Multi-pass forging method for aluminum alloy sheath of particle reinforced aluminum matrix composite

Abstract

The invention relates to the technical field of aluminum matrix composite forging, in particular to a multi-pass forging method for an aluminum alloy sheath of a particle reinforced aluminum matrix composite. In order to solve the problem that efficient, stable and crack-free forging is difficult to realize due to the characteristics of poor plasticity, defect sensitivity, stress concentration and the like in the forging process of the particle reinforced aluminum matrix composite, the method comprises the following steps of: sheathing a particle reinforced aluminum matrix composite billet by adopting an aluminum alloy, and forging the sheathed particle reinforced aluminum matrix composite, the forging is one-way forging or multi-way forging. According to the method, the particle reinforced aluminum matrix composite forge piece with good surface appearance can be obtained.

Description

Technical Field

[0001] This invention relates to the field of aluminum matrix composite forging technology, specifically to a multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composites. Background Technology

[0002] As a new type of advanced structural material, particle-reinforced aluminum matrix composites have demonstrated irreplaceable strategic value in the field of high-end equipment due to their excellent comprehensive performance. This material not only has the mechanical advantages of high specific strength and high specific modulus, but also has excellent physical properties such as wear resistance, low expansion, and high thermal conductivity. Therefore, it is widely used in the manufacturing of core components of key equipment such as load-bearing structures for manned spaceflight, high-precision weapon equipment components, and nuclear reactor shielding components, becoming an important basic material supporting the development of high-end equipment.

[0003] Currently, the main methods for preparing particle-reinforced aluminum matrix composites include powder metallurgy and stir casting. However, the composite ingots obtained by these methods generally suffer from low density and poor plasticity, making it difficult to directly meet the performance requirements of high-end equipment components. They typically require further improvement in microstructure and properties through plastic forming processes. Among various plastic forming processes, forging has become an important choice for the plastic processing of particle-reinforced aluminum matrix composites due to its advantages such as simple process, low production cost, and ability to produce components of different shapes and sizes.

[0004] However, the forging process of particle-reinforced aluminum matrix composites faces severe challenges. On the one hand, the addition of reinforcing particles significantly reduces the plastic deformation capacity of the aluminum matrix, making the material prone to stress concentration during forging. On the other hand, defects such as porosity and looseness inside the billet further increase the difficulty of plastic processing, causing the composite billet to be prone to cracking during forging, which seriously affects the forming quality and production efficiency of the product and restricts the large-scale application of particle-reinforced aluminum matrix composites in the field of high-end equipment.

[0005] Currently, there are few patent studies on forging processes for particle-reinforced aluminum matrix composites, and existing technologies still have significant shortcomings. For example, patent CN200910241853.3 discloses a method for constraining the forging of aluminum matrix composites with a steel cladding to avoid crack formation. However, the use of the steel cladding has significant drawbacks: steel itself has high strength and relatively low plasticity, requiring a large forging force to deform it, which places higher demands on forging equipment and increases production energy consumption and costs. At the same time, the physical properties of steel and aluminum matrix composites differ greatly, making it impossible to achieve coordinated deformation during forging, which easily leads to stress concentration at the interface and increases the risk of cracking.

[0006] Another patent, CN201611113534.0, proposes a composite process of "particle-reinforced aluminum matrix composite extrusion + multi-pass forging" to suppress forging cracks and improve forging efficiency and yield. However, this method has limitations in its applicability: the extrusion process before forging is usually only suitable for processing small to medium-sized billets, making it difficult to meet the needs of preparing large-sized forgings; furthermore, extrusion and forging are two independent processes, requiring separate design and optimization of process parameters, resulting in a longer process flow and increased complexity in process control, which is not conducive to efficient implementation in industrial production. In addition, the forging processes involved in the above two patents are both unidirectional forging, which cannot fully release the internal stress of the material and is difficult to achieve uniform deformation of the material, thus having a limited effect on suppressing cracks.

[0007] In summary, existing forging processes for particle-reinforced aluminum matrix composites still have many shortcomings in addressing the problem of easy cracking in materials. There is an urgent need to develop a new forging method that can effectively suppress forging cracks, is applicable to billets of different sizes, and has a simple process, so as to promote the widespread application of particle-reinforced aluminum matrix composites in the field of high-end equipment. Summary of the Invention

[0008] This invention aims to address the challenge of achieving efficient, stable, and crack-free forging of particle-reinforced aluminum matrix composites during the forging process due to their poor plasticity, defect sensitivity, and stress concentration. Instead, it provides a multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composites.

