Die-casting aluminum alloy material and preparation method thereof

Abstract

The invention relates to the technical field of die-casting aluminum alloys, in particular to a die-casting aluminum alloy material and a preparation method thereof. The die-casting aluminum alloy material comprises, by mass, 8.7%-9.5% of Si, 0.5%-1.0% of Cu, 0.5%-0.7% of Ti, 0.5%-0.8% of Zn, 0.3%-0.6% of Mn, 0.2%-0.4% of Mg, 0.17%-0.35% of Co, 0.15%-0.25% of B, 0.2%-0.3% of Ni, smaller than or equal to 0.3% of Fe, smaller than or equal to 0.3% of inevitable impurity elements in total and the balance Al. The ratio of the content of Ti to the content of Co is (2-3): 1. When the die-casting aluminum alloy material is prepared, AlTi10 is added step by step, an ultrasonic-electromagnetic-ultrasonic treatment mode is adopted, meanwhile, technological parameters are accurately controlled, and therefore the obtained die-casting aluminum alloy material has excellent strength and heat resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of die-casting aluminum alloy, in particular to a die-casting aluminum alloy material and a preparation method thereof. BACKGROUND

[0002] Die-casting aluminum alloy is a metal part material formed by injecting aluminum or aluminum alloy heated to a liquid state into a mold through a die-casting process, and then cooling and solidifying to form a metal part material with a specific shape and size. Its core characteristics include lightweight (density about 2.7 g / cm³), good mechanical properties (such as high strength, impact resistance) and processing adaptability, which can realize precise forming of complex shapes through a mold.

[0003] At present, eutectic or near-eutectic aluminum-silicon alloy is the most important die-casting aluminum alloy, such as ADC12, A380, and AlSi10MnMg, which is the most widely used. With the development of new energy vehicles, conventional aluminum alloy materials cannot meet the use requirements of high-strength castings such as new energy vehicle motor housings.

[0004] In recent years, it has been found that low content of titanium element (≤0.2%) has a multi-dimensional effect on the improvement of aluminum alloy performance, and its core influence is reflected in grain refinement, strength improvement, heat resistance optimization, etc. For example, CN115961186B discloses a die-casting aluminum alloy material containing titanium 0.08-0.15% titanium element; CN117568671B discloses a die-casting aluminum alloy material containing Ti 0.1-0.134%, the strength of the above-mentioned die-casting aluminum alloy materials is improved to some extent.

[0005] However, due to the low content of titanium element in the above-mentioned die-casting aluminum alloy, it is difficult to effectively improve the heat resistance of the die-casting alloy. However, if the content of titanium element is increased, too much titanium element will cause abnormal grain growth to form coarse grains, which will reduce the performance of the material. This leads to the fact that Ti cannot be added in large quantities in aluminum alloy, and its improvement effect on the strength and heat resistance of aluminum alloy is limited. SUMMARY

[0006] To solve at least one of the above problems, the present application provides a die-casting aluminum alloy material and a preparation method thereof, which controls the content of each element in the alloy to increase the addition amount of Ti element, and the obtained die-casting aluminum alloy material has excellent strength and heat resistance.

[0007] In a first aspect, the present application provides a die-casting aluminum alloy material, comprising, in mass fraction: Si 8.7-9.5%, Cu 0.5-1.0%, Ti 0.5-0.7%, Zn 0.5-0.8%, Mn 0.3-0.6%, Mg 0.2-0.4%, Co 0.17-0.35%, B 0.15-0.25%, Ni 0.2-0.3%, Fe≤0.3%, unavoidable impurity elements≤0.3%, and the balance being Al; the ratio of Ti and Co contents is 2-3:1.

[0008] Optionally, the die-casting aluminum alloy material comprises, in mass fraction: Si 9.0-9.5%, Cu 0.5-1.0%, Ti 0.54-0.63%, Zn 0.5-0.6%, Mn 0.3-0.5%, Mg 0.2-0.4%, Co 0.18-0.31%, B 0.18-0.21%, Ni 0.2-0.3%, Fe≤0.3%, unavoidable impurity elements≤0.3%, and the balance being Al; the ratio of Ti and Co contents is 2-3:1, and the ratio of Ti and B contents is 3:1.

