A lightweight aluminum alloy composite material for automobiles and its preparation method

Abstract

This invention provides a lightweight aluminum alloy composite material for automobiles. The lightweight aluminum profile has a sandwich structure, consisting of a core layer, a surface layer, and a protective layer. The core layer, surface layer, and protective layer have different hardnesses, and the strength of the surface layer and protective layer is greater than that of the core layer. The preparation method is as follows: S1. AlCl3•6H2O is dissolved in water to obtain an AlCl3 solution. Al powder is then added, and the mixture is heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution is added, and the mixture is stirred evenly to obtain a spinnable sol precursor. S2. Electrospinning is performed using an electrospinning instrument to obtain a precursor film. S3. The precursor film is configured as a surface layer, a core layer, and a protective layer. The surface layer and protective layer portions of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film. S4. The composite precursor film is calcined to obtain a composite ceramic film. S5. Molten aluminum is poured onto the composite ceramic film to obtain a lightweight aluminum alloy material.

Description

Technical Field

[0001] This invention relates to the field of high-strength aluminum alloy materials, specifically to lightweight aluminum alloy composite materials for automobiles and their preparation methods. Background Technology

[0002] Automotive lightweighting technology includes material lightweighting technology and structural lightweighting technology. Material lightweighting involves using materials with lower density, such as magnesium-aluminum alloys, carbon materials, and high-performance plastics, to replace commonly used steel materials to achieve the goal of weight reduction. Structural lightweighting refers to the use of new structures that meet performance requirements. For example, welded plates are such an advanced structure, which achieves different performance requirements through combinations of different strengths and thicknesses, thereby achieving the goal of weight reduction.

[0003] Aluminum alloys are widely used in automobiles, high-speed rail, aviation and construction due to their excellent properties such as light weight, high strength, corrosion resistance, good formability, good thermal and electrical conductivity, good weldability, impact resistance, non-toxicity, non-magnetic properties and recyclability. They are also a hot topic of concern in the structural materials industry at home and abroad.

[0004] Carbon fiber composites are carbon fiber reinforced resin matrix composites (CFRP). Carbon fiber is a high-strength carbon material with a carbon content of over 95%, which determines the lightweight, high strength, and excellent corrosion resistance of carbon fiber composites. The density of carbon fiber composites is approximately 1.6 g / cm³. 3 With a strength approximately one-fifth that of steel and a tensile strength exceeding 1200 MPa, carbon fiber composites have become an ideal material for automotive lightweighting, replacing steel. The lightweight and high-strength characteristics of carbon fiber composites have led to their increasing application in automotive lightweighting research. However, due to the high cost of carbon fiber, its application is currently limited to high-end models. Therefore, exploring low-cost aluminum alloy composites with guaranteed strength is a pressing priority. Summary of the Invention

[0005] Technical problem to be solved: The purpose of this invention is to provide a lightweight aluminum alloy composite material for automobiles and its preparation method, which adopts a composite structure to improve the strength of the aluminum alloy composite material.

[0006] Technical solution: A lightweight aluminum alloy composite material for automobiles, wherein the lightweight aluminum profile has a sandwich structure, which consists of a core layer, a surface layer, and a protective layer. The core layer, the surface layer, and the protective layer have different hardnesses, and the strength of the surface layer and the protective layer is greater than that of the core layer.

[0007] The above-mentioned method for preparing lightweight aluminum alloy composite materials for automobiles includes the following steps:

[0008] S1. Dissolve AlCl3•6H2O in water to obtain AlCl3 solution, then add Al powder, heat and reflux to react, and obtain a transparent sol. After aging the sol, add PVP ethanol solution, stir evenly, and obtain a spinnable sol precursor.

[0009] S2. Electrospinning was performed using an electrospinning instrument to obtain a precursor membrane with a porosity of 85-95% and a thickness of 2-4 mm;

[0010] S3. The precursor membrane is composed of a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1-1.2 mm, and the rest is the core layer. The surface layer and the protective layer of the precursor membrane are respectively immersed in a polycarbosilane solution to obtain a composite precursor membrane.

