Aluminum alloy comprehensive modifier and preparation method thereof

Abstract

The application provides an aluminum alloy comprehensive modifier and a preparation method thereof. The modifier comprises an Al matrix, TiC x seeds and a second phase in the Al matrix, wherein the second phase comprises Al and a transition metal element, the TiC x seeds comprise a first TiC x seed with a sub-micron scale and a second TiC x seed with a nanometer scale, at least a part of the first TiC x seed is dispersed in the Al matrix, and at least a part of the second TiC x seed is coated by the second phase, wherein x satisfies x < 1. The modifier can modify an Fe-rich phase in an aluminum alloy containing an Fe element and refine an α-Al phase.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials, and specifically relates to a comprehensive modifier for aluminum alloys and its preparation method. Background Technology

[0002] High-strength and ultra-high-strength wrought aluminum alloys in the 2xxx, 6xxx, and 7xxx series are widely used in aerospace, industrial machinery, and other fields due to their excellent mechanical properties. For example, 7050 aluminum alloy is used to manufacture high-stress components such as aircraft structural spars, landing gear, and frame shells.

[0003] In addition, these aluminum alloys are widely used in rail transportation, high-end molds, and machinery equipment, for tooling fixtures and lightweight structural components that need to withstand high loads. The high strength and good formability of these aluminum alloys meet the industrial sector's dual requirements for lightweight and durable materials.

[0004] Grain refinement is commonly used to improve the strength and toughness of alloys and enhance their casting quality. For example, Al-5Ti-1B master alloy can be used to refine the α-Al grains in aluminum alloys, thereby improving their mechanical properties.

[0005] However, with increasingly stringent requirements for the mechanical properties of aluminum alloys, there is a desire to further improve their microstructure, for example, to refine the α-Al grains. Therefore, methods for further refining the α-Al grains in aluminum alloys are being continuously researched.

[0006] Furthermore, it is of greater concern that aluminum alloys inevitably contain Fe, especially given the increasing use of recycled aluminum. Fe typically exists as a Fe-rich phase, which is usually elongated or large blocky in shape. This morphology negatively impacts performance, for example, leading to decreased corrosion resistance, deterioration of mechanical properties, and particularly reduced fatigue performance. Therefore, it is desirable to reduce the size of the Fe-rich phase in aluminum alloys to mitigate its adverse effects on performance. Summary of the Invention

[0007] The purpose of this invention is to provide a modifier capable of modifying the Fe-rich phase in Fe-containing aluminum alloys and its preparation method.

[0008] Another objective of this invention is to provide a modifier that can both refine α-Al and modify the Fe-rich phase, and a method for preparing the same.

[0009] According to one aspect of the present invention, a modifier is provided, the modifier comprising an Al matrix and TiC. x Seed crystals and a second phase located in the Al matrix, the second phase comprising Al and transition metal elements, the TiC xThe seed crystal contains a first TiC with a submicron scale. x Seed crystals and second TiC with nanoscale x Seed crystal, the first TiC x At least a portion of the seed crystals are dispersed in the Al matrix, and the second TiC x At least a portion of the seed crystal is coated with the second phase, wherein x satisfies x < 1.

[0010] Optionally, the transition metal element includes at least one of the three elements Mn, Cr, and V.

[0011] Optionally, a single second phase is coated with a plurality of second TiC. x Seed crystal.

[0012] Optionally, the modifier is used in an aluminum alloy containing Fe, the aluminum alloy comprising α-Al and a Fe-rich phase, wherein the first TiC x Seed crystals are used to refine the α-Al in the aluminum alloy, and the second TiC x Seed crystals are used to modify Fe-rich phases.

[0013] Optionally, the first TiC x The seed crystal size is between 100nm and 600nm, and the second TiC x The size of the seed crystal is less than 100 nm.

[0014] Optionally, the first TiC x Seed crystals and the second TiC x All seed crystals are generated in situ.

[0015] Optionally, based on 100 wt.% of the modifier, TiC x The seed crystals have a mass percentage of 0.1 wt.% to 5 wt.%.

