Ultralow-plasticity, high-strength and high-hardness medium and low temperature forming technology

Abstract

The invention relates to the field of manufacturing and forming, and discloses an ultralow-plasticity, high-strength and high-hardness medium and low temperature forming technology which comprises the following steps: selecting a forming material according to requirements, and constructing a green body by using the forming material through additive manufacturing; performing medium-low-temperature forming rough machining on the blank body through medium-low-temperature machining equipment to obtain a rough blank; carrying out secondary forming on the rough blank by carrying out ultrasonic-assisted medium-low temperature processing equipment through ultrasonic vibration equipment, so as to obtain a workpiece; performing hot isostatic pressing treatment on the workpiece through hot isostatic pressing equipment to obtain a treated part; and the processed part is subjected to electric spark machining through an electric spark machining machine tool, and a finish machined part is obtained. Through the combination of medium and low temperature forming and ultrasonic assistance and other technologies, the deformation resistance of the material is remarkably reduced, in the medium and low temperature forging and rolling process, the temperature and deformation parameters are controlled, the material can generate plastic deformation under the relatively low pressure, the fluidity of the material is further improved through ultrasonic assistance, and the pressure needed by forming is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing and forming, and specifically to an ultra-low plasticity, high-strength, high-hardness medium and low-temperature forming technology. Background Art

[0002] In modern manufacturing, with the rapid development of fields such as aerospace, automotive industry, and electronic equipment, the requirements for the performance and precision of components are becoming increasingly stringent. The progress of materials science has led to the continuous emergence of new materials. Among them, ultra-low plasticity, high-strength, and high-hardness materials have shown great application potential in many fields due to their unique performance advantages. Such materials can withstand higher loads, have better wear resistance and corrosion resistance, which helps to achieve the lightweight design of products and improve the reliability and service life of products.

[0003] Currently, for the forming of ultra-low plasticity, high-strength, and high-hardness materials, high temperature and high pressure are usually used to promote plastic deformation of the materials. In a high-temperature environment, a huge pressure is applied through large forging equipment. To overcome the deformation resistance of ultra-low plasticity, high-strength, and high-hardness materials, forging equipment with an extremely large tonnage needs to be equipped, which not only makes the equipment procurement cost extremely high, often tens of millions of yuan or even higher, but also the equipment occupies a large area and has strict requirements for the plant infrastructure, increasing the construction cost and being not conducive to the wide popularization of the technology. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides an ultra-low plasticity, high-strength, high-hardness medium and low-temperature forming technology, which solves the problem that for the forming of traditional ultra-low plasticity, high-strength, high-hardness materials, forging equipment with an extremely large tonnage needs to be equipped to overcome the deformation resistance of ultra-low plasticity, high-strength, high-hardness materials, and is not conducive to the wide popularization of the technology.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: an ultra-low plasticity, high-strength, high-hardness medium and low-temperature forming technology, including the following steps: S1. Select a forming material according to requirements and construct a blank through additive manufacturing; S2. Perform medium and low-temperature rough machining on the blank through a medium and low-temperature processing device to obtain a rough blank; S3. Carry out secondary forming on the rough blank through an ultrasonic vibration device to assist the medium and low-temperature processing device to obtain a workpiece; S4. Perform hot isostatic pressing treatment on the workpiece through a hot isostatic pressing device to obtain a treated part; S5. Perform electrical discharge machining on the treated part through an electrical discharge machining machine tool to obtain a precision-machined part; S6. Perform surface treatment on the precision-machined part through a physical vapor deposition device or a laser surface alloying device to obtain a forged part, and establish a collaborative optimization model according to various parameters.

[0006] Preferably, the forming material in S1 includes silicon carbide aluminum alloy material. The additive manufacturing blank body specifically includes the following steps: S101. Design a product model according to requirements, and use the gas atomization method to prepare the forming material into powder; S102. Adopt plasma treatment technology to introduce active groups on the surface of the powder and perform surface modification treatment on the powder; S103. Use a selective laser melting equipment equipped with a fiber laser to build in a closed forming cavity filled with argon, and use an adaptive scanning strategy according to the structural complexity of different parts of the model. The scanning path adopts a partitioned alternating scanning method to build a blank body.

[0007] Preferably, the power of the fiber laser is 400 - 1000W, the oxygen content in the closed forming cavity is controlled below 0.1%, the laser scanning speed of the laser melting equipment is 800 - 1200mm / s, and the layer thickness is 0.02 - 0.05mm.

