CN110802122B

CN110802122B - Aluminum-clad magnesium composite plate/profile and preparation method thereof

Info

Publication number: CN110802122B
Application number: CN201911136714.4A
Authority: CN
Inventors: 郭丽丽; 汪建强; 运新兵
Original assignee: Dalian Jiaotong University
Current assignee: Dalian Jiaotong University
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2021-04-30
Anticipated expiration: 2039-11-19
Also published as: CN110802122A

Abstract

The invention discloses an aluminum-clad magnesium composite plate/section and a preparation method thereof, belonging to the field of material processing for preparing aluminum, magnesium alloy and polymer composite materials. The method comprises the steps of cleaning the surface of a magnesium alloy core material for later use, inserting the obtained magnesium alloy core material into an aluminum alloy pipe, reserving a certain gap between the magnesium alloy core material and the aluminum alloy pipe, and compacting by using a press; and (3) conveying the assembled and compacted material to an extrusion wheel groove of a continuous extruder, adjusting a compaction wheel to enable the rod material to deform up and down, expanding the rod material in a lateral direction to contact with the extrusion wheel groove, establishing an effective friction condition, guiding the aluminum rod material containing the magnesium core into a deformation area under the rotation of the extrusion wheel, entering a 90-degree corner area, and finally entering an extrusion die to obtain the aluminum-containing rod material. The invention has the advantages of room temperature completion, no need of heating, high yield, no toxicity, no odor, no emission, good wear resistance and corrosion resistance of the produced product, and the like.

Description

Aluminum-clad magnesium composite plate/profile and preparation method thereof

Technical Field

The invention belongs to the field of material processing for preparing aluminum, magnesium alloy or polymer composite materials, and particularly relates to an aluminum-clad magnesium composite plate/section and a preparation method thereof.

Background

The magnesium alloy has abundant reserves, belongs to a metal structure material with a large amount of reserves, and the reserves of magnesium resources in China are at the top of the world. The magnesium has the characteristics of light weight, high specific stiffness and specific strength, and the magnesium alloy has excellent damping performance, good electromagnetic interference and shielding performance, good thermal conductivity and recyclability. However, because the magnesium alloy has a HCP crystal structure, the plastic deformation capacity at room temperature is poor, the elongation is low, the surface corrosion resistance is poor, and the magnesium alloy is easy to oxidize and burn in the processing process, so that the production difficulty is increased, and the application of the magnesium alloy is limited. The aluminum-clad magnesium alloy composite material can improve the plastic deformation capacity of the magnesium alloy, improve the corrosion resistance of the surface of the magnesium alloy, improve the ductility of the magnesium alloy, and achieve the comprehensive performance which can not be achieved by a single metal by compounding. The existing common extrusion compounding process and the liquid pouring process are deformed at high temperature, and have the problems of complex process, more composite interface oxides, coarse material grains and poor performance. The shape-feeding solid-state compounding is carried out by utilizing a large plastic deformation technology of a continuous extrusion method, so that the feeding continuous production at room temperature can be realized, the bonding strength of an interface composite layer is improved, and the mechanical property of the material is improved.

The invention is different from Chinese patent (Beijing university of science and technology): CN103691910A, the magnesium alloy is cast on a heated magnesium alloy billet by using an aluminum alloy solution and then hot rolled. Chinese patent (north river university of industry): CN109047368A is a continuous casting and rolling process, which is to heat and melt an aluminum alloy to coat the aluminum alloy on a magnesium alloy wire rod, and belongs to the continuous casting and rolling range. Chinese patent (chongqing materials institute) CN 102642344A: an aluminum-clad magnesium alloy wire and a preparation method thereof, which carry out drawing treatment after composite treatment and hot rolling and welding. The invention relates to a method for preparing a solid composite material, which is characterized in that an aluminum alloy pipe and a magnesium alloy rod material or magnesium alloy cutting scraps or granules are deformed together by using a continuous extrusion method, so that the aim of solid composite is fulfilled. Compared with the prior art, the method has the characteristics of short process, the raw materials are not required to be heated to the melting point of the metal, the composite material is prepared in a solid state, the energy can be saved, the characteristic of recycling of the magnesium alloy is fully utilized, the strength of the material can be improved, and the mechanical property of the composite material is improved.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a novel preparation method of an extruded aluminum-magnesium alloy composite material with short flow, low cost, firm composite interface, high binding force, corrosion resistance and other properties.

