Al-Mn series die-casting aluminum alloy and preparation method and application thereof

Abstract

The invention discloses an Al-Mn series die-casting aluminum alloy and a preparation method and application thereof. The aluminum alloy material comprises 0.5-1.9 wt.% of Mn, 0.5-1.9 wt.% of Al, 0.5-1.9 wt.% of Mn, and the balance % of Mg: 0.01 to 3.0 wt.%; %, 0.01 to 0.2 wt.% of Ti; % of Zr: 0.01 to 0.2 wt.%; % of V: 0.01 to 0.2 wt.%; % of Cu: 0.01 to 0.5 wt.%; the M comprises at least one of Co and Cr, the sum of the total amount of impurities is smaller than or equal to 0.2 wt%, and the balance is Al. The liquidus of the alloy is smaller than or equal to 660 DEG C, the material structure is mainly composed of an alpha-Al matrix, good die-casting formability and anodizing property are achieved, the Al-Mn series die-casting aluminum alloy can be used for preparing a die casting and conducting anodizing, a compact and uniform anodizing film layer is obtained, and therefore a decorative-level die-casting exterior part is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to an Al-Mn series die-cast aluminum alloy and a preparation method and application thereof. Background Art

[0002] In atmospheric conditions, a very thin oxide film tends to spontaneously form on the surface of aluminum alloy products. However, this oxide film has limited corrosion resistance and can cause the surface of aluminum alloy parts to lose their original luster. To improve the appearance of aluminum alloy products and increase their corrosion resistance, aluminum alloy parts need to be anodized.

[0003] Existing aluminum alloys for anodizing are typically manufactured using an aluminum extrusion followed by machining, followed by an anodizing surface treatment, resulting in smooth, brightly colored exterior parts. Die casting offers the advantages of high dimensional accuracy and the possibility of single-shot molding. Direct die casting of aluminum alloy exterior parts requiring anodization can eliminate or significantly reduce machining time, lowering part manufacturing costs. Due to the relatively small wall thickness of die-cast parts, Al-Si casting aluminum alloys (such as ADC12 and A380) are often used to ensure melt filling. However, Si is a semiconductor. During anodization, the Si phase precipitated in the material structure differs from the physicochemical properties of the aluminum alloy matrix, resulting in uneven anodized films and difficulty in coloring aluminum alloy die-cast parts. Although aluminum extrusions have relatively good anodizability, their high liquidus and high tendency to hot cracking during casting make them unsuitable for die casting. This demonstrates the conflict between anodizability and die-casting suitability of existing aluminum alloys. Summary of the Invention

[0004] The present invention aims to provide an Al-Mn die-cast aluminum alloy, its preparation method, and its application, aiming to resolve the conflict between die-castability and anodizability in existing aluminum alloys and achieve relatively good mechanical properties without heat treatment (in the die-cast state). The key to achieving both die-castability and anodizability lies in regulating the alloy's solidification range and ensuring the most uniform physicochemical properties possible. By adding alloying elements, the alloy's solidification range is regulated, maintaining a liquidus of ≤660°C and ensuring die-castability. Furthermore, by leveraging the high cooling rate of die casting and the appropriate design of alloying elements, strengthening elements are incorporated into the alloy matrix as solid solutions, minimizing the formation of coarse secondary phases. This prevents the anodic oxidation effect of the component surface, which is affected by the different corrosion rates and electrochemical properties of the secondary phases and the matrix, and achieves excellent mechanical properties in the die-cast state without heat treatment (in the die-cast state).

[0005] The purpose of the present invention can be achieved through the following technical solutions: An Al-Mn die-casting aluminum alloy, comprising the following components by mass percentage: Mn: 0.5-1.9 wt.% Mg: 0.01-3.0 wt.% Ti: 0.01-0.2 wt.% Zr: 0.01-0.2 wt.% V: 0.01-0.2 wt.% Cu: 0.01-0.5 wt.% M: 0-0.5 wt.%, wherein M includes at least one of Co and Cr; The total amount of other impurities ≤ 0.2 wt.% The balance is Al.

