A high-strength and high-damping Al-Zn eutectoid damping alloy and its preparation method

Abstract

The present invention discloses a high-strength and high-damping Al-Zn eutectoid damping alloy and a preparation method thereof. The alloy, in atomic percentage, comprises: 45-54 at.% of Al, 45-54 at.% of Zn, 0.05-0.5 at.% of Ce, and 0.5-2 at.% of Ti. By adding trace amounts of Ti and Ce elements as inoculants and modifiers, the present application can refine the microstructure of the Al-Zn eutectoid damping alloy, and further obtain a multi-scale micro-nano α+η eutectoid structure by adjusting the hot extrusion process of the alloy after homogenization treatment. The tensile strength of the Al-Zn eutectoid damping alloy prepared in the present invention can reach 390 MPa, and the mechanical properties are significantly improved compared with the existing Al-Zn alloys. Moreover, the preparation method of the high-strength and high-damping Al-Zn eutectoid damping alloy prepared in the present invention is simple, easy to operate and has low production cost, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of damping alloys, and particularly relates to a high-strength and high-damping Al-Zn eutectoid damping alloy and a preparation method thereof. Background Art

[0002] With the development of modern industry, controlling vibration and reducing noise have attracted great attention in all walks of life. Vibration and noise will not only have a negative impact on the quality, life, precision and raw material consumption of products, but also the harm to people's psychology and physiology cannot be ignored. By using damping materials, vibration and noise can be reduced or prevented from the source.

[0003] Al-Zn eutectoid damping alloys have attracted much attention due to their high damping capacity and good processing performance, and have broad application prospects in the fields of aerospace, rail transit, automobiles, etc. Research shows that Al-Zn eutectoid damping alloys belong to complex-phase damping alloys, and their damping mechanism is mainly the viscous sliding at the α / η phase interface, supplemented by the microplastic deformation of the α phase. However, the mechanical properties of Al-Zn eutectoid damping alloys are relatively poor, especially their tensile strength is relatively low. According to relevant literature reports, the tensile strength of Al-Zn-based damping alloys is usually less than 300 MPa, which to a certain extent limits the wider application of such alloys. Therefore, improving the comprehensive properties of Al-Zn eutectoid damping alloys, especially their mechanical properties, is of great significance for the research, development and application of this alloy. Summary of the Invention

[0004] In view of the above-mentioned prior art, the present invention provides a high-strength and high-damping Al-Zn eutectoid damping alloy and a preparation method thereof to solve the technical problem of poor mechanical properties of Al-Zn eutectoid damping alloys.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: to provide a high-strength and high-damping Al-Zn eutectoid damping alloy, which, in atomic percentage, includes: Al 45-54 at.%, Zn 45-54 at.%, Ce 0.05-0.5 at.% and Ti 0.5-2 at.%.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Further, the high-strength and high-damping Al-Zn eutectoid damping alloy, in atomic percentage, includes: Al 50 at.%, Zn 48.9 at.%, Ce 0.1 at.% and Ti 1 at.%.

[0008] The present invention also discloses a preparation method of a high-strength and high-damping Al-Zn eutectoid damping alloy, including the following steps:

[0009] S1: Prepare raw materials according to the alloy composition ratio. The raw materials include aluminum blocks, zinc blocks, Al-Ce alloy blocks, and Al-Ti alloy blocks. The mass ratio of Ce in the Al-Ce alloy blocks is 10%, and the mass ratio of Ti in the Al-Ti alloy blocks is 10%.

[0010] S2: Heat the aluminum blocks to 700 - 800 °C and keep them warm until the aluminum blocks are completely melted. Then add the Al-Ti alloy blocks to the molten aluminum. After they are completely melted, blow air to remove slag and keep warm for 15 - 25 minutes. Then cool down to 630 - 670 °C, and add the zinc blocks. After they are completely melted, blow air to remove slag and keep warm for 15 - 25 minutes. Then heat up again to 700 - 750 °C, add the Al-Ce alloy blocks to it. After they are completely melted, blow air to remove slag, and then cool with the furnace to room temperature to obtain a rough blank.