[0009] A multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material is specifically carried out according to the following steps:

[0010] 1. An aluminum alloy is used to encapsulate and weld the particle-reinforced aluminum matrix composite billet to form an encapsulated particle-reinforced aluminum matrix composite material;

[0011] 2. The encapsulated particle-reinforced aluminum matrix composite material is subjected to preheating and heat preservation treatment;

[0012] 3. The preheated and heat-insulated cladding particle-reinforced aluminum matrix composite material is subjected to multi-pass forging; between two adjacent forging passes, the cladding particle-reinforced aluminum matrix composite material forged in the previous pass is subjected to furnace heat preservation treatment.

[0013] 4. After all forging passes are completed, the encapsulated particle-reinforced aluminum matrix composite material is air-cooled.

[0014] 5. After air cooling, the cladding particle-reinforced aluminum matrix composite material is machined to remove the aluminum alloy cladding on its surface, thus completing the forging process.

[0015] Preferably, the particle-reinforced aluminum matrix composite billet in step one is cylindrical with a height-to-diameter ratio of 0.3 to 2; the reinforcement in the particle-reinforced aluminum matrix composite billet is one or a mixture of several of boron carbide, silicon carbide, titanium carbide, alumina, titanium diboride and tungsten; the particle size of the reinforcement is 1 μm to 40 μm, and the volume fraction of the reinforcement is 1% to 40%; the billet is prepared by powder metallurgy, stirring casting or hot isostatic pressing.

[0016] Preferably, the aluminum alloy in step one is made of the same series of wrought aluminum alloys as the aluminum matrix of the particle-reinforced aluminum matrix composite ingot.

[0017] Preferably, in step one, the aluminum alloy serves as a sheath comprising an outer shell and a top cover. The inner diameter of the outer shell is 0.1 mm to 0.5 mm smaller than the diameter of the particle-reinforced aluminum matrix composite billet, and the diameter of the top cover is 0.1 mm to 0.5 mm larger than the diameter of the particle-reinforced aluminum matrix composite billet. The thickness of both the outer shell and the top cover is 10% to 30% of the diameter of the particle-reinforced aluminum matrix composite billet.

[0018] Preferably, the encapsulation in step one is a combination of heat sealing and welding. First, the outer shell is heated to 300℃~450℃, then the particle-reinforced aluminum matrix composite billet is inserted, the top cover is placed in, and welding is performed.

[0019] Preferably, the preheating temperature of the preheating and heat preservation treatment in step two is 410℃~510℃, and the heat preservation time is 1~3 times the outer diameter of the sleeve, wherein the heat preservation time is in min and the outer diameter of the sleeve is in mm.

[0020] Preferably, the multi-pass forging in step three is unidirectional forging or multidirectional forging; when unidirectional forging is used, the deformation per pass is 5% to 20%, and the cumulative deformation is 50% to 90%; when multidirectional forging is used, the deformation per pass is 5% to 20%, and the cumulative deformation is 100% to 400%.

[0021] Preferably, the forging equipment used is a press, air hammer, or hydraulic press; the forging speed is 1 mm / s to 10 mm / s; the surfaces of the upper and lower anvils are coated with a lubricant, which is graphite powder, graphite flakes, or graphite + machine oil; and the temperature of the upper and lower anvils is 0 to 30°C lower than the preheating temperature of the granular reinforced aluminum matrix composite material.

[0022] Preferably, the annealing temperature for the re-annealing treatment in step three is 410℃~510℃, and the holding time is 0.2~1 times the outer diameter of the initial sheath, where the holding time is in min and the outer diameter of the initial sheath is in mm.

[0023] Preferably, in step three, the final forging temperature is not lower than 80°C below the preheating temperature of the cladding particle-reinforced aluminum matrix composite material.

