Aluminum alloy modified by rare earth flux and preparation method thereof

Abstract

The present invention relates to the technical field of aluminum alloys, and more particularly to an aluminum alloy modified with a rare earth flux and a preparation method thereof, comprising the following steps: weighing aluminum alloy raw materials according to weight: 1-3 parts Si, 1-2 parts Mg, 1-2 parts Cu, 2-3 parts of a rare earth flux-based modifier, 0.2-0.5 parts Ni, 0.3-0.5 parts Ti, 0.1-0.2 parts B, 0.1-0.15 parts Sc, and 35-40 parts Al. The aluminum alloy modified with a rare earth flux of the present invention uses Si, Mg, Cu, Ni, Ti, B, Sc, and Al as raw materials, adds the rare earth flux-based modifier as a functional additive, and simultaneously performs ultrasonic treatment in a modified ultrasonic liquid and a blending heat improvement treatment, thereby achieving balanced and coordinated improvements in thermal conductivity, electrical conductivity, and impact toughness of the resulting alloy product.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum alloy modified by a rare earth flux and a preparation method thereof. Background Art

[0002] Aluminum alloys are the most widely used nonferrous structural materials in industry, with extensive applications in aviation, aerospace, automotive, machinery manufacturing, shipbuilding, and the chemical industry. The rapid development of the industrial economy has led to an increasing demand for welded aluminum alloy components, leading to in-depth research on the weldability of aluminum alloys.

[0003] Existing aluminum alloys have poor thermal conductivity. In order to improve the thermal conductivity of the product, it is easy to affect the impact toughness and electrical conductivity of the alloy. It is difficult to balance and coordinate the improvement of the thermal conductivity, electrical conductivity and impact toughness of the product. At the same time, the product has poor acid and alkali corrosion stability, and the acid and alkali concentration has a great influence on the stability of the product, which further limits the product's efficiency. Summary of the Invention

[0004] In view of the defects of the prior art, the purpose of the present invention is to provide an aluminum alloy modified by rare earth flux and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] The present invention provides a method for preparing an aluminum alloy modified by a rare earth flux, comprising the following steps:

[0007] Step 1: Weigh the aluminum alloy raw materials according to weight:

[0008] Si 1-3 parts, Mg 1-2 parts, Cu 1-2 parts, rare earth flux-based modifier 2-3 parts, Ni 0.2-0.5 parts, Ti 0.3-0.5 parts, B 0.1-0.2 parts, Sc 0.1-0.15 parts and Al 35-40 parts;

[0009] Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body;

[0010] Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body;

[0011] Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified with rare earth flux according to the present invention is obtained.

[0012] Preferably, the ultrasonic power of the ultrasonic treatment is 350-400W, the ultrasonic time is 20-30min, and the casting speed is 150mm / min;

[0013] The temperature of the thermal improvement treatment is 510-520°C for 1 hour, then cooled to 350°C at a rate of 2-5°C / min, kept warm for 30 minutes, and then air-cooled to room temperature.

[0014] Preferably, the preparation method of the rare earth flux-based modifier is:

[0015] S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution;

[0016] S02: treating the graphene at 210-220° C. for 10-20 min, then cooling to 60° C. at a rate of 1-3° C. / min and keeping the temperature, to obtain a thermally homogenized graphene body;

[0017] S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica;

[0018] The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux;

[0019] S04: The heat-homogenized graphene body and the rare earth flux-based nano-silica liquid are mixed and ball-milled in a weight ratio of 5:(2-3). After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier.

[0020] Preferably, the mass fraction of the sodium citrate solution is 2-5%; the mass fraction of the lanthanum chloride solution is 3-6%.

[0021] Preferably, the mixing and ball milling treatment is performed at a ball milling speed of 1200 to 1500 r / min, and the ball milling is performed for 2 hours.

