High-corrosion-resistance die-casting aluminum alloy as well as preparation method and application thereof

Abstract

The invention provides a high-corrosion-resistance die-casting aluminum alloy and a preparation method and application thereof. The high-corrosion-resistance die-casting aluminum alloy comprises the following components in percentage by mass: 8 to 9 weight percent of Si, 0.2 to 1 weight percent of Mg, 0.1 to 1 weight percent of Fe, 0.005 to 0.05 weight percent of Sr, 0.2 to 1 weight percent of Mn, 0.05 to 0.2 weight percent of Ti, 0.05 to 0.15 weight percent of Cr, 0 to 0.05 weight percent of Cu, 0 to 0.05 weight percent of Zn and the balance of Al and inevitable impurities, and the sum of the mass percent of the inevitable impurities is not more than 0.5 weight percent. The forming performance of the aluminum alloy is guaranteed by regulating and controlling the content of silicon in the die-casting aluminum alloy, the content of Si, Mg, Fe, Sr, Mn, Ti, Cr, Cu, Zn and Al is reasonably controlled by regulating and controlling the content of Cu, Zn, Cr and Sr to be within the range of the die-casting aluminum alloy, and the corrosion resistance of the die-casting aluminum alloy is improved.

Description

Technical Field

[0001] This application relates to the field of aluminum alloy materials technology, specifically to a high corrosion-resistant die-cast aluminum alloy, its preparation method, and its application. Background Technology

[0002] Aluminum alloys have low density but high strength and good plasticity, and possess excellent electrical and thermal conductivity and corrosion resistance, making them widely used in industry. Die casting is the most widely used forming process for aluminum alloys. In recent years, the application of aluminum alloys has increased, the requirements for product performance have become more stringent, competition has intensified, and cost pressures have increased. Currently, for products requiring high corrosion resistance, the commonly used die-cast aluminum alloy ADC12 has relatively poor corrosion resistance. Summary of the Invention

[0003] The purpose of this application is to provide a highly corrosion-resistant die-cast aluminum alloy to improve the corrosion resistance of die-cast aluminum alloys.

[0004] The first aspect of this application provides a high corrosion-resistant die-cast aluminum alloy comprising the following components in weight percentage: 8 wt% to 9 wt% Si, 0.2 wt% to 1 wt% Mg, 0.1 wt% to 1 wt% Fe, 0.005 wt% to 0.05 wt% Sr, 0.2 wt% to 1 wt% Mn, 0.05 wt% to 0.2 wt% Ti, 0.05 wt% to 0.15 wt% Cr, 0 wt% to 0.05 wt% Cu, 0 wt% to 0.05 wt% Zn, with the remainder being Al and unavoidable impurities, the unavoidable impurities comprising no more than 0.5 wt% by weight.

[0005] In one embodiment of this application, the mass percentage content of Fe, Mn and Cr in the high corrosion resistant die-cast aluminum alloy satisfies: Fe:(Mn+Cr)=(0.6~0.8):1.

[0006] In one embodiment of this application, the microstructure of the high corrosion-resistant die-cast aluminum alloy includes eutectic α-Al phase, eutectic Al-Si phase and dispersed phase, wherein the dispersed phase includes at least one of Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, Al(Fe,Cr)Si phase, Al6Mn phase or Al3Fe phase.

[0007] In one embodiment of this application, the high corrosion-resistant die-cast aluminum alloy is prepared by the following method: 1) High-purity Al raw material is put into a heating furnace and heated to 670℃~690℃, and held at that temperature for 14min~16min; 2) The temperature is raised to 750℃~770℃, and Si and Al-Fe alloy raw materials are added; 3) The temperature is lowered to 720℃~740℃, and Al-Cr, Al-Mn and Al-Ti alloy raw materials are added; 4) The temperature is lowered to 710℃~730℃, and pure Mg and Al-Sr metal material raw materials are added; 5) After all the above raw materials are melted, the alloy is cast to obtain the high corrosion-resistant die-cast aluminum alloy.

