Method for producing an aluminum matrix composite plate

Abstract

The application relates to a preparation method of an aluminum-based composite material plate. After sintering and forging, an aluminum-based composite material powder blank with a length-width ratio of 1.5-2 and a thickness of 70mm-110mm is pressed three times to prepare an aluminum-based composite material plate with a length-width ratio of 9-12 and a thickness of 10mm-35mm. The sintered blank is densified under small deformation through the first pressing, the sintered blank which has been densified is deformed in a large size under low pressure through the second pressing, the sintered blank is filled under low pressure through the third pressing, near-net-shape forming is realized, and thus the aluminum-based composite material plate without circumferential cracks and with consistent internal density is obtained.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, and in particular to a method for preparing aluminum-based composite material plates. Background Technology

[0002] When preparing aluminum matrix composite plates using rolling methods, cracks easily form on the sides of the plates due to the presence of reinforcing phase particles. Theoretically, stirred casting can only produce aluminum matrix composite plates with low reinforcing phase content; when preparing plates with high reinforcing phase content, reinforcing phase deposition problems occur, leading to uneven reinforcing phase distribution. Powder metallurgy can produce aluminum matrix composite plates with high reinforcing phase content, but for aluminum matrix composite plates with an aspect ratio ≥9 and a thickness of 10mm~35mm, uneven pressing force distribution during the forming stage easily occurs, resulting in density differences between the ends and the middle of the powder blank. This leads to cracks on the sides of the powder blank after pressing and delamination after sintering. Summary of the Invention

[0003] Based on this, it is necessary to provide a method for preparing aluminum-based composite material plates with an aspect ratio ≥9 and a thickness of 10mm~35mm. The aluminum-based composite material plates prepared by this method have a uniform density distribution, are free from cracks, and can achieve near-net-shape forming of aluminum-based composite material plates.

[0004] A method for preparing an aluminum-based composite material plate includes the following steps:

[0005] Provide aluminum-based composite material preforms with an aspect ratio of 1.5~2 and a thickness of 70mm~110mm;

[0006] A shaping mold is provided, the shaping mold having a cavity adapted to the aluminum-based composite material plate to be prepared;

[0007] After the powder blank is sintered, it is placed in the forming mold and isothermally forged three times to allow the sintered blank to undergo multiple deformations before filling the entire mold cavity and demolding to obtain an aluminum-based composite material plate with an aspect ratio of 9~12 and a thickness of 10mm~35mm.

[0008] In one embodiment, the step of isothermal forging three times to subject the sintered billet to multiple deformations before filling the forming mold specifically involves:

[0009] The first isothermal forging controlled the deformation of the sintered billet in the length direction to within 10%.

[0010] The second isothermal forging controlled the deformation of the sintered billet in the length direction to within 210%~250%;

[0011] The third isothermal forging deforms the sintered billet and fills the entire mold cavity.

[0012] In one embodiment, the temperature of the first isothermal forging is 540°C to 560°C, the pressure is 180MPa to 220MPa, and the holding time is 10s to 30s.

[0013] In one embodiment, the temperature of the second isothermal forging is 570°C to 580°C, the pressure is 80MPa to 100MPa, and the holding time is 25s to 40s.

[0014] In one embodiment, the temperature of the third isothermal forging is 570°C to 580°C, the pressure is 50MPa to 80MPa, and the holding time is 15s to 30s.

[0015] In one embodiment, the sintering temperature is 540℃~600℃, and the holding time is 120min~300min.

[0016] In one embodiment, the aluminum-based composite powder preform is prepared by the following method:

[0017] Provide aluminum-based composite material powder;

[0018] After the raw material powder is mixed evenly, it is pressed into a powder blank with a length-to-width ratio of 1.5~2 and a thickness of 70mm~110mm.

[0019] In one embodiment, the raw material powder, by mass percentage, consists of 35% to 45% reinforcing phase, 4% to 7% copper, 0.8% to 2% magnesium, 0.1% to 0.8% zinc, and the balance aluminum.

[0020] In one embodiment, the reinforcing phase is boron carbide or silicon carbide.