[0022] Preferably, the preparation method of the modified ultrasonic liquid is:

[0023] S11: The silicon carbide whiskers are first stirred thoroughly in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0024] S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

[0025] Preferably, the ultrasonic modification treatment is performed at an ultrasonic power of 400 to 450 W and for 20 to 30 minutes.

[0026] Preferably, the modified liquid comprises the following raw materials in parts by weight:

[0027] 4-6 parts of kaolin, 7-11 parts of dopamine hydrochloride solution, 2-3 parts of wollastonite, 1-2 parts of silane coupling agent and 1-2 parts of stearic acid.

[0028] Preferably, the mass fraction of the dopamine hydrochloride solution is 4-6%; and the silane coupling agent is silane coupling agent KH550.

[0029] The present invention also provides an aluminum alloy modified with a rare earth flux and prepared by a method for preparing the aluminum alloy modified with a rare earth flux.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The aluminum alloy modified by rare earth flux of the present invention uses Si, Mg, Cu, Ni, Ti, B, Sc and Al as raw materials. By adding a modifier based on rare earth flux as a functional additive, and combining it with ultrasonic treatment in a modified ultrasonic liquid and a blending heat improvement treatment, the obtained alloy product has a balanced and coordinated improvement in thermal conductivity, electrical conductivity and impact toughness. At the same time, the product has excellent acid and alkali corrosion resistance and stability, and the product stability performance is still excellent at high acid and alkali concentrations;

[0032] 2. The rare earth flux-based modifier uses rare earth cerium powder and rare earth yttrium powder as a matrix and is dispersed with sodium citrate solution to better disperse the rare earth raw materials into the system interface. At the same time, nano-silica is immersed in lanthanum chloride solution to obtain lanthanum-doped nano-silica. The lanthanum-doped nano-silica is then blended with rare earth liquid, so that the raw materials can be better filled into the alloy system, the interfacial activity between the raw materials is optimized, and the grains are refined and strengthened during smelting, and the product performance is further improved. At the same time, the graphene is treated at 210-220°C for 10-20 minutes. After the treatment is completed, it is cooled to 60°C at a rate of 1-3°C / min. The activity of the graphene after thermal homogenization is more stable. The rare earth flux-based modifier obtained by coordinating with the rare earth flux-based nano-silica liquid can better coordinate and reinforce the raw materials, enhance the interface of the raw materials, improve the balance of thermal conductivity, electrical conductivity and impact toughness of the product, and improve the stability of product performance.

[0033] 3. The modified ultrasonic liquid uses silicon carbide whiskers activated by potassium permanganate solution to optimize the active efficiency of the silicon carbide whiskers, and then through preheating treatment, the whiskers can better cooperate with the modified liquid. The kaolin in the modified liquid is used as the base material, and wollastonite is used as an auxiliary agent. The lamellar kaolin is used to blend the needle-shaped wollastonite, and then the whisker-shaped whiskers are dispersed, so that the modified ultrasonic liquid can be better coordinated to optimize the alloy body and the wettability alloy. The dopamine hydrochloride solution, silane coupling agent and stearic acid in the modified liquid are synergistically matched to better improve the interface of the alloy body. At the same time, with the thermal improvement process, the grains are further strengthened and the alloy structure is reinforced, the alloy system structure is more compacted, and the performance of the product is further improved. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. 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 making creative efforts are within the scope of protection of the present invention.

[0035] The method for preparing an aluminum alloy modified with a rare earth flux according to the present embodiment comprises the following steps:

[0036] Step 1: Weigh the aluminum alloy raw materials according to weight:

[0037] Si 1-3 parts, Mg 1-2 parts, Cu 1-2 parts, rare earth flux-based modifier 2-3 parts, Ni 0.2-0.5 parts, Ti 0.3-0.5 parts, B 0.1-0.2 parts, Sc 0.1-0.15 parts and Al 35-40 parts;

[0038] Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body;

[0039] Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body;

[0040] Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified with rare earth flux according to the present invention is obtained.

