Aluminum alloy based on rare earth flux modification and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloys, in particular to a rare earth flux-based modified aluminum alloy and a preparation method thereof, and the preparation method comprises the following steps: weighing the following aluminum alloy raw materials in parts by weight: 1-3 parts of Si, 1-2 parts of Mg, 1-2 parts of Cu, 2-3 parts of a rare earth flux-based modifier, 0.2-0.5 part of Ni, 0.3-0.5 part of Ti, 0.1-0.2 part of B, 0.1-0.15 part of Sc and 35-40 parts of Al; according to the aluminum alloy modified based on the rare earth flux, Si, Mg, Cu, Ni, Ti, B, Sc and Al are adopted as raw materials, the modifier based on the rare earth flux is added to serve as a functional auxiliary, ultrasonic treatment in modified ultrasonic liquid and blending heat improvement treatment are matched, and the heat conductivity, the electric conductivity and the impact toughness of an obtained alloy product are improved in a balanced and coordinated mode.

Description

Technical Field

[0001] The 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 alloy is the most widely used nonferrous metal structural material in industry, and has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and chemical industries. With the rapid development of industrial economy, the demand for aluminum alloy welded structural parts is increasing, which has led to in-depth research on the weldability of aluminum alloy.

[0003] Existing aluminum alloys have poor thermal conductivity. In order to improve the thermal conductivity of the product, the impact toughness and electrical conductivity of the alloy are easily affected. 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 product stability, 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 solution:

[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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed 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 by 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 at this temperature 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 at a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent to a sodium citrate solution at a weight ratio of 2:5 and stirring to obtain a rare earth solution;

[0016] S02: treating the graphene at 210-220° C. for 10-20 min, and 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide;

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

[0019] S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux 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 fluid is:

[0023] S11: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

[0024] S12: subjecting the preheated silicon carbide whisker body and the modified liquid to ultrasonic modification treatment 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 min.

[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 by a rare earth flux and prepared by a method for preparing the aluminum alloy modified by 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 adopts Si, Mg, Cu, Ni, Ti, B, Sc and Al as raw materials, and adds a modifier based on rare earth flux as a functional additive, and at the same time cooperates with ultrasonic treatment in modified ultrasonic liquid and blending heat improvement treatment, so that the thermal conductivity, electrical conductivity and impact toughness of the obtained alloy product are balanced and coordinated improved, and the product has excellent acid and alkali corrosion stability, and the acid and alkali concentration is high, and the product stability performance is still excellent;

[0032] 2. The rare earth flux-based modifier uses rare earth cerium powder and rare earth yttrium powder as the 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-silicon dioxide is immersed in lanthanum chloride solution to obtain lanthanum-doped nano-silicon dioxide. The lanthanum-doped nano-silicon dioxide is then blended with rare earth liquid, so that the raw materials can be better filled into the alloy system, and the interfacial activity between the raw materials is optimized, thereby refining the grains and strengthening the grains during smelting, and the product performance is further improved. At the same time, graphene is treated at 210-220°C for 10-20min, and then cooled to 60°C at a rate of 1-3°C / min after the treatment is completed. The activity of the graphene after thermal homogenization is more stable, and the rare earth flux-based nano-silicon dioxide liquid is coordinated to obtain a rare earth flux-based modifier that can better coordinate and reinforce the raw materials, enhance the interface of the raw materials, improve the balance and coordination of the 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 activity efficiency of 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 blended with 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 moisturize the 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 compact, 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 creative work are within the scope of protection of the present invention.

[0035] A method for preparing an aluminum alloy modified by 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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed 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 by rare earth flux according to the present invention is obtained.

[0041] The ultrasonic power of the ultrasonic treatment in this embodiment is 350-400W, the ultrasonic time is 20-30min; the casting speed of the pouring 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 at this temperature 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:

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

[0045] S02: treating the graphene at 210-220° C. for 10-20 min, and 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide;

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

[0048] S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux 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 process of this embodiment has a ball milling speed of 1200-1500 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: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

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

[0054] The ultrasonic power of the ultrasonic modification treatment in this embodiment is 400-450W, and the ultrasonic treatment is performed for 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 by a rare earth flux, and prepares an aluminum alloy modified by a rare earth flux.

[0059] Example 1.

[0060] A method for preparing an aluminum alloy modified by 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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed 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 by 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:

[0069] S01: mixing rare earth cerium powder and rare earth yttrium powder at a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent to a sodium citrate solution at a weight ratio of 2:5 and stirring 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide;

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

[0073] S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux are mixed and ball-milled in a weight ratio of 5:2. 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 carried out at a ball milling speed of 1200 r / min and the ball milling was carried out for 2 h.

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

[0077] S11: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 55° C. for 1 hour to obtain a preheated silicon carbide whisker body;

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

[0079] The ultrasonic power of the ultrasonic modification treatment in this embodiment is 400W, and the ultrasonic treatment is performed for 20 minutes.

[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 by a rare earth flux, and prepares an aluminum alloy modified by a rare earth flux.

[0084] Example 2.

[0085] A method for preparing an aluminum alloy modified by 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] Si 3 parts, Mg 2 parts, Cu 2 parts, rare earth flux-based modifier 3 parts, Ni 0.5 parts, Ti 0.5 parts, B 0.2 parts, Sc 0.15 parts and Al 40 parts;

[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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed 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 by 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 of the pouring 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:

[0094] S01: mixing rare earth cerium powder and rare earth yttrium powder at a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent to a sodium citrate solution at a weight ratio of 2:5 and stirring 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide;

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

[0098] S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux are mixed and ball-milled in a weight ratio of 5:3. 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 ball milling process in this embodiment has a ball milling speed of 1500 r / min and a ball milling time of 2 h.

