Preparation method of large-size intermetallic compound plate with three-dimensional net-shaped structure

Abstract

The invention discloses a preparation method of a large-size intermetallic compound plate with a three-dimensional net structure. The metal wire mesh and the foil are adopted as raw materials for reaction synthesis, the coarse grain areas and the fine grain areas which are alternately distributed exist in the three-dimensional space of the synthesized metal plate blank, the coarse grain areas guarantee the high strength of the material, the fine grain areas enable the toughness of the material to be enhanced, and meanwhile the coarse grain areas and the fine grain areas which alternately exist can improve the toughness of the material. The expansion of cracks is effectively inhibited, so that the fracture toughness of the material is remarkably enhanced. The metal net is adopted as a reaction matrix of a high-melting-point element, and the breadth width of the final plate blank is effectively enlarged by utilizing the breadth width advantage of the metal net; and the hot pressing condition with the temperature higher than that of the low-melting-point material is adopted, and the liquidity of liquid metal is utilized, so that the problem that the material performance is reduced due to foil gaps in the continuous winding process is effectively solved. And the grain size and distribution form of the microstructure of the synthesized material are controlled by adjusting the parameters of the metal net, so that the regulation and control of the material performance are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of intermetallic compound plate preparation, and relates to a method for preparing a large-size intermetallic compound plate. Background Art

[0002] The new generation of aerospace vehicles is developing rapidly in the direction of high Mach number, high load, ultra-long flight time and ultra-long range. The demand for lightweight, high-temperature resistant thin-walled components is increasing. Typical demands include important components such as skins and engine turbine guide blades. Faced with higher service temperatures and more stringent working conditions, existing titanium alloys can no longer meet the requirements. Although nickel-based high-temperature alloys can serve at higher temperatures, their high density can easily cause overweight structures. Therefore, new lightweight, high-temperature resistant structural materials such as intermetallic compounds such as TiAl and NiAl have gradually become a research hotspot. Intermetallic compounds such as TiAl and NiAl have the advantages of high service temperature, low density, high specific strength, high specific stiffness and excellent oxidation resistance, and have broad application prospects in the aerospace field.

[0003] Common preparation methods for NiAl alloys include melt casting, combustion synthesis, powder metallurgy, element foil lamination rolling, element foil reaction synthesis, etc. The melt casting method, combustion synthesis method, powder metallurgy, etc. can be used to prepare a block billet of a certain size of intermetallic compound, and then a slab is obtained by rolling, etc. However, intermetallic compounds have intrinsic brittleness at room temperature, and their high-temperature brittle-ductile transition temperature is usually not less than 500°C, so the rolling process of the slab is extremely difficult. Intermetallic compound sheets can be directly prepared by methods such as element foil lamination rolling and element foil reaction synthesis. The invention application of publication number CN103057203A proposes a method for preparing a NiA1 slab, which is to perform two hot pressing composites on the alternating laminated slabs of Ni foil and A1 foil to finally obtain a layered NiA1 alloy sheet. The invention application with publication number CN1667144A proposes a method for preparing NiA1 shape memory alloy film by cold-rolling ultra-thin laminated alloying. The method is to repeatedly cold-roll the alternating laminated slabs of Ni foil and Al foil, and obtain an alloy film with uniform composition through a heat treatment process. The invention application with publication number CN105414219A proposes a method for preparing a metal / intermetallic compound layered composite material. The method is to cold-roll the alternating laminated slabs of Ni foil and Al foil, and then obtain Ni / NiAl3 intermetallic compound through a heat treatment process. Intermetallic compound slabs can be prepared by reaction synthesis using foil materials, but due to the limited width of the metal foil, the width of the final slab is also limited. To this end, the invention patent publication number CN112091049A proposes the use of continuous winding of metal foil strips to prepare intermetallic compound thin-walled components. The use of continuous winding of foil strips has to some extent broken through the width limitation of the foil strips and can prepare larger-sized components. However, since the process uses a solid-phase reaction, the gaps between the foil strips during the winding process are difficult to eliminate, which to some extent affects the mechanical properties of the final component.