[0041] The ultrasonic power of the ultrasonic treatment in this embodiment is 350-400W, and the ultrasonic time is 20-30min; the casting speed is 150mm / min;

[0042] The temperature of the thermal improvement treatment is 510-520°C for 1 hour, then cooled to 350°C at a rate of 2-5°C / min, kept warm for 30 minutes, and then air-cooled to room temperature.

[0043] The preparation method of the rare earth flux-based modifier of this embodiment is as follows:

[0044] S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution;

[0045] S02: treating the graphene at 210-220° C. for 10-20 min, then cooling to 60° C. at a rate of 1-3° C. / min and keeping the temperature, to obtain a thermally homogenized graphene body;

[0046] S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica;

[0047] The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux;

[0048] S04: The heat-homogenized graphene body and the rare earth flux-based nano-silica liquid are mixed and ball-milled in a weight ratio of 5:(2-3). After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier.

[0049] The mass fraction of the sodium citrate solution in this embodiment is 2-5%; the mass fraction of the lanthanum chloride solution is 3-6%.

[0050] The mixing and ball milling treatment in this embodiment is performed at a ball milling speed of 1200 to 1500 r / min, and the ball milling is performed for 2 hours.

[0051] The preparation method of the modified ultrasonic liquid of this embodiment is:

[0052] S11: The silicon carbide whiskers are first stirred thoroughly in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0053] S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

[0054] The ultrasonic modification treatment in this embodiment has an ultrasonic power of 400-450W and an ultrasonic treatment time of 20-30 minutes.

[0055] The modified solution of this embodiment includes the following raw materials in parts by weight:

[0056] 4-6 parts of kaolin, 7-11 parts of dopamine hydrochloride solution, 2-3 parts of wollastonite, 1-2 parts of silane coupling agent and 1-2 parts of stearic acid.

[0057] The mass fraction of the dopamine hydrochloride solution in this embodiment is 4-6%; the silane coupling agent is silane coupling agent KH550.

[0058] The present embodiment provides a method for preparing an aluminum alloy modified with a rare earth flux, which prepares an aluminum alloy modified with a rare earth flux.

[0059] Example 1.

[0060] The method for preparing an aluminum alloy modified with a rare earth flux according to the present embodiment comprises the following steps:

[0061] Step 1: Weigh the aluminum alloy raw materials according to weight:

[0062] Si 1 part, Mg 1 part, Cu 1 part, rare earth flux-based modifier 2 parts, Ni 0.2 parts, Ti 0.3 parts, B 0.1 parts, Sc 0.1 parts and Al 35 parts;

[0063] Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body;

[0064] Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body;

[0065] Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified with rare earth flux according to the present invention is obtained.

[0066] The ultrasonic power of the ultrasonic treatment in this embodiment is 350W, the ultrasonic time is 20min, and the casting speed is 150mm / min.

[0067] The temperature of the thermal improvement treatment is 510°C for 1 hour, then cooled to 350°C at a rate of 2°C / min, kept at this temperature for 30 minutes, and then air-cooled to room temperature.

[0068] The preparation method of the rare earth flux-based modifier of this embodiment is as follows:

[0069] S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution;

[0070] S02: treating the graphene at 210°C for 10 min, then cooling to 60°C at a rate of 1°C / min and keeping the temperature to obtain a thermally homogenized graphene body;

[0071] S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica;

[0072] The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux;

[0073] S04: The heat-homogenized graphene body and the rare earth flux-based nano-silica liquid are mixed in a weight ratio of 5:2 and subjected to ball milling. After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier.

[0074] The mass fraction of the sodium citrate solution in this embodiment is 2%; the mass fraction of the lanthanum chloride solution is 3%.

[0075] The mixing and ball milling process in this embodiment was performed at a ball milling speed of 1200 r / min for 2 h.

[0076] The preparation method of the modified ultrasonic liquid of this embodiment is:

[0077] S11: The silicon carbide whiskers are first stirred thoroughly in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at 55° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0078] S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

[0079] The ultrasonic modification treatment in this embodiment was performed with an ultrasonic power of 400 W and an ultrasonic treatment time of 20 min.

