High-performance rare earth aluminum alloy, preparation method and application of high-performance rare earth aluminum alloy in six-cylinder engine air inlet pipe

Abstract

The invention discloses a high-performance rare earth aluminum alloy which comprises the following components in percentage by mass: 6.5%-7.6% of Si, 1.2%-2.1% of Mg, 0.8%-1.3% of Cu, 0.05%-0.11% of Sr, 0.4%-0.9% of Zn, 0.4%-0.8% of Mn, 0.2%-0.7% of Fe, 1.1%-1.7% of Ni, 0.25%-0.44% of Ti, 0.07%-0.15% of Ba, 0.32%-0.9% of RE, no more than 0.4% of other metal and non-metal impurity elements in total, and the balance of Al. The preparation method comprises the steps of raw material preparation, smelting under specific temperature control, refining, die casting, solid solution quenching, aging treatment and the like. The aluminum alloy is good in high-temperature stability, has the characteristics of high strength and high toughness, and shows many advantages in application of the six-cylinder engine air inlet pipe.

Description

[Technical field]

[0001] The invention relates to the field of aluminum alloy preparation, and in particular to a high-performance rare earth aluminum alloy, a preparation method and application thereof in an intake pipe of a six-cylinder engine. [Background technology]

[0002] With the rapid development of the automobile industry, the performance of automobile engines has been continuously improved, and the performance requirements for intake pipes have become increasingly stringent. Aluminum alloys have occupied an important position in the field of engine intake pipe manufacturing due to their advantages such as good casting performance, high strength and toughness.

[0003] However, the performance of traditional aluminum alloys under high temperature and high load conditions faces many challenges. Under high temperature, aluminum alloys are prone to deformation, causing the shape of the intake pipe to change, affecting the intake efficiency; at the same time, the strength decreases, making the intake pipe prone to rupture when under pressure. These problems not only affect the normal operation of the engine, but may also reduce the service life of the engine.

[0004] In order to meet the requirements of automobile engines for intake pipe performance, it is imperative to develop a high-performance rare earth aluminum alloy for die-cast six-cylinder engine intake pipes. By optimizing the composition of aluminum alloys and improving the manufacturing process, the performance of aluminum alloys under high temperature and high load can be improved so that they can better adapt to the working environment of the engine intake pipe, which is of great significance to promoting the development of the automobile industry. This not only helps to improve the performance and reliability of the engine, but also contributes to energy conservation and emission reduction of automobiles.

[0005] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. [Summary of the invention]

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a high-performance rare earth aluminum alloy, a preparation method and an application thereof in an intake pipe of a six-cylinder engine.

[0007] To this end, the present invention adopts the following technical solutions:

[0008] A high-performance rare earth aluminum alloy comprises the following components, measured by mass percentage: Si: 6.5%-7.6%, Mg: 1.2%-2.1%, Cu: 0.8%-1.3%, Sr: 0.05%-0.11%, Zn: 0.4%-0.9%, Mn: 0.4%-0.8%, Fe: 0.2%-0.7%, Ni: 1.1%-1.7%, Ti: 0.25%-0.44%, Ba: 0.07%-0.15%, RE: 0.32%-0.9%, the total amount of other metal and non-metal impurity elements does not exceed 0.4%, and the rest is Al.

[0009] Preferably, the RE elements in the high-performance rare earth aluminum alloy composition include one or more of Y, Er, Gd, Ce, and La; wherein the addition ratio of each element is calculated by mass percentage as follows: Y: 0.13%-0.5%, Er: 0.03%-0.06%, Gd: 0.08%-0.14%, Ce: 0.03%-0.08%, La: 0.05-0.09%.

[0010] Preferably, the high-performance rare earth aluminum alloy includes the following components, calculated by mass percentage: Si: 7.0%, Mg: 1.6%, Cu: 1.0%, Sr: 0.08%, Zn: 0.6%, Mn: 0.6%, Fe: 0.4%, Ni: 1.4%, Ti: 0.35%, Ba: 0.10%, Y: 0.3%, Er: 0.06%, Gd: 0.1%, Ce: 0.05%, La: 0.07%, the total amount of other metal and non-metal impurity elements does not exceed 0.25%, and the rest is Al.

[0011] A method for preparing a high-performance rare earth aluminum alloy comprises the following steps:

[0012] S1. Raw material preparation: calculate and weigh the amount of each raw material of pure aluminum ingot, magnesium ingot, aluminum-nickel alloy, aluminum-zinc alloy, iron-aluminum alloy, aluminum-titanium alloy, electrolytic copper, aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-barium master alloy, and rare earth master alloy;

[0013] S2. Melting: adding pure aluminum ingots, magnesium ingots, and aluminum-silicon master alloys to a smelting furnace and heating them. During heating, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, aluminum-barium master alloys, and rare earth master alloys are placed at the side of the smelting furnace for preheating. After heating to 760-780°C and stirring to completely melt the alloy, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, and aluminum-barium master alloys are added, and the temperature is continued to rise to 785-815°C. After all the alloy elements are melted, an aluminum alloy melt is obtained. During this process, the alloy liquid is continuously stirred with a high-temperature resistant graphite stirring paddle;

