Mechanical property regulation method for high-purity aluminum prepared by hydrogen atmosphere assisted directional solidification

Abstract

The application discloses a mechanical property regulation and control method for preparing high-purity aluminum by hydrogen atmosphere assisted directional solidification, and realizes directional control of the mechanical property of the high-purity aluminum by regulating and controlling hydrogen pressure and solidification parameters. In the range of 0.2-0.6 MPa hydrogen pressure, with the change of the hydrogen pressure, the Vickers hardness of the product can be adjusted in the range of 18.5-21.5 HV: when the hydrogen pressure is 0.2 MPa, the structure is uniform and stable, and the hardness is 18.93 HV; when the hydrogen pressure is 0.4 MPa, the number of H-vacancy complexes reaches a peak, and the hardness can be as high as 21.02 HV; when the hydrogen pressure is 0.6 MPa, the uniformity of the structure is the best, and the hardness fluctuation is the smallest. By controlling the hydrogen pressure, the occurrence state (solid solution hydrogen, H-vacancy complex, molecular hydrogen cluster) of hydrogen in aluminum can be regulated and controlled, and then the strengthening mechanism and the mechanical property of the material are influenced. The method can realize directional regulation and control of the mechanical property of the high-purity aluminum by single directional solidification, and is simple in process, low in cost and suitable for the differentiated demand for the mechanical property in different application scenarios.

Description

Technical Field

[0001] This invention relates to the field of metal material performance regulation technology, and more specifically, to a method for directional control of the mechanical properties of high-purity aluminum by regulating hydrogen pressure. Background Technology

[0002] High-purity aluminum (purity ≥ 99.99%) is widely used in integrated circuit sputtering targets, high-performance aluminum alloys, and electrolytic capacitor foils due to its excellent electrical and thermal conductivity and ductility. In practical applications, high-purity aluminum is required not only to have extremely high purity but also to possess good mechanical properties to meet the demands of different operating conditions.

[0003] Traditional vacuum directional solidification technology primarily improves aluminum purity through multiple solidification processes, but it is difficult to effectively control the mechanical properties of the product. Recent studies have found that directional solidification in a hydrogen atmosphere not only improves impurity removal efficiency but also influences the mechanical properties of the product. Research indicates that hydrogen in aluminum is not simply a solid solution but rather interacts in complex ways with crystal defects, directly affecting mechanical properties.

[0004] Currently, research on the influence of hydrogen pressure on the mechanical properties of high-purity aluminum is insufficient, and systematic control methods are lacking. To address these issues, this invention proposes a method for directional control of the mechanical properties of high-purity aluminum by adjusting hydrogen pressure. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the mechanical properties of high-purity aluminum prepared in a hydrogen atmosphere-assisted directional manner, aiming to solve the technical problem that the mechanical properties of high-purity aluminum are difficult to control in a directional manner in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for controlling the mechanical properties of high-purity aluminum prepared in a hydrogen atmosphere-assisted directional manner, comprising the following steps: S1. Raw material pretreatment: The aluminum raw material with a purity of ≥99.99% is subjected to surface cleaning and drying treatment; S2. Melting: The pretreated aluminum raw material is placed in a vacuum directional solidification furnace, a vacuum is drawn, and then it is heated until the aluminum raw material is completely melted to obtain aluminum melt. S3. Atmosphere control: Introduce high-purity hydrogen into the furnace, adjust the hydrogen pressure to the target value, and keep it at the temperature for 10-30 minutes. S4. Directional solidification: Start the directional solidification program, control the solidification rate to be 0.5~5mm / min, and the temperature gradient to be 30~80℃ / cm, so that the aluminum melt crystallizes in a directional manner. S5. Post-processing: After solidification, the impurity-rich portions at the beginning and end of the ingot are removed to obtain high-purity aluminum products.

[0007] Furthermore, step S2 specifically involves evacuating the vacuum to below 5 × 10⁻² Pa.

[0008] Furthermore, the hydrogen pressure range in step S3 is 0.1~0.6 MPa.

[0009] Furthermore, different hydrogen pressure windows are adopted for different mechanical performance targets: when stable and uniform mechanical properties are required, the hydrogen pressure is preferably 0.2 MPa or 0.6 MPa; when the highest hardness is required, the hydrogen pressure is preferably 0.4 MPa.

[0010] Furthermore, the high-purity aluminum products prepared by the above method have an adjustable Vickers hardness in the range of 18.5~21.5 HV, and the hardness can be directionally controlled by selecting different hydrogen pressures.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. Directional Control of Mechanical Properties: This invention achieves directional control of the mechanical properties of high-purity aluminum products by adjusting the hydrogen pressure. Stable and uniform mechanical properties can be obtained under 0.2 MPa hydrogen pressure; the highest hardness can be obtained under 0.4 MPa hydrogen pressure; and the product with the best microstructure uniformity can be obtained under 0.6 MPa hydrogen pressure.