[0016] Optionally, based on 100 wt.% of the modifier, the total mass percentage of at least one of the three elements Mn, Cr, and V is less than or equal to 0.9 wt.%. Based on 100 wt.% of the modifier, the mass percentage of any single element among Mn, Cr, and V is less than or equal to 0.3 wt.%.

[0017] Optionally, x satisfies 0.7≤x≤0.9.

[0018] According to another aspect of the present invention, a method for preparing a modifier is provided, the method comprising: preparing an Al-Ti alloy melt; adding an aluminum alloy containing submicron-sized Al4C3 to the Al-Ti alloy melt, holding at 1100℃-1250℃ for 3 min-15 min to obtain a first melt; lowering the temperature to 1000℃-1150℃, adding an aluminum alloy containing nanoscale Al4C3 to the first melt, stirring for 2 min-10 min to obtain a second melt; adding an aluminum alloy containing transition metal elements to the second melt, lowering the temperature to 800℃-930℃, and then casting.

[0019] Optionally, the melt temperature when adding aluminum alloys containing nanoscale Al4C3 is lower than the melt temperature when adding aluminum alloys containing submicron-scale Al4C3. The aluminum alloys containing submicron-scale Al4C3 and the aluminum alloys containing nanoscale Al4C3 are Al-C alloys.

[0020] Optionally, the step of preparing the Al-Ti alloy melt includes: melting Al and heating it to 780℃-820℃, then adding sponge Ti.

[0021] Optionally, the aluminum alloy containing transition metal elements includes at least one of Al-Mn, Al-Cr, and Al-V.

[0022] Optionally, the preparation method further includes a step of refining the alloy melt by blowing air before casting.

[0023] According to another aspect of the present invention, a method for modifying an aluminum alloy containing Fe is provided, the method comprising: melting the aluminum alloy containing Fe and heating it to 700°C to 750°C to form a melt; adding a modifier as described above to the melt, holding it at the temperature for 10 min to 30 min, and then casting it.

[0024] Optionally, based on 100 wt.% of the Fe-containing aluminum alloy, the amount of the modifier added is 0.05-1.0 wt.%.

[0025] Optionally, the Fe-containing aluminum alloy is an Al-Zn-Mg-Cu series, an Al-Cu series, or an Al-Mg-Si series aluminum alloy.

[0026] According to another aspect of the present invention, an aluminum alloy containing Fe element is provided that is modified according to the modifier described above.

[0027] According to another aspect of the present invention, an aluminum alloy containing Fe element is provided that is modified according to the modifier described above.

[0028] Submicron TiC in the modifier according to embodiments of the present invention x It can effectively refine α-Al and improve its morphology, thereby enhancing strength and casting quality. The modifier contains nano-TiC. x (i.e., a second TiC with nanoscale) x Seed crystals can fully metamorphose the Fe-rich phase, reduce its size and improve its morphology, thereby effectively improving corrosion resistance, mechanical properties and fatigue performance.

[0029] The method for preparing the degrading agent according to embodiments of the present invention is simple, environmentally friendly, and has broad prospects for industrial application. Attached Figure Description

[0030] Figure 1 The present invention relates to the microstructure and EPMA analysis of the modifier according to an embodiment of the present invention, wherein (a) is submicron TiC and nano-TiC in Mn-rich phase, and (b) is surface scan analysis of Al, Mn, Ti and C using EPMA.

[0031] Figure 2 The images show SEM surface scans of the grain structure and Fe-rich phase of 7050 aluminum alloy before and after refinement modification. (a), (a1), and (a2) show the grain structure and Fe-rich phase of 7050 aluminum alloy before refinement modification; (b), (b1), and (b2) show the grain structure and Fe-rich phase of 7050 aluminum alloy after refinement modification using 0.3 wt% Al-5Ti-1B master alloy; and (c), (c1), and (c2) show the grain structure and Fe-rich phase of 7050 aluminum alloy after refinement modification using 0.3 wt% of the modifier of this invention. Detailed Implementation

[0032] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the products and methods described herein. However, after understanding this disclosure, various changes, modifications, and equivalents of the products and methods described herein will become clear. For example, the order of steps in the methods described herein is merely illustrative and is not limited to the order set forth herein, but may be changed as will become clear after understanding this disclosure, except for steps that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0033] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways in which the products and methods described herein may be understood upon understanding the contents of this disclosure.

