WO2014124582A1

WO2014124582A1 - Method for preparing ultra-fine grain aluminum alloy and composite material thereof

Info

Publication number: WO2014124582A1
Application number: PCT/CN2013/088569
Authority: WO
Inventors: 赵玉涛; 陈刚; 张松利
Original assignee: 江苏大学
Priority date: 2013-02-18
Filing date: 2013-12-05
Publication date: 2014-08-21
Also published as: CN103352193B; CN103352193A

Abstract

A method for preparing an ultra-fine grain aluminum alloy and a composite material thereof comprises the steps: first processing the aluminum alloy or aluminum-based composite material to a plate, then abutting the plate against a block material (5) having a certain thickness and a same material with the plate, heating the plate with a pressed friction heating part (2) under pressure, and heating the plate and the block material (5) to an assigned temperature, subsequently introducing a rotating stirring rod (3) between the plate and the block material (5), stirring with pressing, simultaneously moving the friction heating part (2) and the stirring rod (3) from one end of the plate to the other end of the plate until the stirring rod (3) is moved out of the material; and then abutting another plate having a same material with the plate against the larger face of the above plate, repeating the above steps to realize connection, continuously connecting new plates until a required thickness is reached, and removing the initial block material (5) to obtain a fine grain block material.

Description

Method for preparing ultrafine crystal aluminum alloy and composite material thereof

[0001] The present invention relates to an aluminum alloy and a composite material thereof, and more particularly to a method for preparing an ultrafine grain aluminum alloy and a composite material thereof by a friction stir method.

technical background

[0002] Grain refinement can effectively improve the material strength, and at the same time, the plasticity and toughness of the material can be greatly improved, so the application potential of the ultrafine grain material having a grain size smaller than lm is huge; at present, the preparation method of the ultrafine grain material It mainly includes spray deposition method, mechanical grinding method, mechanical alloying method, amorphous crystallization method, friction and compression method, electrolytic deposition method, rapid solidification method and strong plastic deformation method; however, the above methods are limited by their respective techniques. For example, the process of jet deposition is complicated, and the process of amorphization by amorphous crystallization is difficult, and it is still possible to realize industrial applications.

[0003] Friction stir processing is a new technology for the preparation of fine-grained materials. This method uses the stirring head to cause severe plastic deformation, mixing, crushing and heat exposure of the material in the processing zone to achieve densification and homogenization of the microstructure of the material. Refining; using this technology to prepare fine-grained aluminum alloy with grain size of nanometer, the strength and plasticity of the aluminum alloy are greatly improved; the basic process of the method is: after the rotation of the stirring head is started, the material to be processed is inserted at a certain speed; After a period of time, the material in the vicinity of the stirring head is sufficiently frictional heat to be softened and deformed; at this time, the treatment can be carried out, and the thermoplasticized material is continuously transferred backward by the stirring head, and the material can be under the action of a certain forging pressure. Forming a strong diffusion connection with the surrounding materials; During the friction and friction processing, under the dual action of heat and mechanical, the material undergoes severe plastic deformation and recovery and recrystallization, which promotes grain refinement, makes the material structure uniform and compact, and reduces defects; Currently, this technology is mainly used to improve the microstructure of various cast alloys, thereby Integrated high performance alloys.

[0004] However, studies have shown that since the heating method of the friction stir processing is heating from one end, the processing thickness of the material is greatly limited, and the currently processed materials are generally plate types, and the cut thickness is less than 10 mm; FSP passes to improve the uniformity of material organization and obtain a wide range of FSP materials, but still can not get a uniform distribution of tissue in the full sense; from the current research, the FSP implementation can not be separated from the FSW mode, which is It is fundamentally difficult to solve the problem of material microstructure inhomogeneity. Therefore, there is an urgent need to develop a new material preparation process based on the basic idea of FSP to break through the bottleneck of tissue uniformity and material thickness.

