CN116511245A

CN116511245A - Vermicular pressing equipment for metal composite material

Info

Publication number: CN116511245A
Application number: CN202211553111.6A
Authority: CN
Inventors: 史长根; 罗旭川; 王海涛; 杨小强; 孙泽瑞; 吴晓明
Original assignee: Army Engineering University of PLA
Current assignee: Army Engineering University of PLA
Priority date: 2022-12-05
Filing date: 2022-12-05
Publication date: 2023-08-01

Abstract

The invention relates to the technical field of metal composite materials and mechanical manufacturing synthesis, in particular to a creep pressure integrated device for manufacturing a metal layered composite material. Comprises an equipment body and a control system. The device body is internally provided with a heating body, a guide column, a temperature sensor, a pressurizing partition board and a working area between the pressurizing partition boards; a pressurizing device is arranged above the equipment body. The control system is internally provided with a motor, a hydraulic pump, an electromagnetic reversing valve, a pressure sensor and a heater control circuit; the control system is connected with the equipment body through a cable and is connected with the pressurizing device through a high-pressure conduit and a low-pressure conduit; the control system is externally provided with a display screen and control buttons. The working area size was 1000mm by 2000mm. The heating temperature, the pressurizing pressure and the heating time are determined by calculating different substitute processed blanks through molecular dynamics. The invention has the advantages of optimizing the creep press composite processing technology and improving the creep press composite production efficiency.

Description

Vermicular pressing equipment for metal composite material

Technical Field

The invention relates to the technical field of metal composite materials and mechanical manufacturing synthesis, in particular to a creep pressure integrated device for manufacturing a metal layered composite material.

Background

The layered metal composite material is a novel material obtained by adopting different manufacturing methods to achieve metallurgical bonding between two or more metals with different properties. The existing manufacturing methods of the layered metal composite material mainly comprise four main types of novel methods of explosion welding, explosion and rolling, rolling and vermicular pressing.

The explosion welding utilizes the huge energy generated by detonation of the explosive to finish solid/solid phase metallurgical bonding of the same kind or a metal composite material at one instant. Has the advantages of simple process, low cost, high bonding strength and the like. The explosion and rolling are to carry out subsequent rolling treatment on the explosion composite material on the basis of explosion welding, so that the surface roughness, shape precision, thickness dimension precision and processability of the material can be improved. But the explosion welding and the explosion and rolling plate type control are poor, the environmental pollution is generated, the recombination rate is lower in the process of manufacturing the thin plate, and the production efficiency and the yield are lower. The vacuum rolling can improve the production efficiency and the yield, reduce the environmental pollution and improve the bonding strength. However, the rolling is only suitable for compounding metals with similar performances, the compounding effect on metals with larger performance differences is poor, the energy consumption of rolling is larger, and the energy utilization rate is low.

Although the vacuum creep (CN 114043178A) and vacuum rolling (CN 106180186A) are the same in both the vacuum control process and the assembly process, the combination mechanism, the energy action principle and the final effect of the two processes are significantly different essentially, and the differences of the two processes are mainly:

1. the two manufacturing methods are distinctly different in the mechanism of bonding. Rolling is a metal working process, which is a press working method in which a metal blank is passed through a gap between a pair of rotating rolls, and the cross section of the material is reduced by compression of the rolls, thereby increasing the length. Whereas the vacuum rolling of the comparative documents 1 and 2 is to use a huge pressure (reduction) of a pair of rotating rolls in a vacuum environment to make the material to be compounded undergo a reduction in cross section and an increase in length even if the material to be compounded undergoes a severe plastic deformation to form a bond. The vacuum creeping pressure is to make the composite material to be combined without plastic deformation under the vacuum environment, and to make the two surfaces to be combined closely contact by applying small pressure for a certain time to make the two interfaces fully contact to maintain the atomic distance and form the metal atomic solid phase combination. Although good joints can be formed as long as the atomic distance is reached between two fresh interfaces for the layered composite material, the energy of vacuum rolling and explosion welding far exceeds the bonding energy of the interfaces, which is also long thought by the industry that the bonding of the two interfaces requires great energy to cause plastic deformation or high-temperature melting of the two materials to be combined to form metallurgical bonds (rather than atomic bonds). Because the interfacial bonding mechanism of the manufacturing method of the layered composite material such as explosive cladding, vacuum rolling and the like is not known deeply and fully in the industry, no simple method for compacting the composite material is proposed at home and abroad so far.

