Semi-solid casting process for 6063 aluminum alloy reinforced by rare earth metal and application of semi-solid casting process

Abstract

The invention relates to the technical field of metal materials and processing thereof, and discloses a rare earth metal reinforced 6063 aluminum alloy semi-solid casting process which comprises the following steps: S1, preparing 0.6-0.7% of magnesium; 0.5%-0.7% of silicon; 0.05%-0.1% of manganese; 0.1%-0.3% of copper; 0.05%-0.15% of titanium; 0.05% to 0.15% of zirconium; 0.1%-0.3% of rare earth elements; s2, the high-purity aluminum ingot is placed in a vacuum melting furnace to be heated until the high-purity aluminum ingot is completely melted; s3, cooling the melt to a liquid-solid two-phase region; s4, the melt subjected to semi-solid treatment is injected into a metal mold with the dynamic temperature control function; s5, the casting is subjected to staged dynamic heat treatment; and S6, leftover materials generated in the casting process are classified and screened. And the precipitation form and distribution of a strengthening phase are optimized through variable-temperature solid solution and two-stage aging processes in dynamic heat treatment, and the toughness of the material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials and processing thereof, in particular to a rare earth metal reinforced 6063 aluminum alloy semi-solid casting process and application thereof. Background Art

[0002] Aluminum alloys are widely used in the fields of construction, transportation, and high-temperature industrial equipment due to their light weight, high strength, excellent corrosion resistance, and processing performance. Among them, 6063 aluminum alloy has become a commonly used aluminum alloy in industrial production due to its excellent processability and mechanical properties. However, in actual use, with the continuous improvement of material performance requirements in application fields, the performance of 6063 aluminum alloy under dynamic loads, high temperature environments, and complex mechanical stress conditions still faces some technical bottlenecks that need to be improved.

[0003] 6063 aluminum alloy is traditionally made by gravity casting or pressure casting. Although these processes can meet the needs of conventional structural parts, they often lead to coarse grains or uneven structure during the cooling and solidification of the castings due to the difficulty in accurately controlling the cooling rate. This structural characteristic will cause internal stress concentration in the material under dynamic load and fatigue cycle conditions, weakening the fatigue resistance, and is more prone to performance degradation in long-term use. At the same time, the uneven distribution of the solid and liquid phases in the casting also makes the mechanical properties of the material significantly anisotropic, affecting the reliability of the material in the load-bearing parts. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a rare earth metal reinforced 6063 aluminum alloy semi-solid casting process and application thereof, which solves the problems of coarse grains, uneven structure, insufficient strength-toughness balance and low rare earth element utilization efficiency of the existing 6063 aluminum alloy under dynamic load, high temperature environment and complex mechanical stress conditions.

[0005] To achieve the above objectives, the present invention is implemented by the following technical solutions: A rare earth metal reinforced 6063 aluminum alloy, comprising, by weight percentage:

[0006] Magnesium 0.6%-0.7%;

[0007] Silicon 0.5%-0.7%;

[0008] Manganese 0.05%-0.1%;

[0009] Copper 0.1%-0.3%;

[0010] Titanium 0.05%-0.15%;

[0011] Zirconium 0.05%-0.15%;

[0012] Rare earth elements 0.1%-0.3%;

[0013] Strontium 0.02%-0.05%;

[0014] Aluminum 98%-99%.

[0015] Preferably, the rare earth elements include:

[0016] Yttrium 0.05%-0.1%;

[0017] Cerium 0.05%-0.1%;

[0018] Lanthanum 0.01%-0.05%.

[0019] A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process comprises the following steps:

[0020] S1. Prepare high-purity aluminum ingots, magnesium, silicon, manganese, copper, titanium, zirconium, rare earth elements, and strontium, and pre-mix the rare earth elements to form a uniform composite rare earth additive;

[0021] S2, placing a high-purity aluminum ingot in a vacuum melting furnace and heating it until it is completely melted, then adding strengthening elements and refining elements in sequence, and obtaining a melt with a specific primary crystal morphology through two-stage stirring and dynamic gas protection;

[0022] S3, gradually cooling the melt from 700℃±5℃ to 625℃-640℃ in the liquid-solid two-phase region, and then using stirring-flow control technology to achieve grain refinement and microstructure homogenization under a limited flow field;

[0023] S4, injecting the semi-solid treated melt into a metal mold with dynamic temperature control to obtain a casting;

[0024] S5. Perform dynamic heat treatment on the casting in stages, including variable temperature solution treatment and fine aging treatment;

[0025] S6. The scraps produced during the casting process are graded and screened and then reused in step S2.

[0026] Preferably, the rare earth composite additive in step S1 is prepared by the following method:

[0027] S11, mixing yttrium, cerium and lanthanum in a ratio of 1:1:0.5;

[0028] S12, using a high temperature melting method under argon protection to melt the rare earth elements to form a uniform composite rare earth melt;

[0029] S13. The composite rare earth is formed into a granular additive through a rapid cooling process, and the particle size is controlled at 0.05 mm-0.1 mm.

