Method for fine control of high degree of freedom of microstructure of metal material

Abstract

The application discloses a kind of high degree of freedom fine control methods of metal material microstructure, it is related to material preparation technical field, the method includes the following specific steps: pretreatment preparation: selecting metal material and cutting polishing, while selecting and grinding ball and matched pressure head adapted to metal hardness;The application realizes the high degree of freedom accurate control to metal material surface microstructure by multi-step fine parameter control, in the links such as pretreatment, surface mechanical grinding nanocrystallization treatment and local heating / cooling treatment forming, from material selection, grinding parameter setting to cooling heating unit layout and temperature control, can be flexibly adjusted according to specific demand, so that various complex, unique microstructure can be prepared, whether it is the requirement of high-end manufacturing field to material specific performance, or the pursuit to unique appearance in artistic creation, can be satisfied, greatly expand the applicability of metal material in different application scenarios.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, specifically to a method for highly free and precise control of the microstructure of metallic materials. Background Technology

[0002] In the field of materials preparation, metallic materials are widely used in aerospace, automobile manufacturing, electronic information, and building decoration due to their excellent mechanical properties, electrical conductivity, thermal conductivity, and good machinability. The microstructure of metallic materials, such as grain size, grain boundary characteristics, phase composition, and micromorphology, plays a decisive role in their macroscopic properties. Different microstructures can lead to significant differences in the strength, hardness, toughness, corrosion resistance, and electrical conductivity of metallic materials. Therefore, achieving effective control over the microstructure of metallic materials is the key to meeting the diverse performance requirements of metallic materials in different fields and promoting the development of metallic material applications.

[0003] Traditional metal processing techniques have many limitations in controlling the microstructure of metal materials, making it difficult to meet the diverse and refined demands of modern industry and technology for microstructure control. Taking the heat treatment and surface etching processes in the production of spotted copper as an example, in the spotting stage, if the firing temperature is too low, the raw materials cannot fully react to form the ideal crystal form, resulting in the metal material's performance failing to meet expectations. If the temperature is too high, it can easily damage the workpiece, wasting raw materials and increasing production costs and process complexity. Furthermore, the spotting process lacks systematic scientific theoretical guidance, making large-scale industrial production and technology transfer difficult. Furthermore, the traditional process of heating and annealing copper products as a whole results in a uniform grain etching morphology, mostly large-sized coarse grains, which severely limits the exquisiteness and innovation of metal crafts. From the perspective of the common problem of controlling the microstructure of metal materials, metals, as good conductors of heat, have an overall recrystallization behavior that is difficult to control precisely. When bulk local recrystallization is used to prepare specific external surface structures, the recrystallization nucleation is random, resulting in uncontrollable microstructures at local locations. It is impossible to accurately control the microstructure characteristics such as grain size, distribution and morphology, making it difficult to meet the special performance requirements of metal materials microstructure in different fields. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for highly flexible and precise control of the microstructure of metallic materials. This method enables the fabrication of various complex and unique microstructures by precisely controlling parameters such as material selection and processing, selection of grinding balls and indenters, applied load, grinding ball indentation depth, indenter movement speed, cooling unit temperature, heating unit temperature, and contact time between the printing device and the nanocrystalline layer surface. This allows for the creation of diverse and unique microstructures to meet the specific performance requirements of different applications. The method not only offers advantages such as precise microstructure control, significant process advantages, outstanding cost-effectiveness, and high design flexibility, but also opens up new avenues for performance optimization and innovative applications of metallic materials in high-end manufacturing, artistic creation, and other fields, possessing significant scientific and practical value.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for high-degree-of-freedom fine control of the microstructure of metallic materials, the method comprising the following specific steps:

[0006] Pre-treatment preparation: Select metal materials and cut and grind them, while selecting grinding balls and matching pressure heads that are compatible with the hardness of the metal;

[0007] Surface mechanical grinding nano-sizing treatment: Using a pressure head with grinding balls to apply pressure to the surface of a fixed metal sheet and move it to grind, so that a uniform nano-crystalline deformation layer is formed on the surface of the sheet.

[0008] Printing device preparation and parameter setting: Insert the semiconductor cooling unit and heating unit with specific temperature control range into the heat insulation bracket as designed and connect the control device, set the temperature of the cooling and heating units and the contact time between the printing device and the nanocrystalline layer;

[0009] Local heating and cooling process forming: After the cooling and heating units reach the set temperature, the printing device is attached to the surface of the nanocrystalline layer and kept in contact for a set time to obtain a heterogeneous structure metal material with controllable grain size distribution.