2. The energy addition modes are different. Vacuum rolling is not only very positive, but also lateral shear forces, which are required to plastically deform the material to be compounded, i.e. to exceed the yield strength of the material, typically by more than a few hundred megapascals. The vacuum creep pressure is only small static positive pressure which maintains the two interfaces to reach the atomic distance and is generally smaller than the yield strength of the material. The invention tests that the pressure is 1Mpa, which is far less than the yield strength of the material. And vacuum creep is static and free of lateral shear forces, thus reducing significant energy consumption.

3. The energy utilization rate is different. The rolling method consumes most of energy on plastic deformation of the composite material, and the bonding energy of the interface is only a small part in practice, and the simulation calculation shows that: the combination energy only accounts for 10% -20% of the total energy, and meanwhile, excessive energy can form microscopic defects such as overmelting, dislocation and the like at the interface. The creep pressure is very small, namely the consumed energy is very small, and most of the only pressure, namely gravitational potential energy, is converted into interface bonding energy, so that the creep pressure adopts the principle of minimum action amount in nature and physics, consumes less energy, has high energy utilization rate, and truly realizes the low-carbon energy conservation and sustainable development in the field of layered composite material manufacturing. The popularization and application of the peristaltic pressure method are a major innovation breakthrough in the field of composite materials, and a primary upgrading and updating can be brought to the fields of industrial equipment, military engineering and the like in China.

Compared with the former three manufacturing methods, the novel creep pressing compounding method overcomes the problems, can realize compounding among the same kind or one kind of metal, is suitable for manufacturing large-size composite boards, and has the advantages of reducing manufacturing cost, improving product quality, realizing green energy-saving manufacturing and the like.

The main technological process of the new peristaltic pressing compounding method comprises the following steps: surface treatment, base composite plate leveling, assembly sealing welding, heat treatment and creeping press combination. Wherein the heat treatment and the vermicular compression are two key steps, the temperature and the pressure of the compounding process are controlled respectively, and the temperature and the pressure can directly influence the bonding strength of the vermicular compression composite material. In the general creeping press compounding process, after heat treatment is carried out on the blank in a heat treatment furnace, the blank is transferred to the lower part of a corresponding oil press for creeping press combination. The heat of the blank can be dissipated in the process of transferring the blank from the heat treatment furnace to the oil press, the control of the temperature of the blank is inconvenient, and the temperature of the blank can be rapidly reduced in the vermicular pressing process, so that the yield of products is affected.

In order to solve the problems, the invention provides a metal layered composite material vermicular pressing device, which is used for carrying out molecular dynamics calculation on a material to be compounded before processing and determining the pressurizing time, the heating temperature and the pressurizing pressure by combining with an actual processing environment. And then placing the blank into the equipment provided by the invention, setting the heating temperature, the pressurizing pressure and the pressurizing time, and automatically adjusting corresponding parameters by the equipment.

Disclosure of Invention

1. Vermicular compression equipment structure composition and function

The invention aims to provide a creep pressure integrated device capable of controlling temperature and pressure for metal creep pressure compounding, which solves the problem of controlling temperature and pressure in the creep pressure process. The technical scheme adopted by the invention is as follows: the creep pressure integrated equipment for manufacturing the metal layered composite material comprises an equipment body, an internal structure of the equipment body and a control system.

The equipment body comprises an equipment shell, a cover plate, a support column and a pressurizing device. The bottom of equipment body is provided with the base, and pressurizing device is installed to equipment body top, and its side fixed mounting has the support column. The equipment body is connected with the control system through a cable, a high-pressure conduit and a low-pressure conduit.