[0030] Preferably, the order of adding strengthening elements in step S2 is:

[0031] S21, first add magnesium, silicon and manganese, maintain the temperature at 720°C-740°C, and stir for 5min-10min;

[0032] S22, then add the composite rare earth additive, maintain the temperature at 700°C, and stir for 10min-20min;

[0033] S23. Finally, add titanium, zirconium and strontium, continue stirring for 10 min-15 min, and introduce argon protection at the same time.

[0034] Preferably, the S3 step comprises:

[0035] S31, using a double-axis electromagnetic stirring device, controlling the stirring speed at 300rpm-500rpm, and combining cooling control technology to gradually cool the melt to the liquid-solid two-phase region of 625℃-640℃;

[0036] S32. During the stirring process, a stable annular flow field is formed through the electromagnetic field to ensure that the solid and liquid phases are evenly distributed, and the solid content is controlled at 25%-35%;

[0037] S33, control the stirring time to 25min-35min, and keep injecting protective gas into the melt surface during this process.

[0038] Preferably, the protective gas injected in step S33 includes but is not limited to one or more of sulfur hexafluoride, nitrogen, and argon.

[0039] Preferably, the S4 step comprises:

[0040] S41, preheat the mold to 350℃-400℃, control the flow rate of cooling medium to form a temperature gradient of 10℃ / mm-20℃ / mm;

[0041] S42, by installing a cooling auxiliary device on the outside of the mold, the cooling rate of the mold is controlled in different zones to perform direction control.

[0042] Preferably, the S5 step comprises:

[0043] S51, variable temperature solution treatment: the temperature is gradually increased from 520℃ to 550℃, the heating rate is controlled at 10℃ / min-15℃ / min, and the holding time is 1.5h;

[0044] S52, fine aging treatment: double-stage aging is carried out in the range of 165℃-185℃, with the first stage keeping warm for 6h and the second stage keeping warm for 4h.

[0045] An application of a rare earth metal reinforced 6063 aluminum alloy, the alloy is used to manufacture industrial and civil structural parts requiring high strength, corrosion resistance and thermal stability, including but not limited to building profiles, mechanical parts, transportation equipment parts and structural parts used in high temperature environments.

[0046] The present invention provides a rare earth metal reinforced 6063 aluminum alloy semi-solid casting process and application thereof, which has the following beneficial effects:

[0047] 1. The present invention adopts semi-solid casting process and cooling gradient control technology to achieve directional distribution and homogenization of grains, so that the material exhibits excellent fatigue resistance in dynamic loads and fatigue cycles.

[0048] 2. The variable temperature solid solution and two-stage aging process in the dynamic heat treatment of the present invention optimizes the precipitation morphology and distribution of the strengthening phase. The variable temperature solid solution reduces thermal stress by gradually increasing the temperature, thereby improving the toughness of the material; the two-stage aging process maintains a good balance between ductility and fatigue resistance while enhancing the strength of the alloy, further improving the comprehensive performance of the material and meeting the needs for strength and toughness in multiple fields.

[0049] 3. Through the synergistic effect of rare earth elements and precise proportion design, the present invention achieves the dual effects of grain refinement and matrix strengthening, significantly improving the tensile strength and yield strength of 6063 aluminum alloy. Compared with traditional 6063 aluminum alloy, the tensile strength is increased by about 10%-20%, the yield strength is increased by 15%-25%, and the ductility is also optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the method steps of the present invention. DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Please refer to the attached Figure 1 An embodiment of the present invention provides a rare earth metal-reinforced 6063 aluminum alloy, which includes, by weight percentage: 0.6%-0.7% magnesium; 0.5%-0.7% silicon; 0.05%-0.1% manganese; 0.1%-0.3% copper; 0.05%-0.15% titanium; 0.05%-0.15% zirconium; 0.1%-0.3% rare earth elements; 0.02%-0.05% strontium; and 98%-99% aluminum.

[0053] Rare earth elements include: yttrium 0.05%-0.1%; cerium 0.05%-0.1%; lanthanum 0.01%-0.05%.

[0054] Specifically, the rare earth metal reinforced 6063 aluminum alloy design composition of the present invention is based on the traditional 6063 aluminum alloy, and the alloy is significantly improved in mechanical properties, corrosion resistance and thermal stability by optimizing the ratio of strengthening elements (such as rare earth, magnesium, silicon) and refining elements (such as strontium, titanium, zirconium). The addition of rare earth elements not only refines the grains through the synergistic effect of yttrium, cerium and lanthanum, but also can generate fine second phase particles with other elements (such as aluminum and silicon), further enhancing the high temperature performance and fatigue resistance of the material. In addition, the optimized ratio of rare earth elements can effectively suppress the harmful effects of impurity elements (such as iron), improve the overall uniformity and toughness of the material, thereby meeting the needs of industrial and civilian fields for high-performance aluminum alloys.