[0014] S3. Refining; the temperature of the aluminum alloy melt is adjusted to 730-750 ° C, and a refining agent is sprayed for refining treatment. After the refining is completed, the aluminum alloy melt is allowed to stand for 15-20 minutes, the surface slag of the aluminum alloy melt is removed, and then the temperature is raised to 750-770 ° C, a rare earth master alloy is added, and argon gas is introduced for refining. The degassing time is 10-15 minutes. After the degassing is completed, the composition of the aluminum alloy melt is inspected, and the second slag is removed after the inspection is qualified to complete the refining process; the refined aluminum alloy melt is allowed to stand until the temperature of the aluminum alloy melt drops to 700 ° C;

[0015] S4: Die casting: preheat the mold to 145-155°C, spray a water-based mold release agent into the mold cavity, continue to preheat the mold cavity to 220-260°C, and then inject the aluminum alloy melt treated in step S3 into the mold cavity for die casting;

[0016] S5: Solution quenching and aging treatment: The quenching heating temperature is 510-550℃, the quenching holding time is 1-1.5h, and the parking time after quenching is 3.5h; the quenched aluminum alloy die casting is placed in an aging furnace for three-stage treatment, and high-performance rare earth aluminum alloy is produced after completion.

[0017] Preferably, the rare earth master alloy includes one or more of yttrium-magnesium alloy, aluminum-erbium alloy, aluminum-gadolinium alloy, aluminum-cerium alloy, and aluminum-lanthanum alloy.

[0018] Preferably, the amount of the refining agent added is 2-5% of the mass of the aluminum alloy melt.

[0019] Preferably, the refining agent comprises the following components by mass percentage: CaF2: 3wt%, Na3A1F6: 12wt%, MgCl2: 10wt%, NaCl: 40wt%, NaNO3: 10wt%, KCl: 10wt%;

[0020] The preparation method of the refining agent comprises the following steps:

[0021] a. Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, dry them under the protection of argon gas, set the temperature at 100℃, and dry them for 2 hours to remove moisture;

[0022] b. The pretreated raw material powders were mixed evenly and placed in a ball mill, and grinding balls were added, the ball-to-material ratio was set to 15:1, the speed was set to 350 rpm, the ball milling time was 1.5 h, and the ball milling was performed;

[0023] c. The ball-milled powder is placed in a crucible, and the crucible is then placed in a muffle furnace and sintered at 600°C for 2h;

[0024] d. The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 150; unqualified large particles are removed to obtain the finished refining agent.

[0025] Preferably, the S4 die-casting process is as follows: the molten metal flow rate at the beginning of filling is 0.22-0.26 m / s, and the casting pressure is 50-55 MPa; after the filling rate exceeds 30%, the molten metal flow rate is 0.75-0.97 m / s, and the casting pressure is 58-62 MPa; after the filling rate exceeds 60%, the molten metal flow rate is increased to 1.50-1.73 m / s, and the casting pressure is 68-73 MPa; when the filling rate is 90%, the aluminum alloy molten metal flow rate is 1.88-1.96 m / s, and the casting pressure is 74-80 MPa, until the filling die-casting is completed.

[0026] Preferably, the three-stage processing steps in S5 are as follows:

[0027] Aging stage 1: Aging temperature is 100-120℃, and aging treatment time is 1.2-1.5h;

[0028] Aging stage 2: Aging temperature is 125-155℃, and aging treatment time is 1.5-2h;

[0029] Three stages of aging: aging temperature is 160-200℃, and aging treatment time is 2-4h.

[0030] The present invention also provides an application of the high-performance rare earth aluminum alloy produced according to the method in manufacturing an intake pipe of a six-cylinder engine.

[0031] The design principle of the aluminum alloy raw material composition of the present invention is as follows:

[0032] 1. The main alloy elements work together to build a comprehensive performance foundation

[0033] Strengthening mechanism of Si-Mg-Cu system: Silicon (Si) and magnesium (Mg) interact during the aging heat treatment process to precipitate the Mg2Si strengthening phase, which significantly improves the strength of the alloy. At the same time, Cu and Al form the Al2Cu strengthening phase, further enhancing the strengthening effect of the alloy. Si can also improve the casting properties of the alloy, lower the melting point, and increase fluidity, which is conducive to the molding of complex-shaped castings. This synergistic effect between Si, Mg, and Cu effectively improves the strength while ensuring that the alloy has good casting properties, laying the foundation for the alloy to be used in components such as engine intake pipes that have high requirements for strength and shape accuracy.

[0034] Optimization of high temperature performance by Ni and Ti: Nickel (Ni) and titanium (Ti) play a key role in optimizing the high temperature performance of the alloy. Ni works in synergy with elements such as Cu and Mg to form stable intermetallic compounds, improve the mechanical properties and creep resistance of the alloy at high temperatures, and ensure that the alloy operates stably for a long time under high temperature conditions of the engine. As a grain refiner, Ti forms heterogeneous nucleation cores such as TiAl3 and refines the grain structure, which not only enhances the strength and toughness of the alloy, but also improves its fatigue resistance, enabling the alloy to maintain good performance in high temperature and high stress environments, extending the service life of components such as the engine intake pipe.