The device body internal structure comprises a heating body and a temperature sensor, wherein the inner wall surface of the heating body is provided with a guide post, the middle of the heating body is fixedly provided with a pressurizing partition plate, and a working area is arranged between the pressurizing partition plate and the pressurizing partition plate. The upper part of the uppermost pressurizing partition plate is provided with a pressure head of the pressurizing device. The pressure head is connected with the uppermost pressurizing baffle plate in the equipment body through bolts.

The control system is internally provided with a motor, a hydraulic pump, an electromagnetic reversing valve, a pressure sensor, a pressure regulating device and a control circuit, and can provide high-pressure oil or other high-pressure liquid for the press. The motor, hydraulic pump, electromagnetic directional valve, pressure sensor and other parts inside the control system and the upper press, high pressure conduit and low pressure conduit constitute the hydraulic system. The hydraulic system can realize the pressurizing function of the blank. The control system is connected with the equipment body through a cable, the heating body can be controlled to generate heat, and the temperature sensor in the equipment body can also feed back the temperature to the control system in real time. The control circuit and the temperature sensor form a temperature control system, so that heating and heat preservation functions of the blank can be realized. The control system is provided with a display screen and control buttons, and the display screen can display set temperature, real-time pressure, heated time, heat preservation time and pressurized time. The device body can be controlled to heat, preserve heat and pressurize the blank through the operation button.

Further, the piston stroke of the pressurizing device can reach 600mm, and the pressurizing pressure can reach 10MPa at maximum.

Further, six pressurizing clapboards are arranged in the equipment body, and a working area is arranged between the two pressurizing clapboards. In the working process, the middle pressurizing partition plate is used as a lower pressurizing partition plate of the upper working area and an upper pressurizing partition plate of the lower working area at the same time. The pressurizing baffle plate is arranged and fixed on the guide post through the guide hole on the pressurizing baffle plate. The number of working areas can be increased by simply increasing the number of pressurized baffles.

Further, the cover plate is connected with the equipment body through bolts, and a through hole for the piston of the pressurizing device to pass through is formed in the middle of the cover plate. The piston is connected with the pressure head through a bolt.

Further, the pressurizing separator of the invention adopts a high temperature resistant material and has a special coating on the surface thereof, so that the sample is prevented from being combined with the separator during the heating and pressurizing processes.

Further, the door inner surface of the equipment body and the equipment inner surface are provided with the heat insulation layer, so that the heat insulation effect can be achieved, and the heat is prevented from overflowing.

Furthermore, three surfaces in the equipment body are heated simultaneously, so that the temperature uniformity of a sample can be ensured, the temperature control precision is +/-3 ℃, and the temperature uniformity precision of a heating chamber is +/-5 ℃.

The invention provides a creep pressure integrated device for manufacturing a metal layered composite material. The beneficial effects are as follows:

1. in the process of compacting, a blank to be processed is placed in a working area, and the heating body can heat the blank. And through the feedback of the temperature sensor, after the blank reaches the required temperature, the equipment can reduce the heating value of the heating body so as to realize automatic control of the heating temperature of the blank.

2. When the blank is heated to the required temperature, the pressurizing device can be controlled to pressurize the blank, so that heat dissipation in the process of transferring the blank to the pressurizing device is avoided. Meanwhile, the pressurizing device is provided with the pressure sensor, so that the pressurizing pressure can be reflected in real time, the blank can be pressed under the most suitable pressure, the bonding strength of a metal interface is further improved, and the product yield is improved.

3. The single working area of the equipment disclosed by the invention has the size of 1000mm multiplied by 2000mm, the oversized blank can be processed, and the equipment is provided with a plurality of working areas up and down, so that a plurality of blanks can be processed at one time, and equipment support is provided for batch processing of the blanks. Further, by changing the distance between the upper working area and the lower working area, blanks with different thicknesses can be processed, and the practicability of the equipment is improved.