[0008] Preferably, the medium and low temperature forming and rough machining in S2 includes medium and low temperature forging and medium and low temperature rolling. The forging temperature of the medium and low temperature forging is 400 - 700°C, the deformation per pass is 10% - 20%, the forging pressure is 50 - 200MPa, the rolling temperature of the medium and low temperature rolling is 400 - 700°C, the reduction per pass is 0.5 - 2mm, and the rolling force is 30 - 150kN.

[0009] Preferably, the output frequency of the ultrasonic generator of the ultrasonic vibration equipment in S3 is 20 - 40kHz, the power is 50 - 1500W, the amplitude on the surface of the mold is 0.01 - 0.1mm, and the mold temperature of the low temperature processing equipment is 240 - 260°C.

[0010] Preferably, the heating rate of the hot isostatic pressing equipment in S4 is 1 - 10°C / min, the pressure is 50 - 200MPa, and the vacuum degree is 10 -3 -10 -4 Pa.

[0011] Preferably, the output voltage of the pulse power supply of the electric discharge machining machine tool in S5 is 60 - 120V, the pulse width is 1 - 50μs, the pulse interval is 5 - 100μs, and deionized water is used as the working fluid, and the working fluid temperature is 20 - 30°C.

[0012] Preferably, in S6, the argon flow rate of the physical vapor deposition equipment is 20 - 50 sccm, the nitrogen flow rate is 5 - 20 sccm, the substrate bias voltage is -50 to -200 V, the deposition temperature is 200 - 500 °C, the deposition time is 2 - 4 h, the coating thickness is 1 - 5 μm, the laser power of the laser surface alloying equipment is 1 - 5 kW, the scanning speed is 5 - 20 mm / s, the spot diameter is 0.5 - 2 mm, and the depth of the instantaneous melting of the workpiece surface is 0.1 - 0.5 mm.

[0013] Preferably, establishing a collaborative optimization model according to the parameters in S6 includes the following steps: S601. Take the parameters of additive manufacturing, medium and low temperature forming rough machining, secondary forming, hot isostatic pressing treatment, electrical discharge machining, and surface treatment as variables; S602. Construct an objective function with the performance of the forming material and the quality indexes of the forging; S603. Through an intelligent optimization algorithm, construct a model based on the variables and the objective function, solve the model, and obtain the optimized parameters through iterative calculation.

[0014] Preferably, in S602, the performance includes strength, hardness, plasticity, and fatigue life, the quality indexes include dimensional accuracy, surface roughness, and internal defect rate, and the intelligent optimization algorithms in S603 include genetic algorithm, particle swarm optimization algorithm, and simulated annealing algorithm.

[0015] The present invention provides an ultra-low plasticity, high-strength, and high-hardness medium and low temperature forming technology, having the following beneficial effects: 1. By combining medium and low temperature forming with ultrasonic assistance and other technologies, the present invention significantly reduces the material deformation resistance. During medium and low temperature forging and rolling processes, by controlling the temperature and deformation parameters, the material can undergo plastic deformation under relatively low pressure, and ultrasonic assistance further improves the material fluidity and reduces the pressure required for forming. Therefore, there is no need for extra-large tonnage equipment, reducing the equipment procurement and maintenance costs, improving the economy and flexibility of production, and promoting the wide spread of the technology.

[0016] 2. By precisely constructing the blank through additive manufacturing, medium and low temperature forming rough machining refines the material grains, improves the material density and uniformity, hot isostatic pressing treatment effectively eliminates internal pores, shrinkage porosity and other defects, improves the material mechanical properties, electrical discharge machining achieves high-precision surface machining with low surface roughness, physical vapor deposition and laser surface alloying endow the product with excellent surface properties. By integrating the functions of each process, the finally formed thin-walled, thin web, high rib plate and other complex forgings have high quality and high precision, meeting the high-end application requirements.

[0017] 3. The present invention reduces material waste by additive manufacturing to deposit materials as needed; during medium and low-temperature forming and subsequent processing, the process parameters are precisely controlled to reduce the reject rate. By establishing a collaborative optimization model, the combination of process parameters is optimized to improve production efficiency, shorten the production cycle, further reduce the comprehensive production cost, and enhance the market competitiveness of the product.