[0008] The second aspect of this application provides an application of the high corrosion-resistant die-cast aluminum alloy described in the first aspect of this application in die-cast housing parts.

[0009] In one embodiment of this application, the application includes die-casting a highly corrosion-resistant die-cast aluminum alloy to produce a housing-type die-cast part.

[0010] In one embodiment of this application, the die-cast shell part includes a first surface and a second surface, wherein the second surface is sealed and meets the C5-M corrosion level of the international standard ISO12944-6.

[0011] In one embodiment of this application, the die casting process includes: a) melting the high corrosion-resistant die-cast aluminum alloy at 690℃~710℃ to obtain a molten alloy; b) injecting the molten alloy into a die-casting mold using a low-speed injection followed by a high-speed injection method, wherein the temperature of the die-casting mold is 180℃~220℃, the low-speed injection is 0.2m / s~0.4m / s and the low-speed time is 1.3s~1.7s; the high-speed injection is 4m / s~5m / s and the high-speed time is 0.2s~0.4s; followed by mold retention, solidification, demolding, passivation powder spraying, and obtaining a shell-type die-cast part.

[0012] In one embodiment of this application, the thickness of the die-cast shell part is 1 mm to 4 mm.

[0013] The beneficial effects of this application are:

[0014] This application provides a high corrosion-resistant die-cast aluminum alloy comprising the following components by mass percentage: 8 wt%–9 wt% Si, 0.2 wt%–1 wt% Mg, 0.1 wt%–1 wt% Fe, 0.005 wt%–0.05 wt% Sr, 0.2 wt%–1 wt% Mn, 0.05 wt%–0.2 wt% Ti, 0.05 wt%–0.15 wt% Cr, 0 wt%–0.05 wt% Cu, 0 wt%–0.05 wt% Zn, with the remainder being Al and unavoidable impurities, the total mass percentage of unavoidable impurities not exceeding 0.5 wt%. By controlling the silicon content in the die-cast aluminum alloy, the formability of the aluminum alloy is ensured. By controlling the contents of Cu, Zn, Cr, and Sr within the range specified in this application, and by rationally controlling the contents of Si, Mg, Fe, Mn, Ti, and Al, the corrosion resistance of the die-cast aluminum alloy is improved.

[0015] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0017] Figure 1 This is a metallographic diagram of the die-cast aluminum alloy provided in Embodiment 1-1 of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0019] The first aspect of this application provides a high corrosion-resistant die-cast aluminum alloy comprising the following components in weight percentage: 8 wt% to 9 wt% Si, 0.2 wt% to 1 wt% Mg, 0.1 wt% to 1 wt% Fe, 0.005 wt% to 0.05 wt% Sr, 0.2 wt% to 1 wt% Mn, 0.05 wt% to 0.2 wt% Ti, 0.05 wt% to 0.15 wt% Cr, 0 wt% to 0.05 wt% Cu, 0 wt% to 0.05 wt% Zn, with the remainder being Al and unavoidable impurities, the unavoidable impurities comprising no more than 0.5 wt% by weight. For example, the mass percentage of Si can be 8 wt%, 8.2 wt%, 8.4 wt%, 8.6 wt%, 8.8 wt%, 9 wt%, or any range of two such values; the mass percentage of Mg can be 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, or any range of two such values; the mass percentage of Fe can be 0.1 wt%, 0.2 wt%, 0.3 wt%. The mass percentage of Sr can be 0.005wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, or any two of these values; the mass percentage of Mn can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, or any two of these values. The mass percentage of Ti can be 0.05wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.15wt%, 0.18wt%, 0.2wt%, or any two of these values; the mass percentage of Cr can be 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.11wt%, 0. The mass percentage of Cu can be 12wt%, 0.13wt%, 0.14wt%, 0.15wt%, or any two of these values; the mass percentage of Cu can be 0wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, or any two of these values; the mass percentage of Zn can be 0wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, or any two of these values.Since the increase of impurity elements will reduce the performance of the material, this application controls the total content of unavoidable impurity elements to no more than 0.5 wt%. By adjusting the silicon content in the die-cast aluminum alloy, the forming performance of the aluminum alloy is guaranteed. By adjusting the content of Cu, Zn, Cr and Sr elements within the range of this application, the content of Si, Mg, Fe, Mn, Ti and Al elements is reasonably controlled to improve the corrosion resistance of the die-cast aluminum alloy.