[0011] S3: Heat the rough blank obtained in S2 to melting and keep warm for 15 - 25 minutes, then cast to obtain an initial ingot.

[0012] S4: Perform homogenization treatment on the initial ingot obtained in S3, and then cool it to room temperature with water.

[0013] S5: Perform hot extrusion on the ingot after being treated in S4, and then cool it to room temperature with water to obtain the product.

[0014] The preparation method can be further improved as follows on the basis of the above technical solution.

[0015] Further, the heating rate for the two times of heating in S2 is 3 - 6 °C / min.

[0016] Further, the heating rate for the two times of heating in S2 is both 4 °C / min.

[0017] Further, the final temperature for heating the aluminum blocks in S2 is 740 °C, and the holding time for the first time is 20 minutes; before adding the zinc blocks, the system temperature is 660 °C, and the holding time for the second time is 20 minutes; before adding the Al-Ce alloy blocks, the system temperature is 700 °C.

[0018] Further, the temperature for homogenization treatment in S4 is 350 - 400 °C, and the treatment time is 18 - 22 h.

[0019] Further, the temperature for homogenization treatment is 380 °C, and the treatment time is 20 h.

[0020] Further, the temperature for hot extrusion in S5 is 285 - 375 °C, the extrusion rate is 0.1 - 10 mm / s, and the extrusion ratio is 6 - 16.

[0021] The beneficial effects of the present invention are:

[0022] 1. By adding trace amounts of Ti and Ce elements as inoculants and modifiers, this application can refine the microstructure of the Al-Zn eutectoid damping alloy, and further obtain a multi-scale micro-nano α+η eutectoid structure by adjusting the hot extrusion process of the alloy after homogenization treatment. Among them, the size of the eutectoid cell is about 4-6 μm, and the eutectoid cell exhibits micro-nano structural characteristics of three scales: the first is an equiaxed granular structure with a particle size of about 500-700 nm; the second is a lamellar structure with a certain aspect ratio (about 4:1) and a particle size of about 40-150 nm; the third is a nano-scale precipitation structure of η-Zn in the α-Al matrix with a size of about 10-20 nm. That is, adding trace amounts of Ti and Ce elements can refine the microstructure of the Al-Zn eutectoid damping alloy, increase the area of the α / η phase interface (the number of damping sources), and thus improve its damping performance. In addition, the damping performance and mechanical properties of the Al-Zn eutectoid damping alloy can be further improved after further thermoplastic processing.

[0023] 2. The tensile strength of the prepared Al-Zn eutectoid damping alloy in this invention can reach 390 MPa, and its mechanical properties are significantly improved compared with the existing Al-Zn alloys (the reported tensile strength of Al-Zn-based alloys in the literature is usually less than 300 MPa).

[0024] 3. The multi-scale micro-nano Al-Zn eutectoid damping alloy prepared in this invention still has high damping performance while obtaining high strength.

[0025] 4. The preparation method of the high-strength and high-damping Al-Zn eutectoid damping alloy prepared in this invention is simple, easy to operate and has low production cost, and has broad application prospects. Description of the Drawings

[0026] Figure 1 SEM photograph of the high-strength and high-damping Al-Zn eutectoid damping alloy in Example 1;

[0027] Figure 2 TEM photograph of the equiaxed granular structure of the high-strength and high-damping Al-Zn eutectoid damping alloy in Example 1;

[0028] Figure 3 TEM photograph of the lamellar structure of the high-strength and high-damping Al-Zn eutectoid damping alloy in the Example;

[0029] Figure 4 TEM photograph of the nano-scale precipitation structure of the high-strength and high-damping Al-Zn eutectoid damping alloy in the Example;

[0030] Figure 5 Room temperature tensile curve of the high-strength and high-damping Al-Zn eutectoid damping alloy in Example 1

[0031] Figure 6 It is the damping performance-strain amplitude curve of the high-strength and high-damping Al-Zn eutectoid damping alloy in Example 1;

[0032] Figure 7 It is the SEM photograph of the Al-Zn eutectoid damping alloy in Comparative Example 1;

[0033] Figure 8 It is the room-temperature tensile curve of the Al-Zn eutectoid damping alloy in Comparative Example 1;

[0034] Figure 9 It is the damping performance-strain amplitude curve of the Al-Zn eutectoid damping alloy in Comparative Example 1. Detailed implementation manners

[0035] The following combines examples to make a detailed description of the specific implementation manners of the present invention.