[0009] Optionally, the die-casting aluminum alloy material comprises, in mass fraction: Si 9.0-9.5%, Cu 0.5-1.0%, Ti 0.54-0.63%, Zn 0.5-0.6%, Mn 0.3-0.5%, Mg 0.2-0.4%, Co 0.18-0.31%, B 0.18-0.21%, Ni 0.2-0.3%, Fe≤0.3%, unavoidable impurity elements≤0.3%, and the balance being Al; the ratio of Ti and Co contents is 2-3:1, the ratio of Ti and B contents is 3:1, and the total content of Mg and Fe is≤0.5%. The unavoidable impurities include, but are not limited to, gaseous elements such as hydrogen, oxygen, nitrogen, and trace metal elements such as vanadium and chromium.

[0010] Optionally, the die-casting aluminum alloy material maintains≥90% of room temperature strength in an environment of 200℃, and the room temperature tensile strength is≥340Mpa, and / or the room temperature yield strength is≥220Mpa, and / or the room temperature elongation is≥5.0%.

[0011] The application improves fluidity by a proper amount of silicon, enhances strength by copper, and improves corrosion resistance by magnesium, and the three elements form a preliminary strengthening phase network together to improve the comprehensive mechanical properties of the material; on this basis, the application uses the competitive nucleation sites between titanium and cobalt, the synergistic refinement of boron and titanium, and the solid solution strengthening effect of nickel and cobalt, and cooperates with the accurate control of the above element dosage, so as to reduce the influence of high content of titanium on the material, obtain a more uniform and fine grain structure, and further improve the strength of the material; in addition, the application also uses the solid solution strengthening effect of nickel and cobalt and limits the total content of manganese and iron to improve the tensile strength and yield limit of the material, and also improves the recrystallization temperature to further refine the grains. Based on the increase of the content of titanium element and the high-temperature resistance of cobalt element, the die-casting aluminum alloy material obtained has excellent strength and heat resistance, that is, it can maintain ≥90% of the room temperature strength in an environment of 200℃, and the room temperature tensile strength is ≥340Mpa, and / or the room temperature yield strength is ≥220Mpa, and / or the room temperature elongation is ≥5.0%.

[0012] In a second aspect, the application provides a preparation method of the die-casting aluminum alloy material, comprising the following steps: Raw material preparation: Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10 and AlFe10 are subjected to drying treatment, wherein the AlTi10 is evenly divided into two parts for standby; First melting: the Al ingot is melted, and when the temperature is increased to 800-850℃, one part of AlTi10 and AlMg10, AlB10 and AlNi10 are added as needed, and after holding and melting for 10±2min, AlCo10 and the other part of AlTi10 are added until completely melted to obtain a first melt; Second melting: the temperature of the first melt is controlled at 730-750℃, AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and after holding and melting until completely melted, a deslagging agent is added and degassed by inert gas, and after the alloy melt composition is detected to reach the qualified range, a second melt is obtained; Alloy die-casting: after the second melt is cooled to 650-670℃, it is subjected to ultrasonic-electromagnetic-ultrasonic treatment, and then the treated second melt is subjected to high-pressure die-casting to obtain the die-casting aluminum alloy material.

[0013] By adopting the technical scheme, the AlTi10 is added twice, the first addition is mainly used for promoting nucleation, and the second addition is used for supplementing the refining effect, so that the grain unevenness caused by one-time addition is reduced; in addition, the high-melting-point elements (such as Ti, B, Ni, etc.) are added in the high-temperature stage to ensure that the elements are fully dissolved, and the low-melting-point elements (such as Si, Cu, etc.) are added in the low-temperature stage to reduce the burning loss of the elements. Moreover, the AlTi10 and the AlB10 are added in the high-temperature stage at the same time to better realize the synergistic effect, further refine the grains and increase the recrystallization temperature.

[0014] On this basis, the application also cooperates with the ultrasonic-electromagnetic-ultrasonic processing mode, the local high temperature and high pressure (>5000K, >1000atm) when the cavitation bubble collapses of the ultrasonic wave increases the nucleation rate; the electromagnetic field can induce melt flow, break the temperature gradient and improve the solidification structure; the interaction of the two can better realize grain refinement and reduce segregation; finally, the ultrasonic treatment can promote the coalescence and floating of cavitation bubbles to remove gas, and drive impurities in the material to the surface for easy slag removal and reduce material defects.

