A method for friction stir processing of an end face of an age-hardened aluminum alloy plate

Abstract

The application discloses an aging strengthening aluminum alloy plate end face friction stir processing method and belongs to the technical field of aluminum alloy thick plate preparation and processing. The solid solution state aging strengthening aluminum alloy plate is butted with a dissimilar plate and is clamped and fixed, and a starting plate and a leading-out plate are arranged on the side of the aging strengthening aluminum alloy plate and the dissimilar plate. A stirring needle is arranged at the bottom end of a stirring head, the distance between the outer edge of the stirring needle and the end face of the aging strengthening aluminum alloy plate is 0.01-5 mm, the stirring head is screwed into the starting plate, the aging strengthening aluminum alloy plate is subjected to underwater friction stir processing treatment or liquid nitrogen cooling friction stir processing treatment, the processed aging strengthening aluminum alloy plate is taken down, and aging treatment is carried out. The application can improve the organization layering phenomenon of the plate through the plastic flow of the material in the plate thickness direction, improve the interlayer bonding strength of the plate, and effectively prevent the end face layering cracking of the plate.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy thick plate preparation and processing technology, specifically relating to a method for friction stirring processing of the end face of age-strengthened aluminum alloy plates. Background Technology

[0002] With the development of modern warfare, armored vehicles will face more devastating attacks from all directions in future combat, placing new and higher demands on the protection and survivability of armor materials. 7-series and 2-series age-hardened aluminum alloys, with their advantages of good machinability, lightweight, good impact resistance, excellent weldability, and good corrosion resistance, have become the main materials for amphibious and airborne armored vehicle bodies. However, due to the uneven microstructure of laminated armor aluminum alloys and thick armor aluminum alloy plates, delamination and cracking are prone to occur on the end faces of armor aluminum alloy plates during armored vehicle operation under the influence of its own power, road impact, and load. CN201520994763.2 describes a method of preventing delamination and cracking on the end faces of armor aluminum alloys by welding. While this method can prevent cracking of thick aluminum alloy plates to some extent, end-face welding not only wastes a lot of materials and labor but also affects the overall appearance of the vehicle. Therefore, how to provide a friction stir processing method for the end faces of age-hardened aluminum alloy plates is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0003] The main objective of this invention is to provide a friction stir processing method for the end face of age-hardened aluminum alloy sheets to solve the aforementioned technical problems. This method improves the delamination phenomenon in the microstructure of age-hardened aluminum alloy sheets through plastic flow of material in the thickness direction, enhances the interlayer bonding strength, and effectively prevents delamination cracking on the end face of the age-hardened aluminum alloy sheets.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for friction stir processing of the end face of age-hardened aluminum alloy sheet includes the following steps: S1, the solution-treated age-hardened aluminum alloy sheet is butt-jointed with the dissimilar sheet and clamped and fixed. A welding start plate and a lead-out plate are respectively set on the side of the age-hardened aluminum alloy sheet and the dissimilar sheet after they are connected. S2, A stirring pin is provided at the bottom of the stirring head. The distance between the outer edge of the stirring pin and the end face of the age-hardened aluminum alloy sheet is kept at 0.01-5mm. The stirring pin is then screwed into the starting plate. S3, underwater stirring friction processing or liquid nitrogen-cooled stirring friction processing is performed on age-hardened aluminum alloy sheets. S4. Remove the processed age-strengthened aluminum alloy sheet and perform age treatment.

[0005] Furthermore, the age-hardened aluminum alloy sheet mentioned in S1 is a solution-quenched age-hardened aluminum sheet or a laminated aluminum sheet; the non-standard sheet is a high-melting-point steel sheet or titanium material, and the thickness of the non-standard sheet is 0.001-1mm less than the thickness of the age-hardened aluminum alloy sheet; the starting plate and the lead-out plate of the same thickness are respectively provided on both sides of the age-hardened aluminum alloy sheet.

