阅读说明：本技术 一种可伐合金和无氧铜复合材料的生产方法 (Production method of kovar alloy and oxygen-free copper composite material ) 是由 杨若雅 夏金民 杨宇军 黄志鸽 王玉龙 于 2021-07-26 设计创作，主要内容包括：本发明属于可伐合金和无氧铜复合材料技术领域,具体公开一种可伐合金和无氧铜复合材料的生产方法,采用了爆炸+轧制复合法,主要工艺为原材料处理-真空爆炸焊接-热处理-热轧-退火-冷轧-终退火-精整工艺,为了保证可伐合金和无氧铜复合达到使用要求,该生产方法中的爆炸焊接工艺采用了真空爆炸,从而有效地控制了两种金属结合面所产生的脆性氧化物,保证了两种金属的结合强度,解决了这种复合材料在焊接时出现分离的难题；可伐合金和无氧铜复合材料主要用作金属和陶瓷焊接的过渡板,应用于半导体、电子行业,其前景广阔。(The invention belongs to the technical field of kovar alloy and oxygen-free copper composite materials, and particularly discloses a production method of kovar alloy and oxygen-free copper composite materials, which adopts an explosion and rolling composite method, wherein the main process comprises the steps of raw material treatment, vacuum explosion welding, heat treatment, hot rolling, annealing, cold rolling, final annealing and finishing; the kovar alloy and oxygen-free copper composite material is mainly used as a transition plate for welding metal and ceramic, is applied to the semiconductor and electronic industries, and has wide prospect.)

1. A production method of a kovar alloy and oxygen-free copper composite material is characterized by comprising the following steps:

(1) pretreatment of raw materials: cleaning the surfaces of the kovar alloy plate and the oxygen-free copper plate by using a laser to ensure that the surfaces are clean, free of oil stains and oxidation layers, smooth, free of defects and free of concave-convex;

(2) and (3) vacuum explosion welding: placing a Kovar alloy plate on a sandy soil foundation, arranging supports around the Kovar alloy plate, laying oxygen-free copper on the supports at the upper part of the Kovar alloy plate, sealing the Kovar alloy plate and the oxygen-free copper plate for a circle by using a sealing material outside the supports, reserving a pumping hole on the sealing material, vacuumizing, laying explosives on the oxygen-free copper plate, embedding detonators, and detonating to obtain a composite material plate blank;

(3) and (3) heat treatment: stress relief annealing is carried out on the composite material plate blank at the temperature of 550-650 ℃;

(4) hot rolling: performing multi-pass rolling on the composite material plate blank subjected to heat treatment at the temperature of 300-400 ℃, and performing hot rolling on the plate blank to an intermediate blank with a preset thickness, wherein the rolling ratio of each pass is controlled to be 70-80%;

(5) and (3) diffusion annealing: carrying out diffusion annealing on the intermediate blank at 500-600 ℃;

(6) cold rolling: carrying out small-deformation multi-pass rolling on the intermediate blank after diffusion annealing, wherein the rolling ratio of each pass is controlled to be 80-90% until the rolling ratio is more than or equal to 50%, and finally obtaining a target composite material with the target thickness;

(7) final annealing and finishing: annealing the target composite material subjected to cold rolling at 400-500 ℃, wherein the annealing time is 1-2 hours, and adjusting the thickness, the flatness and the roughness of the target composite material to ensure that the thickness error is +/-0.1, the flatness is 2mm/m, and the roughness Ra is less than or equal to 3.2.

2. A method of producing a kovar alloy and oxygen-free copper composite as claimed in claim 1, wherein: in the step (1), the thickness of the raw material Kovar alloy plate and the oxygen-free copper plate is 5 times of that of the target Kovar alloy plate and the oxygen-free copper plate, the thickness of the raw material Kovar alloy plate is 2.5-10 mm, the thickness of the oxygen-free copper plate is 2.5-5 mm, the thickness of the target Kovar alloy plate is 0.5-2 mm, and the thickness of the target oxygen-free copper plate is 0.5-1 mm.

3. A method of producing a kovar alloy and oxygen-free copper composite as claimed in claim 2, wherein: in the step (2), the distance between the Kovar alloy plate and the oxygen-free copper plate is 5-6mm, the laying thickness of the explosive is 8-10 times the thickness of the copper plate, the explosion velocity of the explosive is 1800 and 2000m/s, and the explosive brisance is 7-9 mm.

4. A method of producing a kovar alloy and oxygen free copper composite as claimed in claim 3, wherein: the thickness of the intermediate blank in the step (4) is 3 mm.