[0015] Optionally, in the alloy die casting step, the ultrasonic-electromagnetic-ultrasonic processing is first ultrasonic treatment for 40-50s, then electromagnetic treatment for 6-10min by connecting the magnetic field, and finally ultrasonic treatment for 40-50s again.

[0016] By adopting the technical scheme, the application first performs phased processing before die casting, the first ultrasonic treatment mainly realizes the crushing of dendrites through cavitation effect to lay a foundation for subsequent processing; the electromagnetic treatment utilizes the magnetic field to induce melt flow, the cobalt therein is a magnetic material and can realize internal magnetic conduction of the material to improve the flow efficiency of the fluid and promote uniform distribution of components; finally, the ultrasonic treatment is performed to consolidate and further refine the grains, so that the die-casting aluminum alloy material with more excellent performance is obtained.

[0017] Optionally, in the alloy die casting step, the ultrasonic power is 1500-1800W.

[0018] Optionally, in the alloy die casting step, the magnetic field strength is 300-400Gs.

[0019] Optionally, in the alloy die casting step, the die casting temperature of the high-pressure die casting is 680-700℃, the pressure is 50-70Mpa, and the die casting speed is 7-8m / s.

[0020] Optionally, in the secondary melting step, the degassing and deslagging time is 15-20min.

[0021] The present application adopts 1500-1800w ultrasonic power to generate sufficient cavitation bubbles to effectively refine the grains, if the power is too high, it may cause excessive disturbance of the melt, and if it is too low, the effect is insufficient; the magnetic field strength of 300-400Gs generates sufficient Lorentz force to drive the melt flow, promote the uniform distribution of solute and reduce composition segregation; on this basis, the control of die casting temperature, pressure and injection speed ensures good melt flowability, reduces filling defects and improves density, thereby improving the first-time qualification rate of the product; the time for degassing and deslagging is further limited during secondary melting, so that the inert gas has sufficient time to carry the hydrogen bubbles out of the melt and the deslagging agent fully contacts and reacts with the melt to ensure excellent impurity removal effect.

[0022] In summary, the present application has the following beneficial effects: 1. The present application uses silicon, copper and magnesium elements to form a preliminary strengthening phase network, and then precisely controls the amount of titanium, cobalt, boron, nickel, manganese and iron elements, thereby obtaining a die casting aluminum alloy material with excellent strength and heat resistance, which maintains ≥90% of room temperature strength in an environment of 200℃, and the room temperature tensile strength is ≥340Mpa, and / or the room temperature yield strength is ≥220Mpa, and / or the room temperature elongation is ≥5.0%.

[0023] 2. In the preparation of the die casting aluminum alloy material, the step-by-step addition of AlTi10 can further refine the grains and increase the recrystallization temperature, thereby obtaining a die casting aluminum alloy material with more excellent strength and heat resistance.

[0024] 3. The present application adopts the processing mode of ultrasonic-electromagnetic-ultrasonic and precisely controls the parameters, which can promote effective grain refinement and uniform distribution of each element, improve product density and first-time qualification rate, and further enhance the strength of the die casting aluminum alloy material. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the microstructure diagram of the die casting aluminum alloy material of Example 1 of the present application; Figure 2 is the microstructure diagram of the die casting aluminum alloy material of Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below. In the following description, a large number of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0027] The raw materials of the present application are mainly added in the form of pure Al ingot combined with each alloyed aluminum ingot, and are all derived from conventional commercially available products, specifically, Si is added in the form of AlSi20 ingot, Cu is added in the form of AlCu10 ingot, Ti is added in the form of AlTi10 ingot, Zn is added in the form of AlZn10 ingot, Mn is added in the form of AlMn10 ingot, Mg is added in the form of AlMg10 ingot, Co is added in the form of AlCo10 ingot, B is added in the form of AlB10 ingot, Ni is added in the form of AlNi10 ingot, Fe is added in the form of AlFe10 ingot, and the remaining insufficient Al is supplemented with pure Al ingot. In addition, the impurity content of the above pure Al ingot and each alloyed aluminum ingot is controlled to be ≤0.1%.

[0028] The slag remover used in the preparation of the die-casting aluminum alloy material of the present application is also a conventional commercially available product, specifically purchased from Xuzhou Suyuan Aluminum Industry Co., Ltd., a first-grade aluminum alloy slag remover suitable for a treatment temperature of 700-780℃, in a powder state, with an effective ingredient content ≥99%.