[0036] Example 1

[0037] A high-strength and high-damping Al-Zn eutectoid damping alloy, in atomic percentage, includes 50 at.% of Al, 48.9 at.% of Zn, 0.1 at.% of Ce, and 1 at.% of Ti.

[0038] The high-strength and high-damping Al-Zn eutectoid damping alloy in this example is prepared through the following steps:

[0039] S1: Weigh the elemental Al block, elemental Zn block, Al-Ce alloy block, and Al-Ti alloy block according to the component ratio of 50 at.% Al, 48.9 at.% Zn, 0.1 at.% Ce, and 1 at.% Ti. The purity of each raw material is greater than 99 wt.%. The mass ratio of Ce in the Al-Ce alloy block is 10%, and the ratio of Ti in the Al-Ti alloy block is 10%;

[0040] S2: Put the aluminum block into the crucible of the pit-type resistance furnace, heat it to 740 °C at a heating rate of 4 °C / min and hold for heat preservation until the aluminum block is completely melted; add the Al-Ti alloy block, and after it is completely melted, blow argon gas and remove slag, and hold for heat preservation for 20 min; then cool down to 660 °C, add the Zn block, and after it is completely melted, blow argon gas and remove slag, and hold for heat preservation for 20 min; heat up to 700 °C again, add the Al-Ce alloy block, press it to the bottom, and after all are melted, blow argon gas and remove slag, and hold for heat preservation for 25 min; after the heat preservation ends, cool it to room temperature with the furnace to obtain a rough blank;

[0041] S3: Carry out electrical discharge machining on the rough blank obtained in S2 to obtain several alloy blocks with smaller sizes, put them into a vacuum induction melting furnace, gradually increase the heating power to 15 kW, hold for heat preservation for 20 min, and then cast to obtain an initial ingot;

[0042] S4: Put the initial ingot obtained in S3 into a heat treatment furnace for homogenization treatment. The homogenization treatment is to raise the temperature to 380 °C and hold for 20 h. After the holding ends, take it out and cool it with water to room temperature;

[0043] S5: Perform electrical discharge machining on the ingot after homogenization treatment in S4 to obtain a number of cylindrical specimens with a diameter of 30 mm and a height of 15 mm. Put the cylindrical specimens in the above homogeneous state into a 200T four-column hydraulic press for hot extrusion. The hot extrusion temperature is 375 °C, the extrusion rate is 1 mm / s, the extrusion ratio λ is 9, and cool it with water to room temperature to obtain a high-strength and high-damping Al-Zn eutectoid damping alloy.

[0044] Example 2

[0045] A high-strength and high-damping Al-Zn eutectoid damping alloy, in atomic percentage, includes 45 at.% Al, 54 at.% Zn, 0.5 at.% Ce, and 0.5 at.% Ti.

[0046] The high-strength and high-damping Al-Zn eutectoid damping alloy in this example is prepared through the following steps:

[0047] S1: Weigh elemental Al blocks, elemental Zn blocks, Al-Ce alloy blocks, and Al-Ti alloy blocks according to the composition ratio of 45 at.% Al, 54 at.% Zn, 0.5 at.% Ce, and 0.5 at.% Ti. The purity of each raw material is greater than 99 wt.%. The mass ratio of Ce in the Al-Ce alloy block is 10%, and the ratio of Ti in the Al-Ti alloy block is 10%;