[0055] A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process comprises the following steps:

[0056] S1. Prepare high-purity aluminum ingots, magnesium, silicon, manganese, copper, titanium, zirconium, rare earth elements, and strontium, and pre-mix the rare earth elements to form a uniform composite rare earth additive;

[0057] S11, mixing yttrium, cerium and lanthanum in a ratio of 1:1:0.5;

[0058] S12, using a high temperature melting method under argon protection to melt the rare earth elements to form a uniform composite rare earth melt;

[0059] S13. The composite rare earth is formed into a granular additive through a rapid cooling process, and the particle size is controlled at 0.05 mm-0.1 mm.

[0060] Specifically, in this step, by selecting high-purity aluminum ingots (purity above 99%) and high-quality alloying elements, the low impurity content of the raw materials is ensured, and the inclusions and uneven components in the casting process are reduced. At the same time, the rare earth elements (yttrium, cerium, lanthanum) are mixed in a specific ratio to form a composite rare earth additive to ensure the uniform distribution of the rare earth elements in the aluminum matrix. In order to improve the utilization rate of rare earths, step S11 mixes yttrium, cerium and lanthanum in a ratio of 1:1:0.5. This specific ratio design can give full play to the grain refinement effect of yttrium, the strengthening phase precipitation regulation ability of cerium and the casting fluidity improvement effect of lanthanum.

[0061] In step S12, a high-temperature melting method under argon protection is used to melt the rare earth elements to form a uniform composite rare earth melt. During the melting process, the rare earth elements are completely dissolved in the aluminum melt, and the oxidation and volatilization losses of the rare earth elements are effectively avoided under the protection of argon. The melting temperature is controlled in the range of 700°C to 750°C. This temperature range can minimize the oxidation risk of the rare earth elements while ensuring their reactivity with the aluminum matrix. Argon, as a protective gas, effectively prevents the melt from contacting with the air by forming an inert atmosphere, thereby improving the purity of the rare earth melt.

[0062] In step S13, the composite rare earth is formed into a granular additive by a rapid cooling process, and the particle size is controlled at 0.05mm-0.1mm. Rapid cooling can ensure the miniaturization and homogenization of rare earth particles, while avoiding the excessive growth of rare earth compounds and maintaining their good dispersion distribution performance. The control of particle size is crucial, and small-sized particles can form more nucleation points in the aluminum matrix, thereby significantly refining the alloy grains. In addition, micron-sized rare earth particles are easier to be evenly distributed during smelting and casting, thereby enhancing the overall homogeneity and isotropy of the material. Finally, the prepared rare earth composite particles have the advantages of high purity, uniform particle size and smooth surface, which lays the foundation for subsequent smelting and semi-solid casting.

[0063] S2, placing a high-purity aluminum ingot in a vacuum melting furnace and heating it until it is completely melted, then adding strengthening elements and refining elements in sequence, and obtaining a melt with a specific primary crystal morphology through two-stage stirring and dynamic gas protection;

[0064] S21, first add magnesium, silicon and manganese, maintain the temperature at 720°C-740°C, and stir for 5min-10min;

[0065] S22, then add the composite rare earth additive, maintain the temperature at 700°C, and stir for 10min-20min;

[0066] S23. Finally, add titanium, zirconium and strontium, continue stirring for 10 min-15 min, and introduce argon protection at the same time.

[0067] Specifically, after the high-purity aluminum ingot is placed in a vacuum melting furnace and heated until it is completely melted, strengthening elements and refining elements are added in sequence. Through a two-stage stirring process and dynamic gas protection, the uniformity of the melt and the formation of a specific primary crystal morphology are ensured. The vacuum melting furnace is used to minimize impurities and oxides in the melt and ensure the purity of the melt. At the same time, argon protection is maintained on the surface of the melt to effectively inhibit the oxidation reaction of aluminum alloys and strengthening elements at high temperatures. During the smelting process, precise temperature control and optimization of the stirring process are key factors affecting the performance of the alloy.

[0068] After the melt is heated to a temperature range of 720℃-740℃, magnesium, silicon and manganese are first added to evenly distribute the strengthening elements in the first stage. Magnesium, as the main strengthening element, forms Mg2Si phase with silicon, significantly improving the strength and corrosion resistance of the alloy; silicon can further improve the fluidity of the aluminum matrix and synergistically strengthen the alloy matrix with magnesium; manganese improves the wear resistance and toughness of the alloy by inhibiting the formation of harmful Fe phase. At this stage, the stirring time is controlled at 5min-10min to ensure that the strengthening elements are fully dissolved and evenly distributed, while avoiding temperature fluctuations in the melt due to too long a time.