[0029] The present application is further described in detail below in combination with examples and comparative examples. Example Example 1

[0030] A die-casting aluminum alloy material, by mass fraction, comprising: Si 8.7%, Cu 0.5%, Ti 0.5%, Zn 0.5%, Mn 0.3%, Mg 0.2%, Co 0.17%, B 0.15%, Ni 0.2%, Fe 0.3%, the sum of unavoidable impurity elements ≤0.3%, and the balance being Al.

[0031] The preparation method of the above die-casting aluminum alloy material comprises the following steps: Raw material preparation: Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10, and AlFe10 are dried and treated, wherein the AlTi10 is evenly divided into two parts for standby; Primary smelting: melt the Al ingot, when the temperature is raised to 830℃, add one part of AlTi10 and AlMg10, AlB10, and AlNi10 as needed, after holding and smelting for 10±2 min, add AlCo10 and the other part of AlTi10 until completely melted to obtain a first melt; Secondary melting: the temperature of the first melt is controlled at 740℃, AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and the melting is kept until complete, a deoxidizing agent is added and deoxidized by inert gas, the amount of the deoxidizing agent is 0.3% of the total weight of the first melt, the deoxidizing agent is dispersed on the surface of the first melt, and is stirred uniformly by the stirring rotor; the inert gas is argon, which is directly introduced into the first melt at a pressure of 0.25 MPa, and the stirring is carried out at the same time, the whole deoxidizing and deoxidizing treatment time is controlled within 18 min, and after the alloy melt composition detection reaches the qualified range, the second melt is obtained; Alloy die casting: the second melt is cooled to 660℃ and then subjected to ultrasonic-electromagnetic-ultrasonic treatment; The ultrasonic treatment is to convert high-frequency electric energy into mechanical vibration by a transducer, and then transmit it to the melt through a high-temperature amplitude rod (tungsten alloy amplitude rod). The specific arrangement is that the probe (ZW5P high-temperature probe from Beijing Times Haofang) is installed at the output end of the amplitude rod, the amplitude rod is vertically inserted into the second melt, the insertion depth is 1 / 2 from the bottom of the furnace, the probe is connected with a cooling system and keeps the starting state, and the temperature sensor is ensured to display the probe temperature < 150℃; The magnetic field treatment realizes the flow control of molten metal through electromagnetic induction principle. The specific arrangement is that a copper tube is wound into a coil with a diameter of 10 mm and a wall thickness of 1.5 mm, the coil is installed on the side wall and the bottom of the furnace and keeps a distance of 80±5 mm from the surface of the melt, the coil power is controlled within 200-300 kW, a horizontal magnetic field is adopted, and the magnetic field direction is parallel to the flow direction of the second melt, so as to refine the grains and reduce segregation, and at the same time, a water cooling system is used with a flow rate of 5-10 L / min to prevent the coil from overheating; The above ultrasonic-electromagnetic-ultrasonic treatment is to first ultrasonic treatment for 45 s at an ultrasonic power of 1650 w, then electromagnetic treatment for 8 min at a magnetic field strength of 350 Gs when the ultrasonic treatment is finished, and finally ultrasonic treatment for 45 s at an ultrasonic power of 1650 w when the electromagnetic treatment is finished. The second melt treated is subjected to high-pressure die casting, the die casting temperature of the high-pressure die casting is 690℃, the pressure is 60 MPa, and the die setting speed is 7.5 m / s, so as to obtain the die casting aluminum alloy material. Examples 2-6

[0032] Examples 2-6 are prepared based on the preparation method of Example 1, and the weight content of each element of the obtained die casting aluminum alloy material is shown in Table 1 below, and the balance is Al.