[0035] Contributions of Ba, Zn, Mn, and Fe to multiple properties: Barium (Ba) improves alloy fluidity, improves casting performance, reduces casting defects, and ensures high-quality molding of complex-shaped castings such as intake pipes. Zinc (Zn) improves corrosion resistance while increasing alloy strength, increasing the service life of the alloy in corrosive environments, which is particularly important for engine intake pipes that may come into contact with corrosive media such as water vapor and acidic substances. Manganese (Mn) refines grains, reduces thermal cracking tendencies, stabilizes comprehensive performance, and ensures that the alloy can work reliably under various working conditions. Iron (Fe) forms strengthening compounds with other elements in appropriate amounts to enhance strength and hardness, and to a certain extent improves casting performance and wear resistance, adapting to the friction and wear conditions that the engine intake pipe may face during operation.

[0036] 2. Unique role of rare earth elements and synergistic improvement of alloy performance upper limit

[0037] Synergy between grain refinement and organizational optimization: Rare earth elements such as yttrium (Y), erbium (Er) and lanthanum (La) have a synergistic effect in grain refinement. Y forms a dispersed phase at the grain boundary to hinder grain growth, Er reduces the dendrite spacing and improves the solidification organizational morphology, and La further refines the grains. The three work together to make the grain structure finer and more uniform. This refined grain structure provides a better strength and toughness foundation for the alloy, while improving the stability of the alloy, which helps to improve the performance of the engine intake pipe under complex stress and working environments.

[0038] Enhanced and stable high-temperature performance: The intermetallic compounds formed by Y, Mg and Al improve heat resistance, and Gd cooperates with them to optimize high-temperature creep resistance and mechanical stability, so that the alloy can maintain good performance under high-temperature conditions of the engine. For example, in the intake pipe of a six-cylinder engine, high-temperature stability ensures the reliability of the intake system under long-term high-temperature operation, maintains the efficient power output of the engine, and reduces the risk of engine failure caused by deformation or performance degradation of the intake pipe.

[0039] Improved corrosion and oxidation resistance: Ce's ability to deoxidize, desulfurize, and preferentially oxidize to form a protective film, combined with Gd's ability to optimize the passive film structure, effectively improves the alloy's oxidation and corrosion resistance. In engine intake pipe applications, this performance can prevent the intrusion of corrosive media, maintain structural integrity and performance stability, avoid leakage and damage caused by corrosion, improve the reliability of the engine intake system, extend the service life of the intake pipe, and reduce maintenance costs.

[0040] 3. Precise control of ingredients to achieve performance balance and optimization

[0041] Precise balance of the content of main alloying elements: Precise control of the content of each main alloying element is crucial. For example, the Si content needs to be between 6.5% and 7.6%. Too high will increase brittleness, while too low will not fully play its role in synergistic strengthening with other elements. The content of elements such as Mg, Cu, and Ni must also be strictly controlled within a specific range to ensure the best effect in mechanisms such as solid solution strengthening, aging strengthening, and the formation of intermetallic compounds, to achieve a balance of multiple performance aspects such as strength, toughness, heat resistance, and casting performance, and to meet the use requirements of the engine intake pipe under complex working conditions.

[0042] Optimization and synergy of rare earth element ratios: The total amount of rare earth elements and the ratio between each element also affect the performance of the alloy. The unique effects of different rare earth elements cooperate with each other, such as the reasonable ratio of Y, Er, Gd, Ce, La and other elements, so that they can play a synergistic effect in grain refinement, strengthening phase formation, and anti-oxidation corrosion. When the Y content is in the range of 0.13%-0.5%, Er in the range of 0.03%-0.06%, Gd in the range of 0.08%-0.14%, Ce in the range of 0.03%-0.08%, and La in the range of 0.05%-0.09%, the comprehensive performance of the alloy can be optimized, and the rare earth elements can give full play to the improvement of the alloy performance, so that it can show excellent performance advantages in engine intake pipe applications.

[0043] Through the careful design and in-depth understanding of the synergistic effects of the main alloying elements and rare earth elements, as well as the precise control of the content of each element, the aluminum alloy raw material composition design of the present invention can achieve an optimized combination of high performance, meet the strict requirements of high-performance components such as six-cylinder engine intake pipes on aluminum alloy materials in multiple performance aspects, and provide reliable material support for the development of automobile engine technology.

[0044] The beneficial effects of the present invention include:

[0045] 1. High temperature stability ensures efficient operation of the engine

[0046] When a six-cylinder engine is working, the intake pipe is in a high-temperature environment. The rare earth elements (such as Y, Gd, etc.) in the aluminum alloy of the present invention form stable intermetallic compounds with other alloying elements, which have excellent thermal stability and can hinder dislocation movement and grain boundary sliding at high temperatures. Compared with traditional aluminum alloy intake pipes, the product of the present invention has less strength loss at high temperatures, can effectively resist high-temperature impact, maintain the stability of the engine intake system, ensure efficient power output, and reduce the risk of reduced intake efficiency due to deformation of the intake pipe.