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

[0102] S11: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 60° C. for 1 hour to obtain a preheated silicon carbide whisker body;

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

[0104] The ultrasonic power of the ultrasonic modification treatment in this embodiment is 450W, and the ultrasonic treatment is carried out for 30 minutes.

[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 by a rare earth flux, and prepares an aluminum alloy modified by a rare earth flux.

[0109] Example 3.

[0110] A method for preparing an aluminum alloy modified by 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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed 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 by 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 of the pouring 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:

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

[0120] S02: treating the graphene at 215°C for 15 min, 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide;

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

[0123] S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux 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 ball milling process in this embodiment was carried out at a ball milling speed of 1350 r / min and the ball milling was carried out for 2 h.

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

[0127] S11: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 57.5° C. for 1 hour to obtain a preheated silicon carbide whisker body;

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

[0129] The ultrasonic power of the ultrasonic modification treatment in this embodiment is 425W, and the ultrasonic treatment is carried out for 25 minutes.

[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 by a rare earth flux, and prepares an aluminum alloy modified by 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-silicon dioxide liquid is added in the preparation of the rare earth flux-based modifier.

[0140] Comparative Example 4.

[0141] The difference from Example 3 is that lanthanum-doped nano-silicon dioxide is not added in the preparation of the nano-silicon dioxide 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 into 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 is 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-base stability. The test results are as follows;

[0158]

[0159]

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

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

[0162] The present invention does not add a rare earth flux-based modifier, does not use a modified ultrasonic liquid treatment, and the performance of the product is significantly deteriorated, and the stability of the product under acid and alkaline conditions is significantly reduced. The two are used in coordination to synergistically enhance the performance of the product.

[0163] The performance of the product deteriorated significantly when the heat-homogenized graphene body was not added in the preparation of the rare earth flux-based modifier and the nano-silicon dioxide liquid based on the rare earth flux was not added in the preparation of the rare earth flux-based modifier;

[0164] In addition, the performance of the products tends to deteriorate to varying degrees when no lanthanum-doped nano-silicon dioxide is added to the preparation of nano-silicon dioxide liquid based on rare earth flux, nano-silicon dioxide is used to replace lanthanum-doped nano-silicon dioxide, rare earth liquid is not added to the preparation of modifier based on rare earth flux, and the preparation methods of rare earth liquid are different;

[0165] The rare earth liquid obtained by the specific method of the present invention is combined with the nano-silicon dioxide liquid based on rare earth flux obtained by lanthanum-doped nano-silicon dioxide, 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 other methods are not as significant as the effect 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, especially 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 liquid.

[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 liquid.

[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 mist for 12 hours to test the high concentration acid-base 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 has a tendency 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 has a tendency 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 modified 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0186] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description 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 may also be appropriately combined to form other implementation modes 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: immersing the casting body in a sufficient amount of modified ultrasonic liquid for ultrasonic treatment, and after the ultrasonic treatment is finished, filtering and drying are performed to obtain a modified alloy body; Step 4: thermal improvement treatment of the modified alloy body. After the thermal improvement and treatment are completed, the aluminum alloy modified by rare earth flux according to the present invention is obtained.

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 of the pouring is 150mm / min; 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 at this temperature for 30 minutes, 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 preparation method of the rare earth flux-based modifier is: S01: mixing rare earth cerium powder and rare earth yttrium powder at a weight ratio of 2:1 to obtain a composite rare earth agent, and then adding the composite rare earth agent to a sodium citrate solution at a weight ratio of 2:5 and stirring to obtain a rare earth solution; S02: treating the graphene at 210-220° C. for 10-20 min, and 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-silicon dioxide into a sufficient amount of lanthanum chloride solution and stirring it sufficiently, then filtering and drying it to obtain lanthanum-doped nano-silicon dioxide; The lanthanum-doped nano-silicon dioxide and the rare earth liquid are uniformly stirred in a weight ratio of 2:5 to obtain a nano-silicon dioxide liquid based on a rare earth flux; S04: The heat-homogenized graphene body and the nano-silicon dioxide liquid based on the rare earth flux 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.

4. The method for preparing an aluminum alloy modified by rare earth flux according to claim 3, 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%.

5. The method for preparing an aluminum alloy modified by rare earth flux according to claim 3, characterized in that: The mixing and ball milling treatment is performed at a ball milling speed of 1200-1500 r / min, and the ball milling is performed for 2 hours.

6. The method for preparing an aluminum alloy modified by rare earth flux according to claim 1, characterized in that: The preparation method of the modified ultrasonic liquid is: S11: Stir the silicon carbide whisker in a sufficient amount of 5% by mass potassium permanganate solution, then filter and dry, and preheat the dried silicon carbide whisker at 55-60° C. for 1 hour to obtain a preheated silicon carbide whisker body; S12: subjecting the preheated silicon carbide whisker body and the modified liquid to ultrasonic modification treatment in a weight ratio of 3:5, and completing the ultrasonic modification to obtain a modified ultrasonic liquid.

7. The method for preparing an aluminum alloy modified by rare earth flux according to claim 6, characterized in that: The ultrasonic modification treatment has an ultrasonic power of 400-450W and an ultrasonic treatment time of 20-30 minutes.

8. The method for preparing an aluminum alloy modified by rare earth flux according to claim 6, characterized in that: 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.

9. The aluminum alloy modified by rare earth flux according to claim 8, characterized in that: The mass fraction of the dopamine hydrochloride solution is 4-6%; the silane coupling agent is silane coupling agent KH550.

10. 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 9.

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