[0033] Table 1: Element content of die casting aluminum alloy materials of Examples 1-6 and Comparative Examples 1-4 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Si 8.70 9.00 9.20 9.50 9.50 9.20 9.20 9.20 9.20 9.20 Cu 0.50 0.50 0.80 1.00 1.00 0.80 0.80 0.80 0.80 0.80 Ti 0.50 0.54 0.60 0.63 0.70 0.60 0.60 0.60 0.60 0.15 Zn 0.50 0.50 0.55 0.60 0.80 0.55 0.55 0.55 0.55 0.55 Mn 0.30 0.30 0.40 0.50 0.60 0.40 0.40 0.40 0.40 0.40 Mg 0.20 0.20 0.25 0.40 0.40 0.25 0.25 0.25 0.25 0.25 Co 0.17 0.18 0.24 0.31 0.35 0.24 / 0.20 / 0.20 B 0.15 0.18 0.20 0.21 0.25 0.20 / / 0.20 0.20 Ni 0.20 0.20 0.25 0.30 0.30 0.25 0.25 0.25 0.25 0.25 Fe 0.30 0.20 0.15 0.10 0.10 0.30 0.15 0.15 0.15 0.15 Sum of impurity elements ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 ≤0.30 Example 7

[0034] The die-casting aluminum alloy material of the present example is based on the raw material ratio of Example 3, and the process parameters in the preparation method are adjusted, specifically including the following steps: Raw material preparation: Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10, and AlFe10 are dried and treated, and AlTi10 is divided into two parts for standby; First melting: melt Al ingot, when the temperature is raised to 800℃, add one part of AlTi10 and AlMg10, AlB10 and AlNi10 as needed, after holding and melting for 10±2min, add AlCo10 and another part of AlTi10 until completely melted to obtain a first melt; Second melting: the temperature of the first melt is controlled at 730℃, AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and the melt is held and melted until completely melted. Add a deslagging agent and degas and deslag with inert gas. The addition amount of the deslagging agent is 0.3% of the total weight of the first melt. The deslagging agent is dispersed on the surface of the first melt and stirred uniformly by the stirring rotor. Inert gas is argon, which is directly introduced into the first melt at a pressure of 0.25Mpa. The degassing also stirs the first melt. The whole degassing and deslagging treatment time is controlled within 15min. After the alloy melt composition detection reaches the qualified range, a second melt is obtained; Alloy die-casting: after the second melt is cooled to 650℃, ultrasonic-electromagnetic-ultrasonic treatment is carried out. The arrangement of ultrasonic and electromagnetic is the same as above. The ultrasonic-electromagnetic-ultrasonic treatment is first ultrasonic treatment at 1500w for 40s, then electromagnetic treatment in a magnetic field with a magnetic field strength of 300Gs for 6min, and finally ultrasonic treatment at 1500w for 40s again. The treated second melt is then subjected to high-pressure die-casting. The die-casting temperature of the high-pressure die-casting is 680℃, the pressure is 50Mpa, and the die-casting speed is 7m / s. The die-casting aluminum alloy material is obtained. Example 8

[0035] The die-casting aluminum alloy material of the present example is based on the raw material ratio of Example 3, and the process parameters in the preparation method are adjusted, specifically including the following steps: Raw material preparation: Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10, and AlFe10 are dried and treated, and AlTi10 is divided into two parts for standby; First smelting: melt the Al ingot, and when the temperature is raised to 850℃, add one portion of AlTi10 and AlMg10, AlB10 and AlNi10 as needed, and after holding and smelting for 10±2 min, add AlCo10 and another portion of AlTi10 until complete melting to obtain a first melt; Second smelting: the temperature of the first melt is controlled at 750℃, and AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and after holding and smelting until complete melting, a deslagging agent is added and inert gas is used for degassing and deslagging, the addition amount of the deslagging agent is 0.3% of the total weight of the first melt, the deslagging agent is dispersed on the surface of the first melt, and stirring is performed by using a stirring rotor; the inert gas is argon, which is directly introduced into the first melt at a pressure of 0.25Mpa, and the argon can also be used for stirring the first melt during degassing, the whole degassing and deslagging treatment time is controlled within 20 min, and after the alloy melt composition is detected to be within the qualified range, a second melt is obtained; Alloy die casting: after the second melt is cooled to 670℃, ultrasonic-electromagnetic-ultrasonic treatment is performed, the ultrasonic and electromagnetic arrangement modes are the same as above, the ultrasonic-electromagnetic-ultrasonic treatment is first ultrasonic treatment at an ultrasonic power of 1800w for 50s, then electromagnetic treatment in a magnetic field with a magnetic field strength of 400Gs for 8min, and finally ultrasonic treatment at an ultrasonic power of 1800w for 50s; then the treated second melt is subjected to high-pressure die casting, the die casting temperature of the high-pressure die casting is 700℃, the pressure is 70Mpa, and the die casting speed is 8m / s, and the die-cast aluminum alloy material is obtained. Example 9

