RU2572955C2 - Production of microstructure multiply composites from different metals or alloys - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming. Claimed method comprises cutting of initial sheets of various metals to lengths, processing of their surfaces, assembling of cut lengths to stacks, hot processing of stacks by their heating and rolling to get the sandwiched stack work pieces. Said jobs are reiterated to get the sandwiched sheet composite material with preset number of applies and of required depth. Initial blanks are composed of sheets of diverse metal alloys mutually soluble in the range of heating temperatures at hot forming. Cut blanks are assembled to the stack consisting of least three plies at alternation of plies of fusible metal with less fusible metal. A dislocation barrier is produced at heating to inhibit the propagation of recrystallization from one ply into the other and microstructure is produced. Sandwiched sheet composite composed of stacked blanks is produced by plastic deformation at multistep processing to final depth. Note here that stack plies feature the microstructure. Then, thermal diffusion alloying is performed including the diffusion annealing of duration providing the penetration of diffusion zones of different contacting plies of material that make the stack to the depth, in each, comparable with that of one ply. Then, thermal hardening is performed including the quenching and ageing at temperature corresponding to quenching and ageing temperatures of fusible material. Invention allows the production of sandwiched composite of ply microstructure and with alternating plies, and increase in efficiency.

EFFECT: sandwiched composite of ply microstructure.

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Description

The invention relates to the field of metal forming and can be used for thermal diffusion alloying of microstructural multilayer composite materials of dissimilar metals to form the desired microstructure and mechanical characteristics during hot plastic deformation.

A known method for producing microstructural multilayer composite materials from dissimilar metals or alloys, including measuring cutting of the initial blanks from sheets, processing their surfaces, assembling the cut blanks into a bag, hot processing of the pressure of the package by heating and rolling it, followed by repeating the data of technological operations for obtaining a super-multilayer sheet with a given number of layers and the required thickness (see, for example, RF patent No. 2380234, B32B 15/00, published on January 27, 2010).

The main disadvantages of the known method is the impossibility of its application in obtaining supernormalized sheet compositions with different sequence of arrangement of layers, as well as its significant complication when using the operation of evacuation, due to its technical features, which takes a long duration of the entire processing stage.

The basis of the invention is the task of improving the known method for the possibility of thermal diffusion alloying of microstructural multilayer composite materials of dissimilar metals with different sequence of layers, while excluding the operation of evacuation from the entire processing cycle.

The problem is solved in that in the method for producing microstructural multilayer composite materials from dissimilar metals or alloys, including measuring cutting of the initial blanks from sheets, processing their surfaces, assembling the cut blanks into a bag, hot processing the pressure of the bag by heating and rolling it, followed by repetition of technological operations to obtain a super-multilayer sheet compositions, the original super-multilayer composite material is obtained from a package consisting of sheets of different native metals or alloys of the same or different thicknesses with different sequences of their arrangement, mutually soluble in each other metals or alloys in the temperature range of hot forming, which are plastically deformed according to a multistage scheme to a final thickness at which the dimensions of its layers are brought closer to the micrometric range wherein the package contains at least three layers of these materials, one of which plays the role of a separation layer, which serves as a dislocation barrier for passage recrystallization from one layer to another and the main factor for the formation of the microstructure, while the resulting composite is subjected to thermal diffusion doping at the final stage, including diffusion annealing for a duration, which ensures that the diffusion zones of heterogeneous contacting layers of metals or alloys that form the packet, to each depth, are comparable with a thickness of one layer, as well as the final stage of hardening heat treatment, consisting of hardening and aging.

Since the initial super-multilayer composite material is obtained from a package consisting of sheets of dissimilar metals or alloys of the same or different thickness with different sequence of their arrangement, mutually soluble in each other metals or alloys in the temperature range of hot processing, which is plastically deformed according to a multistage scheme to a final thickness at which the dimensions of its constituent layers will be close to the micrometric range, while the package must contain at least three layers of these materials, one of which plays the role of a separation layer, which serves as a dislocation barrier for the passage of recrystallization from one layer to another and is the main factor for the formation of a microstructure, while the resulting composite is subjected to thermal diffusion doping at the final stage, including diffusion annealing with a duration that ensures penetration of diffusion zones heterogeneous contacting layers of metals or alloys that form the package, to a depth in each, commensurate with the thickness o Nogo layer as well as the final step of hardening heat treatment consisting of quenching and aging, thus ensuring the thermal diffusion doping microstructural multilayer composites of dissimilar metals with different arrangement order of layers while avoiding vacuum operation.

The method of thermal diffusion alloying of microstructural multilayer composite materials of dissimilar metals is carried out as follows.

At the initial stage, a super multilayer sheet composition is obtained. In the process of obtaining it from the raw sheet materials, dimensional blanks with the same dimensions in the plan are cut. Surface treatment is carried out to remove technological grease, surface contaminants, oxide films and can be carried out both by mechanical, chemical methods, and their combination. After surface treatment, the assembly of cut sheets into a bag is carried out. The sheets in the bag are fastened with rivets.

After assembling the package, it is heated in a furnace to a temperature at which recrystallization processes in a material with a low melting point are actively occurring. When assembling packages from materials subject to strong oxidation during heating, the packages should be heated in a process jacket, for example, from aluminum foil. Then, the heated bag is plastically deformed in the rolls of the rolling mill to a thickness equal to or less than the thickness of the layer included in the bag. The minimum possible thickness is limited by the thermophysical properties of the rolled material and depends on its ability to maintain a given temperature range during deformation.