[0047] 2. High strength and high toughness extend the service life of the intake pipe

[0048] The reasonable proportion of the main alloy elements and the synergistic effect of rare earth elements make the aluminum alloy have both high strength and good toughness. The working conditions of the engine are complex, and the intake pipe needs to withstand a variety of external forces. The high strength of the aluminum alloy of the present invention can resist external forces to avoid rupture, and the good toughness enables it to absorb energy through plastic deformation and improve fatigue resistance. This helps the intake pipe maintain structural integrity during long-term use, significantly prolongs its service life, reduces the number of repairs and replacements of the engine due to intake pipe failure, and reduces maintenance costs.

[0049] 3. Optimize casting performance to ensure the quality of intake pipe molding

[0050] The element Ba improves the fluidity of aluminum alloys. When casting complex-shaped castings such as the intake pipe of a six-cylinder engine, the alloy liquid can fill the mold cavity more smoothly, reducing casting defects such as pores and shrinkage. Rare earth elements refine the grains and optimize the alloy composition, making the intake pipe uniform and dense after casting, improving mechanical properties and surface quality, ensuring size and shape accuracy, ensuring precise matching with other engine components, and improving the overall assembly quality and performance stability of the engine.

[0051] 4. Good corrosion resistance improves engine system reliability

[0052] The dense protective film formed by rare earth elements such as Ce and the passivation film structure optimized by elements such as Gd effectively prevent the corrosion of the intake pipe by corrosive media (such as water vapor and acidic substances in the engine working environment). During the long-term use of the engine, the corrosion resistance of the intake pipe is enhanced, which can maintain the structural integrity and performance stability, avoid leakage and damage caused by corrosion, improve the reliability of the engine intake system, reduce engine failures caused by intake pipe corrosion, and ensure the safe and stable operation of the engine.

[0053] 5. Comprehensive performance advantages help engines save energy and reduce emissions

[0054] The aluminum alloy intake pipe of the present invention has advantages in many aspects of performance, which enables the engine to run stably and efficiently. The stable intake system is conducive to accurately controlling the oil-gas mixture ratio, making combustion more complete, improving fuel utilization, and reducing fuel consumption and tail gas emissions. The long life and high reliability of the intake pipe reduce energy consumption and waste emissions caused by parts replacement, helping the engine achieve energy conservation and emission reduction goals, and meeting the environmental protection and energy conservation requirements of the automotive industry.

Brief Description of the Drawings

[0055] Figure 1 This is a product picture of the six-cylinder engine intake pipe prepared in Example 1 of the present invention. [Specific implementation method]

[0056] The foregoing has broadly described the features and technical advantages of the present invention so that the detailed description of the present invention can be better understood. Other features and advantages of the present invention will be described below. It should be understood by those skilled in the art that the disclosed concepts and specific embodiments can be easily used as a basis for modifying or designing other structures to accomplish the same purpose of the present invention. It should also be recognized by those skilled in the art that such equivalent constructions do not deviate from the spirit and scope of the present invention. The novel features, structures and methods of operation thereof, and further objects and advantages that are considered to be characteristic of the present invention will be better understood from the following description. However, it should be deeply recognized that each feature provided is only for description and illustration, and is not intended to limit the definition of the present invention.

[0057] In an embodiment of the present invention, the high performance rare earth aluminum alloy comprises the following components, measured by mass percentage: Si: 6.5%-7.6%, Mg: 1.2%-2.1%, Cu: 0.8%-1.3%, Sr: 0.05%-0.11%, Zn: 0.4%-0.9%, Mn: 0.4%-0.8%, Fe: 0.2%-0.7%, Ni: 1.1%-1.7%, Ti: 0.25%-0.44%, Ba: 0.07%-0.15%, RE: 0.32%-0.9%, the total amount of other metal and non-metal impurity elements does not exceed 0.4%, and the rest is Al.

[0058] The RE elements in the high-performance rare earth aluminum alloy composition include one or more of Y, Er, Gd, Ce, and La; the addition ratio of each element is calculated by mass percentage as follows: Y: 0.13%-0.5%, Er: 0.03%-0.06%, Gd: 0.08%-0.14%, Ce: 0.03%-0.08%, and La: 0.05-0.09%.

[0059] The method for preparing the high-performance rare earth aluminum alloy comprises the following steps:

[0060] S1. Raw material preparation: calculate and weigh the amount of each raw material of pure aluminum ingot, magnesium ingot, aluminum-nickel alloy, aluminum-zinc alloy, iron-aluminum alloy, aluminum-titanium alloy, electrolytic copper, aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-barium master alloy, and rare earth master alloy; the rare earth master alloy includes one or more of yttrium-magnesium alloy, aluminum-erbium alloy, aluminum-gadolinium alloy, aluminum-cerium alloy, and aluminum-lanthanum alloy;

[0061] S2. Melting: adding pure aluminum ingots, magnesium ingots, and aluminum-silicon master alloys to a smelting furnace and heating them. During heating, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, aluminum-barium master alloys, and rare earth master alloys are placed at the side of the smelting furnace for preheating. After heating to 760-780°C and stirring to completely melt the alloy, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, and aluminum-barium master alloys are added, and the temperature is continued to rise to 785-815°C. After all the alloy elements are melted, an aluminum alloy melt is obtained. During this process, the alloy liquid is continuously stirred with a high-temperature resistant graphite stirring paddle;

