Extrusion deformation technology for olefinic carbon aluminum alloy large-size section bar

Abstract

The invention discloses an olefinic carbon aluminum alloy large-size section extrusion deformation technology. The method is characterized in that a conventional moderate-strength aluminum alloy induced rheology aluminum bar (drainage bar) with a specific length is connected to the extruded and deformed front end of an olefinic carbon aluminum alloy ingot blank in advance, and meanwhile, high-temperature and high-strain-rate extrusion deformation is kept. According to the technical scheme, the extrusion breakthrough pressure can be reduced by connecting the drainage rod in advance; and meanwhile, high-temperature (0.78-0.89 Tm) high-strain-rate extrusion deformation is kept, the extrusion deformation rheological resistance can be reduced, and the surface quality of the profile is improved through surface dynamic recrystallization. The technical scheme is low in practical application cost, high in profile forming quality, compatible with conventional aluminum alloy extrusion equipment and suitable for continuous extrusion production of large-size section profiles.

Description

TECHNICAL FIELD

[0001] The application discloses an extrusion deformation technology for large-size section profile of olefin-carbon aluminum alloy, and belongs to the technical field of metal matrix composites. BACKGROUND

[0002] Olefin-carbon aluminum alloy is a composite material formed by adding carbon nanotubes, graphene and other new reinforcing phases in aluminum alloy. Olefin-carbon aluminum alloy not only has excellent mechanical properties such as low density, high modulus and high strength, but also integrates functions such as electrical conductivity, thermal conductivity, heat resistance, wear resistance, damping, noise reduction, radiation shielding, etc., and becomes an indispensable lightweight structural material and functional material in high-tech fields such as military defense, aerospace, etc., and has been more and more applied in the fields of national economy and high-tech such as transportation, electronics, energy and environment.

[0003] Olefin-carbon aluminum alloy benefits from the strengthening and thermal stabilization effect of nanometer olefin-carbon, and has stable microstructure, usually smaller and more uniform grain size, with 1-5 micron ultra-fine grain structure. The existence of nanometer reinforcing phase in olefin-carbon aluminum alloy hinders dislocation movement, and its work hardening phenomenon is more obvious than that of conventional aluminum alloy, which not only increases the processing difficulty, but also easily leads to the generation of processing defects. In the deformation process, due to the addition of nanometer reinforcing phase, its sensitivity to temperature may be enhanced, and the thermal deformation process is more difficult to control. Because the composition and organization of olefin-carbon aluminum alloy are relatively complex, its deformation behavior is comprehensively affected by various factors, such as the type, content and distribution state of nanometer reinforcing phase, as well as processing temperature, speed, strain rate, etc., therefore, if the process parameters are not properly selected, the performance advantages of olefin-carbon aluminum alloy may not be fully utilized. Especially for the extrusion deformation of large-size section profile material, there are problems such as uneven flow in different parts, large temperature gradient, large residual stress, etc. Therefore, compared with conventional aluminum alloy, the high-temperature rheology of olefin-carbon aluminum alloy is difficult, the thermal deformation process window is narrow, and the extrusion deformation of complex section profile material, especially large-size section profile material, has high breakthrough pressure, poor deformation continuity, and is easy to produce surface orange peel and cracking defects. This makes the extrusion deformation of large-size section profile material of olefin-carbon aluminum alloy a difficult problem. Patent CN 116043079A "High-strength and high-toughness aluminum alloy, hollow structural profile thereof and preparation method" discloses a high-strength and high-toughness aluminum alloy, a hollow structural profile thereof and a preparation method. The welding performance and mechanical properties of the material are improved by optimizing the alloy composition and multi-stage heat treatment process. However, the problems of poor deformation continuity and many surface defects in the extrusion process are not solved. SUMMARY

[0004] The application provides an extrusion deformation technology for large-size section profile of an en-carbon aluminum alloy. The extrusion deformation technology for large-size section profile of an en-carbon aluminum alloy is characterized in that a conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) with a specific length is connected in advance at the front end of extrusion deformation of an en-carbon aluminum alloy ingot blank, and high-temperature high-strain-rate extrusion deformation is maintained. The extrusion deformation technology comprises the following steps:

[0005] 1) heating an en-carbon aluminum alloy ingot blank and a conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) to (0.78-0.89)T m and maintaining the temperature, T m is the melting point of the en-carbon aluminum alloy;

[0006] 2) preheating an extrusion die and maintaining the temperature sufficiently, and then loading the die;

[0007] 3) extruding the conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) first, and then extruding the en-carbon aluminum alloy ingot blank to form a high-strain-rate extrusion profile;

[0008] 4) quenching the prepared aluminum alloy profile, stretching and straightening the profile, and shaping the profile.