[0006] Furthermore, the stirring needle at the bottom of the stirring head is threaded.

[0007] Furthermore, the backward tilt angle of the stirring head during use is 1~3°; the pressing amount of the stirring head is greater than or equal to the thickness difference between the age-strengthened aluminum alloy sheet and the dissimilar sheet; the feed speed of the stirring head is 50~250mm / min; and the rotation speed is 500~2500r / min.

[0008] Furthermore, in S4, the age-strengthened aluminum alloy sheet is separated from the starting plate, lead-out plate, and dissimilar sheet and then subjected to aging treatment. The aging treatment temperature is 110-190℃ and the time is 8-36h.

[0009] Compared with the prior art, the present invention has the following beneficial effects: 1. In this invention, the plastic flow of material in the thickness direction can improve the delamination phenomenon of age-hardened aluminum alloy sheets, increase the interlayer bonding strength of age-hardened aluminum alloy sheets, and effectively prevent delamination cracking of the end face of age-hardened aluminum alloy sheets.

[0010] 2. The high melting point dissimilar plate in this invention can prevent the end face deformation of the age-hardened aluminum alloy plate while avoiding welding between the age-hardened aluminum alloy plate and the dissimilar plate.

[0011] 3. This invention can improve the hardness and elastic resistance of the stirring zone of age-hardened aluminum alloy sheets through friction stirring and aging treatment.

[0012] 4. This invention can be applied to other metal sheets or metal laminated composite materials to improve the interlayer bonding strength of metal sheets or metal laminated composite materials and effectively prevent delamination cracking at the end faces of metal sheets and metal laminated composite materials.

[0013] 5. This invention is easy to operate and can be easily industrialized. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] Figure 2 This is a microstructure diagram of the laminated aluminum alloy prepared in Example 1.

[0017] Figure 3 The hardness distribution diagrams of the 7A52 aluminum alloys prepared in Example 1 and Comparative Example 1 are shown.

[0018] Among them, 1-Aging-strengthened aluminum alloy sheet, 2-Mixing and processing area, 3-Outlet plate, 4-Mixing head, 5-Irregular sheet, 6-Welding starter plate. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, the present invention provides a method for friction stir processing of the end face of age-hardened aluminum alloy sheet, comprising the following steps: S1, the solution-treated age-strengthened aluminum alloy sheet 1 and the dissimilar sheet 5 are joined and clamped together. A welding starter plate 6 and a lead-out plate 3 are respectively set on the side after the age-strengthened aluminum alloy sheet 1 and the dissimilar sheet 5 are connected. S2, the bottom of the stirring head 4 is equipped with a stirring pin, and the distance between the outer edge of the stirring pin and the end face of the age-strengthened aluminum alloy plate 1 is 0.01-5mm. The stirring pin is then screwed into the welding plate 6. S3, underwater stirring friction processing or liquid nitrogen cooling simultaneous stirring friction processing is performed on age-strengthened aluminum alloy sheet 1. S4, Remove the processed age-strengthened aluminum alloy sheet 1 and perform age treatment.

[0021] In this embodiment, the age-hardened aluminum alloy plate 1 mentioned in S1 is a solution-quenched age-hardened aluminum plate or a laminated aluminum plate; the dissimilar plate 5 is a high-melting-point steel plate or titanium material. The high-melting-point dissimilar plate 5 can avoid deformation of the end face of the age-hardened aluminum alloy plate 1, and can also avoid welding between the dissimilar plate 5 and the age-hardened aluminum alloy plate 1. The thickness of the dissimilar plate 5 is 0.001-1mm less than the thickness of the age-hardened aluminum alloy plate 1. The plastic flow of material in the thickness direction can improve the delamination phenomenon of the age-hardened aluminum alloy plate 1, improve the interlayer bonding strength of the age-hardened aluminum alloy plate 1, and effectively prevent delamination cracking of the end face of the age-hardened aluminum alloy plate 1; a welding starter plate 6 and a lead-out plate 3 of the same thickness are respectively provided on both sides of the age-hardened aluminum alloy plate 1.