[0012] 2. Clear performance control window: Through a large amount of experimental data, this invention has determined the optimal hydrogen pressure window corresponding to different mechanical performance targets, providing reliable process parameters for the industrial production of high-purity aluminum.

[0013] 3. Controllable data fluctuations: By optimizing hydrogen pressure, this invention can control the hardness fluctuation coefficient of the product to within 5%, thus ensuring the stability of product quality. Attached Figure Description

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

[0015] Figure 1 This is a schematic diagram of the process flow of the method of the present invention; Figure 2 This is a schematic diagram of the smelting apparatus of the present invention; Figure 3 A comparison chart of product hardness data fluctuations under different hydrogen pressures; Detailed Implementation

[0016] 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.

[0017] Please see Figure 1-3 A method for controlling the mechanical properties of high-purity aluminum prepared under hydrogen atmosphere-assisted direction, comprising the following steps: S1. Raw material pretreatment: The aluminum raw material with a purity of ≥99.99% is subjected to surface cleaning and drying treatment; S2. Melting: The pretreated aluminum raw material is placed in a vacuum directional solidification furnace, and the vacuum is drawn to below 5×10⁻²Pa. Then it is heated until the aluminum raw material is completely melted to obtain aluminum melt. S3. Atmosphere control: Introduce high-purity hydrogen into the furnace, adjust the hydrogen pressure to 0.1~0.6MPa, and maintain the temperature for 10~30 minutes; S4. Directional solidification: Start the directional solidification program, control the solidification rate to be 0.5~5mm / min, and the temperature gradient to be 30~80℃ / cm, so that the aluminum melt crystallizes in a directional manner. S5. Post-processing: After solidification, the impurity-rich portions at the beginning and end of the ingot are removed to obtain high-purity aluminum products.

[0018] After preparation, the Vickers hardness test (load 100g, holding time 10s) was performed on the product prepared by this method, and the measurement was performed 5 times at different positions of the sample. Example

[0019] High-purity aluminum is prepared according to the preparation method described in the invention. The specific parameters and steps are as follows: S1. Raw material preparation: Use aluminum raw materials with a purity of 4N (99.99%), and perform surface cleaning and drying treatment on the aluminum raw materials.

[0020] S2. Melting: Place the pretreated aluminum raw material in a vacuum directional solidification furnace, close and lock the furnace door, and turn on the vacuum pump to evacuate to 5×10⁻²Pa. Open the circulating cooling water valve, start the heating device, and heat the aluminum raw material to 700℃ to completely melt it, obtaining molten aluminum.

[0021] S3. Atmosphere control: Turn off the vacuum system, fill the furnace with high-purity hydrogen (purity ≥99.999%), adjust the hydrogen pressure to 0.2MPa using a high-precision pressure controller, and keep it at that temperature for 20 minutes.

[0022] S4. Directional solidification: Start the traction system, control the solidification rate to 2 mm / min and the temperature gradient to 50℃ / cm, so that the aluminum melt crystallizes directionally from the bottom up.

[0023] S5. Post-processing: After solidification, wait for the ingot to cool to room temperature, open the vent valve to release the gas in the furnace, and remove the ingot. Cut off 15% of the first end and 10% of the last end of the ingot to obtain high-purity aluminum product. Example

[0024] High-purity aluminum is prepared according to the preparation method described in the invention. The specific parameters and steps are as follows: S1. Raw material preparation: Use aluminum raw materials with a purity of 4N (99.99%), and perform surface cleaning and drying treatment on the aluminum raw materials.

[0025] S2. Melting: Place the pretreated aluminum raw material in a vacuum directional solidification furnace, close and lock the furnace door, and turn on the vacuum pump to evacuate to 5×10⁻²Pa. Open the circulating cooling water valve, start the heating device, and heat the aluminum raw material to 700℃ to completely melt it, obtaining molten aluminum.

[0026] S3. Atmosphere control: Turn off the vacuum system, fill the furnace with high-purity hydrogen (purity ≥99.999%), adjust the hydrogen pressure to 0.4MPa using a high-precision pressure controller, and keep it at that temperature for 20 minutes.

[0027] S4. Directional solidification: Start the traction system, control the solidification rate to 2 mm / min and the temperature gradient to 50℃ / cm, so that the aluminum melt crystallizes directionally from the bottom up.

[0028] S5. Post-processing: After solidification, wait for the ingot to cool to room temperature, open the vent valve to release the gas in the furnace, and remove the ingot. Cut off 15% of the first end and 10% of the last end of the ingot to obtain high-purity aluminum product. Example

[0029] High-purity aluminum is prepared according to the preparation method described in the invention. The specific parameters and steps are as follows: S1. Raw material preparation: Use aluminum raw materials with a purity of 4N (99.99%), and perform surface cleaning and drying treatment on the aluminum raw materials.