[0018] 4. The present invention combines medium and low-temperature forming with ultrasonic-assisted technology. During medium and low-temperature forging and rolling, the temperature and deformation parameters are controlled. The ultrasonic vibration reduces the friction coefficient between the material and the die, promotes atomic diffusion, and improves the material fluidity, thereby achieving the minimization of the material deformation resistance and the maximization of the forming performance. Additive manufacturing deposits materials as needed to reduce waste. The subsequent processes precisely control the parameters to reduce the reject rate. Coupled with the advantage of being able to form under lower loads, high-quality forming of large-scale precision and complex-shaped forgings can be achieved using lower equipment tonnage, significantly improving the material utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of a method for a medium and low-temperature forming technology of ultra-low plasticity, high strength, and high hardness proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to the attached Figure 1 , the embodiment of the present invention provides a medium and low-temperature forming technology of ultra-low plasticity, high strength, and high hardness, including the following steps: S1. Select the forming material according to the requirements and construct a blank by additive manufacturing; the forming material in S1 includes silicon carbide aluminum alloy material, and the specific steps for constructing the blank by additive manufacturing are as follows: S101. Design the product model according to the requirements and prepare the forming material into powder by gas atomization method; S102. Use plasma treatment technology to introduce active groups on the powder surface and perform surface modification treatment on the powder; S103. Use a selective laser melting device equipped with a fiber laser to construct in a closed forming cavity filled with argon, and use an adaptive scanning strategy according to the structural complexity of different parts of the model. The scanning path adopts a partitioned alternating scanning method to construct the blank.

[0022] The power of the fiber laser is 400 - 1000 W, the oxygen content in the closed - formed cavity is controlled below 0.1%, the laser scanning speed of the laser melting equipment is 800 - 1200 mm / s, and the layer thickness is 0.02 - 0.05 mm.

[0023] Specifically, using 3D modeling software, according to the specific functions and structural requirements of the product, the product model is accurately designed. The model should not only reflect the external shape of the product, but also detail the possible complex internal structures, such as lattice structures, porous structures, etc. After completing the model design, the powder is prepared by the gas atomization method. This method sprays the molten silicon carbide aluminum alloy through high - pressure gas, causing it to break into fine droplets, which then quickly cool and solidify to form powder. The powder has uniform particle size and can meet the requirements of subsequent additive manufacturing.

[0024] By using plasma treatment technology to modify the surface of the powder, the plasma treatment equipment generates high - energy plasma, which contains a large number of ions, electrons, and active free radicals. When the powder is in the plasma environment, these active particles react chemically with the powder surface, introducing active groups. Through this surface modification, the binding force of the powder during the subsequent forming process can be effectively enhanced, and the quality of the formed parts can be improved. The introduced active groups can increase the physical adsorption between the powders, enabling the powders to fuse better together during the selective laser melting process and reducing the generation of internal defects.

[0025] The construction is carried out by using a selective laser melting equipment equipped with a fiber laser. The forming chamber of the equipment is a closed structure. Before forming, argon gas is filled into the chamber, and an oxygen content sensor is used to monitor the oxygen content in the chamber in real time to ensure that the oxygen content is controlled below 0.1%. This is because under the action of high-temperature laser, the silicon carbide aluminum alloy powder is extremely easy to react with oxygen, resulting in a decline in material performance. Strictly controlling the oxygen content can effectively avoid the occurrence of oxidation phenomenon. The power of the fiber laser is set between 400 - 1000W. This power range can provide sufficient energy to quickly melt and solidify the powder. The laser scanning speed is maintained at 800 - 1200mm / s, and the layer thickness is controlled at 0.02 - 0.05mm. During the scanning process, an adaptive scanning strategy is used according to the structural complexity of different parts of the model. For parts with complex structures and thin walls, etc., the scanning speed is appropriately reduced and the energy input is increased to ensure that the powder is fully melted and the forming quality; for parts with relatively simple structures, the normal scanning speed is adopted to improve the forming efficiency. The scanning path adopts a partitioned alternating scanning method, which can effectively reduce the accumulation of thermal stress and prevent the blank from deforming or cracking due to excessive thermal stress. Through layer-by-layer stacking, a blank with a complex shape is finally constructed. After the blank is formed, industrial CT is used to perform non-destructive testing on its internal structure, and the detection accuracy can reach 0.1mm to ensure that there are no obvious internal defects; at the same time, the electron backscatter diffraction (EBSD) technology is used to analyze the microstructure of the blank to detect the grain orientation and size distribution, providing a basis for the adjustment of subsequent process parameters.