Summary of the invention

[0005] The present invention provides a method for preparing an ultrafine grain aluminum alloy and a composite material thereof, the principle of which is: by friction heating in a thickness direction of a plate of a certain thickness, and then by partial pressure and across the entire plate width The stirring action of the stirring rod connects the large flat parts of the plate together to realize the material organization while achieving the connection Refining; the method is heated over the entire width of the material to achieve a larger range of agitation refinement; and the use of a partial pressurization method allows a smaller device to apply more pressure to the portion to be joined, and more Conducive to the walking of the stirring rod.

[0006] The present invention provides a method for preparing an ultrafine crystal aluminum alloy and a composite material thereof, specifically: firstly preparing an aluminum alloy or an aluminum matrix composite material into a sheet material, and then the sheet material and a block of the same material with a certain thickness The body material is laminated, the plate is heated under pressure by a friction heating component, the plate and the block material are heated to a specified temperature, and then a rotating stirring rod is introduced between the plate and the block material, and the friction heating part and the stirring are performed. The rods are moved from one end of the sheet to the other end, and are stirred while being pressed until the stirring rod is removed from the material; then another sheet of the same material is attached to the large plane of the sheet, and the above process is repeated to realize the connection, so that the connection is continuously The new sheet material, until the desired thickness is reached, removes the original bulk material portion to obtain a bulk fine-grained material.

[0007] The sheet material referred to refers to an aluminum alloy or a particle reinforced aluminum matrix composite material sheet having a thickness of 3 to 6 mm and a width of 50 to 160 mm.

[0008] The bulk material of the same material of a certain thickness refers to an aluminum alloy or aluminum-based composite material having a thickness of 5 to 10 mm, a length, a width, and a material similar to that of a sheet material.

[0009] The friction heating component refers to a friction heating component consisting of 5 to 8 rotatable friction heads, and the side of the friction head and the plate is formed into a common shape of the current friction grinding shoulder, such as The concentric convex ring shape, the diameter of the friction head is 9~18mm, the distance between adjacent friction heads is l~2mm, and the wider the plate, the more the number of friction heads.

[0010] The pressure action involved means that the friction heating member is bonded to the surface of the sheet material at a compressive stress of 0.5 to 5.0 MPa.

[0011] The heating to the specified temperature refers to heating the plate by the friction heating component, and heating the block material through the plate, the heating temperature is 0.8~0.9T _m , wherein 1„ is the melting point of the plate, and the unit is K.

[0012] The stirring rod involved refers to a high-speed steel cylindrical rod with a diameter of 4 to 8 mm and a standard thread. The length of the stirring rod is equal to the width of the sheet, and the longer the length, the larger the diameter.

[0013] The thermal insulation baffle refers to a baffle made of heat-resistant thermal insulation material, such as fire-resistant cotton, having a diameter of 8 to 15 mm and a thickness of 10 to 15 mm, and the heat-insulating baffles on both sides are integrated with the stirring rod. The stirring rod is connected centrally with the heat insulating baffle.

[0014] The friction heating member involved moves from one end of the sheet to the other end together with the stirring rod, which means that the friction heating member is in front, the stirring rod is behind, the symmetric center line of the friction heating member along the width direction of the sheet and the central axis of the stirring rod The horizontal distance is 5~10mm apart and moves from one end of the plate to the other at the same moving speed of 30~80mm/min.

[0015] When the side is pressed and agitated, it means that the stirring rod is followed by the friction heating member, and the friction heating member is opposite to the plate. A compressive stress of 0.5 to 5.0 MPa is applied to the surface of the material, and the rotating speed of the stirring rod is 800 to 1200 rpm.

[0016] The method proposed by the invention has the advantages that: the heating range is wider, the pressure is larger, the equipment arrangement is more flexible, the material organization is more uniform, and the aluminum alloy can be processed or compared with the prior method. The aluminum-based composite material is processed, and the principle can also be applied to other alloy materials and composite materials thereof, and a large-sized ultra-fine crystal material can be obtained. DRAWINGS

1 is a schematic view of a device according to the present invention, wherein 1 is a sheet to be processed, 2 is a friction heating member, and 3 is a stirring rod.

4 is a heat preservation baffle, 5 is a block material of the same material or a processed material;

2 is a friction heating member of the present invention, wherein 1 is a friction head and 2 is a friction heating member frame.

