A method for preparing alloy materials with different grade gradient structures

Abstract

This invention belongs to the field of explosive welding technology and discloses a method for preparing alloy materials with different grades of gradient structures. The method includes: selecting a substrate and a flyer plate according to the grain size of the base material from large to small, and performing explosive welding layer by layer to obtain a primary gradient structure composite plate; subjecting the primary gradient structure composite plate to cold deformation, followed by recrystallization treatment at different degrees to obtain a recrystallized gradient structure composite plate; and post-processing the recrystallized gradient structure composite plate to obtain alloy materials with different grades of gradient structures. This method can realize the direct design, preparation, and high-level control of large-size gradient structure materials, and is expected to achieve a synergistic improvement in the comprehensive properties of large-size component materials, such as strength and plasticity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of explosive welding and relates to a preparation method of alloy materials with different grades of gradient structures. BACKGROUND

[0002] A gradient structure is a structure in which one component, organization or phase (or component) gradually transitions to another component, organization or phase (or component). By introducing such a gradient structure with non-uniform distribution into a material structure, the strength and plasticity of the material can be improved, and the gradient structure also plays an important role in improving various properties of the material.

[0003] Traditional gradient structure material preparation methods are complicated and have poor applicability to large-size materials, which makes it difficult to apply them to the production and manufacturing of actual large-size component materials. SUMMARY

[0004] The application aims to solve the problems of traditional gradient structure material preparation methods, such as complicated process and poor applicability to large-size materials, and provides a preparation method of alloy materials with different grades of gradient structures. The method can realize the direct design, preparation and high-level control of large-size gradient structure composite materials, and can comprehensively improve the comprehensive performance of the composite materials.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0006] The application aims to provide a preparation method of alloy materials with different grades of gradient structures, which comprises the following steps:

[0007] Selecting the base plate and the flyer plate according to the grain size of the base material from large to small, determining the thickness of the base plate and the flyer plate, performing explosive welding layer by layer in sequence, and obtaining a primary gradient structure composite plate;

[0008] Performing cold deformation on the primary gradient structure composite plate, and then performing different degrees of recrystallization treatment to obtain a recrystallized gradient structure composite plate;

[0009] Performing post-treatment on the recrystallized gradient structure composite plate to obtain alloy materials with different grades of gradient structures.

[0010] As a further improvement of the application, the step of selecting the base plate and the flyer plate according to the grain size of the base material from large to small, determining the thickness of the base plate and the flyer plate, and performing explosive welding layer by layer in sequence to obtain a primary gradient structure composite plate comprises the following steps:

[0011] Designing the gradient structure composite material to select the base material with the largest grain size as the base plate, determining the thickness of the base plate and the flyer plate, selecting the base material with the second largest grain size as the first flyer plate, and performing the first explosive welding to obtain a first composite plate;

[0012] Taking the first composite plate as a substrate, a third-grain-size base material as a first flyer plate, and the first flyer plate facing upward as a composite surface, a second composite plate is obtained by performing a second explosive welding.

[0013] According to the continuous reduction of the grain size of the base material, the continuous explosive welding is sequentially performed until the final designed layer is completed, and the primary gradient structure composite plate is obtained by cutting off the unwelded area.

[0014] As a further improvement of the present application, the single-layer design thickness of the substrate and the flyer plate is determined according to the total design thickness and the number of layers, and the substrate and the flyer plate corresponding to the first explosive welding and the last explosive welding are 2-3 mm larger than the single-layer design thickness, and the thickness of the flyer plate used in the intermediate welding process is equal or unequal.

[0015] As a further improvement of the present application, in each explosive welding, the thickness of the substrate is greater than the thickness of the corresponding flyer plate.

[0016] As a further improvement of the present application, the designed number of layers of the gradient structure composite material is not less than 3.

[0017] As a further improvement of the present application, the explosive welding parameters are a collision angle of 2-31° and a collision speed of 1700-3000 m / s.