[0026] S2. The blank is subjected to medium and low-temperature forming rough machining through a medium and low-temperature processing equipment to obtain a rough blank; the medium and low-temperature forming rough machining in S2 includes medium and low-temperature forging and medium and low-temperature rolling. The forging temperature of the medium and low-temperature forging is 400 - 700°C, the deformation per pass is 10% - 20%, and the forging pressure is 50 - 200MPa. The rolling temperature of the medium and low-temperature rolling is 400 - 700°C, the reduction per pass is 0.5 - 2mm, and the rolling force is 30 - 150kN.

[0027] Specifically, after the blank is constructed, it enters the medium and low-temperature forming rough machining stage. The medium and low-temperature forming rough machining includes two methods: medium and low-temperature forging and medium and low-temperature rolling. The appropriate processing method is selected according to the shape and performance requirements of the product.

[0028] For medium and low temperature forging, a hydraulic forging machine is used for operation. The forging temperature is controlled between 400 - 700 °C according to the characteristics of the silicon carbide aluminum alloy material. Within this temperature range, the plasticity of the material is improved to a certain extent, while maintaining relatively high strength and hardness. Before forging, the die is preheated and a special high-temperature lubricant is applied. Die preheating can reduce the temperature difference between the blank and the die, reducing thermal stress, while the high-temperature lubricant can significantly reduce the friction coefficient, making it easier for the blank to flow and deform during forging. The forging process adopts a multi-pass forging process, with the deformation amount per pass controlled at 10% - 20%. Through multi-pass forging, the microstructure of the material can be gradually changed to make it more dense, while avoiding material cracking caused by excessive single-pass deformation. The forging pressure range is 50 - 200 MPa. The forging pressure is monitored in real time through a pressure sensor to ensure that the pressure is stable within the set range. After forging, a hardness tester is used to detect the hardness of the blank to ensure that the hardness value meets the expected range; the microstructure of the material is observed through a metallographic microscope to ensure tissue uniformity. In addition, a thermal simulation testing machine is used to simulate the forging process to analyze the dynamic recrystallization behavior of the material under different forging process parameters, providing theoretical support for the optimization of the actual forging process.

[0029] For medium and low temperature rolling, a two-high or four-high rolling mill is used for operation. The rolling temperature is also controlled between 400 - 700 °C. The rolls are preheated before rolling and rolling lubricating oil is applied. Preheating the rolls can reduce the thermal shock between the rolls and the blank, while the rolling lubricating oil can reduce the friction during rolling and improve the rolling quality. The rolling process adopts a multi-pass rolling process, with the reduction per pass controlled at 0.5 - 2 mm. By controlling the reduction, the thickness and properties of the sheet can be precisely adjusted. The rolling force range is 30 - 150 kN. The rolling force is monitored through a rolling force sensor to ensure the stability of the rolling process. After rolling, the thickness tolerance of the sheet is detected and controlled within ±0.1 mm. At the same time, the mechanical properties of the sheet are detected to ensure that they meet the performance requirements of rough-machined parts. An on-line shape detection system is used to monitor the shape of the sheet in real time, and the shape is precisely controlled by adjusting parameters such as roll crown and rolling force distribution to ensure the flatness of the sheet.

[0030] S3. The ultrasonic vibration equipment is used to carry out ultrasonic-assisted medium and low temperature machining on the rough blank for secondary forming to obtain the workpiece. In S3, the output frequency of the ultrasonic generator of the ultrasonic vibration equipment is 20 - 40 kHz, the power is 50 - 1500 W, the amplitude on the die surface is 0.01 - 0.1 mm, and the die temperature of the low temperature machining equipment is 240 - 260 °C.

[0031] Specifically, after the rough blank machining is completed, ultrasonic-assisted medium and low-temperature secondary forming is carried out using an ultrasonic vibration device. The ultrasonic vibration device mainly consists of an ultrasonic generator, a transducer, and a horn. The ultrasonic generator outputs high-frequency electrical signals with a frequency of 20 - 40 kHz and a power of 50 - 1500 W. The transducer converts the electrical signals into mechanical vibrations, and the horn further amplifies the vibration amplitude, generating an amplitude of 0.01 - 0.1 mm on the mold surface.