[0022] In this embodiment, the stirring needle at the bottom of the stirring head 4 is threaded, and the stirring needle is preferably cylindrical, which is beneficial to the plastic flow of materials at the vertical interface.

[0023] In this embodiment, the backward tilt angle of the stirring head 4 during use is 1~3°, preferably 2°; the pressing amount of the stirring head 4 is greater than or equal to the thickness difference between the age-hardened aluminum alloy sheet 1 and the dissimilar sheet 5; the feed speed of the stirring head 4 is 50~250mm / min, preferably 100~180mm / min; the rotation speed is 500~2500r / min, preferably 1000~2000r / min; the continuous stirring of the stirring head 4 can improve the hardness and elastic resistance of the stirring area of ​​the age-hardened aluminum alloy sheet.

[0024] In this embodiment, in step S4, the age-strengthened aluminum alloy sheet 1 is separated from the welding starter plate 6, the lead-out plate 3, and the dissimilar sheet 5 and then subjected to aging treatment. The temperature during aging treatment is 110-190℃ and the time is 8-36h.

[0025] Example 1 S1. After the laminated aluminum alloy sheet (7A52 layer thickness 2.5mm, pure aluminum layer 0.15mm, 7N01 layer 16.5mm) is subjected to 470℃ / 2h solution treatment + room temperature water quenching, it is butt-jointed and clamped to a 19mm thick titanium plate. A welding start plate and a lead-out plate are set on the side of the laminated aluminum alloy sheet. S2, keep the distance between the outer edge of the stirring pin and the end face of the aluminum alloy 0.3mm, and screw the cylindrical threaded stirring pin into the welding plate; S3 uses liquid nitrogen-cooled friction stirring to process the sheet metal, with a stirring head rotation speed of 1500 r / min, a welding speed of 100 mm / min, a downward pressure of 0.15 mm, and a stirring head tilt angle of 2.5°. S4. After separating the laminated aluminum alloy sheet from the soldering plate, lead-out plate, and titanium sheet, perform an aging treatment at 120℃ for 24 hours.

[0026] Comparative Example 1 The laminated aluminum alloy sheet (7A52 layer thickness 2.5mm, pure aluminum layer 0.15mm, 7N01 layer 16.5mm) was subjected to solution treatment at 470℃ for 2h and water quenching at room temperature, followed by aging treatment at 120℃ for 24h.

[0027] Example 2 S1. After the laminated aluminum alloy sheet (2195 layers with a thickness of 8mm, pure aluminum layer of 0.05mm, and 2519 layers with a thickness of 8mm) is subjected to 530℃ / 2h solution treatment and room temperature water quenching, it is butt-jointed and clamped to a 16mm thick titanium plate. A welding starter plate and a lead-out plate are set on the side of the laminated aluminum alloy sheet. S2, keep the distance between the outer edge of the stirring pin and the end face of the aluminum alloy 0.2mm, and screw the cylindrical threaded stirring pin into the welding plate; S3 uses liquid nitrogen-cooled friction stirring to process the sheet metal. The stirring head rotation speed is 1750 r / min, the welding speed is 100 mm / min, the downward pressure is 0.05 mm, and the stirring head tilt angle is 2.5°. S4. After separating the laminated aluminum alloy sheet from the soldering plate, lead-out plate, and titanium sheet, perform an aging treatment at 165℃ for 12 hours.

[0028] Comparative Example 2 The laminated aluminum alloy sheet (2195 layers, 8mm thickness, 0.05mm pure aluminum layer, and 2519 layers, 8mm thickness) was subjected to solution treatment at 530℃ for 2 hours followed by room temperature water quenching, and then aged at 165℃ for 12 hours.