[0069] After the first stage of stirring is completed, the melt temperature is lowered to 700°C and the pre-prepared composite rare earth additive (particle size 0.05mm-0.1mm) is added. The introduction of composite rare earth additives is the core innovation of this process. The specific proportion of yttrium, cerium and lanthanum can not only significantly refine the grains, but also generate fine compound phases (such as Al-RE-Si phase) through reactions with aluminum matrix and silicon, further improving the high temperature strength and fatigue properties of the alloy. The stirring time in this stage is 10min-20min, which aims to ensure the uniform distribution of rare earth additives in the melt. At the same time, the dynamic protection of argon gas effectively prevents the oxidation and volatilization of rare earth elements, thereby improving their utilization efficiency in the alloy matrix.

[0070] After the rare earth elements are evenly distributed, the refining elements titanium, zirconium and strontium are added. These elements can form high melting point crystal nuclei particles (such as TiAl 3 、Al 3 Zr) provides nucleation points for the primary aluminum phase, thereby significantly refining the grains and improving the uniformity of the casting structure. Strontium can further improve the toughness and fatigue properties of the alloy by changing the morphology of eutectic silicon. The stirring time in the final stage is controlled at 10min-15min to ensure that titanium, zirconium and strontium are fully dissolved and evenly distributed. At the same time, argon gas is introduced to protect and cover the surface of the melt, effectively inhibiting the oxidation reaction and maintaining the purity and chemical stability of the melt.

[0071] S3, gradually cooling the melt from 700℃±5℃ to 625℃-640℃ in the liquid-solid two-phase region, and then using stirring-flow control technology to achieve grain refinement and microstructure homogenization under a limited flow field;

[0072] S31, using a double-axis electromagnetic stirring device, controlling the stirring speed at 300rpm-500rpm, and combining cooling control technology to gradually cool the melt to the liquid-solid two-phase region of 625℃-640℃;

[0073] S32. During the stirring process, a stable annular flow field is formed through the electromagnetic field to ensure that the solid and liquid phases are evenly distributed, and the solid content is controlled at 25%-35%;

[0074] S33, controlling the stirring time to be 25min-35min, and injecting protective gas into the melt surface during this process. The protective gas includes but is not limited to one or more of sulfur hexafluoride, nitrogen, and argon.

[0075] Specifically, during the stirring process, a dual-axis electromagnetic stirring device is used, and its stirring speed is controlled within the range of 300rpm-500rpm. Dual-axis electromagnetic stirring can simultaneously introduce radial and axial stirring effects into the melt, forming a complex flow path and enhancing the mixing effect of the liquid-solid two phases. A lower speed (300rpm) is suitable for situations with a high liquid phase ratio, which helps the distribution of primary grains, while a higher speed (500rpm) is suitable for situations with a high solid phase ratio to enhance mixing, thereby avoiding uneven organization caused by insufficient stirring.

[0076] During stirring, an annular flow field is formed through electromagnetic field design. The fluid induction effect of electromagnetic stirring is used to generate a stable vortex area in the liquid-solid two-phase region to ensure that the solid-liquid mixture is evenly distributed throughout the melt. The annular flow field can effectively inhibit the aggregation of solid phase particles and prevent the formation of solid phase agglomeration, thereby ensuring that the particles of the primary α phase are small and dispersed. Through the electromagnetic field parameters optimized by computational fluid dynamics (CFD), the annular path of the flow field can cover the melt volume to the maximum extent, reduce the unevenly distributed areas in the liquid phase, and strengthen the heat transfer and interaction between the solid and the liquid.

[0077] The stirring time is controlled within 25-35 minutes to ensure sufficient mixing and refinement. Too short a stirring time will result in insufficient mixing of the solid and liquid phases and uneven distribution of the structure; while too long a stirring time may further reduce the temperature, increase the excessive growth of the crystal nucleus, and reduce the grain refinement effect. During the stirring process, the melt surface is protected by dynamically injecting protective gas, including but not limited to sulfur hexafluoride (SF 6 ), nitrogen (N 2 ), argon (Ar). Sulfur hexafluoride has extremely strong barrier properties and can effectively prevent melt oxidation, but its application must meet environmental protection regulations; nitrogen has a lower cost and is suitable for mass production processes; argon, due to its high purity and inertness, can provide higher protection in high-end aluminum alloy production.

[0078] S4, injecting the semi-solid treated melt into a metal mold with dynamic temperature control to obtain a casting;

[0079] S41, preheat the mold to 350℃-400℃, control the flow rate of cooling medium to form a temperature gradient of 10℃ / mm-20℃ / mm;

[0080] S42, by installing a cooling auxiliary device on the outside of the mold, the cooling rate of the mold is controlled in different zones to perform direction control.

