: Obtain an alloy ingot with the composition of the central layer through vacuum induction melting, and then obtain the initial billet of the central layer for composite use through forging and hot rolling, with a final rolling temperature of 950°C or higher. Step S2: Obtain alloy ingots with upper and lower outer layer compositions through vacuum induction melting, and then obtain initial billets for composite upper and lower outer layers through forging and hot rolling. The final rolling temperature is 550~600℃, and the deformation amount in the last pass is 40%~45%. Step S3: The initial billet of the central layer and the initial billets of the upper and lower outer layers are rolled into a layered composite billet by cold rolling. The cold rolling deformation is 60%~70%, and it is done in one pass. Step S4: Cold roll the layered composite billet to 0.07~0.09mm, and then perform three-step heat treatment to obtain a composite strip with a strong cubic texture on the surface and a supersaturated solid solution in the core. The first heat treatment process is: heat the strip at 500~550℃ for 2~3 hours by furnace heating and then cool it to room temperature. The second heat treatment process is: heat the strip at 850~900℃ for 2~5 minutes by furnace heating and then cool it to room temperature. The third heat treatment process is: heat the strip at 1200~1230℃ for 5~10 minutes by furnace heating and then cool it to room temperature. Step S5: The composite strip is subjected to low-temperature annealing again to obtain a high-strength cubic textured composite strip. The specific process of low-temperature annealing is as follows: the temperature is kept at 680~720℃ for 2 hours. Through the low-temperature annealing process, a large number of dispersed precipitates are formed in the core to improve the strength of the core, while not reducing the content of strong cubic texture on the surface.

3. The method for preparing the high-strength cubic textured composite tape according to claim 2, characterized in that: In step S1, the initial thickness of the central layer of the billet after hot rolling is 8~8.6mm.

4. The method for preparing the high-strength cubic textured composite tape according to claim 2, characterized in that: In step S2, the initial thickness of the upper and lower outer layers of the billet after hot rolling is 5~5.8mm.

5. The method for preparing the high-strength cubic textured composite tape according to claim 2, characterized in that: In step S3, the initial billet of the central layer and the initial billets of the upper and lower outer layers before cold rolling composite need to have their surface oxide scale removed by grinding.

6. The method for preparing the high-strength cubic textured composite tape according to claim 2, characterized in that: In step S4, the atmosphere for the three heat treatment steps is a mixture of nitrogen and hydrogen, with a nitrogen to hydrogen volume ratio of 2:1.

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