[0010] Furthermore, in the pretreatment preparation step, metal materials are selected and cut and polished. The thickness of the metal sheet is selected between 1-10mm, and the surface roughness is controlled between Ra0.1-Ra1.6μm to effectively remove the oxide layer, impurities, etc. on the surface, providing a good foundation for subsequent surface mechanical grinding.

[0011] Furthermore, in the pretreatment preparation step, the grinding balls are made of high-hardness SiC or Al2O3. For high-hardness metal materials, SiC grinding balls are preferred, while Al2O3 grinding balls are used for softer metal materials. The size of the pressure head is adapted according to the size of the plate to be processed. When the plate is small (side length less than 200mm), a pressure head with a diameter of 20-50mm can be used. When the plate is large (side length greater than 200mm), a pressure head with a diameter of 50-100mm is used to ensure that the pressure head can stably install the grinding balls and accurately apply the required load.

[0012] Furthermore, in the surface mechanical grinding nano-processing step, the applied load F is adjusted within the range of 0.2-40N according to the hardness of the metal material, the grinding ball indentation depth D is 20-200μm, the indenter movement speed V is controlled at 1-30m / s, and the offset of each pass is 0.1-0.4mm.

[0013] Furthermore, in the surface mechanical grinding nano-processing step, the processed metal sheet is firmly fixed on the base to prevent displacement of the sheet during grinding. The pressure head with grinding balls is started, and according to the preset load F, pressing depth D, movement speed V and offset parameters, starting from the upper left corner of the sheet, the grinding balls are rolled and ground on the surface of the sheet in a top-to-bottom and left-to-right sequence. This operation is continued until a uniform nanocrystalline deformation layer with a thickness d not less than 5% of the sheet thickness and in the range of 20-200μm is successfully formed on the surface of the sheet, thereby achieving nano-processing of the sheet surface.

[0014] Furthermore, in the printing device preparation and parameter setting steps, the temperature control range of the semiconductor cooling unit T1 is -100 to 0°C. For situations requiring more fine grain areas, the temperature of the cooling unit T1 can be reduced.

[0015] Furthermore, in the printing device preparation and parameter setting steps, the temperature control range of the heating unit T2 is 100-700℃. For cases where a larger coarse-grained region is desired, the temperature of the heating unit can be appropriately increased.

[0016] Furthermore, in the printing device preparation and parameter setting steps, the number and arrangement of cooling and heating units are reasonably arranged according to the target microstructure. The cooling and heating units are inserted in an orderly manner into an insulating support made of porous vacuum silicon. The thermal conductivity of the insulating support is 0.014 W / (m·K), which can effectively reduce heat conduction between units. The control lines of the cooling and heating units are connected to the corresponding cooling control device and heating control device respectively to accurately control the temperature of each unit. The contact time t between the printing device and the surface of the nanocrystalline layer is set to 20-120s. If the area to be processed is large or the pattern is complex, the contact time can be appropriately extended to ensure sufficient heat transfer and achieve the expected microstructure change.

[0017] Compared with existing technologies, this method for high-degree-of-freedom fine control of the microstructure of metallic materials has the following advantages:

[0018] I. This invention achieves highly flexible and precise control over the microstructure of metal materials through multi-step refined parameter regulation. In the pretreatment, surface mechanical grinding nano-processing, and local heating / cooling forming processes, from material selection and grinding parameter setting to the layout and temperature control of cooling and heating units, everything can be flexibly adjusted according to specific needs. This enables the preparation of various complex and unique microstructures, satisfying both the specific performance requirements of materials in high-end manufacturing and the pursuit of unique appearance in artistic creation. This greatly expands the applicability of metal materials in different application scenarios.

[0019] Second, this invention reduces surface damage to materials through surface mechanical grinding and local heating and cooling processes, preventing severe deformation and effectively maintaining the original properties of the materials. At the same time, the process is relatively simple, with low equipment wear and tear, convenient operation, and strong operability. In addition, the cooling / heating units of the printing device can be freely designed and combined, enabling precise control of any microstructure on a small-scale device, reducing production costs, and creating favorable conditions for the innovative application of metal materials in fields such as artistic creation and micro-nano manufacturing.

[0020] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0022] Figure 1 This is a schematic diagram of a method for high-degree-of-freedom and precise control of the microstructure of metallic materials.