[0021] The above-mentioned method for preparing aluminum-based composite material plates involves sintering aluminum-based composite material powder blanks with an aspect ratio of 1.5-2 and a thickness of 70mm-110mm, followed by forging and pressing three times to deform the sintered blanks three times, resulting in aluminum-based composite material plates with an aspect ratio of 9-12 and a thickness of 10mm-35mm. The first pressing achieves densification of the sintered blank with minimal deformation. The second pressing allows the already densified sintered blank to undergo large-scale deformation under lower pressure. The third pressing fills the sintered blank under lower pressure, achieving near-net-shape forming, thereby obtaining an aluminum-based composite material plate with no circumferential cracks and uniform internal density. (Detailed implementation method)

[0022] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] A method for preparing an aluminum-based composite material plate according to one embodiment includes the following steps S110 to S140:

[0025] S110 provides aluminum-based composite material powder.

[0026] In this embodiment, the aluminum-based composite material raw material powder consists of 35% to 45% by mass of reinforcing phase, 4% to 7% by mass of copper (Cu), 0.8% to 2% by mass of magnesium (Mg), 0.1% to 0.8% by mass of zinc (Zn), and the balance aluminum (Al).

[0027] The reinforcing phase is boron carbide (B4C) or silicon carbide (SiC).

[0028] The raw material powder of the aluminum-based composite material is improved by adding 4% to 7% Cu, which improves the pressing performance of the material and increases the liquid phase content of the billet during the forging and pressing process, thereby improving the flow properties of the material. The strength of the material is improved by adding 0.8% to 2% Mg and 0.1% to 0.8% Zn.

[0029] S120. After the above raw material powders are mixed evenly, they are pressed into powder blanks with a length-to-width ratio of 1.5~2 and a thickness of 70mm~110mm.

[0030] By controlling the length-to-width ratio of the powder blank to 1.5-2 and the thickness to 70mm-110mm, it is possible to prevent the powder blank from being too long or too thin, which could lead to inconsistent pressing density and phenomena such as layered cracks.

[0031] S130. The above powder blank is sintered to obtain a sintered blank.

[0032] In this embodiment, the sintering temperature is 540℃~600℃, and the holding time is 120min~300min.

[0033] The above-mentioned powder blanks are sintered at low temperature for a long time. On the one hand, this can ensure the uniformity of temperature inside and outside the blank, and prevent the excessive temperature difference between the inside and outside of the blank from causing inconsistent sintering shrinkage and cracks. On the other hand, it can ensure that the liquid phase is evenly distributed in the blank, thereby ensuring that no cracks appear in the blank after sintering.

[0034] S140. The above sintered billet is placed in a forming mold and isothermally forged three times to allow the sintered billet to undergo multiple deformations before filling the entire mold cavity to obtain an aluminum-based composite material plate with an aspect ratio of 9~12 and a thickness of 10mm~35mm.

[0035] In this embodiment, the step of "isothermal forging three times to allow the sintered billet to undergo multiple deformations before filling the entire mold cavity" is specifically as follows:

[0036] The first isothermal forging controls the deformation of the sintered billet in the length direction to within 10% (relative to the length of the sintered billet before the first isothermal forging);

[0037] The second isothermal forging controls the deformation of the sintered billet in the length direction to within 210%~250% (relative to the length of the sintered billet before the second isothermal forging);

[0038] The third isothermal forging deforms the sintered billet and fills the entire mold cavity.

[0039] Furthermore, the temperature of the first isothermal forging is 540℃~560℃, the pressure is 180MPa~220MPa, and the holding time is 10s~30s.

[0040] The temperature of the second isothermal forging is 570℃~580℃, the pressure is 80MPa~100MPa, and the holding time is 25s~40s.

[0041] The temperature of the third isothermal forging is 570℃~580℃, the pressure is 50MPa~80MPa, and the holding time is 15s~30s.

[0042] By controlling the temperature, pressure, and holding time of the first isothermal forging, the deformation of the sintered billet in the length direction is controlled within 10%. That is, the sintered billet achieves material density without large plastic deformation, thus avoiding cracks on the side of the billet caused by large-size deformation.