[0032] During the secondary forming process, ultrasonic vibration continuously acts on the contact surface between the mold and the rough blank. On the one hand, ultrasonic vibration can significantly reduce the friction coefficient between the material and the mold. Through experimental tests, the friction coefficient can be reduced by 30% - 50%. By using a friction force sensor to monitor the change in friction force in real time, this enables the material to fill the mold cavity more smoothly during medium and low-temperature forming, reducing the forming pressure and mold wear. On the other hand, the high-frequency vibration of ultrasound can promote atomic diffusion and dislocation movement within the material. In a medium and low-temperature environment, the activity of material atoms is relatively low, while ultrasonic vibration provides additional energy, accelerating the atomic diffusion process, improving the fluidity of the material, and filling the mold cavity more evenly. When manufacturing parts with complex internal cavity structures, ultrasonic assistance can ensure that the material fully fills every corner of the internal cavity, reducing forming defects. The mold temperature of the low-temperature processing equipment is controlled at 240 - 260 °C. The mold temperature is monitored in real time through a temperature sensor, and the mold temperature is precisely regulated through a cooling system or heating device. Within this temperature range, combined with ultrasonic vibration, the forming performance of the material can be better exerted. After forming, the dimensional accuracy of the workpiece is detected, and the dimensional deviation is controlled within ±0.05 mm. The microstructure of the material is observed through a scanning electron microscope to evaluate the improvement effect of ultrasonic vibration on tissue uniformity. The digital image correlation (DIC) technique is used to monitor the deformation behavior of the material during the forming process in real time, and analyze the deformation law of the material under the action of ultrasonic vibration, providing data support for process optimization.

[0033] S4. Perform hot isostatic pressing treatment on the workpiece through a hot isostatic pressing device to obtain a treated part; in S4, the heating rate of the hot isostatic pressing device is 1 - 10 °C / min, the pressure is 50 - 200 MPa, and the vacuum degree is 10 -3 -10 -4 Pa.

[0034] Specifically, after the workpiece is obtained by secondary forming, it is placed in a hot isostatic pressing device for treatment. The hot isostatic pressing device mainly includes a heating system, a pressure system, and a vacuum system.

[0035] The heating system adopts the resistance heating method, and the heating rate can be adjusted within the range of 1 - 10 °C / min, and the temperature control accuracy can reach ±5 °C. Slow heating can avoid the generation of thermal stress in the workpiece due to too rapid temperature change. The pressure system provides pressure through a high-pressure pump, and the pressure range is 50 - 200 MPa, and the pressure fluctuation is controlled within ±1 MPa. The vacuum system uses a combination of a mechanical pump and a molecular pump to pump the vacuum degree in the furnace to 10 -3 -10 -4 Pa. Multiple temperature and pressure sensors are installed inside the equipment to monitor the temperature and pressure at different positions in real time, ensuring uniform temperature and pressure distribution in the furnace. Through the data acquisition and processing system, the sensor data is analyzed and recorded in real time to promptly detect abnormal equipment operation.

[0036] The workpiece is placed into the high-pressure container of the hot isostatic pressing equipment, sealed and evacuated. First, the temperature is raised to a predetermined temperature at a heating rate of 5 - 8 °C / min. This predetermined temperature is determined according to the characteristics of the silicon carbide aluminum alloy material, generally 0.6 - 0.8 times the melting point of the material. Then, the pressure is slowly increased to the set pressure, and the pressure holding time is 2 - 4 h. During the pressure holding process, high temperature and high pressure act on the workpiece together. The high temperature enables the material atoms to obtain sufficient energy for diffusion, and the high pressure promotes the migration of atoms at defects such as pores and shrinkage cavities inside the material to the voids, gradually filling the voids and making the material structure more dense. After processing, the closing condition of the internal pores of the material is observed using a metallographic microscope, the material density is measured using a density detection device, and the density is calculated to ensure that the density reaches more than 99%. A transmission electron microscope (TEM) is used to deeply analyze the microstructure of the material, observe the dislocation configuration, the distribution of second-phase particles, etc., to evaluate the influence of hot isostatic pressing on the microstructure of the material and provide a basis for the research on the performance improvement mechanism.

[0037] S5. The workpiece to be processed is subjected to electrical discharge machining by an electrical discharge machining machine to obtain a precision-machined part; in S5, the output voltage of the pulse power supply of the electrical discharge machining machine is 60 - 120 V, the pulse width is 1 - 50 μs, the pulse interval is 5 - 100 μs, and deionized water is used as the working fluid, and the temperature of the working fluid is 20 - 30 °C.