[0081] Specifically, before casting, the mold is preheated to 350℃-400℃. The purpose of preheating is to reduce the rapid cooling effect when the melt is injected, reduce the thermal stress caused by excessive temperature gradient, and thus avoid the generation of cracks. Precise control of mold temperature helps to maintain the stability of the liquid-solid two-phase melt and provide a uniform initial cooling environment for the casting. After the melt is injected into the mold, a cooling environment with a temperature gradient of 10℃ / mm-20℃ / mm is formed by adjusting the flow rate of the cooling medium (such as water or air). A moderate cooling gradient can effectively control the grain growth rate, thereby forming a fine and uniform grain structure. The upper limit of the temperature gradient (20℃ / mm) is suitable for rapid prototyping of high-strength castings, while the lower limit (10℃ / mm) is suitable for castings requiring higher ductility.

[0082] In order to further optimize the performance of the casting, a cooling auxiliary device is installed on the outside of the mold. The cooling rate of the mold is controlled by partitioning, and the heat dissipation intensity of different areas is adjusted to achieve directional control. In the key parts of the mold (such as the bottom and side walls), areas with higher cooling intensity are set to accelerate cooling and promote the directional growth of grains, thereby improving the fatigue resistance and thermal stability of the casting. In non-critical parts (such as the top or secondary load-bearing parts), the cooling intensity can be appropriately reduced to reduce the risk of cooling stress and thermal cracks. Through the intelligent control of the cooling auxiliary device, the cooling strategy of different areas can be adjusted according to the structural characteristics of the casting, and ultimately the directional distribution of the organization and the regional optimization of performance can be achieved.

[0083] S5. Perform dynamic heat treatment on the casting in stages, including variable temperature solution treatment and fine aging treatment;

[0084] S51, variable temperature solution treatment: the temperature is gradually increased from 520℃ to 550℃, the heating rate is controlled at 10℃ / min-15℃ / min, and the holding time is 1.5h;

[0085] S52, fine aging treatment: double-stage aging is carried out in the range of 165℃-185℃, with the first stage keeping warm for 6h and the second stage keeping warm for 4h.

[0086] Specifically, the key to variable temperature solution treatment is to completely dissolve the strengthening phase (such as Mg2Si) and rare earth element related compounds in the matrix by gradually increasing the temperature, while avoiding the melting of grain boundaries and excessive growth that may be caused by rapid temperature increase. Specifically, the casting is placed in a solution treatment furnace, and the temperature is gradually increased from 520°C to 550°C. The heating rate is controlled at 10°C / min-15°C / min to ensure that the heat is evenly transferred to the inside of the casting and reduce the thermal stress caused by the temperature gradient. During the heating process, the precipitates formed by rare earth elements (such as yttrium, cerium, and lanthanum) are fully integrated with the matrix phase to improve the solid solution strengthening ability of the matrix. After reaching 550°C, keep warm for 1.5 hours to ensure that the strengthening phase is completely dissolved and evenly distributed in the aluminum matrix, while stabilizing the grain boundaries and reducing internal stress. The process optimization at this stage can significantly improve the ductility and corrosion resistance of the material and provide an ideal initial organizational state for aging treatment.

[0087] The refined aging treatment adopts a two-stage aging process, which is completed in the range of 165℃-185℃ and is carried out in two stages. The aging temperature in the first stage is 165℃, and the temperature is kept for 6 hours. The role of this stage is to promote the formation of fine precipitates (such as β′ phase) by controlling the temperature in a lower range, thereby improving the yield strength and hardness of the material, while reducing the precipitation deposition at the grain boundaries and maintaining good ductility. The aging temperature in the second stage is raised to 185℃ and kept for 4 hours. This stage further promotes the uniform distribution of larger precipitates (such as the precipitation of β phase), thereby enhancing the fatigue resistance and high temperature stability of the material. The design of the two-stage aging can give full play to the strengthening effect of the precipitates on the aluminum matrix, while avoiding the problem of grain boundary embrittlement that may occur in the single-stage aging process. The entire aging process is completed in a precisely controlled thermal environment to ensure that the microstructure of the alloy achieves optimal uniformity.

[0088] S6. The scraps produced during the casting process are graded and screened and then reused in step S2.

[0089] Specifically, the scraps are initially classified by size and source to remove significant impurities and non-metallic inclusions. For example, larger pouring and riser scraps are directly sent to the subsequent physical cleaning step, while fine processing scraps are screened to separate usable materials.

[0090] Larger scraps are cleaned and mechanical methods (such as sandblasting or shot blasting) are used to remove surface oxides, oil stains and other attached impurities. For processing waste, vibration separation or magnetic separation is used to further remove non-metallic inclusions and non-metallic fragments.

[0091] The initially cleaned scraps are chemically treated to remove the residual oxide film and possible impurity layer on the surface through dilute acid cleaning or molten salt deoxidation process. This step can significantly improve the purity of the recycled materials to meet the quality requirements of high-performance aluminum alloys.