[0043] By controlling the temperature, pressure, and holding time of the second isothermal forging, the deformation of the already densified sintered billet in the length direction can be controlled within 210%~250%. That is, the already densified sintered billet can achieve large-size deformation at a lower pressure while avoiding the generation of cracks.

[0044] By controlling the temperature, pressure, and holding time of the third isothermal forging, the sintered billet is filled under lower pressure, achieving near-net-shape forming. This avoids mold deformation caused by high pressure and ensures the consistency of density in all parts of the billet.

[0045] The above method can prepare aluminum-based composite material plates with dense density distribution, uniform size, and a length-to-width ratio of 9-12 and a thickness of 10mm-35mm, with a reinforcing phase mass content of more than 35%.

[0046] The following are specific examples.

[0047] Example 1

[0048] Aluminum-based composite material raw material powder is provided, which consists of 35wt% SiC, 4wt% Cu, 0.8wt% Mg, 0.1wt% Zn and the balance Al.

[0049] After the above raw material powders are mixed evenly, they are pressed into a powder blank with a length of 300mm, a width of 200mm, and a thickness of 70mm.

[0050] After sintering, the powder blank was placed in a forming mold and isothermally forged three times. The first isothermal forging was performed at a temperature of 550℃, a pressure of 180MPa, and a holding time of 20s, resulting in a blank length of 330mm. The second isothermal forging was performed at a temperature of 575℃, a pressure of 80MPa, and a holding time of 40s, resulting in a blank length of 1100mm. The third isothermal forging was performed at a temperature of 580℃, a pressure of 50MPa, and a holding time of 25s, resulting in a blank that filled the entire mold cavity. After demolding, an aluminum-based composite material plate with a length of 1200mm, a width of 120mm, and a thickness of 22mm was obtained.

[0051] Testing revealed that the aluminum-based composite material plate prepared in Example 1 was dense, crack-free, and had a uniform internal density.

[0052] Comparative Example 1

[0053] Comparative Example 1 is basically the same as Example 1, except that in Comparative Example 1, after the above raw material powder is mixed evenly, it is directly pressed into a powder blank with a length of 1200mm, a width of 120mm, and a thickness of 29mm, and then sintered and isothermal forged.

[0054] The results showed that powder leakage occurred during the pressing process, and cracks appeared in the powder blank after pressing was completed.

[0055] Comparative Example 2

[0056] Comparative Example 2 is basically the same as Example 1, except that in Comparative Example 2, the raw material powder is pressed into a powder blank with a length of 300 mm, a width of 100 mm, and a thickness of 140 mm.

[0057] The results showed that microcracks existed on the side of the green billet after pressing. After sintering, the side of the billet cracked. The cracks still existed after the first forging, and the billet was scrapped.

[0058] Comparative Example 3

[0059] Comparative Example 3 is basically the same as Example 1, except that the temperature of the first isothermal forging in Comparative Example 3 is 580°C, the pressure is 180MPa, and the holding time is 20s.

[0060] The results showed that due to the excessively high temperature of the first isothermal forging, the material had too good fluidity, and the forging flash seeped out from the gap between the die, resulting in the billet thickness being lower than the theoretical value. Subsequent forging could not produce a product with the required thickness.

[0061] Comparative Example 4

[0062] Comparative Example 4 is basically the same as Example 1, except that the temperature of the second isothermal forging in Comparative Example 4 is 575°C, the pressure is 160MPa, and the holding time is 40s.

[0063] The results showed that due to the excessive pressure of the second isothermal forging, the mold expanded and deformed outward on both sides under high pressure, the gap between the upper mold and the female mold in the length direction increased, and the flash seepage caused the thickness of the shaped blank to be lower than the theoretical value. After the third forging, the thickness of the blank was no longer sufficient to process it into qualified dimensions.

[0064] Example 2

[0065] Aluminum-based composite material raw material powder is provided, which consists of 45wt% SiC, 6wt% Cu, 1wt% Mg, 0.5wt% Zn and the balance Al.

[0066] After the above raw material powders are mixed evenly, they are pressed into a powder blank with a length of 300mm, a width of 150mm, and a thickness of 110mm.