[0029] Figure 2 The image shows the microstructure of the laminated aluminum alloy prepared in Example 1. As can be seen from the image, the end face of the laminated aluminum alloy is flat and not welded to the titanium plate. At the same time, the friction stir process breaks down the interlayer structure. The high temperature and plastic flow generated by the friction stir form the stirring zone. The plastic flow of the material at the vertical interface caused by the friction stir forms an effective structural interlocking zone, thus constructing a three-dimensional spatial structure composed of the stirring zone and the interlocking zone, breaking through the limitation that the interface of traditional laminated aluminum alloy materials is planar.

[0030] Figure 3The figures show the hardness distribution of the 7A52 aluminum alloys prepared in Example 1 and Comparative Example 1. As can be seen from the figures, the hardness of the stirred zone after treatment with this invention is significantly higher than that of the untreated 7A52 aluminum alloy. The interlaminar shear strength of the laminated aluminum alloys was tested using a tensile-shear test. The local interlaminar shear strengths of the 7A52 / pure aluminum / 7N01 laminated aluminum alloys of Comparative Example 1 (untreated) and Example 1 (treated) were 85.6 MPa and 185.2 MPa, respectively. The local interlaminar shear strengths of the 2195 / pure aluminum / 2519 laminated aluminum alloys of Comparative Example 2 (untreated) and Example 2 (treated) were 87.1 MPa and 180.5 MPa, respectively.

[0031] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0032] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for friction stir processing of the end face of age-hardened aluminum alloy sheet, characterized in that, Includes the following steps: S1, the solution-quenched age-strengthened aluminum alloy plate (1) is butt-jointed with the dissimilar plate (5) and clamped and fixed. A welding starter plate (6) and a lead-out plate (3) are respectively set on the side after the age-strengthened aluminum alloy plate (1) and the dissimilar plate (5) are connected. The dissimilar plate (5) is a high melting point steel plate or titanium material. S2, the bottom of the stirring head (4) is equipped with a stirring pin. Keep the distance between the outer edge of the stirring pin and the end face of the age-strengthened aluminum alloy plate (1) 0.01-5mm and screw the stirring pin into the welding plate (6). S3, underwater stirring friction processing or liquid nitrogen cooling stirring friction processing is performed on age-strengthened aluminum alloy sheet (1); S4, remove the processed age-strengthened aluminum alloy sheet (1) and perform age treatment; after separating the age-strengthened aluminum alloy sheet (1) from the starting plate (6), the lead plate (3), and the non-standard sheet (5), perform age treatment.

2. The method for friction stir processing of the end face of age-strengthened aluminum alloy sheet according to claim 1, characterized in that, The age-hardened aluminum alloy plate (1) mentioned in S1 is a solution-quenched age-hardened aluminum plate or a laminated aluminum plate; the thickness of the non-standard plate (5) is 0.001-1mm less than the thickness of the age-hardened aluminum alloy plate (1); the starting plate (6) and the lead-out plate (3) of the same thickness are respectively provided on both sides of the age-hardened aluminum alloy plate (1).

3. The method for friction stir processing of the end face of age-hardened aluminum alloy sheet according to claim 1, characterized in that, The stirring needle at the bottom of the stirring head (4) is threaded.

4. The method for friction stir processing of the end face of age-hardened aluminum alloy sheet according to claim 2, characterized in that, The backward tilt angle of the stirring head (4) during use is 1~3°; the pressing amount of the stirring head (4) is greater than or equal to the thickness difference between the age-strengthened aluminum alloy plate (1) and the non-standard plate (5); the feed speed of the stirring head (4) is 50~250mm / min and the rotation speed is 500~2500r / min.

5. The method for friction stir processing of the end face of age-hardened aluminum alloy sheet according to claim 1, characterized in that, The aging treatment in S4 is carried out at a temperature of 110-190℃ for 8-36 hours.

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