[0004] In addition, the poor room temperature plasticity, low fracture resistance and high temperature strength of intermetallic compounds have also restricted the widespread application of this material to a certain extent. To this end, researchers at home and abroad have adopted microstructure control, alloying, and preparation of composite materials to improve the mechanical properties of intermetallic compounds.

[0005] The preparation of intermetallic compound sheets is one of the most important topics in its practical research. In order to solve the problems of difficulty in preparing large-sized intermetallic compound sheets and poor mechanical properties of materials, it is necessary to develop a new method for manufacturing intermetallic compound sheets. Summary of the invention

[0006] In order to solve the problems of difficulty in preparing large-sized intermetallic compound plates and poor mechanical properties of the materials, the present invention proposes a method for preparing a large-sized intermetallic compound plate with a three-dimensional network structure.

[0007] The technical solution of the present invention:

[0008] A method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure, comprising the following steps:

[0009] Step 1: Determine the quality of raw materials: According to the target intermetallic compound A x B y The mass of raw materials for ingredient calculation, the mass ratio of A and B materials is: x×M A :y×M B , where x and y are the number of atoms of the target intermetallic compound constituent elements A and B, respectively, and M A 、M B are the molar masses of elements A and B respectively;

[0010] Step 2, determining the reaction matrix: select the material with a higher melting point among the two materials and weave it into a metal mesh with metal filaments, the diameter of the filaments is 0.02-0.5mm, the mesh gap is 0.02-0.5mm, and the mesh types include plain, twill, satin, basket weave, woven, and imitation woven; the material with a lower melting point uses a metal foil, and the thickness of the foil is 0.01-0.5mm. Assuming that material A is a material with a high melting point and material B is a material with a low melting point, the mass ratio of the metal mesh to the metal foil is the mass ratio calculated in step 1;

[0011] Step 3: Material pretreatment: Use organic solvent to ultrasonically clean the material surface to remove oil stains;

[0012] Step 4: Material mixing: stack the metal mesh and metal foil in a regular order in the mold;

[0013] Step 5, process selection: Use a vacuum furnace to create a thermal environment and a vacuum environment, place a hot pressing mold that matches the size of the vacuum furnace cavity into the furnace, and cooperate with a press to provide external pressure for reaction; use a sealing plate to create a vacuum environment, use induction heating, heating wire heating, etc. to heat the mold, and cooperate with a press to provide external pressure for reaction;

[0014] Step 6: Diffusion sintering: Reduce the ambient vacuum to below 0.1 Pa, heat the material to a temperature above the melting point of the material with the lower melting point, but not higher than the melting point of the material with the higher melting point; provide a surface pressure of no less than 1 MPa on the entire surface of the plate; maintain high temperature and high pressure for no less than 0.5 hours, until the two elements undergo sufficient diffusion reaction and completely generate A. x B y Intermetallic compounds;

[0015] Step 7: Processing of the slab after forming: Take out the slab after reaction synthesis from the mold and perform necessary cutting and grinding and polishing on it.

[0016] The beneficial effects of the present invention are:

[0017] (1) The present invention provides a method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure, which uses a metal wire mesh and a foil as raw materials for reaction synthesis. The final synthesized metal plate blank has coarse and fine grain regions that are alternately distributed in the three-dimensional space. The existence of the coarse grain region ensures the high strength of the material, and the fine grain region enhances the toughness of the material. At the same time, the alternating coarse and fine grain regions also effectively inhibit the expansion of cracks, thereby significantly enhancing the fracture toughness of the material.

[0018] (2) The present invention provides a method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure, which uses a metal mesh as a reaction matrix for elements with a higher melting point, and utilizes the width advantage of the metal mesh to effectively expand the width of the final plate blank. At the same time, hot pressing conditions with a temperature higher than that of the material with a lower melting point and the fluidity of the liquid metal are used to effectively solve the problem of material performance degradation caused by the gap between the foils during the continuous winding process.