2. Molecular dynamics calculation of pressurization time, heating temperature and pressurization pressure

The molecular dynamics calculation is carried out under the LAMMPS, and the potential function adopts EAM action potentials proposed by Zope and Mishin. Taking a titanium aluminum vermicular-pressed composite board as an example, a box with the size of 12 multiplied by 6nm is firstly created, and the box is divided into two parts A and B along the Z axis, wherein the part A is filled with HCP type Ti atoms, the lattice constant is 2.94, and the part B is filled with atoms, and the lattice constant is 4.05. And a distance of 0.1nm is reserved between the two parts A and B, and the distance is consistent with the position of the composite board before the creep pressure starts in practice. It was then relaxed under an NPT ensemble and its MSD along the Z direction was counted with the diffusion layer thickness.

1. Calculation of the pressurization time

At time t=0, al and Ti are symmetrically distributed at the boundary of z=30a. As time progresses, al, ti type atoms gradually expand toward z=0. Recording the maximum distance that Al and Ti atoms can expand and obtaining the difference to obtain the diffusion layer width. The width of the extension layer gradually increases with time. The diffusion width of Al floats up and down around 11A, while the diffusion width of Ti gradually increases with time, which means that the diffusion of Al is less affected by time. The primary mechanism of atomic diffusion during interfacial migration is the migration of vacancies. From the potential functions provided herein, the vacancy formation energy and vacancy mobility energy of Al are 0.71 and 0.65eV, respectively, while Ti is 1.83 and 0.80eV, so Al diffuses faster than Ti. Whereas the increase in the diffusion layer over time is mainly contributed by the diffusion of Ti atoms. The change of the Mean Square Displacement (MSD) of the atomic group in the diffusion direction Z with time is known. In the time of 0-16.8ps, MSD is expressed as a second power function of time t, the motion of atoms is mainly "ballistic motion", then in the time, MSD is expressed as a first power function of t, and the atomic motion mode is converted from "ballistic motion" into diffusion behavior. I.e. there is a fast diffusion phenomenon for a short time, followed by a slow expansion phase. In practice, the pressurizing time is 15-20 minutes, so that the two interfaces are fully contacted to reach atomic contact and form metal atomic solid-phase bonding.

2. Calculation of the pressure temperature

The creep pressure Ti-Al calculations of 700K,800K and 900K were performed separately to investigate the effect of temperature on creep pressure diffusion, all simulations were performed at 0 pressure to avoid interference of pressure on atomic diffusion, taking 200ps. As the temperature increases, the diffusion of atoms becomes increasingly severe. At the same time, the diffusion width gradually increases with increasing temperature, and the increase in temperature increases the diffusion of Ti atoms significantly more than Al, because the additional energy provided by the increase in temperature helps more Ti atoms to cross the vacancy barrier. Furthermore, the HCP structure of Ti also causes difficulty in diffusing Al atoms thereto. The key of the creep pressure is to ensure that the interfacial shear pressure of the two surfaces of the metal to be compounded reaches the plastic creep pressure of the matrix metal at a certain temperature. Since the two metals to be compounded have different melting points (Tm), the heat treatment temperature is determined with the lower melting point metal as the reference, and the selected heat treatment temperature should also be within the creep temperature range of the higher melting point metal. Firstly, the heat treatment temperature is less than the melting point of two metals to be compounded; and secondly, if the difference of the melting points of the two metals to be combined is larger, the heat treatment temperature can be controlled to be (0.6-0.8) Tm (Tm is the melting point of the metal with lower melting point in the two metals to be combined), and if the difference of the melting points of the two metals to be combined is smaller, the heat treatment temperature is (0.3-0.5) Tm.