[0020] In one embodiment of this application, the mass percentages of Fe, Mn, and Cr in the high corrosion-resistant die-cast aluminum alloy satisfy the following condition: Fe:(Mn+Cr) = (0.6~0.8):1. For example, Fe:(Mn+Cr) can be 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, or a range consisting of any two of these values. By adjusting Fe:(Mn+Cr) within the above range, a relative balance between the die-casting performance and corrosion resistance of the alloy is ensured.

[0021] In one embodiment of this application, the microstructure of the high corrosion-resistant die-cast aluminum alloy comprises a eutectic α-Al phase, a eutectic Al-Si phase, and a dispersed phase. The dispersed phase includes at least one of the following: Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, Al(Fe,Cr)Si phase, Al6Mn phase, or Al3Fe phase. The phase refers to an aggregated state of homogeneous substances with identical physical and chemical properties and composition. The dispersed phase refers to a finely dispersed solid phase. Compared to commonly used materials, the die-cast aluminum alloy satisfying the above characteristics exhibits high corrosion resistance.

[0022] In some embodiments, the precipitated phases in the high corrosion-resistant die-cast aluminum alloy include Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, and Al(Fe,Cr)Si phase.

[0023] In some implementation schemes, such as Figure 1 As shown, the precipitated phases include precipitated phases distributed in a skeletal shape and in a blocky shape.

[0024] In some embodiments, the high corrosion-resistant die-cast aluminum alloy has a tensile strength of 300 MPa to 350 MPa, a yield strength of 150 MPa to 200 MPa, and an elongation of 8% to 10%. For example, the tensile strength can be 300 MPa, 310 MPa, 320 MPa, 330 MPa, 340 MPa, 350 MPa, or any two of these values; the yield strength can be 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, or any two of these values; and the elongation can be 8%, 8.2%, 8.4%, 8.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8%, 10%, or any two of these values. The tensile strength refers to the maximum stress value that the test sample can withstand before it breaks. The yield strength refers to the stress value that produces a non-proportional elongation of 0.2% in the test sample. The elongation refers to the percentage of the total deformation ΔL of the gauge length segment after the test sample breaks under tension to the original gauge length L.

[0025] In one embodiment of this application, the high corrosion-resistant die-cast aluminum alloy is prepared by the following method: 1) High-purity Al raw material is put into a heating furnace and heated to 670℃~690℃, and held at that temperature for 14min~16min; 2) The temperature is raised to 750℃~770℃, and Si and Al-Fe alloy raw materials are added; 3) The temperature is lowered to 720℃~740℃, and Al-Cr, Al-Mn and Al-Ti alloy raw materials are added; 4) The temperature is lowered to 710℃~730℃, and pure Mg and Al-Sr metal material raw materials are added; 5) After all the above raw materials are melted, the alloy is cast to obtain the high corrosion-resistant die-cast aluminum alloy.

[0026] High-purity Al raw material is placed in a heating furnace and heated to 670℃~690℃, then melted and held at that temperature for 14~16 minutes. For example, the heating temperature can be 670℃, 672℃, 674℃, 676℃, 678℃, 680℃, 682℃, 684℃, 686℃, 688℃, 690℃, or any two of these values; the melting and holding time can be 14 minutes, 14.5 minutes, 15 minutes, 15.5 minutes, 16 minutes, or any two of these values.

[0027] The temperature is raised to 750℃~770℃, and Si and Al-Fe alloy raw materials are added. For example, the temperature can be 750℃, 752℃, 754℃, 756℃, 758℃, 760℃, 762℃, 764℃, 766℃, 768℃, 770℃, or any range of two of these values.