[0038] Specifically, after the hot isostatic pressing treatment, according to the final precision requirements of the product, the workpiece to be processed is comprehensively measured using a three-dimensional measuring instrument, and combined with the product design drawing, the parts that need to be finely processed are accurately determined, and then processed using an electrical discharge machining machine.

[0039] Select a suitable tool electrode according to the shape of the machining part. For example, use a tungsten electrode for machining micro-holes and a graphite electrode for machining complex curved surfaces. Control the manufacturing accuracy of the electrode within ±0.005 mm. A high-precision electrode can ensure machining accuracy. During the machining process, the output voltage of the pulse power supply is 60 - 120 V, the pulse width is 1 - 50 μs, and the pulse interval is 5 - 100 μs. By adjusting these parameters, precisely control the discharge energy to meet the requirements of different machining parts and materials. For harder silicon carbide aluminum alloy materials, appropriately increase the pulse voltage and width to increase the discharge energy and enhance the material removal effect. During the machining process, use deionized water as the working fluid, and maintain the cleanliness and temperature stability of the working fluid through a circulation system. Control the working fluid temperature at 20 - 30 °C. Deionized water can effectively cool the machining area, carry away the heat generated by the discharge, and prevent the workpiece from deforming or being damaged due to overheating. At the same time, the working fluid can also play a role in flushing the machining debris to ensure the smooth progress of the machining process. After machining, use a scanning electron microscope to observe the microscopic morphology of the machining surface, detect the surface roughness, and use laser-induced breakdown spectroscopy (LIBS) technology to analyze the elemental composition of the machining surface to detect whether impurities are introduced during the machining process and evaluate the impact of machining on the surface properties of the material.

[0040] S6. Perform surface treatment on the finish-machined part through a physical vapor deposition device or a laser surface alloying device to obtain a forging, and establish a collaborative optimization model based on various parameters; in S6, the argon flow rate of the physical vapor deposition device is 20 - 50 sccm, the nitrogen flow rate is 5 - 20 sccm, the substrate bias voltage is -50 to -200 V, the deposition temperature is 200 - 500 °C, the deposition time is 2 - 4 h, the coating thickness is 1 - 5 μm, the laser power of the laser surface alloying device is 1 - 5 kW, the scanning speed is 5 - 20 mm / s, the spot diameter is 0.5 - 2 mm, and the depth of the instantaneous melting of the workpiece surface is 0.1 - 0.5 mm.

[0041] Specifically, after obtaining the finish-machined part through electrical discharge machining, select a physical vapor deposition device or a laser surface alloying device for surface treatment according to the surface performance requirements of the product.

[0042] If a physical vapor deposition equipment is used, the precision-machined part is placed in a vacuum chamber. Using magnetron sputtering technology, with titanium nitride (TiN), titanium carbide (TiC), etc. as the targets, a hard coating is deposited on the surface of the workpiece. During the deposition process, the argon flow rate is controlled at 20 - 50 sccm, the nitrogen flow rate is adjusted according to the coating composition requirements, generally 5 - 20 sccm, the substrate bias voltage is -50 to -200 V, the deposition temperature is 200 - 500 °C, and the deposition time is 2 - 4 h. By adjusting these parameters, the coating thickness is controlled within the range of 1 - 5 μm. The coating composition is analyzed using an X-ray photoelectron spectrometer (XPS), the coating hardness is detected using a nanoindentation instrument to ensure that the coating hardness reaches 20 - 30 GPa, and an atomic force microscope (AFM) is used to analyze the surface morphology of the coating, detect the surface roughness and microdefects of the coating, and evaluate the coating quality. By performing a scratch test on the coating, the adhesion between the coating and the substrate is detected to ensure that the adhesion meets the usage requirements.

[0043] If a laser surface alloying equipment is used, the parts with special requirements for surface corrosion resistance, oxidation resistance, etc. are processed. The laser power is 1 - 5 kW, the scanning speed is 5 - 20 mm / s, and the spot diameter is 0.5 - 2 mm. Before processing, specific alloying elements (such as chromium, molybdenum, etc.) are evenly coated on the surface of the workpiece in the form of powder or coating. During the laser scanning process, the matrix material at a certain depth on the surface of the workpiece is instantaneously melted, with a depth of 0.1 - 0.5 mm, so that the alloying elements and the matrix material are quickly mixed and solidified to form an alloyed layer with special composition and properties. The composition distribution of the alloyed layer is detected using an energy dispersive spectrometer (EDS), and the corrosion resistance of the alloyed layer is tested using an electrochemical workstation to ensure that the corrosion current density in a specific corrosion medium is reduced by more than one order of magnitude. An X-ray diffractometer (XRD) is used to analyze the phase composition of the alloyed layer, study the crystal structure and phase transformation of the alloyed layer, and provide a basis for the study of the performance improvement mechanism.