[0009] Preferably, the en-carbon aluminum alloy contains 0.5-10.0 vol.% of nano-carbon reinforcing bodies, including one or more of carbon nanotubes, graphene, buckyballs or nano-carbon particles.

[0010] Preferably, the base alloy component of the en-carbon aluminum alloy can be one of 2-series, 5-series, 6-series and 7-series.

[0011] Preferably, the conventional medium-strength aluminum alloy flow guide rod component can be one of 6061, 6063, 6005, 6082 and 5083 5-series and 6-series aluminum alloys.

[0012] Preferably, the die preheating temperature is 450-500°C.

[0013] Preferably, the extrusion exit temperature is 460-520°C.

[0014] Preferably, the extrusion strain is 0.1s -1 -1s -1 .

[0015] The application has the beneficial effect that the conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) with a specific length is connected in advance at the front end of extrusion deformation of the en-carbon aluminum alloy ingot blank, so that the extrusion breakthrough pressure can be reduced, and high-temperature (0.78-0.89T m) high strain rate extrusion deformation, reducing the extrusion deformation rheological resistance, improving the profile surface quality through surface dynamic recrystallization. The technical scheme has low practical application cost, high profile forming quality, is compatible with conventional aluminum alloy extrusion equipment, and is suitable for continuous extrusion production of large-size section profiles. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a sectional view of the profile in Example 1, Figure 2 is a sectional view of the profile in Example 2, Figure 3 is a stress-strain curve in Example 1, Figure 4 is a stress-strain curve in Comparative Example 1, Figure 5 is a stress-strain curve in Example 2, Figure 6 is a stress-strain curve in Comparative Example 2. DETAILED DESCRIPTION

[0017] The application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made. These all belong to the protection scope of the application.

[0018] Example 1

[0019] An en-carbon aluminum alloy with a composition of 2wt.% CNT / 2024, the cross section of the extruded profile is shown in Figure 1 The extrusion deformation technology comprises the following steps:

[0020] 1) Put the 2wt.% CNT / 2024 en-carbon aluminum alloy ingot and the conventional 6061 aluminum alloy ingot into a muffle furnace and heat to 460℃, and keep for 5 hours;

[0021] 2) Preheat the extrusion die to 480℃ and keep for 3 hours, then load the die;

[0022] 3) First, extrude the conventional 6061 aluminum alloy ingot, then extrude the en-carbon aluminum alloy 2wt.% CNT / 2024 ingot, and perform high strain rate extrusion forming, with an extrusion strain of 1s -1 ;

[0023] 4) The prepared en-carbon aluminum alloy 2wt.% CNT / 2024 profile is subjected to online water mist quenching treatment to below 50℃. After the profile is cooled, it is subjected to tensile straightening with a tensile rate of 1%. Immediately after the tensile straightening, the profile is put into an artificial aging furnace for artificial aging, with an aging system of 170℃ for 8 hours.

[0024] The mechanical properties of the final profile were detected and the surface state was checked, and the results are shown in Table 1, and the stress-strain curve is shown in Figure 3 .

[0025] Comparative Example 1

[0026] An alkenide carbon aluminum alloy with a composition of 2wt.% CNT / 2024 was extruded into a profile, and the cross section of the profile is shown in Figure 1 The extrusion deformation technique includes the following steps:

[0027] 1) The 2wt.% CNT / 2024 alkenide carbon aluminum alloy ingot was heated to 460°C in a muffle furnace and kept for 5 hours;

[0028] 2) The extrusion die was preheated to 480°C and kept for 3 hours, and then the die was loaded;

[0029] 3) The 2wt.% CNT / 2024 alkenide carbon aluminum alloy ingot was directly put into the machine to perform high strain rate extrusion molding, and the extrusion strain was 1s -1 ;

[0030] 4) The prepared 2wt.% CNT / 2024 alkenide carbon aluminum alloy profile was subjected to online water mist quenching treatment to below 50°C. After the profile was cooled, it was stretched and straightened, and the stretching rate was 1%. Immediately after the stretching and straightening, the profile was put into an artificial aging furnace for artificial aging, and the aging system was 170°C for 8 hours.

[0031] The mechanical properties of the final profile were detected and the surface state was checked, and the results are shown in Table 1, and the stress-strain curve is shown in Figure 4 .