[0024] The beneficial effects of this invention are:

[0025] This invention addresses the problem of easy cracking during forging of particle-reinforced aluminum matrix composites by proposing a cladding forging process. The aluminum alloy cladding serves two purposes: firstly, it provides insulation, reducing the temperature drop of the composite billet during forging and preventing plastic flow instability caused by uneven billet temperature; secondly, it constrains and coordinates deformation of the composite billet during forging, reducing the tendency for forging cracks; controlling the final forging temperature, with a narrower forging temperature range, helps refine the microstructure and reduce crack formation; and the application of lubricant reduces radial compressive stress during forging and promotes radial flow. Attached Figure Description

[0026] Figure 1 The aluminum alloy casing and top cover of this invention;

[0027] Figure 2 This is a photograph of the particle-reinforced aluminum matrix composite material of the present invention after encapsulation;

[0028] Figure 3 This is a photograph of Example 1 of the present invention after forging and removal of the sheath;

[0029] Figure 4 This is a photograph of Comparative Example 1 of the present invention after forging;

[0030] Figure 5 These are comparative photos of the forging process before and after removing the sheath in Embodiment 2 of the present invention; where a represents before removing the sheath and b represents after removing the sheath.

[0031] Figure 6 This is a photograph of Comparative Example 2 of the present invention after forging. Detailed Implementation

[0032] Specific Implementation Method 1: This implementation method for a multi-pass forging method of aluminum alloy cladding for particle-reinforced aluminum matrix composite materials is carried out according to the following steps:

[0033] 1. An aluminum alloy is used to encapsulate and weld the particle-reinforced aluminum matrix composite billet to form an encapsulated particle-reinforced aluminum matrix composite material;

[0034] 2. The encapsulated particle-reinforced aluminum matrix composite material is subjected to preheating and heat preservation treatment;

[0035] 3. The preheated and heat-insulated cladding particle-reinforced aluminum matrix composite material is subjected to multi-pass forging; between two adjacent forging passes, the cladding particle-reinforced aluminum matrix composite material forged in the previous pass is subjected to furnace heat preservation treatment.

[0036] 4. After all forging passes are completed, the encapsulated particle-reinforced aluminum matrix composite material is air-cooled.

[0037] 5. After air cooling, the cladding particle-reinforced aluminum matrix composite material is machined to remove the aluminum alloy cladding on its surface, thus completing the forging process.

[0038] This implementation method forms an organic whole through the constraint and protection of the aluminum alloy sheath, precise control of temperature parameters, and deformation regulation of multi-pass forging: the sheath provides structural support for temperature stability, ensuring thermal uniformity during preheating and reheating; the uniformity of the temperature field creates conditions for the gradual deformation of multi-pass forging, ensuring that each deformation occurs within the material's optimal plasticity range; and the work hardening generated by multi-pass deformation is eliminated through reheating, reserving plasticity for the next deformation. This synergistic system of "sheath constraint - temperature assurance - deformation optimization" achieves closed-loop control of crack suppression from three dimensions: material, structure, and process, ultimately achieving the technical goal of crack-free forging.

[0039] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the particle-reinforced aluminum matrix composite ingot described in step one is cylindrical with a height-to-diameter ratio of 0.3~2; the reinforcement in the particle-reinforced aluminum matrix composite ingot is one or a mixture of several of boron carbide, silicon carbide, titanium carbide, alumina, titanium diboride, and tungsten; the particle size of the reinforcement is 1μm~40μm, and the volume fraction of the reinforcement is 1%~40%; the ingot is prepared by powder metallurgy, stirred casting, or hot isostatic pressing. Everything else is the same as in Specific Implementation Method One.

[0040] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the aluminum alloy material mentioned in step one is the same series of wrought aluminum alloy as the aluminum matrix of the particle-reinforced aluminum matrix composite ingot. Everything else is the same as in Specific Implementation Method One.

[0041] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that: in step one, the aluminum alloy serves as a sheath comprising an outer shell and a top cover. The inner diameter of the outer shell is 0.1mm~0.5mm smaller than the diameter of the particle-reinforced aluminum matrix composite ingot, while the diameter of the top cover is 0.1mm~0.5mm larger than the diameter of the particle-reinforced aluminum matrix composite ingot. The thickness of both the outer shell and the top cover is 10%~30% of the diameter of the particle-reinforced aluminum matrix composite ingot. Everything else is the same as in Specific Implementation Method One.