3. Calculation of the pressurization pressure

The creep process requires applying a certain force to the composite plate to reach the atomic distance, and it is another problem that we are concerned that the pressure will not affect the interfacial recombination. For this purpose, we relaxed the model in the above temperature interval by varying the pressure of the NPT ensemble based on the model, with the pressure ranges taken to be 0,0.2,0.4,0.6,0.8,1bar, respectively. At the same temperature, the diffusion width of Al, ti and the total diffusion width vary with the pressure. Taking 700K as an example, as the pressure increases from 0 to 1.2b ar, the diffusion width of Al increases from 8.5215A to 13.1683A, while the variation of Ti is more complex, which reaches an optimal diffusion width 8.5739A at 0.6bar with increasing pressure, with subsequent pressurization resulting in a decrease in diffusion width. With the increasing externally applied pressure, the diffusion width assumes a situation of increasing and then decreasing. Maximum diffusion widths occur at 0.6bar at 700K, 750K,850K and 900K, and at 0.8bar at 800K. A certain pressure can promote diffusion between interfaces, but when a given pressure is too great, the ability of the atoms to move will bind, resulting in a decrease in diffusion width. Thus, during the creep process, a suitable pressure is applied to promote bonding of the composite sheet, which pressure range is suitable for Ti-Al creep compounds of about 0.6-0.8 bar.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is an exploded view of the present invention;

FIG. 3 is a side cross-sectional view of the device body of the present invention;

fig. 4 is a front view of the present invention.

Reference numerals: 1-a pressurizing device; 2-a piston; 3-fixing bolts; 4-supporting columns; 5-a base; 6-connecting bolts; 7-cover plate; 8-pressurizing a separator; 9-a heating element; 10-equipment door; 11-a heat insulating material; 12-connecting a hinge; 13-working area; 14-a guide post; 15-an equipment body; 16-pressing head; 17-press; 18-connecting threads; 19-a guide hole; 20-connecting a hinge; 21-a temperature sensor; 22-cables; 23-a control system; 24-a display screen; 25-control buttons; 26-high pressure conduit; 27-low pressure conduit.

Detailed Description

Example 1 TA1-5083-TA1 vacuum creep pressure. The size is as follows: 900mm x 1800mm x (2+20+2) mm piece, the main implementation is as follows:

the invention provides a creep-pressing integrated device for manufacturing a metal layered composite material, wherein a device body 15 can heat and insulate and press a blank. The maximum temperature is 1500 ℃, and the maximum pressure is 10Mpa. The integrated equipment is used for layered metal creeping press compounding.

The pressurizing device 1 is fixed above the equipment body 15 through the support column 4, and a press 17 is arranged above the pressurizing device 1, wherein the press 17 can be a conventional oil press, a hydraulic press or other presses. The piston below the pressurizing device 1 extends to the equipment body 15 through a through hole in the center of the cover plate 7, and is connected with a pressure head 16 in the equipment body 15 through bolts. The ram 16 is connected to the uppermost press diaphragm 8 by welding.

Further, the device body 15 includes six pressurizing partition boards 8, five working areas 13 and eight guide posts 14, heating elements 18 uniformly distributed on the inner surface of the device, a temperature sensor 21, a pressurizing device pressure head 16, and a gap between two adjacent pressurizing partition boards 8 is the working area 13. The pressurizing diaphragm 8 is provided with a guide hole 19, and the pressurizing diaphragm 8 is arranged on the guide column 14 through the guide hole 19 so that the pressurizing diaphragm can only move up and down. Said invented equipment body contains several working areas 13, and the size of said working area is 1000mm x 2000mm x (0 mm-300 mm), and can be used for simultaneously processing five blanks. The spacing between the pressing baffles may also be provided to accommodate blanks of various thicknesses to be processed.

Further, the inner surface of the equipment door 10 is provided with a heat insulation material 11, the equipment door 10 is closed and buckled through a connecting hinge 12 in the creeping process, and the heat insulation material can play a role in heat insulation.

In operation, the equipment door 10 is opened and the pre-processed TA1-5083-TA1 blank is placed in the work area. When the equipment door 10 is closed, the system is electrified, the control system 23 controls the heating body 9 to heat the blank, and the temperature sensor 21 feeds back, so that after the internal temperature of the equipment reaches the expected value of 550 ℃, the heating quantity of the heating body 9 is reduced, and the internal temperature of the equipment is kept at about 550 ℃. The blank was kept warm for 2 hours to allow the interior of the blank to be sufficiently heated. After the blank is fully heated, the press 17 is started by the control system, and the downward pressurizing pressure of the pressing head 16 is controlled to be 0.5-1bar. The control system 23 controls and maintains the pressure according to the set pressure by feedback from the pressure sensor. Meanwhile, the heating body continues to heat, and the expected temperature is kept unchanged. After the heat preservation and pressure maintaining are carried out for 1 hour, the blank achieves the expected combination effect.

