A feeding, stirring and in-situ temperature measuring integrated device and method for preparing magnesium-lithium-based composite materials

Abstract

The application relates to the technical field of metal matrix composite material preparation, in particular to a feeding, stirring and in-situ temperature measuring integrated device and method for magnesium-lithium matrix composite material preparation. The stirring and feeding rod is arranged in the crucible in a lifting mode, a thermocouple channel is arranged at a position close to the inner wall of the crucible, the thermocouple channel is located between the crucible wall and the working position of the stirring paddle, does not contact the crucible wall and does not affect the normal work of the stirring paddle; the stirring paddle and the feeding device are fixedly arranged on the stirring and feeding rod, and the feeding device is located at the gap between the stirring paddles; the temperature sensing end of the thermocouple is arranged in the thermocouple channel, and the thermocouple compensation lead is led out from the upper end of the crucible and is flush with the upper edge of the furnace body. The application solves the problems that the existing vacuum melting furnace has high vacuum leakage risk and great safety hidden danger when preparing magnesium-lithium and other active metal matrix composite materials due to switching of the feeding, stirring and temperature measuring functions, and the traditional stirring paddle cannot provide longitudinal stirring force and cannot enhance the uneven dispersion of the reinforcing phase.

Description

Technical Field

[0001] This invention mainly relates to the field of preparation and processing technology of metal matrix composites (MMCs), specifically an integrated device and method for feeding, stirring and in-situ temperature measurement for the preparation of magnesium-lithium based composites, which is particularly suitable for the preparation of ultra-lightweight and high-strength structural materials in aerospace, defense and military industries and high-end automotive industries. Background Technology

[0002] Magnesium-lithium (Mg-Li) alloys are currently the lowest density structural metallic materials, possessing advantages such as high specific strength and high specific stiffness, and have broad application prospects in aerospace, electronic packaging, and other fields. However, pure Mg-Li alloys still have shortcomings in absolute strength, wear resistance, high-temperature creep resistance, and elastic modulus, limiting their application under certain working conditions. To overcome these shortcomings, the preparation of Mg-Li-based composite materials by adding reinforcing phases such as ceramic particles, whiskers, or fibers to improve their mechanical properties has become a research hotspot in the field of materials science.

[0003] Among numerous manufacturing processes, stir casting is widely used due to its simplicity, low cost, and scalability. This method generates eddies in molten metal through mechanical stirring, entraining and dispersing reinforcing phase particles, which then solidify. However, for the specific system of magnesium-lithium alloys, existing stir casting equipment and processes face significant technical challenges and safety hazards.

[0004] Existing preparation processes (such as those for preparing magnesium-lithium based composites) have the following drawbacks:

[0005] 1. Safety Hazards and Gas Leakage Risks: Magnesium-lithium alloys are extremely chemically reactive in their molten state at high temperatures (e.g., 750°C). During the smelting process, the feeding chamber, stirring chamber, and temperature measuring chamber need to be used sequentially or simultaneously. Frequent switching between functional chambers (e.g., raising the temperature measuring rod, inserting the stirring and feeding rod, opening the feeding chamber) and the insertion and removal of components can severely compromise the furnace's seal, leading to gas leakage. This not only increases the oxidation and burn-off of the magnesium-lithium alloy but also poses serious safety hazards.

[0006] 2. Low stirring efficiency: Traditional stirring blades typically have their working surface perpendicular to the melt surface (at 90°). This design primarily provides radial (lateral) shear force, making it difficult to form effective longitudinal (vertical) circulation within the crucible. This causes the added reinforcing phase (especially particles with large density differences) to easily aggregate at the top of the melt or deposit at the bottom, resulting in uneven distribution and severely affecting the final properties of the composite material.

[0007] 3. Inaccurate temperature measurement: Traditional temperature measuring devices mainly come in two types: one is an insertion-type thermocouple measuring chamber, whose measuring point is usually fixed at the center or top of the melt, making it difficult to reflect the actual temperature at different locations within the crucible. Furthermore, temperature measurement cannot be performed during stirring and feeding, and there is a risk of leakage during insertion and removal. The other type places the thermocouple on the furnace wall. While this does not affect stirring and sealing, it measures the ambient temperature rather than the melt temperature, making it difficult to achieve precise temperature control during the melting process.