[0042] This embodiment uses a wrought aluminum alloy of the same series as the aluminum matrix as the cladding, utilizing their similar coefficients of thermal expansion and plastic deformation characteristics to achieve synchronous deformation during forging. This material matching avoids the problem of interface stress concentration caused by the performance difference between the steel cladding and the aluminum matrix. The cladding forms a uniform radial constraint on the composite billet, effectively suppressing the peeling of the particle-matrix interface and crack initiation. The structural design of the cladding further enhances the constraint effect: the interference fit design with the inner diameter of the outer shell being 0.1mm~0.5mm smaller than the billet diameter, after being hot-fitted at 300℃~450℃, forms a tight fit, and after welding and sealing, a closed deformation space is constructed; the thickness design of the outer shell and the upper cover being 10%~30% of the billet diameter ensures sufficient structural strength to transmit forging force, and also buffers local stress peaks through the plastic flow of the cladding itself, enabling the composite billet to achieve uniform deformation under "flexible constraint".

[0043] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the encapsulation in step one is a combination of heat sealing and welding. First, the outer shell is heated to 300℃~450℃, then the particle-reinforced aluminum matrix composite ingot is inserted, the top cover is placed in, and welding is performed. Everything else is the same as in Specific Implementation Method Four.

[0044] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the preheating temperature for the preheating and heat preservation treatment in step two is 410℃~510℃, and the heat preservation time is 1~3 times the outer diameter of the sheath, where the heat preservation time is in minutes and the outer diameter of the sheath is in millimeters. Everything else is the same as in Specific Implementation Method One.

[0045] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that the multi-pass forging in step three is either unidirectional forging or multidirectional forging. When unidirectional forging is used, the deformation per pass is 5%~20%, and the cumulative deformation is 50%~90%. When multidirectional forging is used, the deformation per pass is 5%~20%, and the cumulative deformation is 100%~400%. Everything else is the same as in Specific Implementation Method One.

[0046] This implementation method utilizes a multi-pass forging technique that overcomes the bottleneck of insufficient plasticity in composite materials through a strategy of "small deformation accumulation + step-by-step stress release." Unidirectional forging combines 5%–20% single-pass deformation with 50%–90% cumulative deformation, or multidirectional forging designs with 100%–400% large cumulative deformation, both avoiding stress concentration caused by large single-pass deformation through gradual deformation. The alternating axial and radial deformation paths of multidirectional forging further facilitate the multi-directional closure of internal pores in the material, reducing stress concentration points at defects.

[0047] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that: the forging equipment used is a press, air hammer, or hydraulic press; the forging speed is 1mm / s to 10mm / s; the surfaces of the upper and lower anvils are coated with a lubricant, which is graphite powder, graphite flakes, or graphite + machine oil; and the temperature of the upper and lower anvils is 0 to 30°C lower than the preheating temperature of the granular reinforced aluminum matrix composite material. Everything else is the same as in Specific Implementation Method Seven.

[0048] In this embodiment, the control of the forging speed (1 mm / s to 10 mm / s) and the synergistic effect of the upper and lower anvil temperatures (0 to 30°C lower than the preheating temperature) ensure the stability of the deformation process and reduce heat loss from the billet surface through anvil temperature compensation. The coating of graphite-based lubricant reduces the coefficient of friction between the billet and the die, promotes radial material flow, further alleviates shear stress at the edges, and avoids edge cracking, a common phenomenon in traditional forging.

[0049] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One in that the furnace annealing temperature for the furnace heat preservation treatment in step three is 410℃~510℃, and the heat preservation time is 0.2~1 times the initial outer diameter of the sheath, where the heat preservation time is in minutes and the initial outer diameter of the sheath is in millimeters. Everything else is the same as in Specific Implementation Method One.

[0050] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method One in that the final forging temperature in step three is not lower than 80°C below the preheating temperature of the cladding particle-reinforced aluminum matrix composite material. Everything else is the same as in Specific Implementation Method One.

[0051] The implementation method precisely matches the preheating temperature range of 410℃~510℃ to the optimal plastic deformation temperature range of the aluminum matrix, avoiding the surge in deformation resistance caused by excessively low temperatures or the grain coarsening caused by excessively high temperatures. The holding time is set according to 1~3 times the outer diameter of the sheath (min / mm) to ensure that heat is uniformly conducted from the sheath to the core of the composite billet, eliminating internal temperature gradients and avoiding uneven deformation cracking caused by insufficient local plasticity. The reheating between passes uses a combination of parameters of annealing temperature of 410℃~510℃ and holding time of 0.2~1 times the initial outer diameter of the sheath (min / mm), forming a "deformation-recovery-recrystallization" cycle mechanism. After each forging pass, reheating eliminates work hardening, restores the plasticity of the matrix, and avoids the cumulative stress exceeding the material strength limit. The limitation that the final forging temperature is not lower than 80℃ below the preheating temperature ensures that the material still maintains sufficient plasticity in the final deformation stage and prevents low-temperature embrittlement cracking.

