CN114043178A

CN114043178A - Novel vacuum creep-pressing compounding method for dissimilar metal composite material

Info

Publication number: CN114043178A
Application number: CN202111487199.1A
Authority: CN
Inventors: 史长根; 吴晓明; 李文轩; 高立; 孙泽瑞
Original assignee: Army Engineering University of PLA
Current assignee: Army Engineering University of PLA
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2022-02-15
Anticipated expiration: 2041-12-07
Also published as: CN114043178B

Abstract

The invention provides a new method for manufacturing metal laminated composite material by vacuum creep pressing of dissimilar metal, which can not only greatly reduce the manufacturing cost of the laminated metal composite material, reduce explosion pollution and realize low-carbon energy-saving green manufacturing, but also can obtain two single-sided or double-sided metal composite materials by one-time creep pressing, the interface of the composite materials is combined by high-quality atoms, and the main manufacturing process comprises the following steps: surface treatment; leveling the base composite material; assembling and sealing; controlling in vacuum; heat treatment; and (5) creep compression bonding.

Description

Novel vacuum creep-pressing compounding method for dissimilar metal composite material

Technical Field

The invention relates to a manufacturing method of a metal composite material, belongs to the technical field of metal composite material and mechanical manufacturing, and particularly relates to a novel vacuum creep-pressing manufacturing method of a dissimilar metal composite material.

Background

The metal layered composite material is widely applied to various industrial fields of aerospace, petrochemical industry, salt and alkali production, shipbuilding electric power, edible hardware and the like due to the flexibility of material combination and structural size. The thickness of the metal layered composite material composite layer is generally more than 0.5mmm, the base layer is more than 2-8mm, and the combination of more than 300 metal materials is realized at present. The manufacturing method mainly comprises three main types of explosive welding, explosion + rolling and rolling.

The explosion welding composite material has high interface bonding strength, and is mainly used for manufacturing metal composite materials with the composite layers of more than 1-2 mm. However, since explosive welding is a solid-phase dynamic combination of two metals, high interface temperature is required, and if the interface temperature is too high, welding failure is caused by excessive melting, so that the main problems of the explosive welding technology are as follows: (1) the high-quality bonding interface is not easy to form for the intermetallic compound which is easy to oxidize and is easy to generate on the base composite material; (2) metal groups with larger differences in physical properties such as the melting points of the base and the composite layers are not easy to form high-quality combination; (3) the impact energy of the multiple layers is large, and brittle fracture or crack is easy to generate in explosive welding to cause combination failure; (4) the composite material with the composite layer of 1-2mm has the advantages of lower production efficiency, lower cost and the like than the rolling technology; (5) in addition, the shock wave and explosive pollution generated by explosive welding are also one of the main disadvantages of the technology. The explosion and rolling comprehensive manufacturing technology aims at two kinds of metal with large difference of mechanical and physical properties of a base layer and a composite layer, firstly adopts an explosion welding process and then adopts a rolling process, and has the defect of high manufacturing cost. The rolling technology has the advantages that the rolling technology is mainly used for large-area composite materials with the composite layers of 0.5-4mm, the thinner the composite layers are, the better the rolling technology is, but the rolling technology needs to enable the base materials and the composite materials to be compounded to generate larger plastic deformation, the thickness uniformity of the composite material composite layers manufactured by the rolling technology is not ideal, and the rolling leakage phenomenon even occurs, so that the yield is greatly reduced.

The invention provides a novel method for manufacturing a metal composite material by vacuum creep compression, which integrates the combination principle and the defects of the three technologies for manufacturing the layered metal composite material, and can greatly reduce the manufacturing cost of the layered metal composite material, reduce the explosion pollution and realize low-carbon, energy-saving and green manufacturing according to the metal interface atomic combination mechanism and the metal plastic deformation creep mechanism.

Disclosure of Invention

First, the scientific principle on which the invention is based

The three manufacturing technologies of the composite material are not the bonding mechanism of fusion welding in nature, but the mechanism of solid phase atom bonding at the material interface. Explosion welding, however, causes melting defects at the interface of some materials due to the dynamic nature of its loading and the high temperature interaction at the interface. The rolling combination has larger difference of deformation resistance due to the plastic deformation characteristic of the base composite material, so that a combination interface is not easy to form.

Static atomic solid phase bonding is one of the easiest ways to form a material bonding interface. The basic scientific principle on which the present invention is based is the two basic conditions required for interfacial bonding. According to the theory of surface physical chemistry and interface physics, the precondition for realizing solid phase atomic force combination of two solids is as follows: (1) the two solids to be compounded have clean and fresh surfaces; (2) the two surfaces can approach each other to atomic distance.