[0062] S3. Refining; the temperature of the aluminum alloy melt is adjusted to 730-750 ° C, and a refining agent is sprayed for refining treatment. The amount of the refining agent added is 2-5% of the mass of the aluminum alloy melt; after the refining is completed, the aluminum alloy melt is allowed to stand for 15-20 minutes, the surface slag of the aluminum alloy melt is removed, and then the temperature is raised to 750-770 ° C, a rare earth master alloy is added, and argon gas is introduced for refining. The degassing time is 10-15 minutes. After the degassing is completed, the composition of the aluminum alloy melt is inspected, and the second slag is removed after the inspection is qualified to complete the refining process; the refined aluminum alloy melt is allowed to stand until the temperature of the aluminum alloy melt drops to 700 ° C;

[0063] S4: Die casting: preheat the mold to 145-155°C, spray the water-based release agent into the mold cavity, continue to preheat the mold cavity to 220-260°C, and then inject the aluminum alloy melt treated in step S3 into the mold cavity for die casting; the melt flow rate at the beginning of filling is 0.22-0.26m / s and the casting pressure is 50-55MPa; after the filling rate exceeds 30%, the melt flow rate is 0.75-0.97m / s and the casting pressure is 58-62MPa; after the filling rate exceeds 60%, increase the melt flow rate to 1.50-1.73m / s and the casting pressure to 68-73MPa; when the filling rate is 90%, the aluminum alloy melt flow rate is 1.88-1.96m / s and the casting pressure is 74-80MPa, until the filling die casting is completed;

[0064] S5: Solution quenching and aging treatment: the quenching heating temperature is 510-550℃, the quenching holding time is 1-1.5h, and the parking time after quenching is 3.5h; the quenched aluminum alloy die casting is placed in an aging furnace for three-stage treatment: Aging stage 1: aging temperature is 100-120℃, aging treatment time is 1.2-1.5h; Aging stage 2: aging temperature is 125-155℃, aging treatment time is 1.5-2h; Aging stage 3: aging temperature is 160-200℃, aging treatment time is 2-4h; after completion, high-performance rare earth aluminum alloy is produced.

[0065] The refining agent comprises the following components by mass percentage: CaF2: 3wt%, Na3A1F6: 12wt%, MgCl2: 10wt%, NaCl: 40wt%, NaNO3: 10wt%, KCl: 10wt%;

[0066] The preparation method of the refining agent comprises the following steps:

[0067] a. Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, dry them under the protection of argon gas, set the temperature at 100℃, and dry them for 2 hours to remove moisture;

[0068] b. The pretreated raw material powders were mixed evenly and placed in a ball mill, and grinding balls were added at the same time. The ball-to-material ratio was set to 15:1, the speed was set to 350 rpm, the ball milling time was 1.5 h, and the ball milling was performed;

[0069] c. The ball-milled powder is placed in a crucible, and the crucible is then placed in a muffle furnace and sintered at 600°C for 2h;

[0070] d. The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 150; unqualified large particles are removed to obtain the finished refining agent.

[0071] In order to make the disclosure of the present invention more complete, it is described below through more specific embodiments.

[0072] Example 1

[0073] A high-performance rare earth aluminum alloy comprises the following components, measured by mass percentage: Si: 7.0%, Mg: 1.6%, Cu: 1.0%, Sr: 0.08%, Zn: 0.6%, Mn: 0.6%, Fe: 0.4%, Ni: 1.4%, Ti: 0.35%, Ba: 0.10%, Y: 0.3%, Er: 0.06%, Gd: 0.1%, Ce: 0.05%, La: 0.07%, the total amount of other metal and non-metal impurity elements does not exceed 0.25%, and the rest is Al.

[0074] The method for preparing the high-performance rare earth aluminum alloy comprises the following steps:

[0075] S1. Raw material preparation: calculate and weigh the amount of each raw material of pure aluminum ingot, magnesium ingot, aluminum-nickel alloy, aluminum-zinc alloy, iron-aluminum alloy, aluminum-titanium alloy, electrolytic copper, aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-barium master alloy, and rare earth master alloy; the rare earth master alloy includes yttrium-magnesium alloy, aluminum-erbium alloy, aluminum-gadolinium alloy, aluminum-cerium alloy, and aluminum-lanthanum alloy;

[0076] S2. Melting: adding pure aluminum ingots, magnesium ingots, and aluminum-silicon master alloys to a smelting furnace and heating them. During the heating, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, aluminum-barium master alloys, and rare earth master alloys are placed at the side of the smelting furnace for preheating. After heating to 775° C. and stirring to completely melt the alloy, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, and aluminum-barium master alloys are added, and the temperature is continued to rise to 805° C. After all the alloy elements are melted, an aluminum alloy melt is obtained. During this process, the alloy liquid is continuously stirred with a high-temperature resistant graphite stirring paddle;

[0077] S3. Refining; the temperature of the aluminum alloy melt was adjusted to 745 ° C, and a refining agent was sprayed into the refining treatment, the amount of the refining agent added was 4% of the mass of the aluminum alloy melt; after the refining was completed, the surface slag of the aluminum alloy melt was removed, and then the temperature was raised to 766 ° C, a rare earth master alloy was added, and argon was introduced for refining. The degassing time was 13 minutes. After the degassing was completed, the composition of the aluminum alloy melt was inspected, and the second slag was removed after the inspection was qualified to complete the refining process; the refined aluminum alloy melt was allowed to stand until the temperature of the aluminum alloy melt dropped to 700 ° C;