[0048] S2: Put the aluminum block into the crucible of a pit resistance furnace, heat it to 700 °C at a heating rate of 3 °C / min and hold until the aluminum block is completely melted; add the Al-Ti alloy block, and after it is completely melted, blow argon gas and remove slag, and hold for 15 min; then cool down to 630 °C, add the Zn block, and after it is completely melted, blow argon gas and remove slag, and hold for 25 min; heat up to 700 °C again, add the Al-Ce alloy block, press it to the bottom, and after all are melted, blow argon gas and remove slag, and hold for 25 min; after the holding ends, cool it in the furnace to room temperature to obtain a rough blank;

[0049] S3: Perform electrical discharge machining on the rough blank obtained in S2 to obtain a number of smaller alloy blocks, put them into a vacuum induction melting furnace, gradually increase the heating power to 15 kW, hold for 15 min, and then cast to obtain an initial ingot;

[0050] S4: Put the initial ingot obtained in S3 into a heat treatment furnace for homogenization treatment. The homogenization treatment is to raise the temperature to 350 °C and hold for 22 h. After the holding ends, take it out and cool it with water to room temperature;

[0051] S5: The ingot after homogenization treatment in S4 is subjected to electrical discharge machining to obtain a number of cylindrical specimens with a diameter of 30 mm and a height of 15 mm. The cylindrical specimens in the above uniform state are placed in a 200T four-column hydraulic press for hot extrusion. The hot extrusion temperature is 285 °C, the extrusion rate is 0.1 mm / s, the extrusion ratio λ is 6, and it is water-cooled to room temperature to obtain a high-strength and high-damping Al-Zn eutectoid damping alloy.

[0052] Example 3

[0053] A high-strength and high-damping Al-Zn eutectoid damping alloy, in atomic percentage, includes 54 at.% Al, 45 at.% Zn, 0.05 at.% Ce, and 0.95 at.% Ti.

[0054] The high-strength and high-damping Al-Zn eutectoid damping alloy in this example is prepared through the following steps:

[0055] S1: Weigh elemental Al blocks, elemental Zn blocks, Al-Ce alloy blocks, and Al-Ti alloy blocks according to the component ratio of 54 at.% Al, 45 at.% Zn, 0.05 at.% Ce, and 0.95 at.% Ti. The purity of each raw material is greater than 99 wt.%. The mass ratio of Ce in the Al-Ce alloy block is 10%, and the ratio of Ti in the Al-Ti alloy block is 10%.

[0056] S2: Place the aluminum block in the crucible of a pit resistance furnace and heat it to 800 °C at a heating rate of 3 °C / min for holding until the aluminum block is completely melted; add the Al-Ti alloy block, and after it is completely melted, introduce argon gas for blowing and slag removal, and hold for 25 min; then cool down to 670 °C, add the Zn block, and after it is completely melted, introduce argon gas for blowing and slag removal, and hold for 15 min; heat up to 750 °C again, add the Al-Ce alloy block, press it to the bottom, and after all are melted, introduce argon gas for blowing and slag removal, and hold for 25 min; after the holding is completed, cool it in the furnace to room temperature to obtain a rough blank.

[0057] S3: The rough blank obtained in S2 is subjected to electrical discharge machining to obtain a number of smaller alloy blocks, which are placed in a vacuum induction melting furnace, and the heating power is gradually increased to 15 kW, and after holding for 25 min, it is cast to obtain an initial ingot.

[0058] S4: The initial ingot obtained in S3 is placed in a heat treatment furnace for homogenization treatment. The homogenization treatment is to raise the temperature to 400 °C and hold for 18 h, and after the holding is completed, take it out and water-cool it to room temperature.

[0059] S5: The ingot after homogenization treatment in S4 is subjected to electrical discharge machining to obtain a number of cylindrical specimens with a diameter of 30 mm and a height of 15 mm. The cylindrical specimens in the above uniform state are placed in a 200T four-column hydraulic press for hot extrusion. The hot extrusion temperature is 375 °C, the extrusion rate is 10 mm / s, the extrusion ratio λ is 16, and it is water-cooled to room temperature to obtain a high-strength and high-damping Al-Zn eutectoid damping alloy.

[0060] Comparative Example 1

[0061] A high-strength and high-damping Al-Zn eutectoid damping alloy, in atomic percentage, includes 50 at.% Al, 48.9 at.% Zn, 0.1 at.% Ce, and 1 at.% Ti.