[0008] Patent CN101219471A discloses an integrated magnesium-based composite material preparation device and method. In this device, the feeding, stirring, and temperature measurement functions are independent. Temperature measurement relies on an insertable thermocouple and a side-wall temperature measuring hole. Frequent insertion and removal of the thermocouple or fixing of the side-wall temperature measuring hole leads to poor sealing performance, easily causing gas leakage and oxidation burn-off. Furthermore, it cannot achieve multi-point real temperature monitoring of the melt, and the dispersion of the reinforcing phase relies on gas pressure infiltration, resulting in insufficient uniformity. Patent CN109280785A discloses a lithium-magnesium alloy production device and method. Its feeding method involves separately adding lithium-magnesium raw materials, with the temperature measuring thermocouple fixed to the internal side wall of the melting device. This only monitors the local ambient temperature and cannot reflect the real temperature at different depths of the melt. Moreover, the stirring blades lack angle adjustment functionality, making it difficult to form longitudinal circulation and failing to solve the problem of reinforcing phase sedimentation or floating. Patent CN105238943A discloses an in-situ strengthening preparation method and apparatus for high-strength, high-plasticity cast magnesium-based composite materials. This apparatus generates the reinforcing phase in situ through nitrogen purging. Stirring relies on a vent pipe driving blades, achieving only simple mechanical stirring and failing to create a three-dimensional flow field. Temperature measurement uses a single thermocouple inserted into the melt, preventing multi-point real-time monitoring. Sealing performance is affected by the vertical movement of the vent pipe, making leakage likely. Patent CN111304505A discloses a method for preparing micro / nano-scale reinforcing hybrid magnesium-lithium-based composite materials. Its feeding relies on the spraying of a gas-powder mixture, easily leading to oxidation and burn-off of the reinforcing material. Stirring requires a combination of ultrasonic treatment and variable-speed stirring to barely improve dispersibility, resulting in complex operation and limited effectiveness. The patent with publication number CN108193109A proposes a magnesium-lithium alloy composite material with a refined dual-phase structure containing ZrO2 and its preparation method. ZrO2 powder is prone to agglomeration or sedimentation, with poor dispersion uniformity. At the same time, it lacks an effective sealing design, which cannot prevent the volatilization of lithium and the oxidation of the melt.

[0009] Therefore, there is an urgent need to design a new type of device to solve the problems of poor sealing, high safety risks, uneven mixing, and inconvenient and inaccurate temperature measurement in the existing technology. Summary of the Invention

[0010] The purpose of this invention is to provide an integrated device and method for feeding, stirring, and in-situ temperature measurement in the preparation of magnesium-lithium-based composite materials, in order to overcome the technical problems of high risk of air leakage, poor stirring effect, and difficulty in temperature measurement in the prior art. It is designed for reinforcing phase composite of highly active, flammable and explosive magnesium-lithium (Mg-Li) alloy matrix, and integrates feeding, three-dimensional stirring and in-situ temperature measurement functions to improve the safety, sealing and convenience of temperature measurement in the vacuum melting process of magnesium-lithium-based composite materials, and achieve uniform dispersion of reinforcing particles.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] An integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials includes a furnace body, a crucible, a stirring and feeding rod, and a feeding device. A heating resistance wire is installed inside the furnace body. The crucible is placed inside the furnace body, and the stirring and feeding rod is vertically and flexibly positioned inside the crucible. One or more thermocouple channels are provided near the inner wall of the crucible, extending from the upper end to the bottom region. The thermocouple channels are located between the crucible wall and the working position of the stirring paddle, without contacting the crucible wall and without affecting the normal operation of the stirring paddle. Stirring paddles and a feeding device are fixedly installed on the stirring and feeding rod, with the feeding device located in the gap between the stirring paddles. The temperature-sensing end of the thermocouple is placed inside the thermocouple channel, and the thermocouple compensation wire is led out from the upper outer edge of the crucible and flush with the upper edge of the furnace body.