[0023] Figure 2 This is a schematic diagram of the surface structure of a metallic material after processing using a method for high-degree-of-freedom and precise control of the microstructure.

[0024] Figure 3 A schematic diagram of a printing device for a method of high-degree-of-freedom fine control of the microstructure of metallic materials;

[0025] Figure 4 This is a schematic diagram illustrating the final surface structure obtained by a method for highly free and precise control of the microstructure of metallic materials. Detailed Implementation

[0026] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0027] Example 1

[0028] High-grade copper-based alloy plates with a thickness of 3mm are selected. The surface roughness is controlled to Ra0.8μm through mechanical grinding to remove surface impurities and oxide layers. Based on the hardness of the copper-based alloy, Al2O3 grinding balls are selected and matched with a 40mm diameter pressure head. During the grinding and tool selection process, relevant process standards are strictly followed to ensure the surface treatment effect and tool compatibility.

[0029] Based on the properties of copper-based alloys, the applied load F is set to 6N, the grinding ball indentation depth D to 60μm, the indenter speed V to 8m / s, and the offset per pass to 0.2mm. The plate is fixed on the base, and the indenter is started to grind according to the predetermined parameters, starting from the upper left corner of the plate, operating sequentially from top to bottom and from left to right. Its movement trajectory is as follows: Figure 1 As shown, a high-precision displacement sensor is used to monitor the position of the pressure head in real time during operation to ensure accurate movement trajectory until a uniform nanocrystalline deformation layer with a thickness of approximately 180μm (meeting a requirement of not less than 5% of the plate thickness) is formed on the surface of the plate. The surface morphology after grinding is as follows. Figure 2 As shown.

[0030] Based on the landscape pattern on the surface of the designed bronze artifact, computer-aided design software was used to simulate the layout of the cooling and heating units to ensure accurate pattern rendering and a reasonable arrangement of the semiconductor cooling and heating units. Figure 3 As shown, insert the porous vacuum silicon heat-insulating bracket, connect the control line to the corresponding control device, set the cooling unit temperature T1 to -60℃, the heating unit temperature T2 to 400℃, and the contact time t between the printing device and the nanocrystalline layer surface to 80s. During the temperature setting process, use a high-precision temperature sensor for calibration to ensure temperature accuracy.

[0031] Turn on the cooling and heating control devices. After the cooling and heating units reach their set temperatures, precisely attach the printing device to the surface of the nanocrystalline layer, maintaining contact for 80 seconds. By precisely controlling the temperature and time, a specific grain size distribution is formed on the surface of the substrate, giving the surface of the bronze artifact a unique pattern resembling landscape textures. Figure 4 As shown, after the treatment, the surface of the handicraft was subjected to microstructure detection and hardness testing. The microstructure showed that the distribution of coarse and nanocrystalline regions met the design expectations. The hardness test results showed that the surface hardness was increased by 20%, which significantly improved the artistic value and ornamental value of the handicraft.

[0032] Example 2

[0033] High-purity copper sheets were selected as raw materials, with a thickness of 1.5mm. A combination of chemical cleaning and mechanical polishing was used to reduce the surface roughness of the copper sheets to Ra0.2μm, thoroughly removing surface oil, oxides, and other impurities to ensure the effectiveness of subsequent processes. First, the copper sheets were soaked in a professional chemical cleaning agent to remove oil and some oxides. Then, high-precision mechanical polishing equipment was used to polish the sheets according to specific polishing process parameters to ensure surface flatness and smoothness. Due to the soft nature of copper sheets, Al2O3 grinding balls were selected, paired with a 25mm diameter pressure head. This combination ensures the grinding effect while avoiding excessive damage to the copper sheets. When selecting grinding balls and pressure heads, their dimensional accuracy and hardness uniformity were strictly tested to ensure compliance with process requirements.

[0034] Based on the material properties of the copper sheet, the applied load F is set to 3N. This load ensures that the grinding ball effectively penetrates the surface of the copper sheet without causing excessive deformation. The grinding ball penetration depth D is set to 50μm to ensure a sufficiently deep plastic deformation zone, promoting the formation of nanocrystals. The indenter speed V is set to 6m / s, with an offset of 0.15mm per pass. This parameter combination ensures uniform grinding on the copper sheet surface. The copper sheet is securely fixed on a custom-designed high-precision base with a special shock absorption and positioning design to reduce the impact of external vibrations on the grinding process. The indenter with the grinding ball is started, and the entire surface of the copper sheet is ground systematically, starting from the upper left corner according to the set parameters. During the grinding process, a high-speed camera monitors the movement of the grinding ball and the deformation of the copper sheet surface in real time. If any abnormality is detected, the machine is stopped immediately for adjustment until a uniform nanocrystal deformation layer with a thickness of approximately 80μm (meeting a requirement of not less than 5% of the sheet thickness) is formed on the copper sheet surface, achieving nano-scale formation of the copper sheet surface.