3 is a photomicrograph of the A356 alloy; wherein (a) is a conventional metal type casting; (b) is an ultrafine crystal prepared by the present invention.

detailed description

The present invention can be carried out according to the following examples, but is not limited to the following examples; the terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art unless otherwise stated; it should be understood that these examples are only The invention is not intended to limit the scope of the invention in any way; in the following examples, various processes and methods not described in detail are conventional methods well known in the art.

Embodiment 1

This embodiment specifically implements a method for preparing an ultrafine grain A356 alloy: firstly, the A356 alloy is prepared into a plate having a thickness of 3 mm, a width of 50 mm, and a length of 200 mm, and then the plate is made of A356 alloy material having a thickness of 5 mm, a width of 50 mm, and a length of 200 mm. Fitting, heating the sheet with a friction heating element under a compressive stress of 0.5 MPa, heating the sheet and the above block material to 550 ° C, and then introducing a rotating stirring rod between the sheet and the bulk material; friction heating part It consists of 5 rotatable friction heads. The side of the friction head and the plate is made into a plurality of concentric convex rings. The diameter of the friction head is 9mm, the distance between adjacent friction heads is 1mm; the stirring rod is 4mm in diameter. , 50mm length, high-speed steel cylindrical rod with standard thread, the stirring rod is integrated with the heat-insulating baffles on both sides, and the stirring rod is connected with the heat-insulating baffle. The heat-insulating baffle has a diameter of 8mm and a thickness of 10mm. Made during the mixing process, the stirring rod is followed by the friction heating part, and the friction heating element applies a compressive stress of 0.5 MPa to the surface of the sheet, and the stirring rod rotates at a speed of 80 0 rpm; In the process, the friction heating part is in front, the stirring rod is in the rear, the symmetrical center line of the friction heating part along the width direction of the sheet is 5 mm away from the horizontal axis of the stirring rod, and the same moving speed of 30 mm/min is used together from the end of the sheet. Move to the other end until the stirring rod removes the material; then, attach another A356 alloy sheet with a thickness of 3mm, a width of 50mm and a length of 200mm to the large plane of the above-mentioned sheet, and repeat the above process. Now connected, so that the new plate is continuously connected until the required thickness of 60mm is reached, and the first 5mm thick part of the bulk material is removed to obtain the bulk fine-grained A356 alloy material; as can be seen from Fig. 3, in the fine-grained A356 alloy The phase is remarkably refined, and the α phase grains are refined from the average 40 m of the conventional metal type to less than ΙΟ μ ηι, and the grain size is uniform, and the eutectic silicon is fine particles.

Embodiment 2

This embodiment specifically implements a method for preparing an ultrafine crystal 6061 alloy: firstly, 6061 alloy is prepared into a plate having a thickness of 6 mm, a width of 160 mm, and a length of 500 mm, and then the plate is made of a 6061 alloy material having a thickness of 10 mm, a width of 160 mm, and a length of 500 mm. Fitting, heating the sheet with a friction heating element under a compressive stress of 5.0 MPa, heating the sheet and the above block material to 450 ° C, and then introducing a rotating stirring rod between the sheet and the bulk material; friction heating part It consists of 8 rotatable friction heads. The side of the friction head and the plate is made into a plurality of concentric convex rings. The diameter of the friction head is 18mm, the distance between adjacent friction heads is 2mm; the stirring rod is 8mm in diameter. 160mm long, high-speed steel cylindrical rod with standard thread, the stirring rod is integrated with the heat-insulating baffles on both sides, and the stirring rod is connected with the heat-insulating baffle; the heat-insulating baffle has a diameter of 15mm and a thickness of 15mm. Made during the mixing process, the stirring rod is followed by the friction heating part, and the friction heating element applies a compressive stress of 5.0 MPa to the surface of the sheet, stir The rotation speed of the mixing rod is 1200 rpm; in the process, the friction heating part is in front, the stirring rod is in the back, the symmetrical center line of the friction heating part along the width direction of the sheet is 10 mm from the horizontal axis of the stirring rod, and the same is 80 mm/min. The moving speed is moved together from one end of the sheet to the other until the stirring rod moves out of the material. Then, on the large plane of the above-mentioned plate, another 6061 alloy plate with a thickness of 6 mm, a width of 160 mm and a length of 500 mm is attached, and the above process is repeated to realize the connection, so that the new plate is continuously connected until the required thickness of 200 mm is reached, and the initial removal is performed. A 10 mm thick portion of the bulk material is obtained as a bulk fine-grained 6061 alloy material.