[0080] The modified solution of this embodiment includes the following raw materials in parts by weight:

[0081] 4 parts of kaolin, 7 parts of dopamine hydrochloride solution, 2 parts of wollastonite, 1 part of silane coupling agent and 1 part of stearic acid.

[0082] The mass fraction of the dopamine hydrochloride solution in this embodiment is 4%; the silane coupling agent is silane coupling agent KH550.

[0083] The present embodiment provides a method for preparing an aluminum alloy modified with a rare earth flux, which prepares an aluminum alloy modified with a rare earth flux.

[0084] Example 2.

[0085] The method for preparing an aluminum alloy modified with a rare earth flux according to the present embodiment comprises the following steps:

[0086] Step 1: Weigh the aluminum alloy raw materials according to weight:

[0087] 3 parts of Si, 2 parts of Mg, 2 parts of Cu, 3 parts of a rare earth flux-based modifier, 0.5 parts of Ni, 0.5 parts of Ti, 0.2 parts of B, 0.15 parts of Sc, and 40 parts of Al;

[0088] Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body;

[0089] Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body;

[0090] Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified with rare earth flux according to the present invention is obtained.

[0091] The ultrasonic power of the ultrasonic treatment in this embodiment is 400W, and the ultrasonic time is 30min; the casting speed is 150mm / min;

[0092] The temperature of the thermal improvement treatment is 520°C for 1 hour, then cooled to 350°C at a rate of 5°C / min, kept at this temperature for 30 minutes, and then air-cooled to room temperature.

[0093] The preparation method of the rare earth flux-based modifier of this embodiment is as follows:

[0094] S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution;

[0095] S02: treating the graphene at 220°C for 20 min, then cooling to 60°C at a rate of 3°C / min and keeping the temperature to obtain a thermally homogenized graphene body;

[0096] S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica;

[0097] The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux;

[0098] S04: The heat-homogenized graphene body and the rare earth flux-based nano-silica liquid are mixed in a weight ratio of 5:3 and subjected to ball milling. After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier.

[0099] The mass fraction of the sodium citrate solution in this embodiment is 5%; the mass fraction of the lanthanum chloride solution is 6%.

[0100] The mixing and ball milling process in this embodiment was performed at a ball milling speed of 1500 r / min for 2 h.

[0101] The preparation method of the modified ultrasonic liquid of this embodiment is:

[0102] S11: The silicon carbide whiskers are first stirred in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at 60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0103] S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

[0104] The ultrasonic modification treatment in this embodiment was performed at an ultrasonic power of 450 W and for 30 min.

[0105] The modified solution of this embodiment includes the following raw materials in parts by weight:

[0106] 6 parts of kaolin, 11 parts of dopamine hydrochloride solution, 3 parts of wollastonite, 2 parts of silane coupling agent and 2 parts of stearic acid.

[0107] The mass fraction of the dopamine hydrochloride solution in this embodiment is 6%; the silane coupling agent is silane coupling agent KH550.

[0108] The present embodiment provides a method for preparing an aluminum alloy modified with a rare earth flux, which prepares an aluminum alloy modified with a rare earth flux.

[0109] Example 3.

[0110] The method for preparing an aluminum alloy modified with a rare earth flux according to the present embodiment comprises the following steps:

[0111] Step 1: Weigh the aluminum alloy raw materials according to weight:

[0112] Si 2 parts, Mg 1.5 parts, Cu 1.5 parts, rare earth flux-based modifier 2.5 parts, Ni 0.35 parts, Ti 0.4 parts, B 0.15 parts, Sc 0.12 parts and Al 37.5 parts;

[0113] Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body;

[0114] Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body;

[0115] Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified with rare earth flux according to the present invention is obtained.