[0052] The effectiveness of the present invention was verified through the following experiments:

[0053] Example 1: A multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composites is carried out according to the following steps:

[0054] I. Composite ingots of (10 vol.% B4Cp + 10 vol.% W) / 6061Al, (20 vol.% B4Cp + 5 vol.% W) / 6061Al, (17.5 vol.% B4Cp + 17.5 vol.% W) / 6061Al, and (15 vol.% B4Cp + 15 vol.% W) / 6061Al were prepared using powder metallurgy. The particle sizes of B4C and W were 12 μm and 10 μm, respectively, and the ingot size was φ100 mm × 60 mm. The cladding was made of 6061Al alloy with a thickness of 20 mm. The outer shell of the cladding was heated to 450 °C, and the composite ingot was placed inside. The top cover was welded on to obtain a cladding blank with a diameter of φ140 mm × 100 mm.

[0055] 2. The encapsulated particle-reinforced aluminum matrix composite material is subjected to preheating and heat preservation treatment; the preheating temperature is 460℃ and the heat preservation time is 200min; the upper and lower cutting boards are heated to 455℃ and kept warm.

[0056] III. Unidirectional forging is performed using a 500-ton press. Before forging, graphite powder is coated onto the upper and lower anvils. The forging direction is parallel to the height direction of the cladding billet, with a speed of 3 mm / s and a deformation of 10% per pass. The final forging temperature is 400℃, the reflow temperature is 460℃, and the reflow holding time is 100 minutes. After the cumulative deformation reaches 50%, the forging is air-cooled. After removing the surface aluminum cladding, the forging is as follows: Figure 3 As shown, the surface is intact and without cracks.

[0057] Comparative Example 1: A (10 vol.% B4Cp + 10 vol.% W) / 6061Al composite ingot was prepared using powder metallurgy. The particle sizes of B4C and W were 12 μm and 10 μm, respectively, and the ingot size was φ100 mm × 60 mm. The ingot was heated to 460℃ and held for 140 min. The upper and lower anvils were heated to 455℃ and held for unidirectional forging using a 500-ton press. Graphite powder was coated onto the upper and lower anvils before forging. The forging direction was parallel to the height direction of the ingot, the speed was 3 mm / s, and the deformation per pass was 10%. The final forging temperature was 400℃, the reflow temperature was 460℃, the reflow holding time was 100 min, and the cumulative deformation reached 50% before air cooling. After removing the surface aluminum cladding, the forging was as follows: Figure 4 As shown, obvious cracks appear around the perimeter.

[0058] Example 2: A 10 vol.% SiCp / 7075Al composite ingot was prepared by stirring casting. The SiC particle size was 15 μm and the ingot size was φ140 mm × 100 mm. The cladding was made of 7085Al alloy with a thickness of 40 mm. The outer shell of the cladding was heated to 400 °C, the composite ingot was placed in it, and the top cover was welded on to obtain a cladding ingot with a diameter of φ220 mm × 180 mm.

[0059] The encapsulated particle-reinforced aluminum matrix composite material is subjected to preheating and heat preservation treatment; the preheating temperature is 445℃, and the heat preservation time is 500 min; the upper and lower cutting boards are heated to 445℃ and kept at that temperature.

[0060] Multi-directional forging was performed using a 1000-ton press. Before forging, graphite powder was coated onto the upper and lower anvils. The forging directions were sequentially axial, first radial, and a second radial perpendicular to the first radial, at a speed of 4 mm / s, with a deformation of 15% per pass. The final forging temperature was 380℃, the reflow temperature was 445℃, and the reflow holding time was 200 minutes. After the cumulative deformation reached 150%, air cooling was performed. The forged product... Figure 5 As shown, the surfaces of the sheath and composite material forgings are intact and free of cracks.