[0013] The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials has at least two rows of stirring blades arranged from top to bottom along the stirring and feeding rod, with each row including no less than four evenly distributed stirring blades.

[0014] The aforementioned integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials has a stirring blade fixed to the stirring and feeding rod via an angle adjustment mechanism. The angle adjustment mechanism adjusts the blade's angle of attack to a range of 0~±90°.

[0015] The aforementioned integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials has a stirring blade in the shape of a square, spiral, or other customized shape. When the stirring and feeding rod rotates, the stirring blade can simultaneously apply radial shear force and longitudinal thrust to the melt, forcing the melt to generate a three-dimensional flow of up and down tumbling. This causes the upper row of blades to press down and the lower row of blades to lift up, forming a longitudinal circulation. This uniformly entrains the reinforcing phase particles released from the feeding device into the entire melt, promoting the uniform dispersion of the reinforcing phase particles.

[0016] The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials has a thermocouple channel made of stainless steel, nickel-based alloy, ceramic material, or tungsten alloy, and in the shape of I-shape, L-shape, or other customized shape.

[0017] The aforementioned integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials uses a three-section composite channel for the thermocouple channel, consisting of a vertical section, a bottom horizontal section, and a top right-angle turning section. The main body of the channel extends in an L-shape along the inner wall of the crucible. The vertical section extends upward close to the side wall of the crucible, and the horizontal section extends close to the bottom of the crucible. At the same time, a right-angle bend is added in the upper part of the channel near the top of the crucible, causing the top of the channel to turn and approach the outer edge of the upper end of the crucible. The bend section connects to the thermocouple channel fixing base.

[0018] The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials places at least one thermocouple at different points in the thermocouple channel, so that the temperature sensing end of the thermocouple can sense the temperature of the melt at different points in real time and in situ.

[0019] The aforementioned integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials includes a feeding device that provides continuous clamping force, such as a mechanical gripper, a perforated particle adder, or other similar feeding device, for placing a reinforcing phase material package wrapped in metal foil or a preform containing the reinforcing phase. The mechanical gripper is suitable for continuous clamping of various reinforcing phase material packages and preforms, while the perforated particle adder is suitable for particulate reinforcing phases.

[0020] An integrated method for feeding, stirring, and in-situ temperature measurement in the preparation of magnesium-lithium-based composite materials includes the following steps:

[0021] (1) After adding the base alloy material and heating to the melting point, the temperature of different points of the melt is monitored in real time by thermocouples. During the melting process, the overall temperature of the melt is controlled by detecting the temperature at different locations, and the process window is precisely controlled to prevent excessive reaction or insufficient temperature.

[0022] (2) Lower the stirring and feeding rod so that the reinforcing phase carried by the feeding device is immersed in the melt;

[0023] (3) Start the stirring and feeding rod to rotate. Adjust the angle of attack of the stirring blade to make the melt flow in three dimensions. The reinforcing phase is broken up by the high-speed shear zone and entrained into the melt.

[0024] (4) After mixing is complete, stop adding materials and mixing, and then proceed with casting.

[0025] The integrated feeding, stirring, and in-situ temperature measurement method for preparing magnesium-lithium-based composite materials, when using two or more feeding devices, selects different feeding positions from top to bottom according to the density of the reinforcing phase, reducing the floating or settling of the reinforcing phase caused by density factors.