[0006] The roles of each element are as follows: Mn element A certain content of Mn element can improve the demoulding property of the alloy. Adding an appropriate amount of Mn element can dissolve in the aluminum matrix to play a solid solution strengthening role. However, excessive addition will raise the liquidus line of the alloy and deteriorate the die-casting formability of the alloy. In addition, excessive addition of Mn element is likely to form coarse blocky AlMn hard phase in the matrix. Since the corrosion rate and electrochemical properties of this phase are inconsistent with those of the matrix, it is easy to cause unsatisfactory anodizing polishing and coloring effects of aluminum alloy parts.

[0007] Mg element An appropriate amount of Mg in the alloy can exist in the form of a solid solution in the α-Al matrix, which can effectively improve the strength of the casting. However, excessive Mg addition can easily form a brittle AlMg phase with a concentrated network distribution on the grain boundaries, which in turn reduces the mechanical properties of the alloy. In addition, this phase has different electrochemical properties from the matrix, and its large-scale formation may deteriorate the material's anodic oxidizability.

[0008] Zr, Ti, V elements Zr, Ti, and V have similar functions in aluminum alloys. By forming AlZr, AlTi, and AlV compounds with aluminum, they can serve as heterogeneous nucleation substrates for the alloy, thereby refining the material structure and improving the alloy's strength. However, the addition of a single element tends to aggregate and form a coarse, hard primary phase, which is detrimental to improving mechanical properties. Furthermore, the difference in electrochemical properties between the coarse, hard primary phase and the matrix can easily degrade the material's anodic oxidizability. Furthermore, excessive addition of these elements is not recommended, as this will raise the alloy's liquidus and reduce its die-castability.

[0009] Cu element The atomic radius of Cu and Al differs significantly. When Cu dissolves into the matrix, it can cause significant lattice distortion, resulting in a significant solid-solution strengthening effect. Furthermore, the addition of Cu can appropriately lower the alloy's solidification range, improving its die-castability. However, a high Cu content in the alloy can cause the oxide film to turn red during anodizing, which is detrimental to anodization.

[0010] Co and Cr elements The M element (i.e., at least one of the two elements Co and Cr) has a certain solid solubility in the Al matrix and can play a role in solid solution strengthening. However, the solid solubility of Co and Cr elements in the matrix is ​​limited. Excessive addition can easily form compounds with a network-like distribution on the grain boundaries, destroying the continuity of the matrix and being detrimental to the improvement of mechanical properties. In addition, due to the difference in electrochemical properties between the Co-containing phase and the Cr-containing phase and the matrix, the anodic oxidizability of the material can be easily deteriorated.

[0011] A method for preparing an Al-Mn series die-cast aluminum alloy comprises the following steps: Step S1: Drying: Preheating and drying the prepared pure Al, pure Mg, Al-Mn, Al-V, Al-Zr, Al-Co, Al-Cr, and Al-Cu master alloys; Step S2: Melting: Heat pure Al, Al-Mn, Al-V, Al-Zr, Al-Co, Al-Cr, and Al-Cu master alloys to 720-760°C. After the alloys are completely melted, lower the melt temperature to 680-700°C. Then, press pure Mg into the bottom of the melt until it is completely melted. Step S3: Refining: heating the completely melted melt to 720-730°C for refining; Step S4: After the melt refined in step S3 reaches the die-casting temperature, the die-casting process is performed to finally complete the production of the die-cast part.

[0012] Furthermore, in step S1, the preheating temperature is 180-220°C.

[0013] Furthermore, the specific method of refining in step S3 is: using a rotary blowing device to pass nitrogen containing refining agent powder into the melt to perform powder spray refining, slag removal, and degassing treatment, and then standing for 10-15 minutes to obtain a refined melt.

[0014] Furthermore, the process parameters of the rotary blowing device are: degassing speed: 300-350r / min, degassing time: 5-10min, gas source pressure during degassing: 0.2-0.4MPa, and gas flow rate: 0.2-0.8sccm.

[0015] Furthermore, the amount of the refining agent added is 0.6-1.0 wt.% of the total weight of the melt.

[0016] Furthermore, in step S4, the casting includes but is not limited to: high pressure casting, squeeze casting, semi-solid casting, gravity casting, and low pressure casting.