[0116] The ultrasonic power of the ultrasonic treatment in this embodiment is 375W, the ultrasonic time is 25min, and the casting speed is 150mm / min;

[0117] The temperature of the thermal improvement treatment is 515°C for 1 hour, then cooled to 350°C at a rate of 3.5°C / min, kept at this temperature for 30 minutes, and then air-cooled to room temperature.

[0118] The preparation method of the rare earth flux-based modifier of this embodiment is as follows:

[0119] S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution;

[0120] S02: treating the graphene at 215°C for 15 minutes, then cooling to 60°C at a rate of 2°C / min and keeping the temperature to obtain a thermally homogenized graphene body;

[0121] S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica;

[0122] The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux;

[0123] S04: The heat-homogenized graphene body and the rare earth flux-based nano-silica liquid are mixed and ball-milled in a weight ratio of 5:2.5. After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier.

[0124] The mass fraction of the sodium citrate solution in this embodiment is 3.5%; the mass fraction of the lanthanum chloride solution is 4.5%.

[0125] The mixing and ball milling treatment in this embodiment was performed at a ball milling speed of 1350 r / min and the ball milling was performed for 2 h.

[0126] The preparation method of the modified ultrasonic liquid of this embodiment is:

[0127] S11: The silicon carbide whiskers are first stirred thoroughly in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at 57.5° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0128] S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

[0129] The ultrasonic modification treatment in this embodiment was performed at an ultrasonic power of 425 W and for 25 min.

[0130] The modified solution of this embodiment includes the following raw materials in parts by weight:

[0131] 5 parts of kaolin, 9 parts of dopamine hydrochloride solution, 2.5 parts of wollastonite, 1.5 parts of silane coupling agent and 1.5 parts of stearic acid.

[0132] The mass fraction of the dopamine hydrochloride solution in this embodiment is 5%; the silane coupling agent is silane coupling agent KH550.

[0133] The present embodiment provides a method for preparing an aluminum alloy modified with a rare earth flux, which prepares an aluminum alloy modified with a rare earth flux.

[0134] Comparative Example 1.

[0135] The difference from Example 3 is that no rare earth flux-based modifier is added.

[0136] Comparative Example 2.

[0137] The difference from Example 3 is that no thermally homogenized graphene body is added in the preparation of the rare earth flux-based modifier.

[0138] Comparative Example 3.

[0139] The difference from Example 3 is that no rare earth flux-based nano-silica liquid is added during the preparation of the rare earth flux-based modifier.

[0140] Comparative Example 4.

[0141] The difference from Example 3 is that lanthanum-doped nano-silica is not added in the preparation of the nano-silica liquid based on rare earth flux.

[0142] Comparative Example 5.

[0143] The difference from Example 3 is that the lanthanum-doped nano-silicon dioxide is replaced by nano-silicon dioxide.

[0144] Comparative Example 6.

[0145] The difference from Example 3 is that no rare earth liquid is added in the preparation of the rare earth flux-based modifier.

[0146] Comparative Example 7.

[0147] The difference from Example 3 is that the preparation method of the rare earth liquid is different: rare earth yttrium powder is added to water at a weight ratio of 2:5 and stirred thoroughly to obtain the rare earth liquid.

[0148] Comparative Example 8.

[0149] The difference from Example 3 is that the modified ultrasonic liquid treatment was not used.

[0150] Comparative Example 9.

[0151] The difference from Example 3 is that no preheated silicon carbide whiskers are added to the modified ultrasonic liquid.

[0152] Comparative Example 10.

[0153] The difference from Example 3 is that the modifying liquid in the modified ultrasonic liquid is replaced by water.