[0044] In S6, establishing a collaborative optimization model based on various parameters includes the following steps: S601: Take the parameters of additive manufacturing, rough machining of medium and low-temperature forming, secondary forming, hot isostatic pressing treatment, electrical discharge machining, and surface treatment as variables; S602: Construct an objective function with the performance of the forming material and the quality indicators of the forging; S603: Through an intelligent optimization algorithm, construct a model based on the variables and the objective function, solve the model, and obtain the optimized parameters through iterative calculation.

[0045] The properties in S602 include strength, hardness, plasticity, and fatigue life, and the quality indicators include dimensional accuracy, surface roughness, and internal defect rate. The intelligent optimization algorithms in S603 include genetic algorithm, particle swarm optimization algorithm, and simulated annealing algorithm.

[0046] Specifically, the parameters of additive manufacturing (such as laser scanning speed, layer thickness, powder characteristics, etc.), the parameters of medium and low-temperature forming rough machining (such as forging temperature of medium and low-temperature forging, deformation per pass, forging pressure, rolling temperature of medium and low-temperature rolling, reduction per pass, rolling force, etc.), the parameters of secondary forming (such as output frequency, power of ultrasonic generator, amplitude of die surface, die temperature of low-temperature processing equipment, etc.), the parameters in hot isostatic pressing (such as heating rate, pressure, vacuum degree, etc.), the parameters in electrical discharge machining (such as output voltage of pulse power supply, pulse width, pulse interval, working fluid temperature, etc.), the parameters in surface treatment (such as argon flow rate, nitrogen flow rate, substrate bias voltage, deposition temperature, deposition time, coating thickness of physical vapor deposition equipment, laser power, scanning speed, spot diameter, depth of instantaneously melted workpiece surface of laser surface alloying equipment, etc.) are taken as variables.

[0047] Construct an objective function based on the properties of silicon carbide aluminum alloy materials (including strength, hardness, plasticity, fatigue life, etc.) and the quality indicators of forgings (including dimensional accuracy, surface roughness, internal defect rate, etc.), and set the weight coefficients according to actual requirements and the importance of each indicator.

[0048] Through intelligent optimization algorithms (such as genetic algorithm, particle swarm optimization algorithm, simulated annealing algorithm, etc.), construct a model based on the variables and the objective function, and solve the model. Taking the genetic algorithm as an example, encode the variables to form an initial population, calculate the objective function value corresponding to each individual in the population as the fitness, and continuously iterate through genetic operations such as selection, crossover, and mutation. In each iteration, retain the individuals with higher fitness and eliminate the individuals with lower fitness. After multiple generations of evolution, obtain a set of process parameter combinations that make the objective function reach the optimal value, that is, the optimized parameters. These optimized parameters can be applied to actual production to further improve product quality and production efficiency.

[0049] By using an ultra-low plasticity, high-strength and high-hardness material as the forming material, and combining processes such as additive manufacturing, medium and low-temperature forming rough machining, ultrasonic-assisted medium and low-temperature secondary forming, hot isostatic pressing treatment, electrical discharge machining, and surface treatment, the key parameters in each process link are precisely controlled, such as laser power, scanning speed, temperature, pressure, vibration parameters, etc., to achieve the synergistic effect of multiple processes. Through the mutual cooperation of each process, the forming performance of the material is improved, the deformation resistance of the material is reduced, the additive manufacturing constructs a complex blank, providing a basis for subsequent processing; the medium and low-temperature forming rough machining forges or rolls the blank at a suitable temperature to improve the material structure; the ultrasonic-assisted secondary forming reduces the friction coefficient, promotes atomic diffusion, and improves the material fluidity; the hot isostatic pressing treatment eliminates internal defects and makes the material structure dense; the electrical discharge machining realizes high-precision machining; the surface treatment improves the surface performance of the material, thus solving the difficulties that forging precision forgings and difficult-to-deform alloys require extra-large tonnage equipment and poor forming performance, and high-quality, high-precision thin-walled, thin-web, high-ribbed plates and other complex forgings can be formed under loads much lower than those of conventional forging.