[0017] Furthermore, in step S4, the casting temperature is preferably 670°C-750°C.

[0018] An application of an Al-Mn series die-casting aluminum alloy. The Al-Mn series die-casting aluminum alloy can be used to prepare die-casting parts and perform anodizing to obtain a dense and uniform anodized film layer, thereby obtaining a decorative-grade die-casting appearance part.

[0019] Beneficial effects of the present invention: 1. The aluminum alloy provided by the present invention has a liquidus of ≤660°C and good fluidity, meeting the die-casting molding conditions. It can replace the existing aluminum profile + CNC processing method, improve production efficiency and reduce production costs.

[0020] 2. By adding an appropriate amount of alloying elements, the added strengthening elements are dissolved into the matrix, and the material structure is α-Al matrix + a small amount of AlMnMg phase. The electrochemical properties of the material structure are uniform and balanced. Without the need for heat treatment to regulate the structure, the casting has good anodizing effect and mechanical properties. The prepared Al-Mn die-cast aluminum alloy has a tensile strength of ≥190MPa, a yield strength of ≥90MPa, an elongation of ≥6%, and excellent performance.

[0021] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 1 is a scanning electron microscope (SEM) microstructure image of the Al-Mn die-cast aluminum alloy material prepared in Example 1; Figure 2 1. This is a physical picture of the die-casting made of Al-Mn die-cast aluminum alloy in Example 1 before and after anodization; Figure 3 The table shows the addition amount of elements and related test results for the aluminum alloys described in 10 examples and 5 comparative examples; Figure 4 This is a product description picture of refining agent. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Refining agent: Torch brand aluminum alloy refining agent, purchased from Zhangjiagang Haohua Light Alloy Material Co., Ltd. Its properties are white powder (such as Figure 4 Product description image).

[0026] Example 1 (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, Al-10Cr, and Al-50Cu master alloy to 200°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-10Zr, Al-10Co, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 750°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0027] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a total weight of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is carried out at a speed of 300 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 10 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0028] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The die casting temperature is 720°C. Other casting parameters are shown in Table 1.

[0029] Table 1 Casting process parameters

[0030] Example 2: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, Al-10Cr, and Al-50Cu master alloy to 190°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-10Zr, Al-10Co, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0031] (3) Refining: The melt is heated to 725°C, and nitrogen gas at a pressure of 0.4 MPa is introduced into the melt. Refining agent powder is added at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 310 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 10 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0032] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 730°C. Other relevant casting process parameters are shown in Table 1.

[0033] Example 3: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, Al-10Cr, and Al-50Cu master alloy to 210°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 700°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0034] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.4 MPa is introduced into the melt. Refining agent powder is added at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 310 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 10 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0035] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 730°C. Other relevant casting process parameters are shown in Table 1.

[0036] Example 4: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, Al-10Cr, and Al-50Cu master alloy to 220°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-10Zr, Al-10Co, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 760°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0037] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 10 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0038] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 720°C. Other relevant casting process parameters are shown in Table 1.

[0039] Example 5: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-Mn, Al-10Co, and Al-50Cu master alloy to 180°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-10Zr, Al-10Co, and Al-50Cu master alloys into a furnace, heat the furnace to 750°C, and after the alloys are completely melted, lower the melt temperature to 680°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0040] (3) Refining: The melt is heated to 730°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is added at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0041] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 700°C. Other relevant casting process parameters are shown in Table 1.

[0042] Example 6: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, and Al-50Cu master alloy to 200°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 680°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0043] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0044] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0045] Example 7: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Co, and Al-50Cu master alloy to 200°C and dry them; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-50Cu, and Al-10Co intermediate alloys into a furnace, heat the furnace to 750°C, and after the alloys are completely melted, lower the melt temperature to 680°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0046] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0047] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0048] Example 8: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, and Al-50Cu master alloy to 200°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-10Ti, Al-Mn, Al-10V, Al-5Zr, Al-10Cr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0049] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0050] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0051] Example 9: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, and Al-50Cu master alloy to 200°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 750°C, and after the alloys are completely melted, lower the melt temperature to 680°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0052] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0053] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0054] Example 10: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu master alloy to 200°C and dry them; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 685°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0055] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0056] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0057] Comparative Example 1: (1) Drying: Preheat the commercially available A380 alloy to 200°C and dry it; (2) Melting: Place the dried commercial A380 alloy into a furnace, heat the furnace to 740°C until the alloy is completely melted, and then stir for 5 minutes.