Embodiment 3

This embodiment specifically implements a method for preparing a fine-grained SiC _p /6061 composite material: First, a SiC/6061 composite material is prepared into a sheet having a thickness of 6 mm, a width of 160 mm, and a length of 400 mm, and then the sheet has a thickness of 10 mm and a width of 160 mm. The SiC/6061 composite material with a length of 400 mm is laminated, and the sheet is heated by a friction heating member under a compressive stress of 3.0 MPa, and the sheet and the above-mentioned bulk material are heated to 500 ° C, and then introduced between the sheet and the bulk material. Rotating stirring rod; friction heating part consists of 8 rotatable friction heads, the side of the friction head and the sheet is made into a plurality of concentric convex rings, the diameter of the friction head is 18mm, between adjacent friction heads The distance between the two is 2mm; the stirring rod is 8mm in diameter and 160mm in length, with high-speed steel cylindrical rod with standard thread. The stirring rod is integrated with the heat-insulating baffles on both sides. The stirring rod is connected with the thermal insulation baffle. The diameter of the thermal insulation baffle is 15mm. , thickness 15mm, by Made of refractory cotton; during the mixing process, the stirring rod is followed by the friction heating part, and a compressive stress of 3.0 MPa is applied to the surface of the sheet by the friction heating part, and the rotating speed of the stirring rod is 1000 rpm; in the process, the friction heating part is in front After the stirring rod is behind, the symmetrical center line of the friction heating member along the width direction of the sheet is 10 mm away from the horizontal axis of the stirring rod, and moves from one end of the sheet to the other end at the same moving speed of 70 mm/min until the stirring rod moves out of the material; Then, another SiCp/6061 composite material plate with a thickness of 6 mm, a width of 160 mm and a length of 400 mm is attached to the large plane of the above-mentioned plate, and the above process is repeated to realize the connection, so that the new plate is continuously connected until the required thickness is 150 mm. The first 10 mm thick bulk material portion was removed to obtain a bulk fine-grained SiCp/6061 composite.

Embodiment 4

This embodiment specifically implements a method for preparing an ultrafine grained TiCp/A356 composite material: firstly, a TiC _p /A356 composite material is prepared into a plate having a thickness of 5 mm, a width of 100 mm, and a length of 300 mm, and then the plate has a thickness of 8 mm and a width of 100 mm. TiC _p / A356 composite material with a length of 300mm is laminated, and the plate is heated by a friction heating element under a compressive stress of 2.0 MPa, and the plate and the above block material are heated to 500 ° C, followed by the plate and the block material. A rotating stirring rod is introduced; the friction heating part is composed of 6 rotatable friction heads, and the side of the friction head and the sheet is made of a plurality of concentric convex rings, the diameter of the friction head is 15 mm, the adjacent friction head The distance between the two is 2mm; the stirring rod is a high-speed steel cylindrical rod with a diameter of 6mm and a length of 100mm. The stirring rod is integrated with the heat-insulating baffles on both sides, and the stirring rod is connected centrally with the heat-insulating baffle. The heat-insulating baffle has a diameter of 10 mm and a thickness of 12 mm, and is made of refractory cotton. During the stirring process, the stirring rod is followed by the friction heating member, and a compressive stress of 2.0 MPa is applied to the surface of the plate by the friction heating member, and the rotation speed of the stirring rod is It is lOOOO rpm; in this process, the friction heating part is in front, the stirring rod is in the back, the symmetrical center line of the friction heating part along the width direction of the sheet is 8 mm horizontal distance from the axis of the stirring rod, and the same moving speed of 60 mm/min is used together from the sheet. One end moves to the other end until the stirring rod moves out of the material; then, another TiCp/A356 composite material sheet with a thickness of 5 mm, a width of 100 mm and a length of 300 mm is attached to the large plane of the above-mentioned sheet, and the above process is repeated to realize the connection. A new sheet is joined until the desired thickness of 150 mm is reached, and the first 8 mm thick portion of the bulk material is removed to obtain a bulk fine grained TiC _p /A356 composite.