[0078] S4: Die casting: preheat the mold to 148°C, spray the water-based release agent into the mold cavity, continue to preheat the mold cavity to 242°C, and then inject the aluminum alloy melt treated in step S3 into the mold cavity for die casting; the melt flow rate at the beginning of filling is 0.23m / s and the casting pressure is 50MPa; after the filling rate exceeds 30%, the melt flow rate is 0.85m / s and the casting pressure is 60MPa; after the filling rate exceeds 60%, increase the melt flow rate to 1.66m / s and the casting pressure to 71MPa; when the filling rate is 90%, the aluminum alloy melt flow rate is 1.93m / s and the casting pressure is 76MPa, until the filling die casting is completed;

[0079] S5: Solution quenching and aging treatment: the quenching heating temperature is 540℃, the quenching holding time is 1.1h, and the parking time after quenching is 3.5h; the quenched aluminum alloy die casting is placed in an aging furnace for three-stage treatment: aging stage 1: aging temperature is 110℃, aging treatment time is 1.3h; aging stage 2: aging temperature is 135℃, aging treatment time is 1.8h; aging stage 3: aging temperature is 177℃, aging treatment time is 3h; after completion, a six-cylinder engine intake pipe product made of high-performance rare earth aluminum alloy is obtained, see Figure 1 .

[0080] The refining agent comprises the following components by mass percentage: CaF2: 3wt%, Na3A1F6: 12wt%, MgCl2: 10wt%, NaCl: 40wt%, NaNO3: 10wt%, KCl: 10wt%;

[0081] The preparation method of the refining agent comprises the following steps:

[0082] a. Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, dry them under the protection of argon gas, set the temperature at 100℃, and dry them for 2 hours to remove moisture;

[0083] b. The pretreated raw material powders were mixed evenly and placed in a ball mill, and grinding balls were added, the ball-to-material ratio was set to 15:1, the speed was set to 350 rpm, the ball milling time was 1.5 h, and the ball milling was performed;

[0084] c. The ball-milled powder is placed in a crucible, and the crucible is then placed in a muffle furnace and sintered at 600°C for 2h;

[0085] d. The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 150; unqualified large particles are removed to obtain the finished refining agent.

[0086] Example 2

[0087] A high-performance rare earth aluminum alloy, the mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is consistent with that in Example 1; the refining agent used and its preparation method are consistent with those in Example 1.

[0088] Example 3

[0089] A high-performance rare earth aluminum alloy, the mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is consistent with that in Example 1; the refining agent used and its preparation method are consistent with those in Example 1.

[0090] Comparative Example 1

[0091] The components are basically the same as those in Example 1, except that no rare earth elements are added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0092] Comparative Example 2

[0093] The components are basically the same as those in Comparative Example 1, except that rare earth element Y is added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0094] Comparative Example 3

[0095] The components are basically the same as those in Comparative Example 1, except that rare earth element Er is added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0096] Comparative Example 4

[0097] The components are basically the same as those in Comparative Example 1, except that rare earth element Gd is added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0098] Comparative Example 5

[0099] The components are basically the same as those in Comparative Example 1, except that rare earth element Ce is added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0100] Comparative Example 6

[0101] The components are basically the same as those in Comparative Example 1, except that rare earth element La is added. The mass percentages of the components except aluminum and impurity elements are shown in Table 1; the preparation method is the same as that in Example 1; the refining agent used and its preparation method are the same as those in Example 1.

[0102] The mass percentages of the components of the aluminum alloys described in Examples 1-3 and Comparative Examples 1-6, except aluminum and impurity elements, are shown in Table 1.

[0103] Table 1: Mass percentage of each component except aluminum and impurity elements in each embodiment and comparative example

[0104]

[0105]

[0106] The performance tests were conducted on the aluminum alloys prepared in Examples 1-3 and Comparative Examples 1-6. The tensile strength, yield strength and elongation of the aluminum alloys were tested at room temperature and at a high temperature of 300° C. The results are shown in Table 2.

[0107] Table 2 Performance test results of the products of the embodiments and comparative examples

[0108]

[0109] Comparing Examples 1-3 (containing multiple rare earth elements) with Comparative Example 1 (without rare earth elements), at room temperature, the tensile strength and yield strength of Examples 1-3 are significantly higher than those of Comparative Example 1, and the elongation is also significantly improved. For example, the room temperature tensile strength of Example 1 reaches 459.8MPa, the yield strength is 437.5MPa, and the elongation is 5.98%; while the corresponding values ​​of Comparative Example 1 are 415.2MPa, 401.8MPa, and 3.31%, respectively. This shows that the addition of rare earth elements effectively improves the strength and plasticity of the alloy, and the reason is that rare earth elements such as Y, Er, Gd, Ce, La, etc. work synergistically with the main alloying elements to refine the grains and form stable intermetallic compounds, thereby enhancing the mechanical properties of the alloy.