[0067] After sintering, the powder blank was placed in a forming mold and isothermally forged three times. The first isothermal forging was performed at a temperature of 540℃, a pressure of 200MPa, and a holding time of 30s, resulting in a blank length of 320mm. The second isothermal forging was performed at a temperature of 580℃, a pressure of 100MPa, and a holding time of 30s, resulting in a blank length of 1120mm. The third isothermal forging was performed at a temperature of 580℃, a pressure of 80MPa, and a holding time of 30s, resulting in a blank that filled the entire mold cavity. After demolding, an aluminum-based composite material plate with a length of 1500mm, a width of 150mm, and a thickness of 25mm was obtained.

[0068] Testing revealed that the aluminum-based composite material plate prepared in Example 2 was dense, crack-free, and had a uniform internal density.

[0069] Example 3

[0070] Aluminum-based composite material raw material powder is provided, which consists of 40wt% B4C, 7wt% Cu, 2wt% Mg, 0.8wt% Zn and the balance Al.

[0071] After the above raw material powders are mixed evenly, they are pressed into a powder blank with a length of 300mm, a width of 150mm, and a thickness of 90mm.

[0072] After sintering, the powder blank was placed in a forming mold and isothermally forged three times. The first isothermal forging was performed at a temperature of 560℃, a pressure of 200MPa, and a holding time of 10s, resulting in a blank length of 315mm. The second isothermal forging was performed at a temperature of 570℃, a pressure of 90MPa, and a holding time of 25s, resulting in a blank length of 980mm. The third isothermal forging was performed at a temperature of 570℃, a pressure of 70MPa, and a holding time of 15s, resulting in a blank that filled the entire mold cavity. After demolding, an aluminum-based composite material plate with a length of 1350mm, a width of 150mm, and a thickness of 35mm was obtained.

[0073] Testing revealed that the aluminum-based composite material plate prepared in Example 3 was dense, crack-free, and had a uniform internal density.

[0074] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing an aluminum-based composite material plate, characterized in that, Includes the following steps: Provide aluminum-based composite material preforms with an aspect ratio of 1.5~2 and a thickness of 70mm~110mm; A shaping mold is provided, the shaping mold having a cavity adapted to the aluminum-based composite material plate to be prepared; After the powder blank is sintered, it is placed in the forming mold and is isothermally forged three times to allow the sintered blank to undergo multiple deformations before filling the entire mold cavity. After demolding, an aluminum-based composite material plate with an aspect ratio of 9~12 and a thickness of 10mm~35mm is obtained. The specific steps of isothermal forging three times to allow the sintered billet to undergo multiple deformations before filling the entire mold cavity are as follows: The first isothermal forging controlled the deformation of the sintered billet in the length direction to within 10%. The second isothermal forging controlled the deformation of the sintered billet in the length direction to be between 210% and 250%. The third isothermal forging deforms the sintered billet and fills the entire mold cavity; The temperature of the first isothermal forging is 540℃~560℃, the pressure is 180MPa~220MPa, and the holding time is 10s~30s; The second isothermal forging is performed at a temperature of 570℃~580℃, a pressure of 80MPa~100MPa, and a holding time of 25s~40s. The temperature of the third isothermal forging is 570℃~580℃, the pressure is 50MPa~80MPa, and the holding time is 15s~30s.

2. The method for preparing the aluminum-based composite material plate according to claim 1, characterized in that, The sintering temperature is 540℃~600℃, and the holding time is 120min~300min.

3. The method for preparing the aluminum-based composite material plate according to claim 1 or 2, characterized in that, The aluminum-based composite material preform is prepared by the following method: Provide aluminum-based composite material powder; After the raw material powder is mixed evenly, it is pressed into a powder blank with a length-to-width ratio of 1.5~2 and a thickness of 70mm~110mm.

4. The method for preparing the aluminum-based composite material plate according to claim 3, characterized in that, The raw material powder, by mass percentage, consists of 35% to 45% reinforcing phase, 4% to 7% copper, 0.8% to 2% magnesium, 0.1% to 0.8% zinc, and the balance aluminum.

5. The method for preparing the aluminum-based composite material plate according to claim 4, characterized in that, The reinforcing phase is boron carbide or silicon carbide.