[0035] Based on the specific requirements of electronic device heat dissipation on the microstructure of copper sheets, the layout of semiconductor cooling and heating units was carefully designed. Different layout schemes were simulated and analyzed using thermal simulation software, and the optimal layout was selected. They were then inserted into the porous vacuum silicon insulation support in an orderly manner, and the control lines were connected to the corresponding cooling control device and heating control device. Considering the thermal conductivity characteristics of copper and heat dissipation requirements, the cooling unit temperature T1 was set to -40℃, the heating unit temperature T2 was set to 200℃, and the contact time t between the printing device and the nanocrystalline layer surface was set to 50s. Before setting the temperature and time parameters, multiple pre-experiments were conducted, and the parameters were fine-tuned based on the experimental results to ensure the best processing effect.

[0036] The cooling and heating control devices are activated, and the temperature changes of the cooling and heating units are closely monitored. Once they stabilize at the set temperatures of -40℃ and 200℃ respectively, a high-precision positioning device is quickly used to precisely attach the printing device to the nanocrystalline surface of the copper sheet, maintaining a contact time of 50 seconds. During this process, the cooling and heating units work together to precisely control the recrystallization behavior of the micro-regions on the copper sheet surface, resulting in a special heterogeneous structure on the copper sheet surface, where some areas consist of fine nanocrystals and others of slightly larger grains. After processing, the microstructure of the copper sheet surface is inspected using a scanning electron microscope (SEM), and the heat dissipation performance of the copper sheet is tested using a thermal imager. The results show that the grain structure on the copper sheet surface meets the expected design. After being applied to the CPU heat dissipation module of a certain model of mobile phone, tests showed that under the same operating conditions, the temperature of the mobile phone CPU was reduced by 5-8℃ compared to when using the untreated copper sheet, effectively improving the mobile phone's operational stability and performance.

[0037] Example 3

[0038] Specific aluminum alloy sheets, 2mm thick, used in the manufacture of automotive engine pistons, were selected. A combination of mechanical grinding and chemical degreasing was used for pretreatment. First, coarse sandpaper was used to initially remove larger defects and oxide layers from the sheet surface. Then, finer sandpaper was used for fine grinding until the surface roughness reached Ra1.2μm. Subsequently, the sheet was immersed in a specially formulated chemical degreasing solution to remove surface oil through a chemical reaction, ensuring the surface cleanliness met subsequent processing standards. Given the medium hardness of this aluminum alloy, SiC grinding balls were selected, compatible with a 50mm diameter indenter. When selecting the grinding balls and indenter, key performance indicators such as hardness and density were rigorously tested to ensure stable quality and compliance with process requirements.

[0039] Based on the properties of aluminum alloy, the applied load F is set to 8N to ensure that the grinding ball can fully penetrate the surface of the plate, causing plastic deformation of the material to form a nanocrystalline structure. The grinding ball penetration depth D is 120μm, the indenter speed V is 12m / s, and the offset per pass is 0.25mm. The aluminum alloy plate is firmly fixed on a specially made high-strength base. The base adopts a shock-absorbing and anti-slip design to effectively reduce the vibration and displacement generated during the grinding process. The indenter is started and, according to the set parameters, it evenly grinds the entire surface of the plate, starting from the upper left corner. During the grinding process, sensors are used to monitor the pressure, speed, and displacement of the indenter in real time to ensure parameter stability. At the same time, the microstructure of the ground area is detected at regular intervals to observe the formation of nanocrystals until a uniform nanocrystalline deformation layer with a thickness of about 120μm (not less than 5% of the plate thickness) is formed on the surface of the plate, completing the surface nano-sizing treatment.