[0058] (3) Refining: The melt is cooled to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is added at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 320 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0059] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 700°C. Other relevant casting process parameters are shown in Table 1.

[0060] Comparative Example 2: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-50Cu, Al-10Cr, and Al-10Co master alloy to 200°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-10Zr, Al-50Cu, Al-10Cr, and Al-10Co intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0061] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is added at a total weight of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a speed of 300 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0062] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 710°C. Other relevant casting process parameters are shown in Table 1.

[0063] Comparative Example 3: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu master alloy to 220°C and perform drying treatment; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 760°C, and after the alloys are completely melted, lower the melt temperature to 700°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0064] (3) Refining: The melt is heated to 730°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a total weight of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is carried out at a speed of 300 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 12 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0065] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 700°C. Other relevant casting process parameters are shown in Table 1.

[0066] Comparative Example 4: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, and Al-50Cu master alloy to 190°C and dry them; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 740°C, and after the alloys are completely melted, lower the melt temperature to 680°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0067] (3) Refining: The melt is heated to 720°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is added at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 330 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 10 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0068] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 730°C. Other relevant casting process parameters are shown in Table 1.

[0069] Comparative Example 5: (1) Drying: Preheat the prepared raw materials of pure Al, pure Mg, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu master alloy to 190°C and dry them; (2) Melting: Place the dried pure Al, Al-Mn, Al-10Ti, Al-10V, Al-5Zr, Al-10Cr, Al-10Co, and Al-50Cu intermediate alloys into a furnace, heat the furnace to 750°C, and after the alloys are completely melted, lower the melt temperature to 690°C. Then, use a bell jar to press pure Mg into the bottom area of ​​the crucible until it is completely melted, and then stir for 5 minutes.

[0070] (3) Refining: The melt is heated to 725°C, and nitrogen gas at a pressure of 0.3 MPa is introduced into the melt. Refining agent powder is introduced at a concentration of 0.8% of the total weight of the melt. The melt is then deslagging and degassing is performed at a rate of 310 r / min and a gas flow rate of 0.5 sccm for 10 minutes. The melt is then allowed to stand for 15 minutes, and the slag is removed. A pre-furnace composition analysis test is then performed. Melts with deviations in composition content are supplemented or diluted to bring the composition within the acceptable range.

[0071] (4) Casting: Preferably, vacuum die casting and a homemade test piece mold are used to form the casting. The pouring (die casting) temperature is 720°C. Other relevant casting process parameters are shown in Table 1.

[0072] According to the described preparation process, 10 aluminum alloys described in the examples and 5 comparative examples were prepared. The addition amount of elements and the related test results are shown in Figure 2. Figure 3 As shown in the table.

[0073] By the attached Figure 3As shown in the table, comparing Examples 1-3 with Comparative Examples 2-3 demonstrates that varying the Mn content within the composition range of the present invention significantly impacts the alloy's mechanical properties, while ensuring castability and anodizability. However, when the Mn content falls below the lower limit of the composition range, castings are susceptible to mold sticking; when it exceeds the upper limit, the anodizing effect of the casting is affected. Comparing Example 1, Examples 4-6, and Comparative Example 4 demonstrates that, when the Mg and Cu content falls within the composition range of the present invention, it does not affect the alloy's anodizability but does significantly impact its mechanical properties. This further demonstrates that the Mg and Cu content can be fine-tuned to meet the requirements of different application scenarios. However, when the Mg and Cu content exceeds the composition range of the present invention, the anodizing effect of the alloy is affected. Comparing Example 1, Examples 7-10, and Comparative Example 5 demonstrates that, within the composition range of the present invention, simply varying the type of M element (Co and Cr) has little effect on the alloy's mechanical properties and anodizability. However, when the M content exceeds the composition range of the present invention, the alloy's mechanical properties (especially elongation) and anodizing effect are adversely affected.