[0092] The cleaned scraps are stored according to their chemical composition and physical properties. The higher purity materials are directly used for smelting, while other secondary materials need to be mixed with high-purity aluminum ingots to ensure the composition stability of the final alloy.

[0093] Example 1: Application in building profiles

[0094] Background: In the construction field, curtain wall brackets, window frames and other load-bearing materials need to be lightweight, high-strength and corrosion-resistant to cope with deformation problems caused by long-term loads, environmental corrosion (such as salt spray environments) and thermal expansion.

[0095] Material formula:

[0096] Magnesium (Mg): 0.65%

[0097] Silicon (Si): 0.6%

[0098] Manganese (Mn): 0.08%

[0099] Copper (Cu): 0.15%

[0100] Titanium (Ti): 0.1%

[0101] Zirconium (Zr): 0.1%

[0102] Rare Earth Elements:

[0103] Yttrium (Y): 0.1%

[0104] Cerium (Ce): 0.1%

[0105] Lanthanum (La): 0.05%

[0106] Strontium (Sr): 0.03%

[0107] Aluminum (Al): balance (total weight 100%).

[0108] Production process:

[0109] The semi-solid casting process is adopted, which is achieved through the following steps:

[0110] Melting: After the aluminum ingot is melted, magnesium, silicon, manganese and rare earth elements are added in sequence, the melt temperature is maintained at 700℃-750℃, and it is fully stirred.

[0111] Semi-solid treatment: Cool to the liquid-solid two-phase region (630°C) and use electromagnetic stirring technology (300 rpm, 30 min) to ensure grain refinement and uniform distribution.

[0112] Casting: The melt is injected into the preheated mold (350°C) and quickly cooled by the cooling medium to ensure the density of the profile.

[0113] Heat treatment: solution temperature 530℃, keep warm for 2h and then water cool; aging treatment 170℃, keep warm for 8h.

[0114] Performance Verification:

[0115] Tensile strength: 295MPa

[0116] Ductility: 12.5%

[0117] Corrosion resistance (salt spray test): In 5% salt solution, the corrosion rate is reduced to 0.15mdd (traditional 6063 alloy is 0.3mdd).

[0118] After 12 months of exposure to severe weather and salt spray environment, there was no significant degradation in structural performance.

[0119] Summary: The rare earth metal reinforced 6063 aluminum alloy in this embodiment significantly improves the corrosion resistance and stability under long-term load, and is particularly suitable for application in high-end building profiles (such as curtain wall brackets, window frames and roof beams), meeting the requirements of lightweight and durability.

[0120] Example 2: Application in transportation equipment components

[0121] Background: The requirements for materials in automobiles, aerospace, and rail transportation equipment focus on light weight, high strength, and fatigue resistance to meet the needs of high-speed operation and complex mechanical stress conditions.

[0122] Material formula:

[0123] Magnesium (Mg): 0.7%

[0124] Silicon (Si): 0.65%

[0125] Manganese (Mn): 0.07%

[0126] Copper (Cu): 0.2%

[0127] Titanium (Ti): 0.1%

[0128] Zirconium (Zr): 0.1%

[0129] Rare Earth Elements:

[0130] Yttrium (Y): 0.15%

[0131] Cerium (Ce): 0.1%

[0132] Lanthanum (La): 0.05%

[0133] Strontium (Sr): 0.03%

[0134] Aluminum (Al): balance (total weight 100%).

[0135] Production process:

[0136] Melting: Melt the aluminum ingot to 740℃, add strengthening and refining elements in sequence, and keep stirring evenly.

[0137] Semi-solid treatment: Cool to 620 °C and use an annular electromagnetic flow field (400 rpm, 25 min) to ensure homogenization of the solid and liquid phases.

[0138] Casting: The mold is preheated to 360°C and shaped by gradient cooling at a cooling rate of 12°C / mm.

[0139] Heat treatment: variable temperature solution treatment (520℃-550℃, 1.5h), double-stage aging (160℃ insulation for 6h, 180℃ insulation for 4h).

[0140] Performance Verification:

[0141] Tensile strength: 305MPa

[0142] Fatigue strength: 140MPa

[0143] Ductility: 11.8%

[0144] In the high-frequency vibration test of the automobile engine hood, the fatigue life is extended by 20%; in the thermal cycle test of aerospace components, the strength at high temperature is increased by 15%.

[0145] Summary: The high strength and fatigue resistance of the rare earth metal reinforced 6063 aluminum alloy in this embodiment make it particularly suitable for use in transportation equipment (such as aviation wing brackets, automobile engine hoods and rail vehicle body frames), meeting the performance requirements under complex dynamic stress environments.

[0146] Example 3: Application of structural parts in high temperature environment

[0147] Background: High-temperature industrial equipment (such as heat exchangers and industrial furnaces) requires materials to maintain stability under long-term high-temperature conditions while having good creep resistance and corrosion resistance.