[0032] Example 2

[0033] An alkenide carbon aluminum alloy with a composition of 1.5wt.% CNT / 6061 was extruded into a profile, and the cross section of the profile is shown in Figure 2 The extrusion deformation technique includes the following steps:

[0034] 1) The 1.5wt.% CNT / 6061 alkenide carbon aluminum alloy ingot and the conventional 6061 aluminum alloy ingot were heated to 470°C in a muffle furnace and kept for 5 hours;

[0035] 2) The extrusion die was preheated to 490°C and kept for 3 hours, and then the die was loaded;

[0036] 3) The conventional 6061 aluminum alloy ingot was first extruded, and then the alkenide carbon aluminum alloy

[0037] 1.5wt.% CNT / 6061 ingot was put into the machine to perform high strain rate extrusion molding, and the extrusion strain was 1s -1 ;

[0038] 4) The prepared 1.5wt.% CNT / 6061 OCA alloy profile was subjected to online water mist quenching treatment to below 50°C. After the profile was cooled, it was subjected to tensile straightening with a tensile rate of 1%. Immediately after the tensile straightening, the profile was placed in an artificial aging furnace for artificial aging, and the aging system was 150°C for 8 hours.

[0039] The final profile was subjected to mechanical property detection and surface state inspection, and the results are shown in Table 1, and the stress-strain curve is shown in Figure 5 .

[0040] Comparative Example 2

[0041] An OCA alloy with a composition of 1.5wt.% CNT / 6061 was extruded into a profile, and the cross section of the profile is shown in Figure 2 The extrusion deformation technique includes the following steps:

[0042] 1) The 1.5wt.% CNT / 6061 OCA alloy ingot was heated to 470°C in a muffle furnace and kept for 5 hours;

[0043] 2) After preheating the extrusion die to 490°C and keeping for 3 hours, the die was loaded;

[0044] 3) The 1.5wt.% CNT / 6061 OCA alloy ingot was directly put into the machine for high strain rate extrusion molding, and the extrusion strain was 1s -1 ;

[0045] 4) The prepared 1.5wt.% CNT / 6061 OCA alloy profile was subjected to online water mist quenching treatment to below 50°C. After the profile was cooled, it was subjected to tensile straightening with a tensile rate of 1%. Immediately after the tensile straightening, the profile was placed in an artificial aging furnace for artificial aging, and the aging system was 150°C for 8 hours.

[0046] The final profile was subjected to mechanical property detection and surface state inspection, and the results are shown in Table 1, and the stress-strain curve is shown in Figure 6 .

[0047] Table 1 Mechanical property detection and surface state inspection results of the extruded profile

[0048]

Claims

1. A technology for extrusion deformation of large-size section profiles of alumin(i)um alloys of the Al-C-E system, characterized in that, At the front end of the extrusion deformation of the olefin-carbon aluminum alloy ingot blank, a specific length of conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) is pre-connected, while maintaining high temperature and high strain rate extrusion deformation. The extrusion deformation method comprises the following steps: 1) heating the ingot of the eutectic aluminum alloy, the conventional medium-strength aluminum alloy and the induced rheological aluminum rod (flow rod) to (0.78-0.89) T m and keeping the temperature, T m is the melting point of the eutectic aluminum alloy; 2) After preheating the extrusion die and keeping it warm, the die is loaded; 3) First, the conventional medium-strength aluminum alloy induced rheological aluminum rod (flow guide rod) is extruded, and then the olefin-carbon aluminum alloy ingot blank is extruded at high strain rate; 4) The prepared aluminum alloy profile is quenched, stretched, straightened and shaped.

2. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The olefin-carbon aluminum alloy contains 0.5-10.0 vol.% of nano-carbon reinforcing agent, including one or more of carbon nanotubes, graphene, buckyballs or nano-carbon particles.

3. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The base alloy composition of the olefin-carbon aluminum alloy can be one of 2 series, 5 series, 6 series, and 7 series.

4. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The composition of the conventional medium-strength aluminum alloy flow guide rod can be one of 6061, 6063, 6005, 6082, 5083, etc. 5 series, 6 series aluminum alloy.

5. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The die preheating temperature is 450-500℃.

6. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The extrusion outlet temperature is 460-520℃.

7. A large-size section extrusion technique of an alumin(i)um alloy according to claim 1, characterized in that The extrusion strain is 0.1 s -1 ~ 1 s -1 .

Images