Upon reaching the final thickness, the rolled billet is cut into measuring parts with the removal of side edges and is cleaned of oxides. The newly formed package, consisting of the obtained multilayer sheet blanks, is repeatedly (possibly repeatedly) subjected to the described processing cycle.

The result of a repeated technological cycle is a flat workpiece of a given size, in the cross section of which there are alternating layers of the required thickness in an unlimited sequence, hard-soft-hard (T-M-T) or soft-hard-soft (M-T-M) and others, differing from each other in the degree of elaboration of the structure.

At the next stage, the obtained supernormal composite material is subjected to diffusion annealing in the temperature range of active diffusion processes in a more fusible material and with a duration that ensures the necessary penetration depth of the diffusion zone and saturation (alloying) of one material with another, which extends at least into the boundary contact areas of heterogeneous layers. In addition, at the final stage, after diffusion annealing, a complex hardening heat treatment is carried out, consisting of quenching, carried out by heating a superlayer composite material to quenching temperatures characteristic of the low-melting component of the composite material and accelerated cooling in a cooling medium (water, oil, etc. ., depending on the type of metal or alloy that forms the basis of the composite material), and aging (natural or artificial), carried out according to the regimes, regulations ovannym fusible component material for the composite material.

This method, due to the use of a prefabricated batch blank, does not require the use of special equipment and tools, has a lower cost, when using thermal diffusion alloying, it allows you to control the microstructure, thereby affecting the mechanical characteristics of a superlayer composite material.

An example implementation of the method. For the manufacture of a super-multilayer sheet material with a thickness of 1 mm, metal cards of a thickness of 0.5 mm made of copper M1 and 2 mm of technically pure aluminum AD1 are used as initial blanks. Cards in the amount of 3 pcs., Of which two from AD1, after cleaning and washing are placed in a bag according to the symmetrical scheme AD1-M1-AD1, after which the bag is placed in a technological foil shell and heated to a temperature of 375 ° C. The heated package is rolled on a sheet rolling mill to a thickness of 1 mm with a deformation in the first pass of 50-75%. Then the resulting strip is cut into cards and, in turn, collect them in a new package. The bag is heated and deformed in the same way. The transformation of the copper layer of the initial thickness (0.5 mm) into the final layer (0.00007 mm) was carried out for 6 cycles of packet formation, while the aluminum layers of the initial thickness (2 mm) were deformed into the final layer (0.0003 mm). Then, the obtained composite material at the stage of thermal diffusion alloying is subjected to diffusion annealing by heating it to a temperature of 450 ° C and prolonged exposure in the oven at this temperature for 7-12 hours. During this time, the temperature in the furnace chamber is slowly reduced (per hour by 20 ° C), until it is cooled to 300 ° C, after which the composite material is cooled in air. After diffusion annealing, hardening heat treatment is carried out — quenching, heating the composite material to a temperature of 450 ° C and abruptly cooling it in room temperature water, and artificial aging at a temperature of 170 ° C and holding for 4-6 hours, followed by cooling in an oven.

During diffusion annealing in the contact zone of the copper and aluminum layers, prolonged exposure led to an increase in the diffusion zone, passing to a depth of 0.0004 mm and commensurate with the thickness of the aluminum layer itself. The degree of aluminum alloying with copper, in such a range of thicknesses, lies in the range from 4 to 8%, which is similar in terms of the copper content in the group of duralumin.

Thus, in the proposed method, the superlayer material is a combination of sheets of dissimilar metals or alloys of different volume fractions and with different arrangement sequences having mutual solubility in each other in the temperature range of hot pressure treatment. In the initial state, the used alloys under normal conditions can have both identical and different crystal lattices, but at the same time they must be mutually soluble in order to allow their thermal diffusion alloying.

Claims (1)

A method of obtaining a multilayer composite material with a micro-dimensional structure of the layers, including measuring cutting of the initial sheet blanks from dissimilar metal materials, processing their surfaces, assembling the cut blanks into bags, hot processing the pressure of the packets by heating and rolling them to obtain multilayer packet blanks, followed by the repetition of the indicated technological operations on batch blanks to obtain a multilayer sheet composite material with a given amount m layer and the required thickness, characterized in that, as the initial blanks, sheets of the same or different thickness from dissimilar metal materials mutually soluble in each other in the range of the heating temperature during hot processing are used, the assembly of the cut blanks in a package consisting of at least three layers, carried out with the alternation of layers of a more fusible material with layers of a less fusible material, providing when heated, the formation of a dislocation barrier to the passage of recrystallization and from one layer to another and the formation of a micro-dimensional structure, while obtaining a multilayer sheet composite material from batch blanks is carried out by plastic deformation according to a multi-stage scheme to a final thickness at which the layers included in it have a micro-dimensional structure, after which thermal diffusion alloying is carried out, including diffusion annealing duration, ensuring the penetration of diffusion zones of heterogeneous contacting layers of materials that form the package, n Each depth commensurate with the thickness of one layer, followed by hardening heat treatment consisting of quenching and aging carried out at temperatures corresponding to temperatures, quenching and aging a fusible material.