[0061] Comparative Example 2: A 10 vol.% SiCp / 7075Al composite ingot was prepared using a stir casting method. The SiC particles had a diameter of 15 μm and a size of φ140 mm × 100 mm. The ingot was heated to 445 °C and held for 300 min. The upper and lower anvils were also heated to 445 °C and held for 30 min. Multi-directional forging was performed using a 1000-ton press. Before forging, graphite powder was coated onto the upper and lower anvils. The forging direction was sequentially along the axial direction, the first radial direction, and the second radial direction perpendicular to the first radial direction, at a speed of 4 mm / s. The deformation per pass was 15%. The final forging temperature was 380 °C, the reflow temperature was 445 °C, the reflow holding time was 120 min, and air cooling was performed after the cumulative deformation reached 135%. The forged ingot was as follows: Figure 6 As shown, cracks appear on the surface of the composite material.

Claims

1. A multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composites, characterized in that... The forging method is carried out in the following steps:

1. An aluminum alloy is used to encapsulate and weld the particle-reinforced aluminum matrix composite billet to form an encapsulated particle-reinforced aluminum matrix composite material; 2. The encapsulated particle-reinforced aluminum matrix composite material is subjected to preheating and heat preservation treatment; 3. The preheated and heat-insulated cladding particle-reinforced aluminum matrix composite material is subjected to multi-pass forging; between two adjacent forging passes, the cladding particle-reinforced aluminum matrix composite material forged in the previous pass is subjected to furnace heat preservation treatment.

4. After all forging passes are completed, the encapsulated particle-reinforced aluminum matrix composite material is air-cooled.

5. After air cooling, the cladding particle-reinforced aluminum matrix composite material is machined to remove the aluminum alloy cladding on its surface, thus completing the forging process.

2. The multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... The particle-reinforced aluminum matrix composite billet mentioned in step one is cylindrical with a height-to-diameter ratio of 0.3 to 2. The reinforcement in the particle-reinforced aluminum matrix composite billet is one or a mixture of several of boron carbide, silicon carbide, titanium carbide, alumina, titanium diboride and tungsten. The particle size of the reinforcement is 1 μm to 40 μm, and the volume fraction of the reinforcement is 1% to 40%. The billet is prepared by powder metallurgy, stirring casting or hot isostatic pressing.

3. The multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... The aluminum alloy mentioned in step one is made of the same series of wrought aluminum alloys as the aluminum matrix of the particle-reinforced aluminum matrix composite ingot.

4. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... In step one, the aluminum alloy serves as a sheath, comprising an outer shell and a top cover. The inner diameter of the outer shell is 0.1 mm to 0.5 mm smaller than the diameter of the particle-reinforced aluminum matrix composite billet, while the diameter of the top cover is 0.1 mm to 0.5 mm larger than the diameter of the particle-reinforced aluminum matrix composite billet. The thickness of both the outer shell and the top cover is 10% to 30% of the diameter of the particle-reinforced aluminum matrix composite billet.

5. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 4, characterized in that... In step one, the encapsulation and welding process involves heat sealing and welding. First, the outer shell is heated to 300℃~450℃, then the particle-reinforced aluminum matrix composite billet is inserted, the top cover is placed in, and welding is performed.

6. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... The preheating temperature for the preheating and heat preservation treatment in step two is 410℃~510℃, and the heat preservation time is 1~3 times the outer diameter of the sheath, where the heat preservation time is in min and the outer diameter of the sheath is in mm.

7. The multi-pass forging method for aluminum alloy cladding of particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... The multi-pass forging mentioned in step three is either unidirectional forging or multidirectional forging. When unidirectional forging is used, the deformation per pass is 5% to 20%, and the cumulative deformation is 50% to 90%. When multidirectional forging is used, the deformation per pass is 5% to 20%, and the cumulative deformation is 100% to 400%.

8. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 7, characterized in that... The forging equipment used is a press, air hammer or hydraulic press; the forging speed is 1mm / s to 10mm / s; the surfaces of the upper and lower anvils are coated with a lubricant, which is graphite powder, graphite flakes or graphite + machine oil; the temperature of the upper and lower anvils is 0 to 30°C lower than the preheating temperature of the granular reinforced aluminum matrix composite.

9. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... In step three, the annealing temperature for the re-annealing treatment is 410℃~510℃, and the holding time is 0.2~1 times the initial outer diameter of the sheath. The holding time is in minutes, and the initial outer diameter of the sheath is in mm.

10. The multi-pass forging method for aluminum alloy cladding of a particle-reinforced aluminum matrix composite material according to claim 1, characterized in that... In step three, the final forging temperature shall not be lower than 80°C below the preheating temperature of the cladding particle-reinforced aluminum matrix composite material.

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