[0036] The die-cast aluminum alloy material of the present embodiment is based on the raw material ratio of Example 3, and the process parameters in the preparation method are adjusted, which specifically includes the following steps: Raw material preparation: dry the Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10 and AlFe10, wherein one portion of AlTi10 is divided into two parts for standby; First smelting: melt the Al ingot, and when the temperature is raised to 830℃, add one portion of AlTi10 and AlMg10, AlB10 and AlNi10 as needed, and after holding and smelting for 10±2 min, add AlCo10 and another portion of AlTi10 until complete melting to obtain a first melt; Secondary smelting: the temperature of the first melt is controlled at 740 DEG C, AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and smelting is carried out until complete melting, a deslagging agent is added and inert gas is used for degassing and deslagging, the amount of the deslagging agent added is 0.3% of the total weight of the first melt, the deslagging agent is dispersed on the surface of the first melt, and stirring is carried out by using a stirring rotor; the inert gas is argon, which is directly introduced into the first melt at a pressure of 0.25 MPa, and the first melt is stirred while being degassed, the whole treatment time for degassing and deslagging is controlled at 18 min, and after the alloy melt composition is detected to be within the qualified range, a second melt is obtained; Alloy die casting: the second melt is cooled to 660 DEG C and then subjected to ultrasonic-electromagnetic treatment, the ultrasonic and electromagnetic arrangement modes are the same as above, the ultrasonic-electromagnetic treatment is first ultrasonic treatment at an ultrasonic power of 1650 W for 90 s, and then electromagnetic treatment in a magnetic field with a magnetic field strength of 350 Gs for 8 min; the treated second melt is subjected to high-pressure die casting, the die casting temperature is 690 DEG C, the pressure is 60 MPa, and the die casting speed is 7.5 m / s, and thus the die-cast aluminum alloy material is obtained. Example 10

[0037] The die-cast aluminum alloy material of the present embodiment is prepared based on the raw material ratio of Example 3, and the process parameters in the preparation method are adjusted, which specifically includes the following steps: Preparation of raw materials: Al ingot, AlSi20, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10 and AlFe10 are dried and prepared for use; Primary smelting: the Al ingot is melted, AlTi10, AlMg10, AlB10 and AlNi10 are added as needed when the temperature is raised to 830 DEG C, AlCo10 is added after 10±2 min of heat preservation smelting until complete melting, and a first melt is obtained; Secondary smelting: the temperature of the first melt is controlled at 740 DEG C, AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed, and smelting is carried out until complete melting, a deslagging agent is added and inert gas is used for degassing and deslagging, the amount of the deslagging agent added is 0.3% of the total weight of the first melt, the deslagging agent is dispersed on the surface of the first melt, and stirring is carried out by using a stirring rotor; the inert gas is argon, which is directly introduced into the first melt at a pressure of 0.25 MPa, and the first melt is stirred while being degassed, the whole treatment time for degassing and deslagging is controlled at 18 min, and after the alloy melt composition is detected to be within the qualified range, a second melt is obtained; Alloy die casting: the second melt is treated by ultrasonic-electromagnetic-ultrasonic after being cooled to 660℃, the ultrasonic and electromagnetic are arranged in the same way as above, the ultrasonic-electromagnetic-ultrasonic treatment is first treated by ultrasonic with an ultrasonic power of 1650w for 45s, then connected to a magnetic field with a magnetic field strength of 350Gs for electromagnetic treatment for 8min, and finally treated by ultrasonic again with an ultrasonic power of 1650w for 45s; then the treated second melt is subjected to high-pressure die casting, the die casting temperature of the high-pressure die casting is 690℃, the pressure is 60Mpa, and the die casting speed is 7.5m / s, thereby obtaining the die casting aluminum alloy material. Comparative example Comparative example 1

[0038] The present comparative example is based on the preparation method of example 3, and the amount of raw materials is adjusted, specifically, no B element and Co element is added, the weight content of each element of the obtained die casting aluminum alloy material is shown in the above table 1, unit is %, and the balance is Al. Comparative example 2