[0018] As a further improvement of the present application, the primary gradient structure composite plate is subjected to cold deformation, and then subjected to different degrees of recrystallization treatment to obtain a recrystallized gradient structure composite plate, comprising:

[0019] The cold deformation amount is designed to be 40-80%, and the direction of the cold deformation amount is the same as the direction of the explosive welding;

[0020] The recrystallization temperature is (0.4-1) times the melting point, or the temperature is higher than the lowest solid solution temperature, and the composite material cannot complete recrystallization and is converted into a completely equiaxed crystal structure; and the recrystallized gradient structure composite plate is obtained.

[0021] As a further improvement of the present application, the recrystallized gradient structure composite plate is subjected to post-treatment to obtain different grades of gradient structure alloy materials, comprising:

[0022] If the base material is an age-hardened alloy, the recrystallized gradient structure composite plate is subjected to aging treatment;

[0023] The recrystallized gradient structure composite plate after aging treatment is subjected to finishing and shaping treatment to obtain a final alloy.

[0024] As a further improvement of the present application, the base material is an annealed pure copper or a solid-solution CuNiSiCr alloy.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application utilizes the unique advantages of large single composite area and high quality of explosion welding joint of the explosion welding technology, designs a gradient structure composite material composed of a single material combined with changes in grain size and thickness and their proportions, and cooperates with subsequent different degree recrystallization deformation heat treatment, so as to promote the heterogeneous degree and range of the composite material to continue to evolve and expand to form a full-space hybrid gradient structure composite material, realize direct design, preparation and high-level control of large-size gradient structure material, break through the cumbersome preparation method process of the previous gradient structure material, poor applicability to large-size material and many other constraints, and is expected to realize the synergistic improvement of the comprehensive performance such as strength and plasticity of large-size component material. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed to be used in the description of the specific embodiments or prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The grain size gradient distribution composite plate provided by the present application is shown in the schematic diagram of the three-layer equal-thickness plate, and the black dashed line is the composite interface.

[0029] Figure 2 The explosion welding parameter selection curve is shown in the curve diagram, and the asterisks shown in (a) and (b) are the corresponding explosion welding parameters. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects of the present application more clearly understood, the present application will be further described in detail in combination with embodiments. 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.

[0031] In the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0032] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or the like means any combination of the items, including a single item or any combination of multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0033] It should be understood that the size of the sequence of the above processes in various embodiments of the present application does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence, and the execution order of the processes should be determined by their functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0034] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0035] The weight of the related components mentioned in the embodiments of the present application can not only refer to the specific content of each component, but also represent the weight ratio relationship between each component, therefore, as long as the content of the related components in the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the embodiments of the present application. Specifically, the mass mentioned in the embodiments of the present application can be μg, mg, g, kg and other mass units commonly known in the chemical field.

[0036] The existing gradient structure material preparation method has many limitations such as complicated process, poor applicability to large-size materials, poor controllability of gradient structure range and degree, etc., which greatly limits the structure design and performance control of large-size gradient structure materials, and therefore it is urgent to develop a method for directly designing, manufacturing and high-level controlling large-size gradient structure materials.

[0037] In view of this, the present application combines the unique advantages of large bonding area and high joint quality of explosive welding, and designs a full-space gradient structure composite material preparation method, comprising the following steps:

[0038] S1, selecting the base plate and the flyer plate according to the grain size of the base material from large to small, determining the thickness of the base plate and the flyer plate, and performing explosive welding layer by layer in sequence to obtain a primary gradient structure composite plate;

[0039] S2, cold deforming the primary gradient structure composite plate, and then performing different degree of recrystallization treatment to obtain a recrystallized gradient structure composite plate.

[0040] S3, the recrystallization state gradient structure composite plate is post-processed to obtain different grade gradient structure alloy materials.

[0041] The application can further promote the formation of full-mixed gradient structure composite materials in cooperation with deformation heat treatment, and is expected to realize direct design and preparation of large-size gradient structure composite materials, and greatly improve the comprehensive performance level of large-tonnage large-size parts.

[0042] The application sequentially uses the base plate and the flying plate with grain size from large to small as the base plate and the flying plate, and performs continuous explosion welding; the composite plate is cold deformed, and then different degree recrystallization treatment is performed; the recrystallization state composite plate is post-processed to obtain the final alloy.