[0028] Cool the temperature to 720℃~740℃ and add Al-Cr, Al-Mn and Al-Ti alloy raw materials. For example, the temperature to which the temperature is cooled can be 720℃, 722℃, 724℃, 726℃, 728℃, 730℃, 732℃, 734℃, 736℃, 738℃, 740℃ or any range of two of these values.

[0029] Cool down to 710℃~730℃ and add pure Mg and Al-Sr metallic raw materials. For example, the temperature can be 710℃, 712℃, 714℃, 716℃, 718℃, 720℃, 722℃, 724℃, 726℃, 728℃, 730℃ or any range of two of these values.

[0030] In some embodiments, the Fe content in the Al-Fe alloy is 19% to 21%, the Cr content in the Al-Cr alloy is 9.5% to 10.5%, the Mn content in the Al-Mn alloy is 9.5% to 10.5%, the Ti content in the Al-Ti alloy is 9.5% to 10.5%, and the Sr content in the Al-Sr metallic material is 9.5% to 10.5%. For example, the Fe content in Al-Fe alloys can be 19%, 19.5%, 20%, 20.5%, 21%, or any range of two of these values; the Cr content in Al-Cr alloys can be 9.5%, 9.8%, 10.2%, 10.5%, or any range of two of these values; the Mn content in Al-Mn alloys can be 9.5%, 9.8%, 10.2%, 10.5%, or any range of two of these values; the Ti content in Al-Ti alloys can be 9.5%, 9.8%, 10.2%, 10.5%, or any range of two of these values; and the Sr content in Al-Sr metallic materials can be 9.5%, 9.8%, 10.2%, 10.5%, or any range of two of these values.

[0031] In some embodiments, the high-purity Al raw materials, Si and Al-Fe alloy raw materials, Al-Cr alloy raw materials, Al-Mn alloy raw materials, Al-Ti alloy raw materials, pure Mg raw materials, and Al-Sr metal material raw materials used in this application are all commercially available conventional substances. This application does not impose any particular restrictions on their sources, as long as they achieve the purpose of this application. For example, the high-purity Al raw material can be high-purity aluminum ingots, the Si raw material is selected from at least one of industrial silicon or readily soluble silicon, and the pure Mg raw material can be magnesium blocks. In this application, the Cu element and the Zn element are derived from impurity elements in high-purity aluminum.

[0032] In some implementation schemes, this application does not impose any particular restrictions on the rate of heating or cooling, as long as the purpose of this application can be achieved.

[0033] The second aspect of this application provides an application of the high corrosion-resistant die-cast aluminum alloy described in the first aspect of this application in die-cast housing parts.

[0034] In one embodiment of this application, the application includes die-casting a highly corrosion-resistant die-cast aluminum alloy to produce a housing-type die-cast part.

[0035] In one embodiment of this application, the die-cast shell part includes a first surface and a second surface, wherein the second surface is sealed and meets the C5-M corrosion level of the international standard ISO12944-6.

[0036] In some implementations, the second surface is the surface of the die-cast part of the housing type that is in direct contact with the external atmospheric environment after assembly, and the first surface is the surface opposite to the second surface.

[0037] In some implementations, this application does not impose any particular restrictions on the method of sealing the first surface, as long as the purpose of this application can be achieved.

[0038] In some implementations, the neutral salt spray test method is conducted according to the international standard ISO 9227, which includes, but is not limited to, the following steps: (1) preparing the salt solution: dissolving (5±1) parts by mass of salt in 95 parts by mass of distilled or deionized water, with a pH value between 6.5 and 7.2; (2) supplying the salt solution to the air through a spray device at a temperature of (35±2)℃ and a relative humidity of ≥85%. After exposing the die-cast parts of the housing type to the above area for at least 720 hours, the die-cast parts of the housing type show no white rust, and the coating obtained by passivation powder spraying shows no blistering, peeling, or cracking.