The invention utilizes the technical advantage of continuous extrusion, can feed at room temperature for continuous production, adopts aluminum alloy pipes, magnesium alloy rod materials, cutting chips or granules and a magnesium core containing polymer filler to feed at room temperature, guides the materials into a deformation area by means of the friction force between an extrusion wheel and the aluminum alloy pipes, enters an extrusion die to realize solid-state compounding, uniformly wraps the aluminum alloy pipes outside the magnesium alloy core materials under the action of high temperature and high pressure, realizes magnesium-aluminum alloy compounding, and simultaneously forms an aluminum layer for preventing oxidation on the outer surface of a section bar or a plate, and the specific steps are as follows:

s1, cleaning the surface of a magnesium alloy core material for later use;

s2, assembling the magnesium core material and the aluminum alloy pipe: inserting the magnesium alloy core material obtained in the step S1 into an aluminum alloy pipe;

s3, continuous extrusion: and (4) conveying the material assembled in the step (S2) to an extrusion wheel groove of a continuous extruder, adjusting a compaction wheel to enable the rod material to deform and compact vertically, expanding laterally to contact with the extrusion wheel groove, establishing effective friction conditions, guiding the aluminum rod material containing the magnesium core into a deformation area under the rotation of the extrusion wheel, entering a 90-degree corner area, and finally entering an extrusion die to obtain the aluminum-clad magnesium composite plate/section.

Further, in the above technical solution, the cleaning method in step S1 specifically includes: wiping the surface of the magnesium rod with alcohol to remove oil stains and oxides, brushing the surface with a metal brush to increase the composite effect of a composite interface, or cleaning magnesium chips, magnesium particles or a magnesium core containing a polymer with dilute acid to remove the oxide layer, removing water with absolute alcohol, and finally drying.

Further, in the above technical solution, the magnesium alloy core material in step S1 includes magnesium chips, magnesium particles, magnesium rods, or magnesium cores containing polymer fillers.

Further, in the above technical solution, when the magnesium alloy core material in the step S2 is a magnesium rod, a gap is required to be left between the magnesium rod and the aluminum alloy pipe, and the gap is 0.1-0.5 mm; in step S2, when the magnesium alloy core material is magnesium chips or magnesium particles and a magnesium core containing a polymer filler, it is compacted by a compactor.

Further, in the above technical solution, in step S3, the compacting roller is adjusted to make the initial pressing amount greater than 1-2 mm.

Further, in the above technical solution, in step S3, the combination degree of the composite layers on the inner and outer surfaces of the magnesium and aluminum alloy is changed by controlling the parameters of the extrusion process, so as to control the thickness of the composite interface.

Further, in the above technical scheme, the extrusion process parameters include rolling reduction, extrusion wheel speed, die structure, and bearing length.

The composite layer is an interface layer formed by the contact of magnesium and aluminum alloy interfaces and the mutual diffusion of atoms or molecules under the high-temperature and high-pressure solid deformation condition, thereby achieving the effect of metallurgical bonding, having an obvious interface and improving the strength of materials.

The invention also provides the aluminum-clad magnesium composite plate/section prepared by the method.

Advantageous effects of the invention

1. Generally, the magnesium alloy needs to be heated to more than 300 ℃ for plastic deformation, which not only wastes energy, but also oxidizes the surface of the magnesium alloy to generate coarse oxides on a composite interface, and is not beneficial to improving the mechanical property of the material. Because the continuous extrusion technology is utilized to have the process characteristic of generating heat by friction, and the whole deformation process is carried out in the closed cavity, the invention can realize less oxidation or no oxidation deformation, not only can form the magnesium alloy which is difficult to deform at room temperature, but also can realize the energy saving in production and improve the performance of the material.

2. After magnesium alloy (magnesium chips, magnesium particles and magnesium rods) is used as a core material or a magnesium core containing polymer filler is deformed together with the aluminum alloy, a modified layer is obtained on the surface of the section and the plate, so that the surface of the section is provided with expected superior texture and performance, the wear resistance, the corrosion resistance and the like of the section are improved to a great extent, meanwhile, the aluminum alloy has good ductility, and the composite magnesium alloy has the dual advantages of magnesium-aluminum alloy and improves the use defects of the magnesium alloy.