[0154] The products of Examples 1 to 3 and Comparative Examples 1 to 10 were subjected to conventional performance tests of thermal conductivity, electrical conductivity and impact toughness. At the same time, the products were placed in 2% hydrochloric acid mist for 12 hours and then placed in 2% sodium hydroxide alkaline mist for 12 hours to test the acid and alkali stability of the products. The test results are as follows:

[0155]

[0156]

[0157] At the same time, the product was placed in 5% hydrochloric acid mist for 12 hours and then placed in 5% sodium hydroxide alkaline mist for 12 hours to test the high concentration acid and alkali stability. The test results are as follows;

[0158]

[0159]

[0160] It can be seen from Comparative Examples 1-10 and Examples 1-3;

[0161] The product of Example 3 has excellent thermal conductivity, electrical conductivity, and impact toughness, and the three can be improved in a coordinated manner. In addition, the product has excellent stability under acid and alkaline conditions, especially under high concentration acid and alkaline conditions, the product performance remains stable;

[0162] The present invention does not add a rare earth flux-based modifier or adopt a modified ultrasonic liquid treatment, which significantly deteriorates the performance of the product and significantly reduces the stability of the product under acidic and alkaline conditions. By using the two together, the synergistic effect is enhanced, and the performance of the product is significantly improved.

[0163] When the rare earth flux-based modifier is prepared without adding heat-homogenized graphene bodies or rare earth flux-based nano-silica liquid, the performance of the product deteriorates significantly.

[0164] In addition, the performance of the products tended to deteriorate to varying degrees when lanthanum-doped nano-silica was not added to the preparation of nano-silica liquid based on rare earth flux, nano-silica was used instead of lanthanum-doped nano-silica, rare earth liquid was not added to the preparation of modifier based on rare earth flux, and the preparation methods of rare earth liquid were different;

[0165] The rare earth solution obtained by the specific method of the present invention is combined with lanthanum-doped nano-silica to obtain a rare earth flux-based nano-silica solution, and then the rare earth flux-based modifier is prepared by blending the heat-homogenized graphene body. The product performance effect is the most obvious, and the effects of other methods are not as significant as those of the present invention.

[0166] When no preheated silicon carbide whiskers were added to the modified ultrasonic liquid and the modifying liquid in the modified ultrasonic liquid was replaced by water, the performance of the product showed a trend of deterioration. In particular, when the modifying liquid in the modified ultrasonic liquid was replaced by water, the product performance deteriorated more significantly. The modified ultrasonic liquid obtained by the specific method of the present invention had the most significant product performance effect.

[0167] The present invention further explores the product performance through the composition of the modified liquid;

[0168] The modified liquid includes the following raw materials in parts by weight:

[0169] 5 parts of kaolin, 9 parts of dopamine hydrochloride solution, 2.5 parts of wollastonite, 1.5 parts of silane coupling agent and 1.5 parts of stearic acid.

[0170] The mass fraction of the dopamine hydrochloride solution in this embodiment is 5%; the silane coupling agent is silane coupling agent KH550.

[0171] Experimental Example 1.

[0172] The only difference from Example 3 is that no kaolin is added to the modified solution.

[0173] Experimental Example 2.

[0174] The only difference from Example 3 is that wollastonite is not added to the modified solution.

[0175] Experimental Example 3.

[0176] The only difference from Example 3 is that the dopamine hydrochloride solution in the modified solution is replaced by water.

[0177] Experimental Example 4.

[0178] The only difference from Example 3 is that no silane coupling agent and stearic acid are added to the modified solution.

[0179] Experimental Example 5.

[0180] The only difference from Example 3 is that the mass fraction of the dopamine hydrochloride solution is 7%.

[0181] The product was placed in 5% hydrochloric acid mist for 12 hours and then placed in 5% sodium hydroxide alkaline mist for 12 hours to test the high concentration acid and alkali stability and test its performance;

[0182]

[0183]

[0184] It can be seen from Experimental Examples 1-5 that when wollastonite is not added to the modifying liquid, the performance of the product changes. Among the components of the modifying liquid, the performance deterioration is the most obvious, followed by the fact that kaolin is not added to the modifying liquid. At the same time, when the dopamine hydrochloride solution in the modifying liquid is replaced by water, and when the silane coupling agent and stearic acid are not added to the modifying liquid, the performance of the product tends to deteriorate. Therefore, the constituent raw materials of the modifying liquid are proprietary. It is also found that when the mass fraction of the dopamine hydrochloride solution is 7%, the performance of the product also tends to deteriorate. The mass fraction of the dopamine hydrochloride solution is also unique. Only within the range of the present invention, the product performance effect is the best, and only when the modifying liquid composition is obtained by using the specific raw materials of the present invention, the product performance effect is the most significant. Replacing the modifying liquid by other methods is not as significant as the effect of the present invention.