Example 2 TA1-A3 Steel vacuum creep. Five pieces of 800mm×900mm× (2+20) mm in size, the main embodiment is as follows:

five pre-treated TA1-A3 steel blanks were simultaneously placed in each working area according to the procedure of example 1, and each blank was heated by the heating element 9 to a desired temperature of 850 c for 2 hours to allow the interior of the blank to be sufficiently heated. The blank is then pressurized by operating the pressurizing device 1, the pressure being set to 1-1.5bar and the pressure being maintained. Meanwhile, the heating body is heated to maintain the temperature unchanged. Preserving heat and pressure for 1.5 hours.

The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes using the descriptions and the drawings of the present invention or directly or indirectly applied to other related technical fields are included in the scope of the invention.

Claims

1. The vermicular pressing equipment for the metal layered composite material is characterized by comprising an equipment body, an internal structure of the equipment body and a control system; the equipment body comprises an equipment shell, a cover plate and a pressurizing device; the device comprises a device body, a temperature sensor, a pressurizing partition board and a working area between the pressurizing partition boards, wherein the heating body, the guide column, the temperature sensor and the pressurizing partition board are arranged in the device body; the control system is internally provided with a motor, a hydraulic pump, an electromagnetic reversing valve, a pressure sensor, a pressure regulating device and a control circuit; the control system is connected with the equipment body through a cable and is connected with the pressurizing device through a high-pressure conduit and a low-pressure conduit; the control system is externally provided with a display screen and control buttons.

2. The apparatus body internal structure according to claim 1, wherein the apparatus interior has 6 pressurizing partitions and 5 working areas between the pressurizing partitions; the pressurizing partition plate is provided with a guide hole, and the pressurizing partition plate is arranged on the guide column through the guide hole; the pressurizing partition board is made of high-temperature resistant materials and is provided with a special coating on the surface, and the size of the working area is 1000mm multiplied by 2000mm; the inner surface of the equipment is provided with an insulating layer, and the number of the pressurizing partition boards can be increased through reasonable transformation in the equipment, so that the number of working areas is increased; the top cover plate of the equipment body is provided with a through hole, and the piston of the pressurizing device is connected with the pressure head inside the equipment through the through hole; the pressurizing device above the equipment body can be an oil press, a hydraulic press or other presses.

3. The vermicular pressing equipment of the metal layered composite material according to claim 1, wherein the motor, the hydraulic pump, the electromagnetic directional valve, the pressure sensor, and the like in the control system form a complete hydraulic system with the upper press, the high-pressure conduit and the low-pressure conduit of the equipment body, and the hydraulic system can realize the pressurizing function of the blank; the control system is connected with the equipment body through a cable, the heating body can be controlled to heat, the temperature sensor in the equipment body can also feed back the temperature to the control system in real time, and the control circuit and the temperature sensor form a temperature control system, so that the heating and heat preservation functions of the blank can be realized.

4. The temperature control system according to claim 3, wherein three surfaces inside the equipment body are heated simultaneously, the temperature uniformity of the sample can be ensured under the adjustment of the temperature control system, the temperature control precision is +/-3 ℃, and the temperature uniformity precision of the heating chamber is +/-5 ℃; the hydraulic system is characterized in that the piston stroke of the pressurizing device can reach 600mm, and the maximum pressurizing pressure can reach 10MPa.

5. Calculating the heating temperature, the pressurizing pressure and the pressurizing time of the blank through molecular dynamics; when the difference of the melting points of the two metals to be combined is large, the heating temperature can be controlled to be (0.6-0.8) Tm (Tm is the melting point of the metal with a lower melting point in the two metals to be combined), and when the difference of the melting points of the two metals to be combined is small, the heating temperature is (0.3-0.5) Tm; the pressurizing pressure can be controlled to be 0.6-5bar; the pressurizing time is controlled to be 15-20 minutes.