[0026] The design concept of this invention is:

[0027] This invention relates to a magnesium-lithium-based composite material that integrates feeding, three-dimensional stirring, and in-situ multi-point temperature measurement into a single device, avoiding seal damage caused by switching between functional components. A crucible and a stirring and feeding rod are used. The crucible has thermocouple channels near its inner wall for inserting multiple thermocouples. The thermocouple lines extend along the upper edge of the crucible wall, enabling real-time in-situ temperature measurement of the melt at multiple points without interfering with stirring. The stirring and feeding rod has two or more rows of blades with adjustable blade angles. A feeding device (mechanical gripper or perforated particle adder) is integrated between the blades to hold the reinforcing phase material package wrapped in matrix alloy foil. This invention, through its "rod-integrated feeding" and "multi-point in-situ real-time temperature measurement" design, avoids gas leakage caused by frequent changes in the feeding and temperature measurement chambers during smelting, as well as the risk of spontaneous combustion of residual melt on the feeding / temperature measurement device upon contact with air. Simultaneously, the variable-angle blades provide an axial flow field, achieving high safety, high efficiency, and high uniformity in the preparation of the magnesium-lithium-based composite material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. Improved safety and purity: The feeding function (via a feeding device) and stirring function (via a paddle) are integrated into a single stirring and feeding rod, while temperature measurement is achieved through a thermocouple channel near the crucible wall. The entire melting process requires only a dynamic seal (rotary seal) on the stirring and feeding rod, eliminating the need to remove the temperature measuring rod and reinsert it, or open the feeding port, as required by traditional equipment. Reinforcing phase particles can be directly fed into the melt through the stirring and feeding rod under vacuum or a protective atmosphere, significantly reducing leakage and oxidation caused by switching functional components. This protects the highly active magnesium-lithium melt from oxidation and greatly enhances the safety of the melting process.

[0030] 2. Achieved uniform particle dispersion: Employs two or more rows of blades with adjustable blade angles. By setting different combinations of angles of attack (such as upper row pressing down, lower row lifting up), a strong longitudinal circulation can be generated, and particles released from the middle of the stirring blades can be quickly entrained into this complex flow field, effectively overcoming the settling or floating of particles caused by density differences, and achieving uniform dispersion of the reinforcing phase.

[0031] 3. Accurate and non-interfering temperature measurement: By setting up a dedicated thermocouple channel inside the crucible and installing multiple thermocouples, the temperature sensing ends of the thermocouples are located at different positions in the melt, enabling real-time, in-situ monitoring of the true temperature of the melt at multiple points. The data response is sensitive, which helps to accurately control the process temperature without affecting the operation of the stirring blades or the furnace seal.

[0032] 4. Compact structure and integrated functions: The integrated design simplifies the structure of the vacuum furnace, reduces failure points, improves the space utilization and reliability of the equipment, and meets the needs of large-scale production of magnesium-lithium based composite materials. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention (longitudinal cross-section, taking two rows of stirring blades, one row of feeding devices and one thermocouple channel as an example).

[0034] Figure 2 yes Figure 1 A schematic diagram of the structure of the mixing and feeding rod 6 (taking two rows of mixing blades and one row of feeding devices as an example).

[0035] Figure 3 This is a schematic diagram of a perforated particle additive.

[0036] Figure 4 This is a schematic diagram of the mechanical gripper.

[0037] Figure 5 This is a schematic diagram of the thermocouple positioning device of the present invention.

[0038] Figure 6 This is a side view cross-sectional diagram of the crucible and thermocouple wiring in this invention (taking one thermocouple channel and two thermocouple temperature measurement points as an example).

[0039] The markings in the diagram are as follows: 1. Furnace body, 2. Heating resistance wire, 3. Crucible, 4. Thermocouple channel, 41. Thermocouple compensation wire, 5. Thermocouple, 6. Stirring and feeding rod, 61. Stirring blade, 62. Feeding device, 63. Angle adjustment mechanism, 621. Perforated particle feeder, 622. Mechanical gripper, 7. Thermocouple channel fixing base, 8. Vacuum chamber. Detailed Implementation

[0040] like Figures 1-6 As shown, this invention proposes an integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials, comprising a furnace body 1, a heating resistance wire 2, a crucible 3, and a stirring and feeding rod 6, with the specific structure as follows:

[0041] The vacuum chamber 8 contains a furnace body 1 and a crucible 3 placed inside the furnace body 1. A heating resistance wire 2 is installed between the inner wall of the furnace body 1 and the outer wall of the crucible 3. A thermocouple channel 4 is fixed inside the crucible 3, which is close to the inner wall of the crucible 3 and does not affect the internal space of the crucible. A thermocouple 5 is inserted through this channel to monitor the temperature of the melt. Multiple thermocouple channels of different shapes can be set as needed to increase the number of thermocouple temperature measuring points. A thermocouple channel fixing base 7 is provided on the edge of the furnace body 1 to fix the position of the thermocouple. The wire of the thermocouple 5 is led out from the upper outer edge of the crucible 3, which is flush with the upper edge of the furnace body 1, facilitating sealing and exiting the vacuum chamber. A stirring and feeding rod 6 extends from above the crucible 3. The stirring and feeding rod 6 integrates stirring and feeding functions. The stirring blade 61 is fixed to the stirring and feeding rod 6 by an angle adjustment mechanism 63, and its angle of attack is adjustable.

[0042] 1. Stirring and Feeding Rod: The stirring and feeding rod 6 extends vertically through the top of the vacuum chamber 8. The lower end of the stirring and feeding rod 6, which extends into the crucible 3, is fitted with stirring blades 61 and a feeding device 62. The stirring and feeding rod 6 can move up and down with the lifting mechanism. The feeding device 62 is located on the stirring and feeding rod 6 between every two rows of stirring blades 61. The specific form of the feeding device 62 is a mechanical gripper 622 that provides continuous clamping force, or a perforated particle adder 621, or other similar feeding device, used to place reinforcing phase material packages wrapped with metal foil (such as Mg foil, Al foil, or Zn foil) or preforms containing reinforcing phases. Among them, the mechanical gripper 622 is suitable for continuous clamping of various reinforcing phase material packages and preforms, and the perforated particle adder 621 is suitable for particulate reinforcing phases (such as SiC, Al2O3), with the aperture selected from 0.1 to 1 mm according to the particle size. Moreover, the feeding device 62 is located in the middle of every two rows of stirring blades 61, which allows the reinforcing phase to be directly fed into the area with the strongest shear force. As soon as it leaves the discharge port, it is dispersed by the high-speed rotating stirring blades 61 and rolled into the melt, reducing the agglomeration of particles in the melt.

[0043] 2. Multi-dimensional stirring blades: The outer wall of the stirring and feeding rod 6 is equipped with at least two rows of stirring blades 61, with each row generally having no fewer than four blades. Crucially, the angle of attack (i.e., the angle between the working plane of the blade and the horizontal plane) of these blades is adjustable. By adjusting the angle of attack, different flow fields can be achieved. When the stirring and feeding rod 6 rotates, these "tilted" blades can simultaneously apply radial shear force and longitudinal thrust (axial force) to the melt, forcing the melt to produce a three-dimensional flow of up-and-down tumbling. It can even cause the upper row of blades to press down and the lower row to lift, forming a strong longitudinal circulation. This uniformly entrains the reinforcing phase particles released from the feeding device into the entire melt, greatly promoting the uniform dispersion of the reinforcing phase.

[0044] 3. Multi-point in-situ real-time temperature measurement system: A thermocouple channel 4 is installed inside the crucible 3, located between the inner wall of the crucible 3 and the working area of ​​the stirring blade 61. The material of the thermocouple channel 4 can be selected from stainless steel, nickel-based alloys, ceramic materials, and tungsten alloys, etc., depending on the requirements. This channel does not affect the operation of the stirring blade 61. Usually, no less than one thermocouple 5 is placed at different points in this channel, so that multiple temperature measuring endpoints (thermal junctions) of the thermocouples can sense the temperature of the melt at different points in real time and in-situ. The leads of the thermocouple 5 are led upward along the channel, out from the upper edge of the crucible 3, and flush with the upper edge of the furnace body 1, ensuring the complete sealing of the side wall of the furnace body 1. A thermocouple channel fixing base 7 is provided at the edge of the furnace body 1 to fix the position of the thermocouples.