Claims

Claim

A method for preparing an ultrafine-grained aluminum alloy and a composite thereof, comprising the steps of: first preparing an aluminum alloy or an aluminum-based composite material into a sheet material, and then using the same material as a bulk material of a certain thickness; Fitting, using a friction heating component to heat the sheet under pressure, heating the sheet and the bulk material to a specified temperature, and then introducing a rotating stirring rod between the sheet and the bulk material, the friction heating member together with the stirring rod Move from one end of the plate to the other, stir while applying pressure until the stir bar removes the material; then attach another piece of the same material to the large plane of the plate, repeat the above process to achieve the connection, so that the new connection is continuously connected The sheet, until the desired thickness is reached, removes the original bulk material portion to obtain a bulk fine-grained material.

2. The method according to claim 1, wherein the sheet material is an aluminum alloy having a thickness of 3 to 6 mm and a width of 50 to 160 mm or Particle reinforced aluminum matrix composite sheet.

3. The method according to claim 1, wherein the block material of the same material having a certain thickness refers to a thickness of 5 to 10 mm, and a length. Aluminum alloy or particle reinforced aluminum matrix composite with the same width and material as the sheet.

4. The method for preparing an ultrafine grain aluminum alloy and a composite thereof according to claim 1, wherein: the friction heating member refers to a friction composed of 5 to 8 rotatable friction heads. The heating part, the side of the friction head and the plate is made into a plurality of concentric convex rings which are commonly used in the current friction stir processing shoulder. The diameter of the friction head is 9~18mm, and the distance between adjacent friction heads is l~2mm. The wider the plate, the more the number of friction heads.

5. The method for preparing an ultrafine-grained aluminum alloy and a composite thereof according to claim 1, wherein: said pressure action means that the friction heating member is bonded at a compressive stress of 0.5 to 5.0 MPa. Designated on the surface of the board.

6. A method of preparing an ultrafine-grained aluminum alloy and a composite thereof according to claim 1, wherein: said heating to a specified temperature means heating the sheet by friction heating means and passing through the sheet pair The bulk material is heated at a heating temperature of 0.8 to 0.9 T _m , where 1 „ is the melting point of the sheet, and the unit is K.

7. The method for preparing an ultrafine grain aluminum alloy and a composite material thereof according to claim 1, wherein: the stirring rod is a high speed steel cylindrical rod with a diameter of 4 to 8 mm and a standard thread. The length of the stirring rod is equal to the width of the sheet. The longer the length, the larger the diameter.

8. The method according to claim 1, wherein the heat insulating baffle refers to a diameter of 8 to 15 mm and a thickness of 10 to 15 mm. The baffle made of heat-resistant and heat-insulating material, the heat-insulating baffle on both sides is integrated with the stirring rod, and the stirring rod is connected centrally with the heat-insulating baffle.

9. The method of preparing an ultrafine grain aluminum alloy and a composite thereof according to claim 1, wherein: The friction heating member moves from one end of the plate to the other end together with the stirring rod, which means that the friction heating member is in front, the stirring rod is behind, and the symmetrical center line of the friction heating member along the width direction of the sheet is horizontally separated from the central axis of the stirring rod by 5~ 10mm, moving from one end of the sheet to the other at the same moving speed of 30~80mm/min.

10. The method for preparing an ultrafine-grained aluminum alloy and a composite material thereof according to claim 1, wherein: the agitating while pressing the side means that the stirring rod is followed by the friction heating member and is rubbed by friction. The heating member applies a compressive stress of 0.5 to 5.0 MPa to the surface of the sheet, and the applied pressure is equal to the pressure applied when the friction heating member heats the sheet. The stirring speed of the stirring rod is 800 to 1200 rpm.