5. The kovar alloy and oxygen free copper composite production process as claimed in any one of claims 1-4 produces a composite for use in the transition soldering and packaging of low cte materials.

Technical Field

The invention belongs to the technical field of kovar alloy and oxygen-free copper composite materials, and particularly relates to a production method of a kovar alloy and oxygen-free copper composite material.

Background

The kovar alloy is also called iron-nickel-cobalt alloy, has good welding performance with high-temperature alloy and high strength, and is mainly used for manufacturing iron-nickel-cobalt alloy strips, bars, plates and pipes which are matched and sealed with hard glass. Oxygen-free copper has good electrical and thermal conductivity, but low strength, and is mainly used for electronic components, antimagnetic instruments, aeronautical instruments, and the like. The kovar alloy and oxygen-free copper composite board is a novel bimetal composite material which takes the kovar alloy as a substrate and is compounded with a kovar alloy layer on a single surface, the compounding aims to obtain better physical properties than single kovar alloy, and the electric conductivity and the heat conductivity of the composite material are 4-5 times of those of the kovar alloy. The oxygen-free copper-kovar alloy composite material not only meets the requirement of conductivity, but also has excellent connection performance with high-temperature alloy.

Since the difference in physicochemical properties between oxygen-free copper and kovar alloys and the special structure of the electrode material make it difficult to obtain satisfactory results with conventional welding methods, the choice of welding method and the study of the process are very critical. The explosive welding method is one of the common production modes of bimetal composite plates, and the explosive cladding realizes the metallurgical bonding of dissimilar materials by utilizing high-pressure pulse load generated during explosive explosion and is commonly used for producing single-sheet plates with single-side cladding.

Disclosure of Invention

The invention aims to provide a production method of a kovar alloy and oxygen-free copper composite material, which utilizes a vacuum explosion welding method to enable the composite material to eliminate interface stress by utilizing high-pressure pulse load generated during explosive explosion so as to achieve metallurgical bonding of dissimilar materials and has the advantage of high bonding strength.

In order to achieve the purpose, the invention adopts the technical scheme that:

a production method of a kovar alloy and oxygen-free copper composite material comprises the following steps:

(1) pretreatment of raw materials: cleaning the surfaces of the kovar alloy plate and the oxygen-free copper plate by using a laser to ensure that the surfaces are clean, free of oil stains and oxidation layers, smooth, free of defects and free of concave-convex;

(2) and (3) vacuum explosion welding: the method comprises the steps of placing a Kovar alloy plate on a sandy soil foundation, arranging supports around the Kovar alloy plate, laying oxygen-free copper on the supports on the upper portion of the Kovar alloy plate, sealing the Kovar alloy plate and the oxygen-free copper plate for a circle by using sealing materials outside the supports, reserving a pumping and exhausting hole on the sealing materials, vacuumizing, laying explosives on the oxygen-free copper plate, and embedding detonators for detonation to obtain a composite material plate blank, vacuumizing a space between the oxygen-free copper and the Kovar alloy during explosion welding, vacuumizing an intermediate space, effectively isolating oxygen in air, and avoiding the phenomenon that metal jet on the surface of a copper material reacts with the oxygen to generate brittle copper oxide in the explosion welding process. And the phenomenon that the surface of the copper material is melted due to the high temperature generated by the nearly adiabatic compressed gas at the interface is avoided, the interface bonding strength and the stability are improved, the interface bonding strength of the plate after the later rolling is favorably ensured, the risk of interface separation in the rolling and welding processes is avoided, and then the explosion welding is carried out. The invention adopts a method of locally extracting vacuum at the interval between the plates, has simple process, low cost, continuous production and high efficiency;

(3) and (3) heat treatment: stress relief annealing is carried out on the composite plate blank at the temperature of 550-650 ℃, stress appears on the joint surface of the kovar alloy and the oxygen-free copper composite material after explosion welding, the stress is relieved by adopting heat treatment, and the heat treatment method is stress relief annealing;

(4) hot rolling: performing multi-pass rolling on the composite material plate blank subjected to heat treatment at 300-400 ℃, performing hot rolling on the plate blank to an intermediate blank with a preset thickness, controlling the rolling ratio of each pass to be 70-80%, rolling the kovar alloy and the oxygen-free copper composite blank subjected to explosive welding, performing hot rolling on the blank, performing multi-pass rolling according to the required thickness, and performing hot rolling on the plate blank to the preset thickness;

(5) and (3) diffusion annealing: performing diffusion annealing on the intermediate blank at 500-600 ℃, and performing diffusion annealing on the Kovar alloy and oxygen-free copper composite material in the rolling process in order to eliminate residual stress generated in the rolling process and avoid cracks on the surface of the plate;