[0011] S4. The composite precursor membrane is calcined to obtain a composite ceramic membrane;

[0012] S5. Pour molten aluminum onto a composite ceramic film to obtain a lightweight aluminum alloy material.

[0013] Preferably, in step S1, the molar ratio of AlCl3•6H2O to Al powder is 1:3-4, the total aluminum concentration in the transparent sol is 1.7-2 mol / L, and the content of PVP in the spinnable sol precursor is 1.6-2.5 wt%.

[0014] Preferably, the method for preparing the polycarbosilane solution in step S3 is as follows: PCS is added to a tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain a polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:10-12 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:6-10 mg / mL.

[0015] Preferably, in step S4, the composite precursor membrane is dried in an 80°C oven for 10-24 h, and then calcined at 1200-1400°C for 1-1.6 h, with a heating rate of 2-3°C / min, to obtain the composite ceramic membrane.

[0016] Preferably, the aluminum liquid has the following composition: Fe 0.2-0.45 wt%, Si 0.4-0.5 wt%, Zn 0.1-0.25 wt%, Cu 0.05-0.15 wt%, Mg 0.05-0.2 wt%, with the balance being Al.

[0017] Preferably, the porosity of the composite membrane surface layer and the protective layer is 80-90%.

[0018] Preferably, the aluminum liquid has the following composition: Fe 0.3-0.4 wt%, Si 0.45-0.5 wt%, Zn 0.12-0.2 wt%, Cu 0.08-0.12 wt%, Mg 0.1-0.15 wt%, with the balance being Al.

[0019] Beneficial effects: The lightweight aluminum alloy composite material for automobiles and its preparation method of the present invention have the following advantages:

[0020] The aluminum alloy composite material prepared by this invention adopts a three-layer structure, and the distribution of the three layers is hard (surface layer)-soft (core layer)-hard (protective layer). The aluminum alloy composite material of this invention exhibits a "sandwich" structure macroscopically, consisting of a surface layer, a core layer and a protective layer from the outside to the inside. The hardness shows a distribution of high-low-high, and the mechanical properties exhibit high anisotropy. The mechanical properties of different parts of the same layer also differ. When subjected to external impact, the layered structure not only facilitates stress diffusion, but the hard outer and inner layers can withstand rigid impacts, while the softer middle layer can absorb most of the impact energy, thus improving the mechanical properties of the aluminum alloy composite material.

[0021] This invention uses electrospinning to manufacture a ceramic composite reinforced film. The surface layer and protective layer of the ceramic composite reinforced film are made of Al2O3 composite SiC material, and the core layer is Al2O3. The use of Al2O3 composite SiC material to reinforce the aluminum alloy gives the surface layer and protective layer high hardness, while the core layer is only reinforced with Al2O3. This combination results in a hard-soft-hard three-layer structure.

[0022] This invention directly uses ceramic reinforcement to obtain a hard-soft-hard three-layer structure. The method is simple and does not require conventional hot rolling. At the same time, the cost of reinforcement using this method is much lower than that of carbon fiber reinforcement. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments:

[0024] Example 1

[0025] The preparation of Al2O3 ceramic precursor films includes the following steps:

[0026] S11. AlCl3•6H2O is dissolved in water to obtain an AlCl3 solution. Al powder is then added, and the mixture is heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution is added, and the mixture is stirred until homogeneous to obtain a spinnable sol precursor. The molar ratio of AlCl3•6H2O to Al powder is 1:3, the total aluminum concentration in the transparent sol is 1.7 mol / L, and the content of PVP in the spinnable sol precursor is 2.5 wt%.

[0027] S12. Electrospinning was performed using an electrospinning apparatus to obtain an Al2O3 ceramic precursor film.