[0039] The present comparative example is based on the preparation method of example 3, and the amount of raw materials is adjusted, the weight content of each element of the obtained die casting aluminum alloy material is shown in the above table 1, unit is %, and the balance is Al. Comparative example 3

[0040] The present comparative example is based on the preparation method of example 3, and the amount of raw materials is adjusted, specifically, no Co element is added, the weight content of each element of the obtained die casting aluminum alloy material is shown in the above table 1, unit is %, and the balance is Al. Comparative example 4

[0041] The present comparative example is based on the preparation method of example 3, and the amount of raw materials is adjusted, the weight content of each element of the obtained die casting aluminum alloy material is shown in the above table 1, unit is %, and the balance is Al. Performance test

[0042] (1) Chemical composition test The die casting aluminum alloy materials prepared in the above examples 1-10 and comparative examples 1-4 are used as samples for chemical composition detection (ICP test), and the specific chemical composition detection results are shown in the above table 1.

[0043] (2) Mechanical property test The die-casting aluminum alloy materials prepared from the above-mentioned Examples 1-10 and Comparative Examples 1-4 were sampled, and the size and performance test standards were implemented in accordance with GB / T 228. The samples were rod-shaped with a circular cross-section, wherein the room temperature tensile test was implemented in accordance with GB / T 228.1-2021, the high temperature tensile test was implemented in accordance with GB / T 228.2-2015, the strength maintenance of the samples in a 200℃ environment was determined, and the higher the maintenance rate, the more excellent the heat resistance. The detection results are shown in Table 2 below.

[0044] Table 2: Mechanical property detection results of Examples 1-10 and Comparative Examples 1-4 Tensile strength at room temperature, MPa Yield strength at room temperature, MPa Elongation at room temperature, % Tensile strength retention at 200°C, % Yield strength retention at 200°C, % Example 1 341 220 11.6 90.5 91.1 Example 2 350 234 10.2 92.0 92.3 Example 3 373 248 9.5 95.7 96.0 Example 4 380 250 8.7 94.2 95.0 Example 5 391 260 5.0 93.1 93.5 Example 6 362 235 9.2 93.8 94.0 Example 7 368 240 8.7 95.0 95.4 Example 8 370 244 9.1 95.3 95.8 Example 9 356 237 8.3 92.8 93.1 Example 10 349 231 7.2 91.2 91.6 Comparative Example 1 282 167 2.6 71.5 72.1 Comparative Example 2 336 200 8.5 85.4 85.7 Comparative Example 3 321 188 7.2 78.1 79.0 Comparative Example 4 345 205 9.0 80.5 81.1 Referring to Table 2 above and the detection results of Examples 1-10 and Comparative Examples 1-4, it can be obtained that the die-casting aluminum alloy of the present application can maintain relatively high room temperature tensile strength, room temperature yield strength and room temperature elongation when a relatively high Ti element content is added, and can still maintain a mechanical property of 90% or more of room temperature at a high temperature environment of 200℃. The excellent strength and heat resistance are obtained.

[0045] Comparing the detection results of Example 3 and Comparative Examples 1-4, it can be seen that a relatively large amount of Ti alone will cause the grain to be coarse (see Figure 2 ). Therefore, the present application needs to strictly control the amounts of Ti, B and Co elements, and control the amounts of other elements such as Si, Cu, Mg, Fe and the like, so as to further refine the grain (see Figure 1 ) and improve the strength and heat resistance of the material.

[0046] Comparing the detection results of Examples 1-6, it can be seen that when the die-casting aluminum alloy material of the present application is limited according to “by mass fraction, including: Si 9.0-9.5%, Cu 0.5-1.0%, Ti 0.54-0.63%, Zn 0.5-0.6%, Mn 0.3-0.5%, Mg 0.2-0.4%, Co 0.17-0.35%, B 0.18-0.21%, Ni 0.2-0.3%, Fe≤0.3%, unavoidable impurity elements total≤0.3%, the balance being Al; the ratio of Ti and Co content is 2-3:1, the ratio of Ti and B content is 3:1, and the total content of Mg and Fe is≤0.5%”, the room temperature tensile strength, room temperature yield strength and maintenance rate of the above two strengths in a 200℃ environment are all more excellent. Although the room temperature elongation is reduced, the reduction amplitude of the room temperature elongation in this interval range is relatively low, and is obviously better than 3.5% of conventional aluminum alloy materials represented by A380 and ADC12. Therefore, it is further preferred.