[0039] In some implementation schemes, the condensation test method is conducted in accordance with the international standard ISO 6270-1 condensation test method. After the die-cast shell parts are exposed to the above-mentioned area for at least 240 hours, the die-cast shell parts are free of white rust, and the coating obtained by passivation powder spraying is free of blistering, peeling, and cracking.

[0040] In some implementation schemes, this application does not impose any particular restrictions on the testing equipment used in the testing method, as long as it can achieve the purpose of this application. For example, it can be observed visually; it can also be observed with a magnifying glass.

[0041] In some implementation schemes, this application does not impose any particular restrictions on the apparatus and materials used in the neutral salt spray test method and the condensation test method, as long as they can achieve the purpose of this application.

[0042] In one embodiment of this application, the die-casting process includes: a) melting the high corrosion-resistant die-casting aluminum alloy at 690℃~710℃ to obtain a molten alloy; b) injecting the molten alloy into a die-casting mold using a low-speed injection followed by a high-speed injection method. The temperature of the die-casting mold is 180℃~220℃, the low-speed injection is 0.2m / s~0.4m / s for 1.3s~1.7s, and the high-speed injection is 4m / s~5m / s for 0.2s~0.4s. The process is then followed by mold retention, solidification, demolding, passivation, and powder spraying to obtain a shell-type die-cast part. By controlling the die-casting process parameters within the above range, the yield of the die-casting process can be improved.

[0043] High corrosion-resistant die-cast aluminum alloy is melted at 690℃ to 710℃ to obtain a molten alloy. For example, the melting temperature of the die-cast aluminum alloy can be 690℃, 692℃, 694℃, 696℃, 698℃, 700℃, 702℃, 704℃, 706℃, 708℃, 710℃, or a range of any two of these values.

[0044] The molten alloy is injected into the die-casting mold using a low-speed injection followed by a high-speed injection. The temperature of the die-casting mold is 180℃~220℃. The low-speed injection is 0.2m / s~0.4m / s, and the low-speed time is 1.3s~1.7s. The high-speed injection is 4m / s~5m / s, and the high-speed time is 0.2s~0.4s. After the injection is completed, the mold is left in place, solidified, demolded, and passivated by powder spraying, resulting in a shell-type die-cast part. For example, the temperature of the die-casting mold can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, or any range of two of these values; the injection speed can be 0.2m / s, 0.22m / s, 0.24m / s, 0.26m / s, 0.28m / s, 0.3m / s, 0.32m / s, 0.34m / s, 0.36m / s, 0.38m / s, 0.4m / s, or any range of two of these values. The range of values ​​is as follows: low speed time is 1.3s, 1.35s, 1.4s, 1.45s, 1.5s, 1.55s, 1.6s, 1.65s, 1.7s, or any two of these values; high speed injection time is 4m / s, 4.2m / s, 4.4m / s, 4.6m / s, 4.8m / s, 5m / s, or any two of these values; high speed injection time is 0.2s, 0.25s, 0.3s, 0.35s, 0.4s, or any two of these values.

[0045] In some implementations, the retention time of the molten alloy in the die-casting mold is 4 to 5 seconds. For example, the retention time can be 4 seconds, 4.2 seconds, 4.4 seconds, 4.6 seconds, 4.8 seconds, 5 seconds, or a range of any two of these values.

[0046] In some implementations, the solidification time of the die-casting can be accelerated by connecting a high-pressure cooling device to the rear wall of the die-casting machine.

[0047] In some implementation schemes, this application does not impose any particular restrictions on the process flow of mold retention, solidification, demolding, passivation powder spraying, as long as the purpose of this application can be achieved.

[0048] In some implementations, the powder coating material used in this application is a commercially available conventional substance. This application does not have any particular restrictions on its source, as long as it can achieve the purpose of this application. For example, the powder coating material can be ordinary polyester powder.

[0049] In some implementations, the powder coating thickness is from 70 μm to 100 μm. For example, the powder coating thickness can be 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, or a range of any two of these values.