[0034] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms such as those defined in a general dictionary shall be interpreted as having the same meaning as in this disclosure and shall not be interpreted in an idealized or overly formalistic manner.

[0035] It should also be understood that the terms “comprising / including” or “having” as used throughout the specification indicate the presence of the said ingredient, step, or operation, but do not exclude the presence or addition of one or more other ingredients. Therefore, unless explicitly stated to the contrary, the words “comprising,” “including,” or “having” will be understood to imply the inclusion of the said ingredient, step, or operation but do not exclude any other ingredient, step, or operation.

[0036] Deteriorating agent

[0037] According to an embodiment of the present invention, a modifier is provided for use in an aluminum alloy containing Fe to refine α-Al in the aluminum alloy and modify the Fe-rich phase, that is, to further refine the grain size of α-Al and improve the morphology of the Fe-rich phase.

[0038] Figure 1 This is a microstructure and EPMA analysis of the modifier according to an embodiment of the present invention, wherein (a) is nano-TiC in submicron TiC and Mn-rich phase, and (b) is surface scan analysis of Al, Mn, Ti and C using EPMA. Figure 1 As shown, the modifier according to embodiments of the present invention may include an Al matrix and TiC. x Seed crystals and a second phase located in the Al matrix, the second phase may contain Al and transition metal elements, TiC x Seed crystals may contain a first TiC with a submicron scale. x Seed crystals and second TiC with nanoscale x Seed crystal, first TiC x At least a portion of the seed crystals are dispersed in the Al matrix, and the second TiC x At least a portion of the seed crystal is coated with a second phase, wherein x satisfies x < 1.

[0039] The following will describe in detail the modifier according to embodiments of the present invention. The modifier according to embodiments of the present invention may contain TiC. x Seed crystals, where x satisfies x < 1. That is, TiC x The seed crystal contains C vacancies. For example... Figure 1 As shown, the region enriched with Ti and C is TiC. xSeed crystal, TiC x The seed crystals are white and have an overall granular morphology.

[0040] In addition to containing TiC, the modifier according to embodiments of the present invention is also present. x In addition to the seed crystal, a second phase may also be included. The second phase may contain Al and transition metal elements. Preferably, the transition metal elements may include at least one of Mn, Cr, and V. Figure 1 The diagram schematically shows that the second phase contains Mn, that is, from Figure 1 As can be seen from the EPMA surface scan analysis, the approximately circular blocky regions enriched with Mn are the second phase. Although Figure 1 Only the second phase containing Mn is shown; however, the invention is not limited thereto. That is, the second phase may also contain Cr or V, or any combination of Mn, Cr, and V. Additionally, as... Figure 1 As shown, the second phase is generally gray, while the Al matrix is ​​generally black.

[0041] from Figure 1 It can be seen that TiC x A significant characteristic of seed crystals is that they possess two scales, namely, TiC with a submicron scale, which is determined by the size of the seed crystal. x The seed crystal is called the first TiC. x Seed crystals, containing nanoscale TiC x The seed crystal is called the second TiC. x Seed crystal. Specifically, the first TiC x The seed crystal size is between 100nm and 600nm, and the second TiC x The seed crystal size is less than 100 nm. This can be calculated using TiC. x The average value of the major and minor axis dimensions of the seed crystal is used to determine the TiC. x The size of the seed crystal. If the calculated TiC... x If the average size of the seed crystals is between 100nm and 600nm, they are classified as first-generation TiC. x Seed crystals, if the calculated TiC x If the average size of the seed crystal is less than 100 nm, it is classified as TiC II. x Seed crystal.

[0042] like Figure 1 As shown, the first TiC x Seed crystals and second TiC x The location of the seed crystal differs. First TiC x At least a portion of the seed crystals are dispersed in the Al matrix, and the second TiC x At least a portion of the seed crystal is coated with a second phase. That is, at least one first TiC with a relatively large size xSeed crystals can be dispersed in an Al matrix, with at least one second TiC crystal having a smaller size. x The seed crystal is coated with a second phase. For example... Figure 1 As shown, a single second phase can coat multiple second TiC phases with smaller dimensions. x Seed crystals, for example, a single second phase may coat at least two, at least three, or at least four second TiC phases. x Seed crystals. Additionally, the first TiC crystal with a relatively large size... x The seed crystal may not be covered by the second phase; for example, it may be dispersed in the Al matrix and separated from the second phase, or it may be adjacent to the second phase in the Al matrix.