[0045] like Figure 1 As shown, the thermocouple channel 4 can be a three-section composite channel consisting of a vertical section, a bottom horizontal section, and a top right-angle turning section. The main body of the channel extends in an L-shape along the inner wall of the crucible (the vertical section extends upward close to the side wall of the crucible, and the horizontal section extends close to the bottom of the crucible). At the same time, an additional right-angle bend is added at the upper part of the channel (the area near the top of the crucible), so that the top of the channel turns and is close to the upper outer edge of the crucible 3. Finally, it is connected to the thermocouple channel fixing base 7 through this bend. The sensing end of the thermocouple 5 is placed inside the thermocouple channel 4, which can measure the temperature at multiple points such as different melt depths and the center position of the bottom of the melt. The thermocouple compensation wire 41 (lead wire) is led out from the upper outer edge of the crucible 3 and is flush with the upper edge of the furnace body 1.

[0046] like Figures 1-6 As shown, the working process of this invention is as follows:

[0047] (1) Place the Mg-Li matrix alloy ingot into crucible 3, evacuate and fill with argon gas for protection.

[0048] (2) Start the furnace body 1 to heat up the Mg-Li matrix alloy to the predetermined temperature (e.g., 750℃) to completely melt it.

[0049] (3) The temperature of the melt is monitored in real time by thermocouple 5.

[0050] (4) Lower the stirring and feeding rod 6 to immerse it in the melt.

[0051] (5) At the same time, the reinforcing phase material bag carried by the feeding device 62 is immersed in the melt, and the metal foil wrapped with the reinforcing phase melts rapidly in the high temperature melt, releasing the reinforcing phase.

[0052] (6) Start the stirring and feeding rod 6 to rotate, and through the pre-adjusted blade angle of the angle adjustment mechanism 63, make the melt generate strong longitudinal and radial mixing.

[0053] (7) After the metal foil wrapped around the reinforcing phase particles melts, the reinforcing phase particles are released into the high-speed shear zone in the middle of the stirring blade 61, where they are quickly dispersed and entrained into the melt.

[0054] (8) Two or more rows of stirring blades 61 with specific angles make the melt generate strong three-dimensional flow, ensuring uniform dispersion of the reinforcing phase.

[0055] (9) During this period, the multi-point thermocouple 5 monitors the melt temperature in real time, accurately controls the process window, and prevents over-reaction or insufficient temperature.

[0056] (10) After mixing, pull out the mixing and feeding rod 6 and cast.

[0057] The present invention will be further described below with reference to specific embodiments. It is worth noting that the embodiments provided are only for illustrating the implementation of the present invention and do not constitute a limitation on the present invention. The scope of protection of the present invention is not limited to the specific content shown in the following embodiments.

[0058] Example 1:

[0059] In this embodiment, the process parameters for preparing SiC-reinforced Mg-Li based composite materials are as follows:

[0060] Feeding method: The reinforcing phase particles are wrapped with Mg foil, because SiC has a relatively high density compared to the matrix (3.2 g / cm³). 3 Therefore, it is placed on the mechanical gripper located in the middle or upper part of the mixing and feeding rod.

[0061] Melting temperature: 730℃ (SiC is prone to react with the matrix, so a lower temperature needs to be controlled), then cool down to the required specific temperature of 640℃, and add the required particles.

[0062] Stirring parameters: Stirring speed 100 rpm, blade angle of attack set to 60°. This angle setting is intended to generate strong eddies and upward longitudinal thrust, reducing the settling of denser reinforcing phase particles at the bottom of the melt.

[0063] Temperature measurement location: Using the multi-point in-situ temperature measurement channel inside the crucible, the sensing end of one thermocouple can be set at 1 / 3 of the melt depth (calculated based on the actual melting mass), and the other thermocouple can be placed in the center area of ​​the bottom of the melt to monitor the average temperature of the melt body.

[0064] Target results: The use of a 60° stirring blade reduces particle settling of the reinforcing phase and results in more uniform dispersion of the reinforcing phase. In-situ temperature measurement enables temperature detection at different melt locations during feeding, facilitating process control and reducing the degree of reaction between the reinforcing phase and the matrix.