[0030] S2. Melting: Place the pretreated aluminum raw material in a vacuum directional solidification furnace, close and lock the furnace door, and turn on the vacuum pump to evacuate to 5×10⁻²Pa. Open the circulating cooling water valve, start the heating device, and heat the aluminum raw material to 700℃ to completely melt it, obtaining molten aluminum.

[0031] S3. Atmosphere control: Turn off the vacuum system, fill the furnace with high-purity hydrogen (purity ≥99.999%), adjust the hydrogen pressure to 0.4MPa using a high-precision pressure controller, and keep it at that temperature for 20 minutes.

[0032] S4. Directional solidification: Start the traction system, control the solidification rate to 2 mm / min and the temperature gradient to 50℃ / cm, so that the aluminum melt crystallizes directionally from the bottom up.

[0033] S5. Post-processing: After solidification, wait for the ingot to cool to room temperature, open the vent valve to release the gas in the furnace, and remove the ingot. Cut off 15% of the first end and 10% of the last end of the ingot to obtain high-purity aluminum product. Example

[0034] High-purity aluminum is prepared according to the preparation method described in the invention. The specific parameters and steps are as follows: S1. Raw material preparation: Use aluminum raw materials with a purity of 4N (99.99%), and perform surface cleaning and drying treatment on the aluminum raw materials.

[0035] S2. Melting: Place the pretreated aluminum raw material in a vacuum directional solidification furnace, close and lock the furnace door, and turn on the vacuum pump to evacuate to 5×10⁻²Pa. Open the circulating cooling water valve, start the heating device, and heat the aluminum raw material to 700℃ to completely melt it, obtaining molten aluminum.

[0036] S3. Atmosphere control: Turn off the vacuum system, fill the furnace with high-purity hydrogen (purity ≥99.999%), adjust the hydrogen pressure to 0.4MPa using a high-precision pressure controller, and keep it at that temperature for 20 minutes.

[0037] S4. Directional solidification: Start the traction system, control the solidification rate to 2 mm / min and the temperature gradient to 50℃ / cm, so that the aluminum melt crystallizes directionally from the bottom up.

[0038] S5. Post-processing: After solidification, wait for the ingot to cool to room temperature, open the vent valve to release the gas in the furnace, and remove the ingot. Cut off 15% of the first end and 10% of the last end of the ingot to obtain high-purity aluminum product.

[0039] The performance results of the products prepared in the above four embodiments are as follows. Under vacuum conditions, the average hardness of the product is 19.25 HV, with a standard deviation of ±0.469. Under 0.2 MPa hydrogen gas conditions, the average hardness of the product is 18.93 HV, slightly lower than under vacuum conditions, but the standard deviation is smaller (±0.333), indicating good microstructure uniformity. Under 0.4 MPa hydrogen gas conditions, the average hardness of the product significantly increases to 21.02 HV, reaching the highest value, but the standard deviation is the largest (±1.004), indicating large data fluctuations and possible microscopic inhomogeneities. Under 0.6 MPa hydrogen gas conditions, the average hardness of the product is 19.48 HV, close to vacuum conditions, but the standard deviation is the smallest (±0.177), indicating the best microstructure uniformity.

[0040] The preferred embodiments of the present invention disclosed above are only for the purpose of illustrating the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation described.

Claims

1. A method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification, characterized in that: Includes the following steps: S1. The aluminum raw material with a purity of ≥99.99% is surface cleaned and dried, and then placed in a vacuum directional solidification furnace. The vacuum is drawn to below 5×10⁻²Pa, and heated to 680~750℃ to completely melt the aluminum raw material and obtain aluminum melt. S2. Introduce high-purity hydrogen into the furnace, adjust the hydrogen pressure to 0.2~0.6MPa, and keep it at that temperature for 10~30 minutes; S3. Start the directional solidification program, control the solidification rate to be 0.5~5mm / min, and the temperature gradient to be 30~80℃ / cm, so that the aluminum melt crystallizes directionally from the bottom up; S4. After solidification, the impurity-rich portions at the beginning and end of the ingot are removed to obtain high-purity aluminum products.

2. The method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification according to claim 1, characterized in that: In step S2, when stable and uniform mechanical properties are required, the hydrogen pressure is preferably 0.2 MPa or 0.6 MPa.

3. The method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification according to claim 1, characterized in that: When the highest hardness is required, the hydrogen pressure is preferably 0.4 MPa.

4. The method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification according to claim 1, characterized in that: The purity of the high-purity hydrogen gas is ≥99.999%.

5. The method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification according to claim 1, characterized in that: In step S4, 10-20% of the ingot's head end and 10-15% of its tail end are specifically removed.

6. A method for controlling the mechanical properties of high-purity aluminum prepared by hydrogen atmosphere-assisted directional solidification according to any one of claims 1-5, characterized in that: The product prepared by this method has an adjustable Vickers hardness in the range of 18.5~21.5HV, and the hardness fluctuation coefficient is ≤5%.

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