[0050] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low temperature and ultra-low plasticity, high strength and high hardness forming technology, characterized in that: The following steps are involved: S1. Select molding materials according to requirements and construct the blank through additive manufacturing; S2, performing medium-low temperature rough forming processing on the blank by medium-low temperature processing equipment, thereby obtaining a rough blank; S3, performing secondary molding of the rough blank by ultrasonic vibration equipment and ultrasonic-assisted medium and low temperature processing equipment to obtain a workpiece; S4, performing hot isostatic pressing treatment on the workpiece by means of a hot isostatic pressing device, thereby obtaining a treated part; S5, performing electric spark machining on the processed part by an electric spark machining machine to obtain a finished part; S6. Perform surface treatment on the finished parts through physical vapor deposition equipment or laser surface alloying equipment to obtain forgings, and establish a collaborative optimization model based on various parameters.

2. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The molding material in S1 includes silicon carbide aluminum alloy material, and the additive manufacturing to build the blank specifically includes the following steps: S101. Design a product model according to the requirements, and prepare the molding material into powder by gas atomization method; S102, using plasma treatment technology to introduce active groups on the surface of the powder to perform surface modification on the powder; S103, using a selective laser melting device equipped with a fiber laser, constructing in a closed molding cavity filled with argon gas, and using an adaptive scanning strategy according to the structural complexity of different parts of the model. The scanning path adopts a partitioned alternating scanning method to construct the blank.

3. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 2, characterized in that: The power of the fiber laser is 400-1000W, the oxygen content of the closed molding cavity is controlled below 0.1%, the laser scanning speed of the laser melting equipment is 800-1200mm / s, and the layer thickness is 0.02-0.05mm.

4. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The medium-low temperature forming rough processing in S2 includes medium-low temperature forging and medium-low temperature rolling. The forging temperature of the medium-low temperature forging is 400-700°C, the deformation amount of each pass is 10%-20, and the forging pressure is 50-200MPa. The rolling temperature of the medium-low temperature rolling is 400-700°C, the reduction amount of each pass is 0.5-2mm, and the rolling force is 30-150kN.

5. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The ultrasonic generator of the ultrasonic vibration equipment in S3 has an output frequency of 20-40kHz, a power of 50-1500W, a mold surface amplitude of 0.01-0.1mm, and a mold temperature of the low-temperature processing equipment of 240-260°C.

6. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The heating rate of the hot isostatic pressing equipment in S4 is 1-10°C / min, the pressure is 50-200MPa, and the vacuum degree is 10-3-10-4Pa.

7. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The output voltage of the pulse power supply of the EDM machine tool in S5 is 60-120V, the pulse width is 1-50μs, the pulse interval is 5-100μs, and deionized water is used as the working fluid with a working fluid temperature of 20-30°C.

8. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The argon flow rate of the physical vapor deposition equipment in S6 is 20-50sccm, the nitrogen flow rate is 5-20sccm, the substrate bias is -50 to -200V, the deposition temperature is 200-500°C, the deposition time is 2-4h, the coating thickness is 1-5μm, the laser power of the laser surface alloying equipment is 1-5kW, the scanning speed is 5-20mm / s, the spot diameter is 0.5-2mm, and the instantaneous melting depth of the workpiece surface is 0.1-0.5mm.

9. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 1, characterized in that: The establishment of the collaborative optimization model according to various parameters in S6 includes the following steps: S601, taking parameters of additive manufacturing, parameters of medium and low temperature rough processing, parameters of secondary molding, parameters in hot isostatic pressing, parameters in electric discharge machining, and parameters in surface treatment as variables; S602, constructing an objective function based on the properties of the forming material and the quality index of the forging; S603, constructing a model based on variables and objective functions through intelligent optimization algorithms, solving the model, and obtaining optimization parameters through iterative calculations.

10. The ultra-low plasticity, high strength, high hardness, medium and low temperature forming technology according to claim 9, characterized in that: The performance in S602 includes strength, hardness, plasticity, and fatigue life; the quality indicators include dimensional accuracy, surface roughness, and internal defect rate; and the intelligent optimization algorithm in S603 includes genetic algorithm, particle swarm optimization algorithm, and simulated annealing algorithm.

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