[0065] Example 2:

[0066] In this embodiment, the process parameters for preparing Al2O3 particle-reinforced Mg-Li-Al composite materials are as follows:

[0067] Feeding method: The matrix contains Al, and the reinforcing phase particles are wrapped with Al foil. This is because Al₂O₃ has a relatively high density compared to the matrix (3.8 g / cm³). 3 Therefore, the perforated particle additive is placed near the top of the mixing and feeding rod.

[0068] Melting temperature: 720℃ (Al2O3 readily reacts with the matrix, so a lower temperature must be controlled), then cool down to the required specific temperature of 620℃, and add the required particles.

[0069] Stirring parameters: stirring speed 120 rpm, blade angle of attack set to 45°. This angle setting is intended to generate vortices with equal lateral and longitudinal thrust, reducing the settling of denser reinforcing phase particles at the bottom of the melt.

[0070] Temperature measurement location: Using the multi-point in-situ temperature measurement channel inside the crucible, the sensing ends of two thermocouples can be set at 1 / 3 and 2 / 3 of the melt depth (calculated based on the actual melting mass), and the third thermocouple is placed in the center area of ​​the bottom of the melt to monitor the temperature at different locations of the melt body.

[0071] Target results: The use of 45° stirring blades significantly reduces the settling of reinforcing phase particles, resulting in more uniform dispersion. In-situ temperature measurement enables temperature detection at different melt locations during feeding, facilitating process control and reducing the degree of reaction between the reinforcing phase and the matrix.

[0072] Example 3:

[0073] In this embodiment, the process parameters for the carbon fiber reinforced magnesium matrix composite material are as follows:

[0074] Feeding method: The reinforcing phase is wrapped with Mg foil. Since the carbon fiber has a density that is similar to or lower than that of the matrix (compared to magnesium matrix), it is placed on a mechanical gripper located in the middle or lower part of the stirring feed rod.

[0075] Melting temperature: 750℃, then cool down to the required specific temperature of 680℃, and add the required reinforcing phase.

[0076] Stirring parameters: Due to the high shear stress which can break the fiber structure, the stirring speed is set to 80 rpm. The carbon fiber density is similar to or lower than that of the matrix, and the blade angle of attack can be set to -45° for the upper row, 90° for the middle row, and 45° for the lower row. This angle setting is designed to provide an up-and-down circulating vortex, allowing the carbon fiber to be more evenly dispersed in the melt.

[0077] Temperature measurement location: Using the multi-point in-situ temperature measurement channel inside the crucible, the sensing end of one thermocouple can be set at 1 / 2 of the melt depth (calculated according to the actual melting mass), and the other thermocouple can be placed in the center area of ​​the bottom of the melt to monitor the average temperature of the melt body.

[0078] Target effect: The composite stirring blades with attack angles of -45°, 90°, and 45° are used to circulate and stir the reinforcing phase in the melt, resulting in more uniform dispersion. In-situ temperature measurement enables temperature detection at different melt locations during the feeding process, facilitating process control.

[0079] The results show that the present invention can solve the problems of high risk of vacuum leakage and significant safety hazards caused by switching between feeding, stirring and temperature measuring chambers in existing vacuum melting furnaces when preparing active metal-based composite materials such as magnesium and lithium, as well as the problems of traditional stirring blades being unable to provide longitudinal stirring force and uneven dispersion of reinforcing phase.

[0080] The above embodiments are merely recommendations for process parameters to achieve the corresponding target effects of the present invention, and are not intended to limit the scope of the present invention. Any equivalent substitutions or modifications made using the concepts and technical solutions of the present invention should fall within the protection scope of the present invention.