[0148] Material formula:

[0149] Magnesium (Mg): 0.6%

[0150] Silicon (Si): 0.7%

[0151] Manganese (Mn): 0.1%

[0152] Copper (Cu): 0.1%

[0153] Titanium (Ti): 0.1%

[0154] Zirconium (Zr): 0.05%

[0155] Rare Earth Elements:

[0156] Yttrium (Y): 0.1%

[0157] Cerium (Ce): 0.1%

[0158] Lanthanum (La): 0.1%

[0159] Strontium (Sr): 0.02%

[0160] Aluminum (Al): balance (total weight 100%).

[0161] Production process:

[0162] Melting: melt the aluminum ingot to 745°C, add rare earth, titanium and zirconium and stir thoroughly (20 minutes).

[0163] Semi-solid treatment: Cool to 640°C and use mechanical stirring (350 rpm, 35 min) to form a stable semi-solid melt.

[0164] Casting: Preheat the mold to 370°C, control the cooling in zones, and form a cooling gradient of 20°C / mm.

[0165] Heat treatment: solution temperature 530℃, keep warm for 1.5h and then water cool; aging treatment 165℃, keep warm for 10h.

[0166] Performance Verification:

[0167] Tensile strength: 300MPa

[0168] High temperature strength (200℃): 190MPa

[0169] Creep resistance: The deformation rate at 200°C for 48 hours is only 0.05% (the traditional 6063 alloy is 0.15%).

[0170] Corrosion resistance: High temperature oxidation resistance is improved by 30%.

[0171] Summary: Rare earth metal reinforced 6063 aluminum alloy exhibits excellent strength and creep resistance under high temperature conditions, and is suitable for equipment such as industrial furnace frames, heat exchangers and high-temperature pipelines.

[0172] Test experiment

[0173] The comprehensive properties of rare earth reinforced 6063 aluminum alloy were tested, including tensile strength, yield strength, ductility, corrosion resistance, high temperature strength, creep resistance and fatigue strength.

[0174] Experimental methods

[0175] Tensile strength and yield strength: tested using a tensile testing machine in accordance with GB / T228.1-2020 standard.

[0176] Corrosion resistance: Through salt spray corrosion test (5% NaCl solution, 48h), measure the mass loss per unit time (mdd).

[0177] High temperature strength: Measure the tensile strength at 200°C.

[0178] Creep resistance: The plastic deformation rate is measured at 200°C and 50MPa constant stress for 48 hours.

[0179] Fatigue strength: Use a high-frequency fatigue testing machine to measure the maximum bearing stress after 10^7 cycles.

[0180]

[0181]

[0182] Note: mdd is the mass loss per unit area per unit time. The lower the value, the better the corrosion resistance.

[0183] Comparative experiment

[0184] Experiment 1: Performance comparison with traditional 6063 aluminum alloy

[0185] Traditional 6063 aluminum alloy and rare earth reinforced 6063 aluminum alloy were selected for performance comparison and testing of mechanical properties and corrosion resistance.

[0186] Experimental data

[0187] Performance Indicators Rare earth reinforced 6063 aluminum alloy Traditional 6063 aluminum alloy Tensile strength(MPa) 305 270 Yield strength(MPa) 250 220 Ductility(%) 11.8 10.5 Corrosion resistance (mdd)* 0.12 0.3 High temperature strength (MPa, 200℃) 200 160 Fatigue strength(MPa) 140 120

[0188] Summary: Rare earth-reinforced 6063 aluminum alloy has improved tensile strength, corrosion resistance and high-temperature strength by 13%, 60% and 25% respectively, while also showing excellent ductility and fatigue strength.

[0189] Experiment 2: Performance comparison of different rare earth addition amounts

[0190] The effects of different addition ratios of rare earth elements (yttrium, cerium, and lanthanum) on the properties of the alloy were tested, with the total addition amounts of rare earth elements being 0.1%, 0.2%, and 0.3%, respectively.

[0191] Experimental data

[0192]

[0193]

[0194] Summary: The overall performance is best when the total rare earth content is 0.2%. Too high an addition may lead to segregation of the rare earth phase and affect the performance.

[0195] Experiment 3: Effects of different cooling rates on grain size and properties

[0196] Different cooling rates (10℃ / mm, 15℃ / mm, 20℃ / mm) were used to test the changes in grain size and mechanical properties.

[0197] Experimental data

[0198] Cooling rate (℃ / mm) Grain size (μm) Tensile strength(MPa) Fatigue strength(MPa) 10 80 280 130 15 50 300 150 20 35 310 155

[0199] Summary: The cooling rate has a significant effect on the grain refinement effect. A cooling rate of 20℃ / mm significantly reduces the grain size and achieves the highest tensile strength and fatigue strength.