(6) cold rolling: carrying out small-deformation multi-pass rolling on the intermediate blank after diffusion annealing, controlling the rolling ratio of each pass to be 80-90% until the rolling ratio is more than or equal to 50%, finally obtaining a target composite material with the target thickness, preventing the plate from cracking due to overlarge one-time deformation, and carrying out multiple small-deformation cold rolling on the annealed composite material to finally reach the target thickness;

(7) final annealing and finishing: annealing the target composite material subjected to cold rolling at 400-500 ℃, wherein the annealing time is 1-2 hours, and adjusting the thickness, the flatness and the roughness of the target composite material to ensure that the thickness error is +/-0.1, the flatness is 2mm/m, and the roughness Ra is less than or equal to 3.2.

Furthermore, in the step (1), the thickness of the raw material Kovar alloy plate and the oxygen-free copper plate is 5 times of that of the target Kovar alloy plate and the oxygen-free copper plate, the thickness of the raw material Kovar alloy plate is 2.5-10 mm, the thickness of the oxygen-free copper plate is 2.5-5 mm, the thickness of the target Kovar alloy plate is 0.5-2 mm, the thickness of the target oxygen-free copper plate is 0.5-1mm, laser cleaning is efficient and rapid, the thermal load and the mechanical load on the substrate are small, and the substrate is not damaged.

Further, in the step (2), the distance between the Kovar alloy plate and the oxygen-free copper plate is 5-6mm, the explosive laying thickness is 8-10 times of the plate thickness (the plate thickness is the initial thickness of the copper plate before explosion welding), the explosive detonation velocity is 1800-2000m/s, the explosive brisance is 7-9mm, in order to ensure the welding quality, the brittle oxide of the joint surface is removed, a special vacuum explosion welding method is adopted, the distance is arranged between the two metals, and the vacuum is extracted. The spacing is designed to be different according to different thicknesses.

Further, the thickness of the intermediate blank in the step (4) is 3 mm.

The invention has the advantages that:

1. if a direct explosion welding method is adopted, the copper plate is easy to be damaged by impact force generated during explosion due to the fact that the oxygen-free copper is thin, more waste products can be generated, and large-scale production cannot be realized;

2. the thick plate is adopted for explosive welding, the thin plate is rolled into a thin plate at the later stage and applied to the field of electronic elements, the thickness of a copper material used for the electronic elements is generally 0.5-1mm, the copper plate is thin, explosive covered on the surface cannot be supported during explosive welding, energy generated by explosion of the explosive directly acts on the surface of the copper plate during the explosion process, the copper plate is easy to tear, the rejection rate is high, vacuum explosive welding is adopted, oxygen in air can be effectively isolated by the vacuum explosive welding, the phenomenon that the surface of the copper material is melted due to high temperature generated by nearly adiabatic compressed gas at the interface is avoided, and the interface bonding strength and stability are improved. And the energy generated by explosive explosion does not need to overcome air resistance to do work, the interface has no influence of gas turbulence disturbance, the explosive welding has three welding characteristics of pressure welding, fusion welding and diffusion welding, the vacuum explosive welding avoids the generation of interface copper oxide, weakens the interface to generate gaps due to fusion, and the interface metallographic phase shows that the interface of the copper/kovar alloy composite plate has a very small amount of melt, the melt is dispersed and disappears in the later rolling process due to the extension of the interface, and the welding stress of the vacuum explosive welding interface is also eliminated in the later heat treatment process.

Drawings

FIG. 1 is a schematic view of a partial vacuum explosion welding structure according to the present invention.

1. A Kovar alloy plate; 2. supporting; 3. an oxygen-free copper plate; 4. an explosive; 5. a detonator; 6. a sealing material; 7. pumping an exhaust hole; 8. a partial vacuum space.

Detailed Description

Example 1

As shown in the figure, the market demands a kovar alloy and oxygen-free copper composite specification with a total thickness of 1.5mm and a width of 300mm, wherein the kovar alloy has a thickness of 1mm and the copper has a thickness of 0.5 mm. The width of the kovar alloy as the raw material purchase size is 350mm, the length is 500mm, the thickness is 5mm, the width of the oxygen-free copper is 350mm, the length is 500mm, and the thickness is 2.5 mm.

1. The Kovar alloy plate 1 is placed on a laser to be cleaned, the oxygen-free copper plate 3 is polished by a thousand-blade wheel, and the Kovar alloy plate is smooth and clean, has the roughness Ra of less than or equal to 3.2 and has the flatness of 2 mm/m.