(1) And obtaining the clean surface. Ideally, smooth, clean and substantially parallel metal surfaces are sufficiently close to each other that no additional energy is required to produce a bond of metal atoms sufficient to form a solid phase bond, and the strength of such a bond is often higher than the strength of the metal matrix involved in the bond. However, the ideal surface does not actually exist. Realistic surfaces, which are first covered with an oxide film, an adsorbed oil film and a gas layer, i.e. not clean, such surface conditions hinder the formation of metallic bonds; secondly, it is difficult to have an absolutely smooth surface in air. Any solid surface, even a carefully polished surface, is always undulating, rough, i.e., there are numerous microscopic raised points (although this is not necessarily detrimental to the formation of the weld interface).

In experiments conducted in surface science, it is generally at about 10^-8In a vacuum of Torr (Torr) or more, a fresh surface (also referred to as a virgin surface) having no oxide film and no adsorbed layer of liquid and gaseous molecules is obtained by ion sputtering of a solid surface. In this case, a layer of constantly moving free electron cloud is present below the surface layer of the metal, which constantly escapes from the metal and returns to the metal again. Due to this process, the surface of the metal is covered by an electrically coupling layer, the negative electrode is the electron cloud, and the positive electrode is the metal after the free electrons have been liberated. The density of the charge of the coupling layer is not uniform across the surface, depending on the microscopic geometry of the surface. At a sharp projecting pointThe electric field strength is the greatest.

A relatively clean surface of metal, not only may be created in a vacuum, it may also occur at the moment when the metal undergoes creep or strong plastic deformation, such as plastic deformation of metal parts, breakage and cutting. On one hand, the strong plastic deformation at the interface to be welded breaks and eliminates the dirt of an oxide film, an adsorption film and the like on the surface, and simultaneously forms metal jet flow, so that the two metals are exposed out of a clean and fresh surface, and the barrier is cleared for the tight combination between atoms on the interface; in addition, the gas between the two plates is also discharged at the moment of collision, and the surface is also scoured in the discharging process. The bonding of the interfaces is easier if the two interfaces are under vacuum.

(2) The surfaces approach each other to achieve atomic separation. In order to obtain solid phase atomic bonding of both metals a and B, the distance between the two surfaces must also be made small enough to allow the atoms on the two surfaces to reach within their attractive force range (a few angstroms) to achieve atomic bonding. At the equilibrium position of the atomic distance, the attractive and repulsive forces between atoms are balanced with each other, that is, the energy of interaction between atoms is the lowest. Therefore, the two fresh surfaces to be bonded must be close to the level of the equilibrium spacing of the atoms, the so-called "true contact" between the surfaces. In the plastic creep process, two metals to be welded are brought into "true contact" over their entire range of even several times the nominal surface area by a certain pressure at a certain temperature, that is, each atom in the surface layer comes into atomic separation with the atom in the corresponding surface layer and is liable to form a bond due to the activation of the high temperature of the interface and the presence of surface defects. Therefore, when the material interface is in a plastic creep state, atoms of the interface of the two materials can reach the atomic distance to automatically form an atomic bonding joint, and therefore, a novel vacuum creep press manufacturing method of the dissimilar metal composite material is provided.

Vacuum creep press manufacturing method for metal composite material

The basic conditions for the two interfacial bonding are "clean and fresh surfaces" and "surfaces close to each other to achieve atomic separation" as described above. Two dissimilar metal plates are subjected to creep pressing once under certain vacuum, temperature and pressure to obtain two or double-sided metal composite materials, and the interface of the composite materials is in high-quality atomic bonding. The main manufacturing process comprises the following steps: surface treatment; leveling the base composite material; assembling and sealing; controlling in vacuum; heat treatment; and (5) creep compression bonding.

1. Surface treatment

The surface treatment is to eliminate the dirt of adsorption film, oxidation film, etc. on the surface of two metals to be compounded, so that both metals are exposed to clean and fresh surface, and this provides basic condition for the tight combination between atoms in the interface and makes the surface roughness greater than Ra3.2 micron after surface treatment to raise the combination strength of two interfaces.

2. Base composite material leveling

The leveling of the base composite material is mainly aimed at the composite material, and in order to enable the base composite material to be easy to reach the atomic distance in the subsequent easy sealing welding and creep compression processes, the parallelism of the composite material after being leveled is controlled to be less than or equal to 1%.

3 group blank seal welding

The edge sealing of the two metal plates is prepared for vacuumizing and creeping pressure, and the sealing is generally carried out by adopting a surfacing welding method to ensure that the two metal edges to be combined are completely combined. The assembly method has three types: if the composite material is made by creeping and pressing composite, the composite material is difficult to weld with different metals such as titanium, steel and the like, a pair of base materials and composite materials are designed to be symmetrically assembled (see figure 1), the

base materials

1 and 7 are sealed and welded, and a release agent is coated between the two composite materials 3 and 5. Or a double-sided composite material is designed to be welded and sealed (see figure 2), and the

composite materials

12 and 16 are sealed and sealed. And thirdly, the composite material of the easy-to-weld metal and alloy with the same edge as the stainless steel and the steel is manufactured by creeping and pressing in a composite mode, so that the base material 20 and the composite material 17 can be directly subjected to surfacing welding and sealing, and the structure is shown in figure 3.