[0043] Optionally, the continuous explosion welding process comprises:

[0044] Different thickness and grain size of the base plate are used during explosion welding, but the base plate and the flying plate corresponding to the first explosion welding and the last explosion welding are 2-3 mm larger than the standard thickness; the single-layer design thickness of the base plate and the flying plate is determined according to the total design thickness and the number of layers, and the thickness of the flying plate used in the middle welding process is equal or unequal. When the thickness is equal, the average thickness is designed, and when the thickness is unequal, the thickness can be increased or decreased near the average thickness, but the difference is not very large.

[0045] The base plate corresponds to the base plate with the largest grain size during the first explosion welding, and the grain size of the base plate is continuously reduced thereafter; the total number of the base plate and the flying plate in the composite material is not less than 3; and the unwelded area is cut off after the welding is completed.

[0046] For example, cold deformation is performed, and then different degree recrystallization treatment is performed, which comprises:

[0047] The cold deformation amount is 40-80%, and is the same as the explosion welding direction; the recrystallization temperature is (0.4-1) times the melting point, and if the base plate is an age-hardening type alloy, the temperature selection should be higher than the lowest solid solution temperature, and the holding time is such that the composite material cannot complete recrystallization and is converted into a completely equiaxed crystal structure.

[0048] As an optional solution, the recrystallization state composite plate is post-processed to obtain the final alloy, which comprises:

[0049] If the base plate is an age-hardening type alloy, the composite material is aged according to the process selected from the material manual; the final alloy is obtained by finishing and shaping the composite plate.

[0050] This invention utilizes the unique advantages of explosive welding technology, such as large single composite area and high quality of explosive welded joints, to provide a method for preparing alloy materials with different grades of gradient structures. It can realize the direct design, preparation and high-level control of large-size gradient structure materials, and overcomes many constraints of previous gradient structure material preparation methods, such as cumbersome process and poor applicability to large-size materials. It is expected to achieve a synergistic improvement in the comprehensive properties of large-size component materials, such as strength and plasticity.

[0051] The following examples illustrate the preparation methods of this application through multiple specific embodiments.

[0052] Example 1

[0053] (1) The gradient structure composite material is designed to consist of three layers. The base material is annealed pure copper with a designed usable thickness of 9mm, distributed in layers of 3mm, 3mm, and 3mm, with equal thickness design. The first explosive welding substrate is 6mm thick (3mm more than the designed thickness) with a grain size of 100μm, and the first fly plate is 3mm thick with a grain size of 10μm. The second explosive welding substrate uses the composite plate obtained in the previous process with a thickness of 9mm and the first fly plate facing upwards as the composite surface. The second fly plate is 5mm thick (2mm more than the designed thickness) with a grain size of 0.1μm. According to the effective explosive welding parameter range (i.e., base plate collision angle 2-31°, collision velocity 1700-3000m / s), the collision angle is selected as 12° and the collision velocity is 2200m / s. Figure 2 Explosive welding was performed using the explosion welding parameters corresponding to the asterisks shown in (a) and (b), and the unwelded areas were removed to obtain the primary gradient structure composite plate.

[0054] Figure 2 Three types of pure copper plates with three grain sizes in annealed state (3mm) were used as the base material, with grain sizes of 100μm, 10μm and 0.1μm, corresponding to hardnesses of HV15, 20 and 120 respectively: (a) the explosion welding window of a 6mm thick substrate (the first composite substrate is 3mm thicker than the standard thickness) and a 3mm thick flyboard during the first composite. After the first explosion welding, the hardness of the composite flyboard increased from HV10 to HV30; (b) the explosion welding window of an 8mm thick substrate and a 5mm thick flyboard (the last composite flyboard is 2mm thicker than the standard thickness) during the second composite.

[0055] (2) The primary gradient structure composite plate was cold rolled with a deformation of 42%. The melting point of pure copper is 1080℃. The plate was held at 500℃ (0.4 times higher than the melting point, i.e., about 430℃) for 30 minutes to obtain an incompletely recrystallized advanced gradient structure composite plate.