[0110] At a high temperature of 300°C, Examples 1-3 also exhibited better performance. The high-temperature tensile strength of Example 1 was 370.2MPa, the yield strength was 369.0MPa, and the elongation was 7.12%; the high-temperature tensile strength of Comparative Example 1 was only 306.9MPa, the yield strength was 322.6MPa, and the elongation was 4.51%. Rare earth elements help to improve the high-temperature stability of the alloy, so that it can still maintain good strength and plasticity in a high-temperature environment, because the compounds formed by rare earth elements and other elements have good thermal stability at high temperatures, hindering dislocation movement and grain boundary sliding.

[0111] Effect of yttrium Y: In comparative example 2, only Y is added. Compared with comparative example 1, at room temperature, the tensile strength of comparative example 2 is 423.4MPa and the yield strength is 410.2MPa, which are higher than those of comparative example 1, and the elongation is 4.12%, which is also higher, but both are lower than those of example 1. At high temperature, the tensile strength of comparative example 2 is 313.6MPa and the yield strength is 330.3MPa, which are higher than those of comparative example 1, but still lower than those of example 1, and the elongation is 5.23%, which is higher than that of comparative example 1. This shows that Y has a certain improvement effect on the alloy performance when added alone, but it is not as significant as the effect of adding multiple rare earth elements in combination. Y has the effects of refining grains and improving heat resistance in the alloy, and can better exert its performance advantages when it works in synergy with other elements.

[0112] Effect of Er: In comparative example 3, only Er is added. Compared with comparative example 1, the tensile strength of 419.5MPa, yield strength of 404.9MPa and elongation of 3.66% at room temperature have certain changes, and the tensile strength of 310.5MPa, yield strength of 329.8MPa and elongation of 4.68% at high temperature have also changed. Er mainly contributes to the refinement of cast structure, the increase of recrystallization temperature and purity, etc. When added alone, the improvement of alloy performance is relatively limited, and it can more effectively optimize alloy performance when it works together with other rare earth elements.

[0113] Effect of gadolinium Gd: Comparative Example 4 only adds Gd. At room temperature, the tensile strength of 429.6MPa, yield strength of 415.8MPa and elongation of 4.23% are different from those of Comparative Example 1. The tensile strength of 319.1MPa, yield strength of 340.5MPa and elongation of 5.19% at high temperature also change. Gd can improve the strength, hardness, corrosion resistance and high temperature performance of the alloy. When added alone, it shows a certain performance improvement effect, but when multiple rare earth elements are added in combination, a better synergistic strengthening effect can be produced.

[0114] Effect of cerium Ce: Comparative Example 5 only adds Ce. Compared with Comparative Example 1, the tensile strength of 421.1MPa, yield strength of 408.5MPa and elongation of 3.85% at room temperature have changed, and the tensile strength of 312.0MPa, yield strength of 333.6MPa and elongation of 4.92% at high temperature have also changed. Ce's deoxidation, desulfurization, grain refinement and anti-oxidation effects make it have a certain influence on the alloy properties when added alone, and can further improve the comprehensive performance of the alloy when it works in synergy with other rare earth elements.

[0115] Effect of lanthanum La: In comparative example 6, only La is added. At room temperature, the tensile strength of 425.7MPa, the yield strength of 412.4MPa and the elongation of 4.29% are different from those of comparative example 1. The tensile strength of 316.8MPa, the yield strength of 338.5MPa and the elongation of 5.50% at high temperature are also different. La has an effect on grain refinement, strength and toughness improvement, and antioxidant and corrosion resistance enhancement. When added alone, it can improve the alloy properties to a certain extent, and when combined with other rare earth elements, it can better optimize the comprehensive properties of the alloy.

[0116] Those skilled in the art will recognize that numerous variations to the above description are possible, and that the examples are intended only to describe one or more specific implementations.

Claims

1. A high performance rare earth aluminum alloy, characterized in that: Calculated by mass percentage, it includes the following components: Si: 6.5%-7.6%, Mg: 1.2%-2.1%, Cu: 0.8%-1.3%, Sr: 0.05%-0.11%, Zn: 0.4%-0.9%, Mn: 0.4%-0.8%, Fe: 0.2%-0.7%, Ni: 1.1%-1.7%, Ti: 0.25%-0.44%, Ba: 0.07%-0.15%, RE: 0.32%-0.9%, the total amount of other metal and non-metal impurity elements does not exceed 0.4%, and the rest is Al.

2. A high performance rare earth aluminum alloy according to claim 1, characterized in that: The RE elements in the composition include one or more of Y, Er, Gd, Ce and La; the addition ratio of each element is calculated by mass percentage as follows: Y: 0.13%-0.5%, Er: 0.03%-0.06%, Gd: 0.08%-0.14%, Ce: 0.03%-0.08%, La: 0.05-0.09%.

3. A high performance rare earth aluminum alloy according to claim 1, characterized in that: The high-performance rare earth aluminum alloy includes the following components, calculated by mass percentage: Si: 7.0%, Mg: 1.6%, Cu: 1.0%, Sr: 0.08%, Zn: 0.6%, Mn: 0.6%, Fe: 0.4%, Ni: 1.4%, Ti: 0.35%, Ba: 0.10%, Y: 0.3%, Er: 0.06%, Gd: 0.1%, Ce: 0.05%, La: 0.07%, the total amount of other metal and non-metal impurity elements does not exceed 0.25%, and the rest is Al.