[0050] In one embodiment of this application, the thickness of the die-cast shell part is between 1 mm and 4 mm. For example, the thickness of the die-cast shell part can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or a range of any two of these values. By controlling the thickness of the die-cast shell part within the above range, it is possible to achieve both high die-casting yield and good mechanical properties.

[0051] Example

[0052] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0053] Test methods and equipment:

[0054] Phase testing within the organizational structure:

[0055] The die-cast aluminum alloy samples in the examples and comparative examples were measured using optical (metallographic) microscopy.

[0056] Using a metallographic microscope, the type of phase (such as primary phase, eutectic phase, dispersed phase, etc.) can be determined by observing the microstructure characteristics such as phase morphology and distribution. The determination method is described in Chapter 10 of Volume 2 of "Metallographic Atlas of Metallic Materials" (China Machine Press, July 2006, First Edition).

[0057] The C5-M corrosion level test in the international standard ISO 12944-6 includes the following:

[0058] Neutral salt spray test:

[0059] The salt spray test chamber is used, and the specific tests are conducted in accordance with the international standard ISO 9227.

[0060] Condensation test:

[0061] The condensation test chamber is used, and the specific tests are conducted in accordance with the international standard ISO 6270-1.

[0062] Example 1-1

[0063] Preparation of High Corrosion-Resistant Die-Cast Aluminum Alloys

[0064] Before feeding, thoroughly clean the furnace, remove the ash and slag, and calculate the weight of high-purity aluminum raw material according to the expected alloy composition (the rest being Al and unavoidable impurities) in Example 1-1 in Table 1. Then feed it into the heating furnace, heat it to 680°C, and hold it at that temperature for 15 minutes until it is completely melted.

[0065] Heat to 760℃ and add Si and Al-Fe alloy (Al-Fe 20%);

[0066] Cool to 730℃ and add Al-Cr alloy (Al-Cr 10%), Al-Mn alloy (Al-Mn 10%), and Al-Ti alloy (Al-Ti 10%).

[0067] Cool down to 720℃ and add pure Mg and Al-Sr metallic materials (Al-Sr 10%);

[0068] After melting all the above raw materials, the mixture is cast at 720°C to obtain a high corrosion-resistant die-cast aluminum alloy.

[0069] <Die Casting>

[0070] The high corrosion-resistant die-cast aluminum alloy obtained from the above steps is melted again at 700℃ to obtain a molten alloy. The molten alloy is pre-filled into the barrel through the die-casting machine punch and then injected into the die-casting mold. The temperature of the die-casting mold is controlled at 200℃. The injection adopts a filling method of low speed first and then high speed. The low injection speed is 0.3m / s and the low speed time is 1.5s. The high injection speed is 4.5m / s and the high speed time is 0.3s. This ensures that each kg of molten alloy is filled into the die-casting mold cavity within 150ms and remains in the die-casting mold for 4.5s. At the same time, a high-pressure cooling device is connected to the rear wall of the die-casting machine to accelerate the solidification time of the product. After demolding, the product is conveyed by a conveyor belt and then passivated. Finally, the second surface is sprayed with powder by a hot spray gun with a powder thickness of 80μm to obtain a shell-type die-cast part.

[0071] In the high corrosion-resistant die-cast aluminum alloy, the mass percentages of Si, Mg, Fe, Sr, Mn, Ti, Cr, Cu, and Zn are 8.5 wt%, 0.6 wt%, 0.5 wt%, 0.03 wt%, 0.6 wt%, 0.12 wt%, 0.08 wt%, 0.025 wt%, and 0.025 wt%, with the remainder being Al and unavoidable impurities. See Table 1 for details.

[0072] Examples 1-2 to Examples 1-9

[0073] Except for adjusting the relevant parameters according to Table 1, and the remaining parameters being Al and unavoidable impurities, the rest are the same as in Examples 1-1.

[0074] Comparative Examples 1 to 4

[0075] Except for adjusting the relevant parameters according to Table 1, and the remaining parameters being Al and unavoidable impurities, the rest are the same as in Examples 1-1.