[0028] Example 2

[0029] The preparation of Al2O3 ceramic precursor films includes the following steps:

[0030] S11. AlCl3•6H2O is dissolved in water to obtain an AlCl3 solution. Al powder is then added, and the mixture is heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution is added, and the mixture is stirred until homogeneous to obtain a spinnable sol precursor. The molar ratio of AlCl3•6H2O to Al powder is 1:4. The total aluminum concentration in the transparent sol is 2 mol / L, and the content of PVP in the spinnable sol precursor is 1.6 wt%.

[0031] S12. Electrospinning was performed using an electrospinning apparatus to obtain an Al2O3 ceramic precursor film.

[0032] Example 3

[0033] The preparation of Al2O3 ceramic precursor films includes the following steps:

[0034] S11. AlCl3•6H2O is dissolved in water to obtain an AlCl3 solution. Al powder is then added, and the mixture is heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution is added, and the mixture is stirred until homogeneous to obtain a spinnable sol precursor. The molar ratio of AlCl3•6H2O to Al powder is 1:3.4, the total aluminum concentration in the transparent sol is 1.8 mol / L, and the content of PVP in the spinnable sol precursor is 2.2 wt%.

[0035] S12. Electrospinning was performed using an electrospinning apparatus to obtain an Al2O3 ceramic precursor film.

[0036] Table 1. Porosity and thickness of Al2O3 ceramic precursor films prepared in Examples 1-3

[0037] Porosity (%) Thickness (mm) Example 1 88.2 3.5 Example 2 92.3 3.5 Example 3 91.6 3.5

[0038] Example 4

[0039] S1. PCS is dissolved in tetrahydrofuran solution, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-to-volume ratio of PCS to tetrahydrofuran is 1:10 mg / mL, and the mass-to-volume ratio of PVP to ethanol is 1:10 mg / mL.

[0040] S2. The Al2O3 ceramic precursor film prepared in Example 1 is configured to consist of a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1.1 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film.

[0041] S3. The composite precursor membrane was dried in an 80℃ oven for 10 h, and then calcined at 1400℃ for 1.6 h at a heating rate of 2℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane is 82.5%;

[0042] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.2wt% Fe, 0.5wt% Si, 0.1wt% Zn, 0.05wt% Cu, 0.05wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0043] Example 5

[0044] S1. PCS is dissolved in tetrahydrofuran solution, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-to-volume ratio of PCS to tetrahydrofuran is 1:12 mg / mL, and the mass-to-volume ratio of PVP to ethanol is 1:6 mg / mL.

[0045] S2. The Al2O3 ceramic precursor film prepared in Example 2 is configured to consist of a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1.2 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film.

[0046] S3. The composite precursor membrane was dried in an 80℃ oven for 24 h, and then calcined at 1400℃ for 1.4 h at a heating rate of 3℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane is 88.2%.

[0047] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.45wt% Fe, 0.4wt% Si, 0.25wt% Zn, 0.15wt% Cu, 0.2wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0048] Example 6

[0049] S1. PCS is added to tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:11 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:8 mg / mL.

[0050] S2. The Al2O3 ceramic precursor film prepared in Example 3 is configured to consist of a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1.1 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film.

[0051] S3. The composite precursor membrane was dried in an 80℃ oven for 18 hours, and then calcined at 1300℃ for 1.2 hours at a heating rate of 3℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane is 87.1%.

[0052] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.3wt% Fe, 0.5wt% Si, 0.2wt% Zn, 0.08wt% Cu, 0.15wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0053] Example 7

[0054] S1. PCS is added to tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:12 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:9 mg / mL.

[0055] S2. The Al2O3 ceramic precursor film prepared in Example 3 is configured to consist of a surface layer, a core layer, and a protective layer. The thickness of the surface layer and the protective layer is 1.2 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film.

[0056] S3. The composite precursor membrane was dried in an 80℃ oven for 15 hours, and then calcined at 150℃ for 1 hour at a heating rate of 2℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane was 85.3%.