4. A method for preparing a high performance rare earth aluminum alloy according to claim 1-2 or 3, characterized in that: The following steps are involved: S1. Raw material preparation: calculate and weigh the amount of each raw material of pure aluminum ingot, magnesium ingot, aluminum-nickel alloy, aluminum-zinc alloy, iron-aluminum alloy, aluminum-titanium alloy, electrolytic copper, aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-barium master alloy, and rare earth master alloy; S2. Melting: adding pure aluminum ingots, magnesium ingots, and aluminum-silicon master alloys to a smelting furnace and heating them. During heating, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, aluminum-barium master alloys, and rare earth master alloys are placed at the side of the smelting furnace for preheating. After heating to 760-780° C. and stirring to completely melt the alloy, aluminum-nickel alloys, aluminum-zinc alloys, iron-aluminum alloys, aluminum-titanium alloys, electrolytic copper, aluminum-silicon master alloys, aluminum-manganese master alloys, and aluminum-barium master alloys are added, and the temperature is continued to rise to 785-815° C. After all the alloy elements are melted, an aluminum alloy melt is obtained. During this process, the alloy liquid is continuously stirred with a high-temperature resistant graphite stirring paddle; S3. Refining; the temperature of the aluminum alloy melt is adjusted to 730-750 ° C, and a refining agent is sprayed for refining. After the refining is completed, the aluminum alloy is allowed to stand for 15-20 minutes, the surface slag of the aluminum alloy melt is removed, and then the temperature is raised to 750-770 ° C, a rare earth master alloy is added, and argon gas is introduced for refining. The degassing time is 10-15 minutes. After the degassing is completed, the composition of the aluminum alloy melt is inspected, and the second slag is removed after the inspection is qualified to complete the refining process; the refined aluminum alloy melt is allowed to stand until the temperature of the aluminum alloy melt drops to 700 ° C; S4: Die casting: preheat the mold to 145-155°C, spray a water-based mold release agent into the mold cavity, continue to preheat the mold cavity to 220-260°C, and then inject the aluminum alloy melt treated in step S3 into the mold cavity for die casting; S5: Solution quenching and aging treatment: The quenching heating temperature is 510-550℃, the quenching holding time is 1-1.5h, and the parking time after quenching is 3.5h; the quenched aluminum alloy die casting is placed in an aging furnace for three-stage treatment, and high-performance rare earth aluminum alloy is produced after completion.

5. The method for preparing a high-performance rare earth aluminum alloy according to claim 4, characterized in that: The rare earth master alloy includes one or more of yttrium-magnesium alloy, aluminum-erbium alloy, aluminum-gadolinium alloy, aluminum-cerium alloy, and aluminum-lanthanum alloy.

6. The method for preparing a high-performance rare earth aluminum alloy according to claim 4, characterized in that: The amount of the refining agent added is 2-5% of the mass of the aluminum alloy melt.

7. The method for preparing a high-performance rare earth aluminum alloy according to claim 4, characterized in that: The refining agent comprises the following components by mass percentage: CaF2: 3wt%, Na3A1F6: 12wt%, MgCl2: 10wt%, NaCl: 40wt%, NaNO3: 10wt%, KCl: 10wt%; The preparation method of the refining agent comprises the following steps: a. Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, dry them under the protection of argon gas, set the temperature at 100℃, and dry them for 2 hours to remove moisture; b. The pretreated raw material powders were mixed evenly and placed in a ball mill, and grinding balls were added at the same time. The ball-to-material ratio was set to 15:1, the speed was set to 350 rpm, the ball milling time was 1.5 h, and the ball milling was performed; c. The ball-milled powder is placed in a crucible, and the crucible is then placed in a muffle furnace and sintered at 600°C for 2h; d. The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 150; unqualified large particles are removed to obtain the finished refining agent.

8. The method for preparing a high-performance rare earth aluminum alloy according to claim 4, characterized in that: The S4 die-casting process is as follows: the molten metal flow rate at the beginning of filling is 0.22-0.26m / s and the casting pressure is 50-55MPa; after the filling rate exceeds 30%, the molten metal flow rate is 0.75-0.97m / s and the casting pressure is 58-62MPa; after the filling rate exceeds 60%, the molten metal flow rate is increased to 1.50-1.73m / s and the casting pressure is 68-73MPa; when the filling rate is 90%, the aluminum alloy molten metal flow rate is 1.88-1.96m / s and the casting pressure is 74-80MPa until the filling die-casting is completed.

9. The method for preparing a high-performance rare earth aluminum alloy according to claim 4, characterized in that: The specific steps of the three-stage processing in S5 are: Aging stage 1: Aging temperature is 100-120℃, and aging treatment time is 1.2-1.5h; Aging stage 2: Aging temperature is 125-155℃, and aging treatment time is 1.5-2h; Three stages of aging: aging temperature is 160-200℃, and aging treatment time is 2-4h.

10. Use of a high-performance rare earth aluminum alloy produced according to the method according to any one of claims 4 to 9 in manufacturing an intake pipe of a six-cylinder engine.

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