[0185] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0186] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing an aluminum alloy modified by a rare earth flux, characterized in that: The following steps are involved: Step 1: Weigh the aluminum alloy raw materials according to weight: Si 1-3 parts, Mg 1-2 parts, Cu 1-2 parts, rare earth flux-based modifier 2-3 parts, Ni 0.2-0.5 parts, Ti 0.3-0.5 parts, B 0.1-0.2 parts, Sc 0.1-0.15 parts and Al 35-40 parts; Step 2: feeding the above raw materials into a smelting furnace for complete smelting, and then pouring to obtain a casting body; Step 3: Immerse the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment. After the ultrasonic treatment is completed, filter and dry to obtain a modified alloy body; Step 4: thermally modifying the modified alloy body, after which the thermal modification and the treatment are completed to obtain an aluminum alloy modified with a rare earth flux; The preparation method of the rare earth flux-based modifier is as follows: S01: mixing rare earth cerium powder and rare earth yttrium powder in a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent in a weight ratio of 2:5 to a sodium citrate solution and stirring thoroughly to obtain a rare earth solution; S02: treating the graphene at 210-220°C for 10-20 minutes, then cooling to 60°C at a rate of 1-3°C / min and keeping the temperature to obtain a thermally homogenized graphene body; S03: immersing the nano-silica into a sufficient amount of lanthanum chloride solution and stirring thoroughly, then filtering and drying to obtain lanthanum-doped nano-silica; The lanthanum-doped nano-silica and rare earth liquid are stirred evenly in a weight ratio of 2:5 to obtain a nano-silica liquid based on a rare earth flux; S04: mixing the heat-homogenized graphene body and the nano-silica liquid based on rare earth flux in a weight ratio of 5:(2-3) and subjecting the mixture to ball milling. After the ball milling is completed, the mixture is filtered and dried to obtain a rare earth flux-based modifier. The preparation method of the modified ultrasonic liquid is: S11: The silicon carbide whiskers are first stirred thoroughly in a sufficient amount of a 5% by mass potassium permanganate solution, then filtered and dried, and the dried silicon carbide whiskers are preheated at a temperature of 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body; S12: ultrasonically modifying the preheated silicon carbide whisker body and the modifying liquid in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid; The modified liquid comprises the following raw materials in parts by weight: 4-6 parts of kaolin, 7-11 parts of dopamine hydrochloride solution, 2-3 parts of wollastonite, 1-2 parts of silane coupling agent and 1-2 parts of stearic acid.

2. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, characterized in that: The ultrasonic power of the ultrasonic treatment is 350-400W, the ultrasonic time is 20-30min; the casting speed is 150mm / min; The temperature of the thermal improvement treatment is 510~520℃ for 1h, then cooled to 350℃ at a rate of 2~5℃ / min, kept warm for 30min, and then air-cooled to room temperature.

3. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, characterized in that: The mass fraction of the sodium citrate solution is 2-5%; the mass fraction of the lanthanum chloride solution is 3-6%.

4. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, wherein: The mixing and ball milling treatment is performed at a ball milling speed of 1200-1500 r / min for 2 h.

5. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, characterized in that: The ultrasonic modification treatment is performed with an ultrasonic power of 400-450W and an ultrasonic treatment time of 20-30 minutes.

6. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, characterized in that: The mass fraction of the dopamine hydrochloride solution is 4-6%; the silane coupling agent is silane coupling agent KH550.

7. A rare earth flux-modified aluminum alloy prepared by the method for preparing a rare earth flux-modified aluminum alloy according to any one of claims 1 to 6.

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