3. The invention belongs to the physical diffusion process in production line, is nontoxic, tasteless and emission-free, belongs to an environment-friendly process, and is environment-friendly.

4. The invention makes full use of the characteristic of magnesium alloy that can be recycled, can make full use of magnesium chips, particles, magnesium alloy fragments or recycled polymers, and the like, and avoids the danger of easy combustion and explosion of light alloy in use.

5. The new process of the invention can not only improve the strength of the magnesium alloy, but also solve the problem of poor corrosion resistance. This will promote the use of magnesium alloys as structural materials in industry (e.g. marine, aerospace);

6. the process is simple, does not need a heating procedure, has a simple extrusion pretreatment process, is easy to control, and can be widely applied to process production;

7. the invention belongs to the national policy support technology and has good application prospect.

Drawings

FIG. 1 is a schematic view of a continuous extrusion forming process of an aluminum-clad magnesium alloy plate/section;

FIG. 2 is a diagram of a trial product of an Al-clad Mg composite rod prepared by the method of the present invention;

FIG. 3 is a cross-sectional view of an Al-clad Mg composite rod material and SEM morphology of a composite interface thereof;

FIG. 4 shows the results of EDS analysis of the magnesium and aluminum cross-section of the inventive material;

FIG. 5 is the results of a three point bend test of the material of the present invention.

Detailed Description

The following non-limiting examples will allow one of ordinary skill in the art to more fully understand the present invention, but are not intended to limit the invention in any way.

Example 1

Preparing an aluminum alloy pipe with a certain size, wherein the outer diameter of the pipe is required to be matched with the size of an extrusion wheel groove, for example, TLJ250 type extrusion equipment is used, the width of the extrusion wheel groove is 8mm, then the aluminum alloy pipe with the outer diameter of 8mm is selected, and the inner diameter is not limited. Meanwhile, preparing a magnesium alloy core material, wherein the core material can be magnesium alloy cutting scraps, magnesium alloy granules, magnesium powder or a magnesium core containing polymer filler and the like. The surface of the magnesium alloy core material is cleaned by dilute acid and alcohol, oil stains and oxides are removed, and the magnesium alloy core material is dried or cleaned. FIG. 1 is a schematic view of a continuous extrusion process for forming an aluminum-clad magnesium alloy plate/section, wherein a magnesium alloy core material is fed into an aluminum alloy pipe and compacted by a press, as shown in FIG. 1; feeding the aluminum alloy pipe filled with the magnesium core into an extrusion wheel groove of a continuous extruder, adjusting a compaction wheel, adjusting the compaction wheel to enable the initial pressing amount to be larger than 1-2mm (adjusted according to different equipment), enabling the aluminum pipe to deform up and down, enabling the aluminum pipe to expand laterally to be in contact with the extrusion wheel groove, establishing effective friction conditions, guiding an aluminum rod material containing the magnesium core into a deformation area under the rotation of the extrusion wheel, carrying out continuous extrusion, and finally enabling the aluminum rod material to enter an extrusion die through a 90-degree corner area, thus obtaining the aluminum alloy pipe. The extrusion die can be a die for plates or profiles with different section shapes and sizes, so that the production of the aluminum-clad magnesium core plates and profiles with different shapes and sizes can be realized.

A trial product of the Al-coated Mg composite rod prepared by the method is shown in FIG. 2, and the Al-coated Mg composite rod can be successfully prepared from the cross section. FIG. 3 is a sectional view of an Al-Mg clad composite rod material and the SEM morphology of a composite interface thereof, and it can be seen that the interface between Al and Mg has an obvious diffusion layer (transition layer), and as indicated by the dotted line labeled area in the figure, the composite interface has uniform thickness and no defects such as holes, damages, burrs and the like, which indicates that the solid-state composite effect is good. FIG. 4 is the EDS component analysis result, and FIG. 4 shows the relationship between the mass percent of the interface magnesium aluminum element and the diffusion distance of the composite material, which shows that the thickness of the diffusion layer from the magnesium element to the aluminum side is about 2 μm or more, the thickness of the integral diffusion layer is 4-5 μm, and the effective solid-state welding is realized. Fig. 5 shows the results of three-point bending tests of the material, and it can be seen that the magnesium-aluminum composite material of the present invention can bear a very high bending force, which can reach 586N, which is close to twice that of AZ31 magnesium alloy, the bending time is increased, a larger bending angle can be realized, and the mechanical properties are greatly improved.