[0043] According to an embodiment of the present invention, the first TiC x Seed crystals and second TiC x All seed crystals are in-situ spontaneously generated. Two different sizes of TiC are formed in-situ by reacting Ti with two different sizes of Al4C3 in Al melt. x Seed crystal. The first TiC formed through in-situ reaction. x Seed crystals and second TiC x The interface between the seed crystal and the aluminum substrate is clean and well bonded.

[0044] According to an embodiment of the present invention, based on 100 wt.% of a modifier, TiC x The mass percentage of seed crystals can range from 0.1 wt.% to 5 wt.%. For example, TiC x The mass percentage of the seed crystal can be 0.5wt.%-4.5%wt.%, 1.0wt.%-4.0%wt.%, 1.5wt.%-3.5%wt.%, or 2.0wt.%-3.0%wt.%.

[0045] TiC x The first TiC in the seed crystal x Seed crystals and second TiC x The weight ratio of seed crystals is not specifically limited, but can be adjusted as needed.

[0046] According to an embodiment of the present invention, based on 100 wt.% of the modifier, the total mass percentage of Mn, Cr, and V is less than or equal to 0.9 wt.%. That is, regardless of whether one, two, or three of the transition metal elements Mn, Cr, and V are specifically selected, their total mass percentage is controlled to be less than or equal to 0.9 wt.% (based on 100 wt.% of the modifier).

[0047] According to an embodiment of the present invention, preferably, based on 100 wt.% of the modifier, the mass percentage of any single element among Mn, Cr, and V is less than or equal to 0.3 wt.%.

[0048] According to an embodiment of the present invention, the first TiC x Seed crystals can be used to refine α-Al and second TiC in iron-containing aluminum alloys. x Seed crystals can be used to modify the Fe-rich phase in iron-containing aluminum alloys. In other words, submicron-sized TiC can serve as a nucleation substrate for α-Al, refining the aluminum matrix grains, while nanoscale TiC can modify the Fe-rich phase.

[0049] The following uses 7050 aluminum alloy as an example to study the refining modification effect of the modifier of the present invention. The composition of 7050 aluminum alloy is Al-6.8Zn-1.95Cu-2Mg-0.12Zr-0.03Ti-0.15Fe. Specifically, the 7050 aluminum alloy is melted and heated to 730°C, and the modifier according to an embodiment of the present invention is added ( Figure 1 The modifier shown in the figure was used for heat treatment for 15 minutes before casting. Based on 100 wt.% 7050 aluminum alloy, the amount of modifier added was 0.3 wt.%.

[0050] As a comparative example, 0.3 wt.% of Al-5Ti-1B master alloy was added to 7050 aluminum alloy, and the melting temperature was also 730℃, with a holding time of 15 min. The Al-5Ti-1B master alloy contains TiB2 particles, which can serve as nucleation sites for α-Al to refine α-Al.

[0051] Figure 2 This is a SEM surface scan analysis of the grain structure and Fe-rich phase of 7050 aluminum alloy before and after refinement modification.

[0052] Figure 2 In the figure, (a), (a1), and (a2) represent the grain structure of the 7050 aluminum alloy before refinement and the SEM surface scan analysis of the Fe-rich phase. Figure 2 As shown in (a), (a1), and (a2), the α-Al grains are coarse and the Fe-rich phase is large in blocky or needle-like form. The size of the α-Al grains is approximately 350 μm, and the size of the Fe-rich phase is approximately 80 μm.

[0053] Figure 2 (b), (b1), and (b2) in the figure represent the grain structure and Fe-rich phase-rich phase SEM surface scan analysis of the 7050 aluminum alloy after refinement and modification using 0.3 wt% Al-5Ti-1B master alloy. Figure 2As shown in (b), (b1), and (b2), the use of the Al-5Ti-1B master alloy resulted in a certain degree of refinement of the α-Al grain size, which was approximately 220 μm. However, after adding the Al-5Ti-1B master alloy, the size of the Fe-rich phase did not change significantly; it remained a large needle-like structure, with a size of approximately 70 μm.