[0200] Final conclusion: Rare earth reinforced 6063 aluminum alloy has significantly improved mechanical properties, corrosion resistance and high temperature strength compared to traditional 6063 aluminum alloy, especially in dynamic loads and extreme environments.

[0201] The control of rare earth addition and cooling rate is the key to optimizing alloy properties. The combination of 0.2% rare earth content and 20℃ / mm cooling rate can achieve the best comprehensive performance.

[0202] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A rare earth metal reinforced 6063 aluminum alloy, characterized in that: In weight percent it includes: Magnesium 0.6%-0.7%; Silicon 0.5%-0.7%; Manganese 0.05%-0.1%; Copper 0.1%-0.3%; Titanium 0.05%-0.15%; Zirconium 0.05%-0.15%; Rare earth elements 0.1%-0.3%; Strontium 0.02%-0.05%; Aluminum 98%-99%.

2. The rare earth metal-reinforced 6063 aluminum alloy according to claim 1, characterized in that: The rare earth elements include: Yttrium 0.05%-0.1%; Cerium 0.05%-0.1%; Lanthanum 0.01%-0.05%.

3. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process, according to any one of claims 1-2, a rare earth metal reinforced 6063 aluminum alloy semi-solid casting process and its application, characterized in that: The following steps are involved: S1. Prepare high-purity aluminum ingots, magnesium, silicon, manganese, copper, titanium, zirconium, rare earth elements, and strontium, and pre-mix the rare earth elements to form a uniform composite rare earth additive; S2, placing a high-purity aluminum ingot in a vacuum melting furnace and heating it until it is completely melted, then adding strengthening elements and refining elements in sequence, and obtaining a melt with a specific primary crystal morphology through two-stage stirring and dynamic gas protection; S3, gradually cooling the melt from 700℃±5℃ to 625℃-640℃ in the liquid-solid two-phase region, and then using stirring-flow control technology to achieve grain refinement and microstructure homogenization under a limited flow field; S4, injecting the semi-solid treated melt into a metal mold with dynamic temperature control to obtain a casting; S5. Perform dynamic heat treatment on the casting in stages, including variable temperature solution treatment and fine aging treatment; S6. The scraps produced during the casting process are graded and screened and then reused in step S2.

4. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 3, characterized in that: The rare earth composite additive in step S1 is prepared by the following method: S11, mixing yttrium, cerium and lanthanum in a ratio of 1:1:0.5; S12, using a high temperature melting method under argon protection to melt the rare earth elements to form a uniform composite rare earth melt; S13. The composite rare earth is formed into a granular additive through a rapid cooling process, and the particle size is controlled at 0.05 mm-0.1 mm.

5. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 3, characterized in that: The order of adding strengthening elements in step S2 is: S21, first add magnesium, silicon and manganese, maintain the temperature at 720°C-740°C, and stir for 5min-10min; S22, then add the composite rare earth additive, maintain the temperature at 700°C, and stir for 10min-20min; S23. Finally, add titanium, zirconium and strontium, continue stirring for 10 min-15 min, and introduce argon protection at the same time.

6. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 3, characterized in that: The S3 step includes: S31, using a double-axis electromagnetic stirring device, controlling the stirring speed at 300rpm-500rpm, and combining cooling control technology to gradually cool the melt to the liquid-solid two-phase region of 625℃-640℃; S32. During the stirring process, a stable annular flow field is formed through the electromagnetic field to ensure that the solid and liquid phases are evenly distributed, and the solid content is controlled at 25%-35%; S33, control the stirring time to 25min-35min, and keep injecting protective gas into the melt surface during this process.

7. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 6, characterized in that: The protective gas injected in the step S33 includes but is not limited to one or more of sulfur hexafluoride, nitrogen, and argon.

8. The rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 3, characterized in that: The S4 step includes: S41, preheat the mold to 350℃-400℃, control the flow rate of cooling medium to form a temperature gradient of 10℃ / mm-20℃ / mm; S42, by installing a cooling auxiliary device on the outside of the mold, the cooling rate of the mold is controlled in different zones to perform direction control.

9. A rare earth metal reinforced 6063 aluminum alloy semi-solid casting process according to claim 3, characterized in that: The S5 step includes: S51, variable temperature solution treatment: the temperature is gradually increased from 520℃ to 550℃, the heating rate is controlled at 10℃ / min-15℃ / min, and the holding time is 1.5h; S52, fine aging treatment: double-stage aging is carried out in the range of 165℃-185℃, with the first stage keeping warm for 6h and the second stage keeping warm for 4h.

10. Application of a rare earth metal-reinforced 6063 aluminum alloy, according to the rare earth metal-reinforced 6063 aluminum alloy according to any one of claims 1-2, characterized in that: The alloy is used to manufacture industrial and civil structural parts that require high strength, corrosion resistance and thermal stability, including but not limited to building profiles, mechanical parts, transportation equipment components and structural parts used in high temperature environments.

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