Example 2

Preparing an aluminum alloy pipe with a certain size, wherein the outer diameter of the pipe is required to be matched with the size of an extrusion wheel groove, for example, TLJ250 type extrusion equipment is used, the width of the extrusion wheel groove is 8mm, then the aluminum alloy pipe with the diameter of 8mm is selected, and the inner diameter is not limited. Preparing a magnesium alloy rod material or a bar material matched with the inner diameter of the aluminum alloy, wherein the diameter of the magnesium alloy rod material is 4.5-4.9 mm if the inner diameter of the aluminum alloy is 5mm, so that the magnesium alloy rod material can be smoothly inserted into the aluminum alloy pipe; wiping the surface of a magnesium alloy core material with alcohol, removing oil stains and oxides, brushing with a metal brush to increase the composite effect of a composite interface, inserting a magnesium alloy rod material into an aluminum alloy pipe, compacting with a press machine, feeding the aluminum alloy pipe filled with a magnesium core or containing a polymer filler into an extrusion wheel groove of a continuous extruder, adjusting a compaction wheel to enable the initial pressing amount to be larger than 1-2mm, enabling the rod material to deform up and down, laterally expanding to be in contact with the extrusion wheel groove, establishing effective friction conditions, guiding the aluminum rod material containing the magnesium core into a deformation area under the rotation of the extrusion wheel, continuously extruding, and finally entering an extrusion die through a 90-degree turning area to obtain the magnesium alloy rod material. The extrusion die can be a die for plates or profiles with different section sizes, so that the production of the aluminum-clad magnesium core plates and profiles with different sizes can be realized.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto.

Claims

1. The preparation method of the aluminum-clad magnesium composite plate/section is characterized by comprising the following steps:

s1, cleaning the surface of the magnesium alloy core material for later use;

s2, assembling the magnesium alloy core material and the aluminum alloy pipe: inserting the magnesium alloy core material obtained in the step S1 into an aluminum alloy pipe;

s3. continuous extrusion: sending the rod material assembled in the step S2 to an extrusion wheel groove of a continuous extruder, adjusting a compaction wheel to enable the initial pressing amount to be larger than 1-2mm, enabling the rod material to be deformed and compacted up and down, laterally expanding and contacting with the extrusion wheel groove, establishing effective friction conditions, guiding the rod material containing the magnesium alloy core material into a deformation area under the rotation of the extrusion wheel, entering a 90-degree corner area, and finally entering an extrusion die to obtain the aluminum-clad magnesium composite plate/section;

in step S3, the combination degree of the composite layers on the inner and outer surfaces of the magnesium alloy and the aluminum alloy is changed by controlling the parameters of the extrusion process, so as to control the thickness of the composite interface.

2. The method of claim 1, wherein the magnesium alloy core material in the step S1 includes magnesium chips, magnesium particles, magnesium rods, or magnesium alloy core material containing polymer filler.

3. The method according to claim 2, wherein the cleaning method in step S1 is specifically: wiping the surface of the magnesium rod by alcohol, removing oil stains and oxides, and brushing the surface by using a metal brush to increase the composite effect of a composite interface; or washing magnesium chips, magnesium particles or magnesium alloy core material containing polymer filler with dilute acid to remove an oxide layer, removing water with absolute alcohol, and finally drying.

4. The method according to claim 2, wherein when the magnesium alloy core material in step S2 is a magnesium rod, a gap is left between the magnesium rod and the aluminum alloy tube, the gap being 0.1-0.5 mm; when the magnesium alloy core material in the step S2 is magnesium chips or magnesium particles or a magnesium alloy core material containing a polymer filler, it is compacted by a compactor.

5. A method of manufacturing as claimed in claim 1 wherein the extrusion process parameters include reduction, extrusion wheel speed, die configuration, bearing length.

6. An aluminum-clad magnesium composite plate/profile prepared by the method of any one of claims 1 to 5.