[0056] (3) The recrystallized gradient structure composite plate is finely repaired and shaped to obtain the finished composite plate.

[0057] In Example 1 of this invention, a gradient structure material is prepared by combining non-uniform continuous variations in grain size, thickness, and composite interface. This can introduce a back stress strengthening mechanism in addition to traditional strengthening methods to achieve a synergistic improvement in the strength and plasticity of composite materials. Furthermore, by promoting the continued evolution of the microstructure through subsequent heat treatment, a full-space hybrid gradient structure composite material can be formed. The gradient structure hierarchy and microstructure anisotropy of the composite material can be controlled as needed, and the comprehensive performance of the gradient structure composite material in all directions can be systematically optimized.

[0058] The composite plate obtained in Example 1 was tested and found to have a gradient structure. By introducing this non-uniformly distributed gradient structure into the material structure, the material strength and plasticity are improved, and the material properties are greatly enhanced.

[0059] Example 2

[0060] (1) The gradient structure composite material is designed to contain 3 layers. The base material is annealed pure copper with a designed usable thickness of 10mm. The thicknesses are 3mm, 4mm and 3mm, respectively, with unequal thicknesses. The first explosive welding substrate is 5mm thick (2mm more than the designed thickness) with a grain size of 100μm. The first fly plate is 4mm thick with a grain size of 10μm. The second explosive welding substrate uses the composite plate obtained in the previous explosion with a thickness of 8mm and the first fly plate facing upward as the composite surface. The second fly plate is 5mm thick (2mm more than the designed thickness) with a grain size of 0.1μm. Explosive welding parameters are designed for explosive welding. The unwelded areas are cut off to obtain the primary gradient structure composite plate.

[0061] (2) The primary gradient structure composite plate was cold rolled with a deformation of 80%, and held at 1000℃ for 5 min to obtain an incompletely recrystallized advanced gradient structure composite plate.

[0062] (3) The recrystallized gradient structure composite plate is finely repaired and shaped to obtain the finished composite plate.

[0063] Example 3

[0064] (1) The gradient structure composite material is designed to contain 3 layers. The base material is annealed pure copper with a design thickness of 9mm. The thickness is distributed in layers of 3mm, 3mm, and 3mm, with equal thickness design. The first explosive welding substrate has a thickness of 5mm (2mm more than the design thickness) and a grain size of 100μm. The first fly plate has a thickness of 3mm and a grain size of 10μm. The second explosive welding substrate uses the composite plate obtained in the previous explosion with a thickness of 8mm and the first fly plate facing upward as the composite surface. The second fly plate has a thickness of 5mm (2mm more than the design thickness) and a grain size of 0.1μm. Explosive welding parameters are designed for explosive welding. The unwelded areas are cut off to obtain the primary gradient structure composite plate.

[0065] (2) The primary gradient structure composite plate was cold rolled with a deformation of 60%, and held at 600℃ for 15 minutes to obtain an incompletely recrystallized advanced gradient structure composite plate.

[0066] (3) The recrystallized gradient structure composite plate is finely repaired and shaped to obtain the finished composite plate.

[0067] Example 4

[0068] (1) The gradient structure composite material is designed to contain 4 layers. The base material is annealed pure copper with a designed usable thickness of 11mm. The thicknesses are distributed as 3mm, 3mm, 2mm and 3mm, with unequal thicknesses. The first explosive welding substrate is 5mm thick (2mm more than the designed thickness) with a grain size of 100μm. The first fly plate is 3mm thick with a grain size of 10μm. The second explosive welding substrate uses the composite plate obtained in the previous process with a thickness of 8mm and the first fly plate facing upwards as the composite surface. The second fly plate is 2mm thick with a grain size of 1μm. The third explosive welding substrate uses the composite plate obtained in the previous process with a thickness of 10mm and the second fly plate facing upwards as the composite surface. The third fly plate is 5mm thick (2mm more than the designed thickness) with a grain size of 0.1μm. Explosive welding parameters are designed for explosive welding. The unwelded areas are cut off to obtain the primary gradient structure composite plate.