[0054] Figure 2 In the figures (c), (c1), and (c2), the grain structure and Fe-rich phase-rich phase of the 7050 aluminum alloy after refinement modification using 0.3 wt% of the modifier of the present invention are obtained through SEM surface scanning analysis. Figure 2 As shown in (c), the α-Al grain refinement effect is very obvious; not only is the size reduced, but the morphology also changes from an irregular shape to a more regular, approximately circular shape with more regular edges. Furthermore, from... Figure 2 As can be seen from (c1) and (c2), compared with the Fe-rich phase before modification and the Fe-rich phase after adding the Al-5Ti-1B master alloy, the morphology and size of the Fe-rich phase in the 7050 aluminum alloy changed significantly after adding the modifier according to the present invention. The size of the Fe-rich phase decreased significantly, and the morphology of the Fe-rich phase also changed from larger needle-like shapes to smaller blocky shapes. In the 7050 aluminum alloy after refinement modification using the modifier of the present invention, the size of the α-Al grains is approximately 80 μm, and the size of the Fe-rich phase is approximately 20 μm.

[0055] This demonstrates that the modifier according to embodiments of the present invention can simultaneously achieve efficient refinement of α-Al grains and effective modification of Fe-rich phases, thereby significantly improving the strength and casting quality of 7050 aluminum alloy, and significantly reducing the adverse effects caused by the morphology of Fe-rich phases, effectively improving corrosion resistance, mechanical properties and fatigue properties.

[0056] Submicron TiC in modifiers x It can effectively refine α-Al and improve its morphology, thereby enhancing strength and casting quality. The modifier contains nano-TiC. x (i.e., a second TiC with nanoscale) x Seed crystals can fully metamorphose the Fe-rich phase, reduce its size and improve its morphology, thereby effectively improving corrosion resistance, mechanical properties and fatigue performance.

[0057] Nano TiC according to the present invention x The phenomenon of Fe-rich phase metamorphism is not limited by specific technical principles. The metamorphism mechanism may be: nano-TiC x TiC is encased in a second phase rich in transition metals (Mn, Cr, V, etc.). xThe interfacial properties change. When a modifier is added to the aluminum alloy melt, the second phase, rich in transition metal elements, dissolves, and the interfacial modified nano-TiC... x Released, the Fe-rich phase will be present in some nano-TiC x Interface nucleation, while the remaining nano-TiC x It also hinders the growth of Fe-rich phases, thus having a metamorphic effect on Fe-rich phases.

[0058] Although the above description uses 7050 aluminum alloy containing Fe as an example, the modifier according to embodiments of the present invention can also be applied to other aluminum alloys containing Fe.

[0059] According to an embodiment of the present invention, TiC x In the seed crystal, x can satisfy 0.7 ≤ x ≤ 0.9. When x satisfies 0.7 ≤ x ≤ 0.9, the refining and modification effects will be more excellent.

[0060] Preparation method of deteriorating agent

[0061] The method for preparing the modifier according to an embodiment of the present invention may include: preparing an Al-Ti alloy melt; adding an aluminum alloy containing submicron-sized Al4C3 to the Al-Ti alloy melt, holding it at 1100℃-1250℃ for 3min-15min to obtain a first melt; lowering the temperature to 1000℃-1150℃, adding an aluminum alloy containing nano-sized Al4C3 to the first melt, stirring for 2min-10min to obtain a second melt; adding an aluminum alloy containing transition metal elements to the second melt, lowering the temperature to 800℃-930℃, and then casting.

[0062] First, an Al-Ti alloy melt is prepared. The steps for preparing the Al-Ti alloy melt may include: melting Al and heating it to 780℃-820℃, then adding sponge Ti until the reaction is complete to form an Al-Ti alloy melt. However, the method for preparing the Al-Ti alloy melt is not limited to this; for example, an Al-Ti alloy melt can also be obtained by directly melting an Al-Ti alloy.