[0074] Figure 1 This is a scanning electron microscope (SEM) image of the anodizable Al-Mn cast aluminum alloy prepared in Example 1. The bright white phase dispersed within the α-Al matrix is ​​the eutectic AlMnMg phase. No other coarse primary phases are observed, indicating a favorable microstructure. Some Mn and Mg elements, along with Cr, Co, and Cu, exist as solid solutions within the matrix, providing a certain degree of solid solution strengthening and improving the mechanical properties of the die-cast alloy. This material, with the aluminum matrix as the primary phase, exhibits uniform and balanced electrochemical properties, free of interference from other coarse primary phases. Consequently, during anodization, the nucleation and growth rates of the film are essentially consistent, resulting in a dense and uniform anodic oxide film and improved coloring.

[0075] Figure 2 This is a comparison of the effects of the die castings prepared with the composition in Example 1 before and after anodizing. It can be seen that the castings prepared with the alloy composition of this patent have good appearance and uniform color after anodizing, indicating that the alloy of this patent has a good anodizing effect.

[0076] In summary, the present invention provides an anodizable Al-Mn die-cast aluminum alloy and a preparation method, which can not only be used to form die-cast parts, eliminating or reducing aluminum profiles + CNC processing to reduce production costs, but also can effectively perform anodization to obtain a dense and uniform anodized film layer with good dyeing effect, thereby obtaining decorative-grade die-cast appearance parts.

[0077] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. An Al-Mn die-cast aluminum alloy, characterized in that: The aluminum alloy comprises the following components by mass percentage: Mn: 0.5-1.9 wt.% Mg: 0.01-3.0 wt.% Ti: 0.01-0.2 wt.% Zr: 0.01-0.2 wt.% V: 0.01-0.2 wt.% Cu: 0.01-0.5 wt.% M: 0-0.5 wt.%, wherein M comprises at least one of Co and Cr; The total amount of other impurities ≤ 0.2 wt.% The balance is Al.

2. A method for preparing the Al-Mn die-cast aluminum alloy according to claim 1, characterized in that: The following steps are involved: Step S1: Drying: Preheat and dry the prepared pure Al, pure Mg, Al-Mn, Al-V, Al-Zr, Al-Co, Al-Cr, and Al-Cu master alloys; Step S2: Melting: Heat pure Al, Al-Mn, Al-V, Al-Zr, Al-Co, Al-Cr, and Al-Cu master alloys to 720-760°C. After the alloys are completely melted, lower the melt temperature to 680-700°C. Then, press pure Mg into the bottom of the melt until it is completely melted. Step S3: Refining: heating the completely melted melt to 720-730°C for refining; Step S4: After the melt refined in step S3 reaches the die-casting temperature, the die-casting process is performed to finally complete the production of the die-cast part.

3. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 2, wherein: In step S1, the preheating temperature is 180-220°C.

4. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 2, wherein: The specific method of refining in step S3 is: using a rotary blowing device to pass nitrogen containing refining agent powder into the melt to perform powder spray refining, slag removal, and degassing treatment, and then standing for 10-15 minutes to obtain a refined melt.

5. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 4, characterized in that: The process parameters of the rotary blowing device are as follows: degassing speed: 300-350r / min, degassing time: 5-10min, gas source pressure during degassing: 0.2-0.4MPa, and gas flow rate: 0.2-0.8sccm.

6. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 4, characterized in that: The amount of the refining agent added is 0.6-1.0 wt.% of the total weight of the melt.

7. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 2, wherein: In step S4, the casting is die casting.

8. The method for preparing an Al-Mn die-cast aluminum alloy according to claim 2, wherein: In step S4, the casting temperature is preferably 670°C-750°C.

9. Use of the Al-Mn die-casting aluminum alloy according to any one of claims 1 to 8, characterized in that: The Al-Mn series die-casting aluminum alloy can be used to prepare die-casting parts and perform anodizing to obtain a dense and uniform anodized film layer, thereby obtaining a decorative-grade die-cast appearance part.

Images