[0076] The preparation parameters and performance parameters of each embodiment and comparative example are shown in Table 1.

[0077] Table 1

[0078]

[0079] The elemental mass percentage content of die-cast aluminum alloys affects their corrosion resistance. As can be seen from Examples 1-1 to 1-9 and Comparative Examples 1 to 4, when the die-cast aluminum alloy includes Si, Mg, Fe, Sr, Mn, Ti, Cr, Cu, Zn, and Al elements, and the mass percentage content of the above elements is within the protection scope of this application, the prepared die-cast aluminum alloy can pass the C5-M corrosion resistance level test in the international standard ISO12944-6, demonstrating that the die-cast aluminum alloy prepared in the examples has superior corrosion resistance.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0081] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0082] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A high corrosion-resistant die-cast aluminum alloy comprising the following components in weight percentage: 8 wt% to 9 wt% Si, 0.2 wt% to 1 wt% Mg, 0.1 wt% to 1 wt% Fe, 0.005 wt% to 0.05 wt% Sr, 0.2 wt% to 1 wt% Mn, 0.05 wt% to 0.2 wt% Ti, 0.05 wt% to 0.15 wt% Cr, 0 wt% to 0.05 wt% Cu, 0 wt% to 0.05 wt% Zn, with the remainder being Al and unavoidable impurities, wherein the weight percentage of said unavoidable impurities does not exceed 0.5 wt%.

2. The high corrosion-resistant die-cast aluminum alloy according to claim 1, wherein, The mass percentage content of Fe, Mn and Cr in the high corrosion resistant die-cast aluminum alloy satisfies: Fe:(Mn+Cr)=(0.6~0.8):

1.

3. The high corrosion-resistant die-cast aluminum alloy according to claim 1, wherein, The microstructure of the high corrosion-resistant die-cast aluminum alloy includes eutectic α-Al phase, eutectic Al-Si phase and dispersed phase, wherein the dispersed phase includes at least one of Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, Al(Fe,Cr)Si phase, Al6Mn phase or Al3Fe phase.

4. The high corrosion-resistant die-cast aluminum alloy according to any one of claims 1 to 3, wherein, The high corrosion-resistant die-cast aluminum alloy is prepared by the following method: 1) Put the high-purity Al raw material into the heating furnace and heat it to 670℃~690℃, then melt and hold it at that temperature for 14min~16min; 2) Heat to 750℃~770℃ and add Si and Al-Fe alloy raw materials; 3) Cool down to 720℃~740℃ and add Al-Cr, Al-Mn and Al-Ti alloy raw materials; 4) Cool down to 710℃~730℃ and add pure Mg and Al-Sr metal materials; 5) After melting all the above raw materials, cast them to obtain the high corrosion resistant die-cast aluminum alloy.

5. The application of a high corrosion-resistant die-cast aluminum alloy according to any one of claims 1 to 4 in die-cast shell-type parts.

6. The application according to claim 5, wherein, The application includes die-casting the high corrosion-resistant die-cast aluminum alloy to produce the housing-type die-cast parts.

7. The application according to claim 5, wherein, The die-cast shell-type part includes a first surface and a second surface. With the first surface sealed, the second surface meets the C5-M corrosion level of the international standard ISO12944-6.

8. The application according to claim 6, wherein, The die-casting process includes: a) Melt the high corrosion-resistant die-cast aluminum alloy at 690℃~710℃ to obtain a molten alloy; b) The molten alloy is injected into the die-casting mold using a low-speed injection followed by a high-speed injection. The temperature of the die-casting mold is 180℃~220℃. The low-speed injection is 0.2m / s~0.4m / s, and the low-speed injection time is 1.3s~1.7s. The high-speed injection is 4m / s~5m / s, and the high-speed injection time is 0.2s~0.4s. After the injection is completed, the mold is left in place, solidified, demolded, and passivated by powder spraying to obtain the die-cast shell-type part.

9. The application according to claim 5, wherein, The thickness of the die-cast shell-type parts is 1 mm to 4 mm.

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