[0063] Then, the melt temperature is adjusted to 1100℃-1250℃, and an aluminum alloy containing submicron-sized Al4C3 is added and held at this temperature for 3-15 minutes to obtain the first melt. Then, after lowering the temperature to 1000℃-1150℃, an aluminum alloy containing nanoscale Al4C3 is added to the first melt, and stirring is applied for 2-10 minutes to obtain the second melt. According to the present invention, TiC is formed by reacting Al4C3 as a carbon support with Ti. xSeed crystals. Additionally, by reacting Al₄C₃ with Ti in two separate reactions with different sizes, a first TiC₃ with submicron scale can be formed by reacting submicron-scale Al₄C₃ with Ti. x Seed crystals are then used to react nanoscale Al4C3 with Ti to form a second TiC with nanoscale crystals. x Seed crystals. If nanoscale Al4C3 is added first, nanoscale TiC will form first. x The material may continue to grow, therefore this invention obtains TiC with two scales by first adding submicron-scale Al4C3 and then adding nanoscale Al4C3. x A modifier for seed crystals.

[0064] The holding temperature for adding aluminum alloys containing submicron-sized Al4C3 is 1100℃-1250℃. If the reaction temperature is below 1100℃, the reaction may not proceed; if the reaction temperature is above 1250℃, the excessively high temperature will result in the formation of TiC. x The size will increase and the aluminum alloy oxidation will be more severe. After adding the aluminum alloy containing submicron-sized Al4C3, hold at a temperature of 3-15 minutes. If the holding time is less than 3 minutes, the reaction may not be complete; if the holding time exceeds 15 minutes, the TiC... x The size may increase.

[0065] When adding aluminum alloys containing nanoscale Al4C3, the temperature is lowered to 1000℃-1150℃. If the reaction temperature is below 1000℃, the reaction may not proceed; if the reaction temperature is above 1150℃, the excessively high temperature will result in the formation of TiC. x The size will increase and the aluminum alloy will oxidize more severely. Additionally, after adding the aluminum alloy containing nanoscale Al4C3, hold the temperature for 2-10 minutes. If the holding time is less than 2 minutes, the reaction may be insufficient; if the holding time exceeds 10 minutes, the TiC... x The size may increase.

[0066] Furthermore, according to embodiments of the present invention, the melt temperature when aluminum alloy containing nanoscale Al4C3 is added is lower than the melt temperature when aluminum alloy containing submicron-scale Al4C3 is added, thereby forming nanoscale TiC in combination with nanoscale Al4C3 raw materials. x Seed crystal.

[0067] According to embodiments of the present invention, aluminum alloys containing submicron-scale Al4C3 and aluminum alloys containing nanoscale Al4C3 can be Al-C alloys. Adding Al4C3 in the form of an Al-C alloy ensures that Al4C3 dissolves more quickly in the aluminum alloy and reacts with Ti, thereby improving dissolution and reaction efficiency.

[0068] According to an embodiment of the present invention, after obtaining the second melt, an aluminum alloy containing transition metal elements is added to the second melt, and the temperature is lowered to 800°C-930°C before casting.

[0069] According to embodiments of the present invention, the aluminum alloy containing transition metal elements includes at least one of Al-Mn, Al-Cr, and Al-V. According to embodiments of the present invention, by lowering the temperature to 800℃-930℃, the nano-TiC generated in the reaction can interact with clusters rich in transition metal elements such as Mn, Cr, and V, forming a coating effect during the casting and cooling process.

[0070] According to embodiments of the present invention, the alloy melt can be further refined by blowing air before casting. Any blowing air refining method known in the art can be used to refine the alloy melt, and the present invention does not impose any specific limitations on this.

[0071] Modification methods for Fe-containing aluminum alloys

[0072] According to embodiments of the present invention, a method for modifying an aluminum alloy containing Fe can also be provided.

[0073] The modification method of the Fe-containing aluminum alloy according to an embodiment of the present invention may include: melting the Fe-containing aluminum alloy and heating it to 700°C to 750°C to form a melt; adding the modifier as described above to the melt, holding it at the temperature for 10 min to 30 min, and then casting it.