[0019] (3) The present invention provides a method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure, which uses a metal mesh as a base material. The method can effectively control the grain size and distribution form of the microstructure of the material after the final reaction synthesis by adjusting parameters such as the metal mesh wire diameter, the metal mesh hole gap, and the mesh type, thereby achieving the regulation of material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A process roadmap for preparing a large-sized intermetallic compound sheet with a three-dimensional network structure;

[0021] Figure 2 Figure 1 is a diagram of metal mesh types, where (a) is a schematic diagram of plain weave, (b) is a schematic diagram of twill weave, (c) is a schematic diagram of satin weave, (d) is a schematic diagram of basket weave, (e) is a schematic diagram of woven weave, and (f) is a schematic diagram of imitation woven weave;

[0022] Figure 3 This is a schematic diagram of diffusion sintering in a vacuum furnace and hot press furnace;

[0023] Figure 4 It is a schematic diagram of a vacuum hot pressing mold;

[0024] Figure 5 Schematic diagram of the microstructure of an intermetallic compound plate with a three-dimensional network structure;

[0025] In the figure: 1-press frame, 2-vacuum high temperature furnace, 3-hot pressing mold, 4-metal foil, 5-metal mesh, 6-vacuum pump, 7-sealing plate, 8-pressing block, 9-die, 10-insulating board, 11-heating plate. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0027] Example 1: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 A method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure is described, and the specific steps are as follows:

[0028] Step 1: Determine the quality of raw materials. According to the target intermetallic compound A x B y The mass of raw materials for ingredient calculation, the mass ratio of A and B materials is: x×M A :y×M B , where x and y are the number of atoms of the target intermetallic compound constituent elements A and B, respectively, and M A 、M B are the molar masses of elements A and B, respectively. Taking NiAl, TiAl, and FeAl alloys as examples, the mass ratio of Ni to Al should be 2.1719:1, the mass ratio of Ti to Al should be 1.7741:1, and the mass ratio of Fe to Al should be 2.0756:1.

[0029] Step 2: Determine the reaction matrix. Select the material with higher melting point among the two materials and weave it into a mesh with metal filaments. The wire diameter of the filaments is 0.02-0.5mm, and the mesh gap is 0.02-0.5mm. The mesh types include plain, twill, satin, basket weave, woven, and imitation woven. The material with lower melting point uses metal foil with a thickness of 0.01-0.5mm. For NiAl, TiAl, and FeAl alloys, select Ni, Ti, and Fe filaments to weave into a mesh, and select Al foil as the filling material.

[0030] Step 3: Material pretreatment: Use organic solvent ultrasonic cleaning or other methods to pretreat the material surface to remove oil stains.

[0031] Step 3: Material mixing: stack the metal mesh and foil in a regular order in a mold, and the mold material is made of alumina, high-strength graphite, etc.

[0032] Step 4: Vacuuming: Use a vacuum pump to reduce the vacuum degree of the vacuum environment box to below 0.1Pa.

[0033] Step 5: Diffusion sintering. Use a vacuum heating furnace to heat the material to a temperature above the melting point of the material with the lower melting point, but not higher than the melting point of the material with the higher melting point. At the same time, provide a surface pressure of no less than 1MPa on the entire surface of the board, which is calculated by dividing the clamping force by the projected area of ​​the board. Maintain high temperature and high pressure for no less than 0.5 hours until the two elements undergo sufficient diffusion reaction and completely generate A. x B y Intermetallic compounds. For NiAl, TiAl, and FeAl alloys, the sintering temperature is greater than 660°C and less than 1200°C.

[0034] Step 6: Post-processing of the slab: Take out the slab from the mold and perform necessary cutting and grinding and polishing.

[0035] The present invention uses metal mesh and foil as raw materials for reaction synthesis, and the final synthesized metal sheet blank has coarse and fine grain regions that are alternately distributed in three-dimensional space, which significantly enhances the fracture toughness while ensuring the high strength of the material. By using metal mesh as the matrix material, the microstructure grain size and distribution form of the sheet material after the final reaction synthesis can be controlled by adjusting parameters such as the metal mesh wire diameter, metal mesh hole gap, and mesh type, thereby achieving regulation of material properties. By using metal mesh as the reaction matrix of the higher melting point element, the width advantage of the metal mesh is utilized to effectively expand the width of the final sheet blank. At the same time, by using hot pressing conditions that are higher than the temperature of the lower melting point material and utilizing the fluidity of the liquid metal, the problem of material performance degradation caused by the gap between the foils during continuous winding is also effectively solved.