4. Vacuum control

The vacuum control of two metal plates to be compounded is an important process step of the invention, and has two functions: firstly, the problem that two metal surfaces to be compounded and oxygen in the air are subjected to chemical reaction to form a brittle oxide which is not easy to combine in the process of heat treatment and creep pressure combination is eliminated; second, vacuum ring with two interfacesThe situation prepares the conditions for the close bonding of the two surfaces to be composited to achieve the atomic distance. The two interfaces are pumped into 10 parts by a molecular vacuum pump through arranging an air exhaust hole^-3Torr to 10^-12A torr vacuum. The interface vacuum degree can be designed to be 10 according to the oxidation performance of the metal to be compounded^-3From about 10 torr^-5Torr (e.g., stainless steel, etc.), 10^-5From about 10 torr^-8Torr (e.g., copper, nickel, etc.) and 10^-8From about 10 torr^-12Two types (e.g., zirconium, titanium, aluminum, etc.) are torr.

5. Thermal treatment

The key of creep pressure is to ensure that the interfacial shear pressure of the two-to-be-compounded metal surface reaches the plastic creep pressure of the matrix metal at a certain temperature. Creep of metal is slowly generated under the action of constant temperature and constant stress for a long time even if the stress is less than the yield strength, but the creep is more remarkable only when the temperature is higher than 0.3Tm (Tm is the melting point of the metal to be combined), so in order to improve the creep speed of the metal and reduce the creep pressure, the temperature is controlled to be (0.3-0.8) Tm by heat treatment. Because the two metals to be compounded have different melting points, when determining the heat treatment temperature, the metal with lower melting point is taken as a reference object, and the selected heat treatment temperature is also within the creep temperature range of the metal with higher melting point. Firstly, the heat treatment temperature is higher than the melting point of two metals to be compounded; secondly, if the difference between the melting points of the two to-be-compounded metals is large, the heat treatment temperature can be controlled to be (0.6-0.8) Tm, if the difference between the melting points of the two to-be-compounded metals is small, the heat treatment temperature is (0.3-0.5) Tm,

6. creeping pressure

The metal material is at creep temperature or even superplastic deformation temperature, has low creep strength and rheological stress, can make two surfaces to be combined closely contact by applying small pressure, and because the two surfaces are completely in a vacuum and fresh state, atomic bonding of metal can be generated between the two surfaces. The test proves that the creep pressure can be controlled to be 20-50 MPa and can be provided by a common oil press or a rolling mill, and the creep pressure is controlled for 15-20 minutes under the pressure, so that the two interfaces are in full contact to achieve atomic contact and form metal atom solid-phase bonding.

Drawings

Fig. 1 is a schematic structural diagram of two pairs of dissimilar refractory metals creep-pressing composite manufacturing assembly, wherein 1 is a

substrate

1, 2 is an air extraction hole, 3 is a

composite material

1, 4 is a surfacing welding seam, 5 is a

composite material

2, 6 is an air extraction hole, 7 is a

substrate

2, 8 is an air extraction hole, 9 is a surfacing welding seam, 10 is an air extraction hole, and 11 is a separant.

FIG. 2 is a schematic structural diagram of a creep-pressing composite manufacturing assembly of two-sided dissimilar refractory metals, wherein 12 is a composite material 1, 13 is a surfacing welding seam, 14 is a suction hole, 15 is a base material, and 16 is a composite material 2.

FIG. 3 is a schematic structural diagram of a creep-compaction composite manufacturing assembly of one-side dissimilar weldable metal, wherein 17 is a composite material, 18 is a weld bead, 19 is a suction hole, and 20 is a base material.

Detailed Description

Example 1 TA1-A3 steel vacuum creep. The size is as follows: two pieces of 200mm x 500mm x (2+20) mm, the main embodiment of which is as follows (see fig. 1):

two composite materials of TA1 and A3 steel are respectively arranged, and the length and the width of the two composite materials are 2-3mm smaller than those of the two base materials; carrying out surface treatment on two metal surfaces, particularly A3 steel, and removing oxide skin, passive film, oil stain and the like on the surfaces to expose active and clean surfaces; leveling the base material and the composite material, wherein the parallelism is less than or equal to 1%; as shown in FIG. 1, the base material A3 steel is drilled at both ends