Claims

1. An integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials, characterized in that, The system includes a furnace body, a crucible, a stirring and feeding rod, and a feeding device. A heating resistance wire is installed inside the furnace body. The crucible is placed inside the furnace body, and the stirring and feeding rod is vertically adjustable within the crucible. One or more thermocouple channels are located near the inner wall of the crucible, extending from the top to the bottom region. These thermocouple channels are positioned between the crucible wall and the working position of the stirring paddle, without contacting the crucible wall or affecting the normal operation of the stirring paddle. Stirring paddles and a feeding device are fixedly mounted on the stirring and feeding rod, with the feeding device located in the gap between the stirring paddles. The sensing end of the thermocouple is placed within the thermocouple channel, and the thermocouple compensation wire extends from the upper outer edge of the crucible and is flush with the upper edge of the furnace body.

2. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 1, characterized in that, The stirring blades are arranged in at least two rows from top to bottom along the stirring and feeding rod, with each row including no less than four evenly distributed stirring blades.

3. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 2, characterized in that, The stirring blades are fixed to the stirring and feeding rod by an angle adjustment mechanism, which adjusts the blade angle of attack to a range of 0~±90°.

4. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 3, characterized in that, The stirring blades are square, spiral, or other custom shapes. When the stirring feed rod rotates, the stirring blades can simultaneously apply radial shear force and longitudinal thrust to the melt, forcing the melt to generate a three-dimensional flow of up and down tumbling. This causes the upper row of blades to press down and the lower row of blades to lift up, forming a longitudinal circulation. This uniformly entrains the reinforcing phase particles released from the feeding device into the entire melt, promoting the uniform dispersion of the reinforcing phase particles.

5. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium-based composite materials according to claim 1, characterized in that, The thermocouple channel is made of stainless steel, nickel-based alloy, ceramic material or tungsten alloy, and its shape is I-shaped, L-shaped or other custom shapes.

6. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 5, characterized in that, The thermocouple channel adopts a three-section composite channel consisting of a vertical section, a bottom horizontal section, and a top right-angle turning section. The main body of the channel extends in an L-shape along the inner wall of the crucible. The vertical section extends upward close to the side wall of the crucible, and the horizontal section extends close to the bottom of the crucible. At the same time, a right-angle bend is added in the upper part of the channel near the top of the crucible, so that the top of the channel turns and is close to the outer edge of the upper end of the crucible. The channel is connected to the thermocouple channel fixing base through this bend.

7. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 1, characterized in that, Place at least one thermocouple at different points in the thermocouple channel so that the sensing end of the thermocouple can sense the temperature of the melt at different points in real time and in situ.

8. The integrated feeding, stirring, and in-situ temperature measurement device for the preparation of magnesium-lithium based composite materials according to claim 1, characterized in that, The specific form of the feeding device is a mechanical gripper or a perforated particle additive or other similar feeding device that provides continuous clamping force, used to place a reinforcing phase material package wrapped with metal foil or a preform containing a reinforcing phase; wherein, the mechanical gripper is suitable for continuous clamping of various reinforcing phase material packages and preforms, and the perforated particle additive is suitable for particulate reinforcing phases.

9. A method for integrating feeding, stirring, and in-situ temperature measurement in the preparation of magnesium-lithium based composite materials using the apparatus described in any one of claims 1 to 8, characterized in that, Includes the following steps: (1) After adding the base alloy material and heating to the melting point, the temperature of different points of the melt is monitored in real time by thermocouples. During the melting process, the overall temperature of the melt is controlled by detecting the temperature at different locations, and the process window is precisely controlled to prevent excessive reaction or insufficient temperature. (2) Lower the stirring and feeding rod so that the reinforcing phase carried by the feeding device is immersed in the melt; (3) Start the stirring and feeding rod to rotate. Adjust the angle of attack of the stirring blade to make the melt flow in three dimensions. The reinforcing phase is broken up by the high-speed shear zone and entrained into the melt. (4) After mixing is complete, stop adding materials and mixing, and then proceed with casting.

10. The integrated method for feeding, stirring, and in-situ temperature measurement in the preparation of magnesium-lithium based composite materials according to claim 9, characterized in that, When there are two or more feeding devices, different feeding positions are selected from top to bottom according to the density of the reinforcing phase, from large to small, to reduce the floating or settling of the reinforcing phase caused by density factors.

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