[0047] Comparing the test results of example 3 with examples 7-10, it can be seen that, in the preparation of the die-casting aluminum alloy, the step-by-step addition of AlTi10 can further refine the grains and increase the recrystallization temperature, and the use of the ultrasonic-electromagnetic-ultrasonic treatment mode and the accurate control of the parameters can promote effective grain refinement and uniform distribution of each element, improve the product density and the first pass yield, thereby obtaining a die-casting aluminum alloy material with more excellent strength and heat resistance.

[0048] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A die-cast aluminum alloy material, characterized in that, By mass fraction, it includes: Si 9.0-9.5%, Cu 0.5-1.0%, Ti 0.54-0.63%, Zn 0.5-0.6%, Mn 0.3-0.5%, Mg 0.2-0.4%, Co 0.18-0.31%, B 0.18-0.21%, Ni 0.2-0.3%, Fe≤0.3%, and the total of unavoidable impurity elements≤0.3%, with the balance being Al; the ratio of Ti to Co content is 2-3:1, and the ratio of Ti to B content is 3:

1. The preparation method of the die-cast aluminum alloy material includes the following steps: Raw material preparation: Dry Al ingots, AlSi2O, AlCu10, AlTi10, AlZn10, AlMn10, AlMg10, AlCo10, AlB10, AlNi10, and AlFe10. Among them, AlTi10 is evenly divided into two portions for later use. First melting: Melt Al ingots, heat to 800-850℃, add one part of AlTi10, AlMg10, AlB10 and AlNi10 as needed, keep the temperature for 10±2min, then add AlCo10 and another part of AlTi10 until completely melted to obtain the first melt; Secondary melting: The temperature of the first melt is controlled at 730-750℃. AlSi20, AlCu10, AlZn10, AlMn10 and AlFe10 are added as needed. The melt is held at the temperature until it is completely melted. A slag remover is added and the melt is degassed and slag removed with inert gas. After the alloy melt composition is tested and found to be within the qualified range, the second melt is obtained. Alloy die casting: After cooling the second melt to 650-670℃, it is subjected to ultrasonic-electromagnetic-ultrasonic treatment, and then the treated second melt is subjected to high-pressure die casting to obtain the die-cast aluminum alloy material.

2. The die-cast aluminum alloy material according to claim 1, characterized in that, The composition by mass fraction includes: Si 9.0-9.5%, Cu 0.5-1.0%, Ti 0.54-0.63%, Zn 0.5-0.6%, Mn 0.3-0.5%, Mg 0.2-0.4%, Co 0.18-0.31%, B 0.18-0.21%, Ni 0.2-0.3%, Fe ≤0.3%, and the total amount of unavoidable impurity elements ≤0.3%, with the balance being Al; the ratio of Ti to Co content is 2-3:1, the ratio of Ti to B content is 3:1, and the total content of Mg and Fe is ≤0.5%.

3. The die-cast aluminum alloy material according to claim 1, characterized in that, The die-cast aluminum alloy material maintains ≥90% of its room temperature strength at 200℃, and has a room temperature tensile strength ≥340 MPa, and / or a room temperature yield strength ≥220 MPa, and / or a room temperature elongation ≥5.0%.

4. The die-cast aluminum alloy material according to claim 1, characterized in that, In the alloy die-casting process, the ultrasonic-electromagnetic-ultrasonic treatment involves first ultrasonic treatment for 40-50 seconds, then electromagnetic treatment for 6-10 minutes by applying a magnetic field, and finally ultrasonic treatment again for 40-50 seconds.

5. The die-cast aluminum alloy material according to claim 4, characterized in that, In the alloy die-casting step, the ultrasonic power is 1500-1800W.

6. The die-cast aluminum alloy material according to claim 4, characterized in that, In the alloy die-casting step, the magnetic field strength is 300-400 Gs.

7. The die-cast aluminum alloy material according to claim 1, characterized in that, In the alloy die-casting step, the high-pressure die-casting temperature is 680-700℃, the pressure is 50-70 MPa, and the casting speed is 7-8 m / s.

8. The die-cast aluminum alloy material according to claim 1, characterized in that, In the secondary smelting step, the degassing and slag removal time is 15-20 minutes.

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