[0062] The high-strength and high-damping Al-Zn eutectoid damping alloy in this example is prepared through the following steps:

[0063] S1: Weigh elemental Al blocks, elemental Zn blocks, Al-Ce alloy blocks, and Al-Ti alloy blocks according to the component ratio of 50 at.% Al, 48.9 at.% Zn, 0.1 at.% Ce, and 1 at.% Ti. The purity of each raw material is greater than 99 wt.%. The mass ratio of Ce in the Al-Ce alloy block is 10%, and the ratio of Ti in the Al-Ti alloy block is 10%;

[0064] S2: Put the aluminum block into the crucible of a pit-type resistance furnace and heat it to 740 °C at a heating rate of 4 °C / min for insulation until the aluminum block is completely melted; add the Al-Ti alloy block, and after it is completely melted, introduce argon gas for blowing and slag removal, and keep it warm for 20 min; then cool it down to 660 °C, add the Zn block, and after it is completely melted, introduce argon gas for blowing and slag removal, and keep it warm for 20 min; heat it up to 700 °C again, add the Al-Ce alloy block, press it to the bottom, and after all are melted, introduce argon gas for blowing and slag removal, and keep it warm for 25 min; after the insulation ends, cool it down to room temperature with the furnace to obtain a rough blank;

[0065] S3: The rough blank obtained in S2 is subjected to electrical discharge machining to obtain a number of smaller alloy blocks, which are put into a vacuum induction melting furnace, and the heating power is gradually increased to 15 kW, and after keeping it warm for 20 min, it is cast to obtain an initial ingot;

[0066] S4: Cut a specimen of 130 mm × 140 mm × 12 mm from the alloy ingot obtained in S3 by wire cutting, remove the oil stain on the surface of the specimen, and dry it for standby;

[0067] S5: Put the specimen obtained in S4 into a heat treatment furnace and heat it to 400 °C for insulation for 1 h;

[0068] S6: Quickly take out the sample in S5 for rolling. Adopt the double-roll rolling method, with the single-pass reduction not exceeding 10% and the total reduction being 50%. After rolling, cool it with water to obtain a high-strength and high-damping Al-Zn eutectoid damping alloy. After each rolling, it needs to be put into the furnace for heat preservation for 2 minutes.

[0069] Experimental example

[0070] Taking the alloy prepared in Example 1 as an example, the properties of the high-strength and high-damping Al-Zn eutectoid damping alloy are described.

[0071] Cut two groups of parallel samples from different parts of the alloy prepared in Example 1 and mark them as #1 and #2 respectively. Use a scanning electron microscope to observe the microstructure of the alloy sample with a size of 10mm×10mm×6mm. The alloy is composed of a multi-scale micro-nano α+η eutectoid structure, and the eutectoid cell size is about 4-6μm, as Figure 1 shown. Use a transmission electron microscope to magnify and observe the microstructure of the Al-Zn eutectoid damping alloy. There are three scales of micro-nano structures in the eutectoid cells of the extruded alloy: the first is an equiaxed granular structure with a particle size of about 500-700nm, as Figure 2 shown; the second is a lamellar structure with a certain aspect ratio (about 4:1) and a particle size of about 40-150nm, as Figure 3 shown; the third is a nano-scale precipitation structure of η-Zn in the α-Al matrix with a size of about 10-20nm, as Figure 4 shown. The area percentages of the three scales of micro-nano structures are about 20%, 70% and 10% respectively. Use an electronic universal testing machine to test the mechanical properties of the alloy sample. The room-temperature tensile curves of the two groups of parallel samples have good coincidence. Its tensile strength σ b is about 390MPa (reported in relevant literature, the tensile strength of Al-Zn-based alloys is usually less than 300MPa. Compared with the comparative example, it is increased by about 25.8%), as Figure 5 shown. Use a dynamic thermomechanical analyzer (DMA Q800) to test the damping properties of the alloy sample with a size of 35mm×10m×1mm. The damping property-strain amplitude curves of the two groups of parallel samples have good coincidence. While the alloy obtains high strength, it still has high damping properties. When the strain amplitude is 8×10 -4 , the value of tanδ is about 0.037 (compared with the comparative example, it is increased by about 85%), as Figure 6 shown.