1 each L-shaped vacuum through hole; coating a release agent on one side of the two composite materials, aligning and placing the two composite materials together, and then symmetrically placing a piece of surface-treated base material A3 steel up and down; welding the edges of the two assembled base materials A3 steel by adopting an argon arc welding method to ensure that the periphery is completely sealed; vacuumizing the interface of the two sealed and welded samples by using a molecular vacuum pump, and testing the vacuum degree of the sample interface and a pressure gauge to be as follows: 10^-3Torr to 10^-12A torr; heating the sample, and controlling the temperature at 800-900 ℃; creep pressing with oil press under 20-50 MPa (about 500 tons) for 20 min to obtain two identical composite materials of TA1-A3 steel, and mechanical property detection shows that the interface is atom bonded and the interface is shearedThe shear strength is greater than that of the explosive composite plate, and the base composite material is not affected by the explosive stress.

Example 2 TA1-5083-TA1 vacuum creep pressure. The size is as follows: 1000mm × 2000mm × 2+20+ 2mm in one piece, the main embodiment of which is as follows (see fig. 2):

two composite materials TA1 and one composite material 5083 are adopted, and the length and the width of the two composite materials are 2-3mm larger than those of the base material; carrying out surface treatment on the surfaces of the two metals to remove oxide skin, passive film, oil stain and the like on the surfaces and expose active and clean surfaces; leveling the base material and the composite material, wherein the parallelism is less than or equal to 1%; as shown in FIG. 2, two ends of base 5083 are drilled

1 each L-shaped vacuum through hole; the two composite materials and the base material are aligned and placed together; welding the edges of the two assembled composite materials TA1 by adopting an argon arc welding method to ensure that the periphery is completely sealed; vacuumizing the interface of the two sealed and welded samples by using a molecular vacuum pump, and testing the vacuum degree of the sample interface and a pressure gauge to be as follows: 10^-3Torr to 10^-12A torr; heating the sample, and controlling the temperature at 500-550 ℃; creep pressing is carried out by an oil press, the pressure is controlled to be 20 MPa-45 MPa, a double-sided TA1-5083-TA1 composite material can be obtained after 20 minutes of creep pressing, the surface is detected by mechanical properties, the interface is in atomic bonding, the shear strength of the interface is greater than that of an explosive composite plate, and the base composite material is not influenced by explosive stress.

Claims

1. A vacuum creeping press method for manufacturing dissimilar metal composite material is characterized in that two or double-sided metal composite materials can be obtained by once creeping press of two dissimilar metal plates under certain vacuum, temperature and pressure, the interface of the composite materials is high-quality atom combination, and the main manufacturing process comprises the following steps: (1) surface treatment; (2) leveling the base composite material; (3) assembling and sealing; (4) controlling in vacuum; (5) heat treatment; (6) and (5) creep compression bonding.

2. The novel vacuum creep press manufacturing method of dissimilar metal composite material according to claim 1, characterized in that the surface treatment is to eliminate dirt such as adsorption film, oxidation film and the like on the surface of the dissimilar metal composite material, and the surface roughness after the surface treatment is more than Ra3.2 μm; the parallelism of the base composite material after being leveled is controlled to be less than or equal to 1 percent.

3. The novel vacuum creep-pressing manufacturing method of dissimilar metal composite material according to claim 1, characterized in that a pair of base materials is generally designed for assembly seal welding, and a composite material is welded by adopting a surfacing welding method to ensure that the two metal edges to be combined are completely and hermetically combined, and the assembly method comprises three methods:

if the composite material is creep-press composite manufacturing of dissimilar metals which are difficult to weld such as titanium, steel and the like, a pair of base materials and composite materials can be designed to be symmetrically assembled, the base material 1 and the base material 7 are sealed and welded, and a release agent is coated between the two composite materials 3 and 5;

or designing a double-sided composite material for surfacing sealing, and sealing the composite materials 12 and 16;

and thirdly, the composite material of the easy-to-weld metal and alloy with the same edge as the stainless steel and the steel is manufactured by creeping and pressing in a composite mode, and the base material 20 and the composite material 17 can be directly subjected to surfacing welding and sealing.

4. The novel vacuum creep press manufacturing method of dissimilar metal composite material according to claim 1, characterized in that vacuum control is to vacuumize the interface of two sealed and welded samples by a molecular vacuum pump, and the vacuum degree is as follows: 10^-3Torr to 10^-12A torr; the heat treatment temperature is higher than the melting points of the two to-be-compounded metals, if the difference between the melting points of the two to-be-compounded metals is larger, the heat treatment temperature can be controlled to be (0.6-0.8) Tm or the difference between the melting points of the two to-be-compounded metals is smaller, and the heat treatment temperature is (0.3-0.5) Tm.

5. The novel vacuum creep press manufacturing method of dissimilar metal composite material according to claim 1, characterized in that the creep press pressure is controlled to be 20 MPa-50 MPa, and the time is 15-20 minutes.