[0057] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.4wt% Fe, 0.45wt% Si, 0.12wt% Zn, 0.12wt% Cu, 0.1wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0058] Example 8

[0059] S1. PCS is added to tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:11 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:8 mg / mL.

[0060] S2. The Al2O3 ceramic precursor film prepared in Example 3 is configured to consist of a surface layer, a core layer, and a protective layer. The thickness of the surface layer and the protective layer is 1.2 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in a polycarbosilane solution to obtain a composite precursor film.

[0061] S3. The composite precursor membrane was dried in an 80℃ oven for 18 hours, and then calcined at 1400℃ for 1.5 hours at a heating rate of 3℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane was 84.6%.

[0062] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.5wt% Fe, 0.48wt% Si, 0.15wt% Zn, 0.1wt% Cu, 0.12wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0063] Comparative Example 1

[0064] S1. AlCl3•6H2O is dissolved in water to obtain an AlCl3 solution. Al powder is then added, and the mixture is heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution is added, and the mixture is stirred until homogeneous to obtain a spinnable sol precursor. The molar ratio of AlCl3•6H2O to Al powder is 1:3.4, the total aluminum concentration in the transparent sol is 1.8 mol / L, and the content of PVP in the spinnable sol precursor is 2 wt%.

[0065] S2. Electrospinning was performed using an electrospinning instrument to obtain an Al2O3 ceramic precursor membrane with a porosity of 92.3%;

[0066] S3. The Al2O3 ceramic precursor film prepared in step S2 is placed in an 80℃ oven and dried for 18h, and then calcined at 1300℃ for 1.2h at a heating rate of 3℃ / min to obtain a composite ceramic film.

[0067] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.3wt% Fe, 0.5wt% Si, 0.2wt% Zn, 0.08wt% Cu, 0.15wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0068] Comparative Example 2

[0069] S1. PCS is added to tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:11 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:8 mg / mL.

[0070] S2. The Al2O3 ceramic precursor film prepared in Example 3 was immersed in a polycarbosilane solution to obtain a composite precursor film;

[0071] S3. The composite precursor membrane was dried in an 80℃ oven for 18 hours, and then calcined at 1300℃ for 1.2 hours at a heating rate of 3℃ / min to obtain the composite ceramic membrane.

[0072] S4. Pour molten aluminum onto a composite ceramic film. The composition of the molten aluminum is 0.3wt% Fe, 0.5wt% Si, 0.2wt% Zn, 0.08wt% Cu, 0.15wt% Mg, with the balance being Al, to obtain a lightweight aluminum alloy material.

[0073] Comparative Example 3

[0074] S1. AlCl3•6H2O was dissolved in water to obtain an AlCl3 solution. Al powder was then added, and the mixture was heated under reflux to obtain a transparent sol. After aging the sol, a PVP ethanol solution was added, and the mixture was stirred until homogeneous to obtain a spinnable sol precursor. The molar ratio of AlCl3•6H2O to Al powder was 1:3.4. The total aluminum concentration in the transparent sol was 1.8 mol / L, and the PVP content in the spinnable sol precursor was 2 wt%.

[0075] S2. Electrospinning was performed using an electrospinning apparatus to obtain an Al2O3 ceramic precursor membrane with a porosity of 91.9%.

[0076] S3. The Al2O3 ceramic precursor film prepared in Example 3 is configured to consist of a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1.2 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor film are immersed in the spinnable precursor solution prepared in step S1 to obtain a composite precursor film.

[0077] S4. The composite precursor membrane was dried in an 80℃ oven for 18 hours, and then calcined at 1400℃ for 1.5 hours at a heating rate of 3℃ / min to obtain a composite ceramic membrane, wherein the porosity of the surface layer and the protective layer of the composite ceramic membrane is 85.9%.

[0078] S5. The aluminum liquid is poured onto a composite ceramic film. The composition of the aluminum liquid is 0.5wt% Fe, 0.48wt% Si, 0.15wt% Zn, 0.1wt% Cu, 0.12wt% Mg, and the balance is Al, to obtain a lightweight aluminum alloy material.