[0072] Two groups of parallel specimens were cut from different parts of the alloy prepared in Comparative Example 1 and were respectively labeled as #3 and #4. The microstructure of the alloy specimens with the size of 10mm×10mm×6mm was observed by a scanning electron microscope. The alloy mainly consists of lamellar α+η eutectoid structure. The eutectoid cell size is about 30-50μm, and the aspect ratio of the α and η lamellae in the eutectoid cell is about 15:1, as Figure 7 shown. The mechanical properties of the alloy specimens were tested by an electronic universal testing machine. The room-temperature tensile curves of the two groups of parallel specimens have good coincidence. The tensile strength σ b is about 310MPa, as Figure 8 shown; the damping properties of the alloy specimens with the size of 35mm×10m×1mm were tested by a dynamic thermomechanical analyzer (DMA Q800). The damping property-strain amplitude curves of the two groups of parallel specimens have good coincidence. When the strain amplitude is 8×10 -4 , the value of tanδ is about 0.02, as Figure 9 shown.

[0073] Although the specific embodiments of the present invention have been described in detail in conjunction with the embodiments, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of this patent.

Claims

1. A high-strength and high-damping Al-Zn eutectoid damping alloy, characterized in that, By atomic percentage, it includes: Al 50 at.%, Zn 48.9 at.%, Ce 0.1 at.%, and Ti 1 at.%, which is prepared through the following steps: S1: Prepare raw materials according to the alloy composition ratio. The raw materials include aluminum blocks, zinc blocks, Al-Ce alloy blocks, and Al-Ti alloy blocks. The mass ratio of Ce in the Al-Ce alloy block is 10%, and the mass ratio of Ti in the Al-Ti alloy block is 10%; S2: Heat the aluminum block to 700 - 800 °C and keep it warm until the aluminum block is completely melted. Then add the Al-Ti alloy block into the molten aluminum. After it is completely melted, blow air to remove slag and keep it warm for 15 - 25 min. Then cool it down to 630 - 670 °C, and add the zinc block. After it is completely melted, blow air to remove slag and keep it warm for 15 - 25 min. Then heat it up again to 700 - 750 °C, add the Al-Ce alloy block into it. After it is completely melted, blow air to remove slag, and then cool it in the furnace to room temperature to obtain a rough blank; S3: Heat the rough blank obtained in S2 to melting and keep it warm for 15 - 25 min, and then cast to obtain an initial ingot; S4: Perform homogenization treatment on the initial ingot obtained in S3, and then water-cool it to room temperature; the temperature of the homogenization treatment is 350 - 400 °C, and the treatment time is 18 - 22 h; S5: Perform hot extrusion on the ingot after being treated in S4, and then water-cool it to room temperature, thus obtaining the product; the temperature of the hot extrusion is 285 - 375 °C, the extrusion rate is 0.1 - 10 mm / s, and the extrusion ratio is 6 - 16.

2. The high-strength and high-damping Al-Zn eutectoid damping alloy according to claim 1, wherein: The heating rate for the two times of heating in S2 is 3 - 6 °C / min.

3. The high-strength and high-damping Al-Zn eutectoid damping alloy according to claim 2, wherein: The heating rate for both times of heating in S2 is 4 °C / min.

4. The high-strength and high-damping Al-Zn eutectoid damping alloy according to claim 1, wherein: The final temperature of heating the aluminum block in S2 is 740 °C, and the time for the first heat preservation is 20 min; before adding the zinc block, the system temperature is 660 °C, and the time for the second heat preservation is 20 min; before adding the Al-Ce alloy block, the system temperature is 700 °C.

5. The high-strength and high-damping Al-Zn eutectoid damping alloy according to claim 1, wherein: The temperature of the homogenization treatment is 380 °C, and the treatment time is 20 h.

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