2. Firstly, the Kovar alloy plate 1 is placed on a sandy soil foundation, and the foundation is required to be flat and solid. A support 2 is placed on the kovar alloy (with a copper sheet as a support) and then an oxygen-free copper plate 3 is placed on the copper support with a 5mm spacing in between. Sealing the gap between the two metals by using a sealing material 6, namely an aluminum foil tape, reserving a pumping and exhausting hole 7, and pumping out air of the two metal supports by using a vacuum machine to enable the two metal supports to reach a vacuum state to form a local vacuum space 8, wherein the vacuum degree is-0.06 to-0.08 MPa. Explosive (powdery emulsion) with the thickness of 25mm is placed on the oxygen-free copper plate 3, a detonator 5 is placed for detonation, the support 2 mainly functions to support the oxygen-free copper plate 3 and the Kovar alloy plate 1 to form a gap between the oxygen-free copper plate and the Kovar alloy plate, the Kovar alloy plate is placed around the plate, 20-40mm boundary effect (poor bonding area) exists in explosive welding, and when a final finished product is cut, the area needs to be cut and removed, and the support is also removed. For copper plate explosive welding, the explosive is low-explosion-rate explosive, the explosion rate is generally 1800-2000m/s, the explosive brisance is 7-9mm, the explosive thickness is generally 8-10 times the plate thickness, and the explosive thickness is a gradient every 5 mm. Under the condition of vacuum interface of the plate, the energy generated by explosive explosion does not need to overcome air resistance to do work, and the influence of gas turbulence disturbance is avoided, so that the plate and the plate are in favor of uniform lamination.

3. The heat treatment method comprises the following steps: the kovar alloy and the oxygen-free copper composite material are subjected to diffusion annealing between two metals at the temperature of 550 ℃, so that the bonding fastness is enhanced, and the effect of no delamination is achieved.

4. Heating the composite material to 300 ℃ in a heating furnace, preserving heat for 1 hour, then carrying out hot rolling, carrying out multi-pass rolling, controlling the rolling ratio of each pass to be 70-80%, and carrying out hot rolling on the plate blank to an intermediate blank with the thickness of about 3 mm;

5. and continuously carrying out diffusion annealing on the intermediate blank after hot rolling, wherein the annealing temperature is 500 ℃.

6. Cold rolling the annealed plate blank, and performing small-deformation multi-pass rolling, wherein the rolling ratio of each pass is controlled to be 80-90%, cracking of the plate wall caused by overlarge deformation is prevented, and finally, the plate blank is rolled to the target thickness of 1.5mm, and the thickness error is controlled to be +/-0.10;

7. finally, diffusion annealing is carried out again, the temperature is 400 ℃, and the annealing time is 1 hour.

8. And (3) finishing the annealed composite material, firstly leveling by using a 21-roller leveling machine until the flatness reaches 2mm/m, then cleaning by using a laser cleaning machine to remove a surface oxide layer, and finally trimming to reach the target size (1 + 0.5) × 300 mm.

Example 2

Example 2 differs from example 1 in that: market demands kovar alloy and oxygen-free copper composite specification total thickness is 1mm, and the width is 300mm, wherein kovar alloy thickness is 0.5mm, and copper thickness is 0.5 mm. The width of the kovar alloy in the raw material purchase size is 350mm, the length is 500mm, the thickness is 2.5mm, the width of oxygen-free copper is 350mm, the length is 500mm, the thickness is 2.5mm, the heat treatment temperature is 550 ℃, the diffusion annealing temperature is 450 ℃, and finally, the edge cutting is carried out to reach the target size (0.5 + 0.5) x 300 mm.

Example 3

Example 3 differs from example 1 in that: the market demands that the total thickness of the kovar alloy and the oxygen-free copper composite material specification is 2mm, the width is 300mm, the thickness of the kovar alloy is 1.4mm, and the thickness of the copper is 0.6 mm. The width of the kovar alloy in the raw material purchasing size is 350mm, the length is 500mm, the thickness is 7mm, the width of the oxygen-free copper is 350mm, the length is 500mm, the thickness is 3mm, the distance between the kovar alloy plate and the oxygen-free copper plate is 6mm, the heat treatment temperature is 600 ℃, the temperature in a heating furnace is 350 ℃, the thickness of the intermediate blank is 4mm, the annealing temperature is 400 ℃, the annealing time is 1 hour, and finally, the edge cutting is carried out to achieve the target size (1.4 + 0.6) × 300 mm.

Examples of the experiments

The composites of examples 1-3 were tested for performance according to the experimental requirements specified by the national standards and the results are shown in table 1.