[0069] (2) The primary gradient structure composite plate was cold rolled with a deformation of 50%, and then held at 500℃ for 20 min to obtain an incompletely recrystallized advanced gradient structure composite plate.

[0070] (3) The recrystallized gradient structure composite plate is finely repaired and shaped to obtain the finished composite plate.

[0071] Example 5

[0072] (1) The gradient structure composite material is designed to contain 3 layers. The base material is a solid solution CuNiSiCr alloy with a designed usable thickness of 9mm. The thickness is distributed in 3mm, 3mm, and 3mm, with equal thickness design. The first explosive welding substrate is 6mm thick (3mm more than the designed thickness) with a grain size of 100μm. The first fly plate is 3mm thick with a grain size of 10μm. The second explosive welding substrate uses the composite plate obtained in the previous explosion with a thickness of 9mm and the first fly plate facing upward as the composite surface. The second fly plate is 5mm thick (2mm more than the designed thickness) with a grain size of 0.1μm. Explosive welding parameters are designed for explosive welding. The unwelded area is cut off to obtain the primary gradient structure composite plate.

[0073] (2) The primary gradient structure composite plate is cold rolled with a deformation of 52% and a copper alloy melting point of 1050℃. It is then held at 900℃ (the alloy can be age-strengthened and the solution temperature is not lower than 900℃) for 30 minutes to obtain an incompletely recrystallized advanced gradient structure composite plate.

[0074] (3) The recrystallized board is aged at 450℃ for 3 hours to obtain the peak aged composite board. Then the composite board is finely repaired and shaped to obtain the finished product.

[0075] All articles and references disclosed above, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0076] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0077] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method of producing a differentially graded structural alloy material, characterized by, The application relates to a gradient structure composite material and a preparation method thereof. Specifically, the largest-grained base material is selected as a base plate, the thickness of the base plate and a flying plate is determined, the second largest-grained base material is selected as a first flying plate, and the first explosion welding is performed to obtain a first composite plate. The first composite plate is used as the base plate, the third largest-grained base material is used as the first flying plate, the first flying plate is used as the composite surface, and the second explosion welding is performed to obtain a second composite plate. The continuous explosion welding is performed according to the continuous decrease of the grain size of the base material until the final designed number of layers is completed, and the primary gradient structure composite plate is obtained by cutting off the unwelded area. The primary gradient structure composite plate is subjected to cold deformation and then different recrystallization treatments to obtain a recrystallized gradient structure composite plate. The cold deformation amount is 40-80%, and the cold deformation direction is the same as the explosion welding direction. The recrystallization temperature is 0.4-1 times the melting point, or the temperature is higher than the lowest solid solution temperature. The recrystallized gradient structure composite plate is subjected to post-treatment to obtain different grade gradient structure alloy materials composed of single materials. The thickness of the single layer of the base plate and the flying plate is determined according to the total design thickness and the number of layers.

2. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: The thickness of the base plate is greater than that of the corresponding flying plate in each explosion welding. ​ 3. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: preparing a first alloy material having a first composition; preparing a second alloy material having a second composition; and mixing the first alloy material and the second alloy material to form the different grade gradient structure alloy material. The number of layers of the gradient structure composite material is not less than 3.

4. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: The explosion welding parameters are a collision angle of 2-31 degrees and a collision speed of 1700-3000 m / s. ​ 5. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: The recrystallized gradient structure composite plate is subjected to post-treatment to obtain different grade gradient structure alloy materials. ​ 6. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: If the base material is an age-hardened alloy, the recrystallized gradient structure composite plate is subjected to aging treatment. The recrystallized gradient structure composite plate after the aging treatment is subjected to finishing and shaping treatment to obtain a final alloy. The base material is a copper alloy.

7. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: The base material is annealed pure copper or solid-solution CuNiSiCr alloy. ​ 8. The method of claim 1, wherein the different grade gradient structure alloy material is prepared by the steps of: ​ ​

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