[0036] Example 2: Combination Figure 4 Note that in step 4, a vacuum sintering mold as shown in the figure is used, and the mold includes a sealing plate 7, a pressing block 8, and a concave mold 9. The sealing plate 7 is a 0.1-0.5 mm thin plate, and is welded with the mold concave mold to achieve complete sealing of the concave mold cavity. The concave mold 9 includes an S-shaped gas flow channel, and the end of the flow channel is connected to a vacuum pump 6, and the vacuum degree inside the mold is reduced to below 0.1 Pa by the vacuum pump. The remaining steps are the same as in Example 1.

[0037] The mold structure shown in the figure is used to achieve environmental vacuum, which can avoid the use of vacuum furnace, effectively reduce equipment investment, and avoid the limitation of vacuum furnace hearth size on slab size.

[0038] Example 3: Combination Figure 4 It is noted that in step 5, the mold is heated by induction heating, resistance wire heating, etc. to reach a preset heating value. The remaining steps are the same as those in the first embodiment.

[0039] The vacuum hot pressing mold is heated by induction heating, heating wire heating, etc., which has a fast heating speed, low equipment requirements, and can avoid the limitation of the heating furnace hearth size on the mold size, thereby obtaining a larger slab.

Claims

1. A method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure, characterized in that: Here are the steps: Step 1: Determine the quality of raw materials: According to the target intermetallic compound A x B y Composition calculation: Raw material mass; Step 2: Determine the reaction matrix: select the material with a higher melting point among the two materials and weave it into a metal mesh with metal filaments; use the material with a lower melting point to make a metal foil, the thickness of the metal foil is 0.01-0.5mm; Step 3: Material pretreatment: Use organic solvent to ultrasonically clean the material surface to remove oil stains; Step 4: Material mixing: stack the metal mesh and metal foil in a regular order in the mold; Step 5: Process selection: Use a vacuum furnace to create a thermal environment and a vacuum environment, place a hot pressing mold that matches the size of the vacuum furnace cavity into the furnace, and use a press to provide external pressure for reaction; The mold heats up and reacts by providing external pressure with the help of the press; Step 6: Diffusion sintering: Reduce the ambient vacuum to below 0.1 Pa, heat the material to a temperature above the melting point of the material with the lower melting point, but not higher than the melting point of the material with the higher melting point; provide a surface pressure of no less than 1 MPa on the entire surface of the plate; maintain high temperature and high pressure for no less than 0.5 hours, until the two elements undergo sufficient diffusion reaction and completely generate A. x B y Intermetallic compounds; Step 7: Processing of the slab after forming: Take out the slab after reaction synthesis from the mold and perform necessary cutting and grinding and polishing on it.

2. The method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure according to claim 1, characterized in that: In step 1, the mass ratio of materials A and B is: x×M A :y×M B , where x and y are the number of atoms of the target intermetallic compound constituent elements A and B, respectively, and M A 、M B are the molar masses of elements A and B respectively.

3. The method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure according to claim 1, characterized in that: In step 2, the wire diameter of the metal filament is 0.02-0.5 mm, the mesh gap of the metal mesh is 0.02-0.5 mm, and the mesh types include plain weave, twill, satin, basket weave, woven, and imitation woven.

4. The method for preparing a large-sized intermetallic compound sheet with a three-dimensional network structure according to claim 1, characterized in that: In step 2, assuming that material A is a material with a high melting point and material B is a material with a low melting point, the mass ratio of the metal mesh to the metal foil is the mass ratio calculated in step 1.

5. The method for preparing a large-sized intermetallic compound plate having a three-dimensional network structure according to claim 1, characterized in that: In step five, a sealing plate is used to create a vacuum environment, and induction heating and heating wire heating are used to heat the mold.

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