[0079] Performance testing: Impact tests were conducted on an impact testing machine in accordance with GB / T 229—2020; tensile tests were conducted on a tensile testing machine in accordance with GB / T 228—2010.

[0080] Table 2 compares the mechanical properties of the aluminum alloy materials in Examples 4-8 and Comparative Examples 1-3.

[0081] Yield strength MPa Tensile strength (MPa) V-shaped impact energy (J) (-20℃) Example 4 398 512 89 Example 5 400 505 92 Example 6 402 514 100 Example 7 412 501 99 Example 8 409 510 95 Comparative Example 1 302 399 69 Comparative Example 2 323 432 70 Comparative Example 3 355 478 78

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lightweight aluminum alloy composite material for automobiles, characterized in that: The lightweight aluminum alloy composite material has a sandwich structure, which consists of three parts: a core layer, a surface layer, and a protective layer. The core layer, the surface layer, and the protective layer have different hardnesses, and the strength of the surface layer and the protective layer is greater than that of the core layer. The preparation method of the aforementioned lightweight aluminum alloy composite material for automobiles includes the following steps: S1. Dissolve AlCl3•6H2O in water to obtain AlCl3 solution, then add Al powder, heat and reflux to react, and obtain transparent sol. After aging the sol, add PVP ethanol solution, stir evenly, and obtain spinnable sol precursor. S2. Electrospinning was performed using an electrospinning instrument to obtain a precursor membrane with a porosity of 85-95% and a thickness of 2-4 mm; S3. The precursor membrane is configured as a surface layer, a core layer and a protective layer. The thickness of the surface layer and the protective layer is 1-1.2 mm, and the rest is the core layer. Parts of the surface layer and the protective layer of the precursor membrane are immersed in a polycarbosilane solution to obtain a composite precursor membrane. S4. The composite precursor membrane is calcined to obtain a composite ceramic membrane; S5. Pour molten aluminum onto a composite ceramic membrane to obtain a lightweight aluminum alloy composite material.

2. The lightweight aluminum alloy composite material for automobiles according to claim 1, characterized in that: In step S1, the molar ratio of AlCl3•6H2O to Al powder is 1:3-4, the total aluminum concentration in the transparent sol is 1.7-2 mol / L, and the content of PVP in the spinnable sol precursor is 1.6-2.5 wt%.

3. The lightweight aluminum alloy composite material for automobiles according to claim 1, characterized in that, The preparation method of the polycarbosilane solution in step S3 is as follows: PCS is added to tetrahydrofuran solution to dissolve it, and then PVP ethanol solution is added to obtain polycarbosilane solution, wherein the mass-volume ratio of PCS to tetrahydrofuran is 1:10-12 mg / mL, and the mass-volume ratio of PVP to ethanol is 1:6-10 mg / mL.

4. The lightweight aluminum alloy composite material for automobiles according to claim 1, characterized in that: In step S4, the composite precursor membrane is dried in an 80°C oven for 10-24 h, and then calcined at 1200-1400°C for 1-1.6 h with a heating rate of 2-3°C / min to obtain the composite ceramic membrane.

5. The lightweight aluminum alloy composite material for automobiles according to claim 1, characterized in that: The composition of the molten aluminum is 0.2-0.45 wt% Fe, 0.4-0.5 wt% Si, 0.1-0.25 wt% Zn, 0.05-0.15 wt% Cu, 0.05-0.2 wt% Mg, with the balance being Al.

6. The lightweight aluminum alloy composite material for automobiles according to claim 4, characterized in that: The porosity of the surface layer and protective layer of the composite ceramic membrane is 80-90%.

7. The lightweight aluminum alloy composite material for automobiles according to claim 5, characterized in that: The aluminum liquid has the following composition: Fe 0.3-0.4 wt%, Si 0.45-0.5 wt%, Zn 0.12-0.2 wt%, Cu 0.08-0.12 wt%, Mg 0.1-0.15 wt%, with the balance being Al.