[0040] Based on the requirements of automotive engine pistons for high-temperature strength and wear resistance of aluminum alloy materials, computer simulation technology was used to optimize the layout of semiconductor cooling and heating units in the insulation bracket to achieve the most ideal microstructure control effect. The cooling and heating units were inserted into the porous vacuum silicon insulation bracket in an orderly manner, and the control lines were connected to the corresponding control devices. The cooling unit temperature T1 was set to -70℃, the heating unit temperature T2 to 550℃, and the contact time t between the printing device and the nanocrystalline layer surface was set to 90s. Before setting these parameters, a large number of simulation experiments and small-batch trial productions were carried out. The changes in the microstructure and performance of aluminum alloy materials under different parameter combinations were comprehensively analyzed to determine the optimal parameter values.

[0041] The cooling and heating control devices are activated, and the temperature changes of the cooling and heating units are closely monitored through a high-precision temperature control system. Once they stabilize at the set temperatures of -70℃ and 550℃ respectively, a highly automated robotic arm with a positioning accuracy of ±0.01mm is used to accurately attach the printing device to the nanocrystalline layer surface of the aluminum alloy sheet, maintaining a contact time of 90 seconds. During this process, the cooling and heating units work together to precisely control the recrystallization behavior of the micro-regions on the surface of the aluminum alloy sheet, resulting in the formation of a specific heterogeneous structure. After the treatment, the aluminum alloy sheet undergoes comprehensive performance testing, including hardness testing, tensile testing, wear resistance testing, and fatigue testing under high-temperature conditions. The results show that compared to the untreated aluminum alloy material, the surface hardness of the treated material is increased by 35%, the wear rate under simulated engine high-temperature conditions is reduced by 30%, and the tensile strength is increased by 20%. The treated aluminum alloy material is used to manufacture automotive engine pistons for bench testing. After a long period of simulated actual working conditions, disassembly and inspection revealed that the wear of the pistons was significantly reduced, effectively extending the piston's service life and improving the overall performance and reliability of the engine.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for high-degree-of-freedom precision control of the microstructure of metallic materials, characterized in that, The method includes the following specific steps: Pre-treatment preparation: Select metal materials and cut and grind them, while selecting grinding balls and matching pressure heads that are compatible with the hardness of the metal; Surface mechanical grinding nano-sizing treatment: Using a pressure head with grinding balls to apply pressure to the surface of a fixed metal sheet and move it to grind, so that a uniform nano-crystalline deformation layer is formed on the surface of the sheet. Printing device preparation and parameter setting: Insert the semiconductor cooling unit and heating unit with specific temperature control range into the heat insulation bracket as designed and connect the control device, set the temperature of the cooling and heating units and the contact time between the printing device and the nanocrystalline layer; Local heating and cooling process forming: After the cooling and heating units reach the set temperature, the printing device is attached to the surface of the nanocrystalline layer and the set contact time is maintained to obtain a heterogeneous structure metal material with controllable grain size distribution.

2. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the pretreatment preparation step, metal materials are selected and cut and polished. The thickness of the metal sheet is selected between 1-10mm, and the surface roughness is controlled between Ra0.1-Ra1.6μm.

3. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the pretreatment preparation step, the grinding balls are made of high-hardness SiC or Al2O3. For high-hardness metal materials, SiC grinding balls are preferred, while Al2O3 grinding balls are used for softer metal materials.

4. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the surface mechanical grinding nano-processing step, the applied load F is adjusted in the range of 0.2-40N according to the hardness of the metal material, the grinding ball indentation depth D is 20-200μm, the indenter movement speed V is controlled in the range of 1-30m / s, and the offset of each pass is 0.1-0.4mm.

5. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the surface mechanical grinding nano-processing step, the processed metal plate is firmly fixed on the base, and the pressure head with grinding balls is started. The plate surface is ground according to the set parameters. The grinding direction is from top to bottom and from left to right until a uniform nanocrystalline deformation layer with a thickness d of not less than 5% of the plate thickness and in the range of 20-200μm is formed on the plate surface.

6. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the steps of preparing and setting parameters for the printing device, the temperature control range of the semiconductor cooling unit is -100 to 0°C.

7. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the steps of preparing and setting parameters for the printing device, the temperature control range of the heating unit is 100-700℃.

8. The method for high-degree-of-freedom fine control of the microstructure of metallic materials according to claim 1, characterized in that, In the steps of preparing and setting parameters for the printing device, the number and arrangement of cooling and heating units are reasonably arranged according to the target microstructure. A heat-insulating bracket made of porous vacuum silicon is inserted, with a thermal conductivity of 0.014 W / (m·K). The contact time t between the printing device and the surface of the nanocrystalline layer is 20-120 s.

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