[0074] First, an aluminum alloy containing Fe is melted in, for example, a melting furnace, and heated to 700°C to 750°C (e.g., 720°C to 740°C) to form a melt. Then, a modifier is added to the melt, and the mixture is held at this temperature for 10 to 30 minutes to fully refine the α-Al and fully modify the Fe-rich phase. Finally, casting is performed. According to embodiments of the invention, based on an aluminum alloy containing 100 wt.% Fe, the amount of modifier added can be 0.05-1.0 wt.%. For example, based on an aluminum alloy containing 100 wt.% Fe, the amount of modifier added can be 0.1-0.8 wt.%, 0.3-0.7 wt.%, or 0.4-0.6 wt.%.

[0075] According to embodiments of the present invention, the Fe-containing aluminum alloy can be an Al-Zn-Mg-Cu, Al-Cu, or Al-Mg-Si aluminum alloy. For example, the Fe-containing aluminum alloy can be 7050 aluminum alloy. The composition of 7050 aluminum alloy can be Al-6.8Zn-1.95Cu-2Mg-0.12Zr-0.03Ti-0.15Fe. However, the specific composition of 7050 aluminum alloy can be adjusted according to the application field, and the present invention does not impose specific limitations on this. Furthermore, as described above, the Fe-containing aluminum alloy according to embodiments of the present invention can also be other series of aluminum alloys besides Al-Zn-Mg-Cu, Al-Cu, and Al-Mg-Si aluminum alloys, as long as they contain a Fe-rich phase, the modification effect can be achieved using the modifier according to the present invention.

[0076] Aluminum alloys containing Fe

[0077] According to embodiments of the present invention, an aluminum alloy containing Fe element modified using the above-mentioned modifier can also be provided. As described above, the aluminum alloy containing Fe element can be an Al-Zn-Mg-Cu series, an Al-Cu series, an Al-Mg-Si series, or other similar aluminum alloys.

[0078] The following will describe specific examples of the modifier and its preparation method according to embodiments of the present invention. However, it should be understood that the scope of protection of the present invention is not limited to these specific examples, but rather to the technical solutions defined in the claims and their equivalents.

[0079] Example 1

[0080] First, according to the modifier TiC in 100 wt.% x The seed crystals have a mass percentage of 0.15 wt.% and the Mn mass ratio is 0.1 wt.%. The raw materials required for preparing the modifier are: pure aluminum, Al-C master alloy containing submicron Al4C3, Al-C master alloy containing nano Al4C3, sponge titanium, and Al-Mn master alloy.

[0081] Pure aluminum was melted and heated to 900℃, and sponge titanium was added until the reaction was complete. The temperature was then adjusted to 1100℃, and an Al-C master alloy containing submicron Al4C3 was added and reacted for 8 minutes. The temperature was then lowered to 1000℃, and another Al-C master alloy containing nano-Al4C3 was added, reacting for 5 minutes. Finally, an Al-Mn master alloy was added, and the temperature was lowered to 880℃, allowing the nano-TiC to interact with the Mn-rich clusters, forming a coating effect during the casting and cooling process.

[0082] Microstructure and surface scan analysis of the modifier prepared in Example 1 are as follows: Figure 1 As shown.

[0083] Examples 2 to 6

[0084] Compared to Example 1, Examples 2 through 6 are mainly in TiC x There are differences in the mass percentage of Al4C3, the mass percentage of transition elements, the reaction temperature and reaction time after adding submicron or nano Al4C3, as shown in Table 1.

[0085] Table 1

[0086]

[0087] By using EPMA analysis, submicron-scale TiC was formed in the modifiers prepared according to Examples 1 to 6. x Seeds and nanoscale TiC x Seed crystals, including nanoscale TiC x The seed crystal is coated with a second phase containing the corresponding transition metal element.

[0088] Furthermore, the 7050 aluminum alloy was refined and modified using the modifiers prepared in Examples 1 to 6 above. The α-Al refining effect was significant, and the size of the Fe-rich phase was significantly reduced, with its morphology changing from larger needle-like structures to smaller blocky structures, exhibiting a clear modification effect. The grain structure and Fe-rich phase morphology of the 7050 aluminum alloy after refining and modifying using the modifier prepared in Example 1 are shown below. Figure 2 As shown in (c), (c1) and (c2).

[0089] The modifier and its preparation method according to embodiments of the present invention can achieve at least, but are not limited to, the beneficial technical effects described below.

[0090] Submicron TiC in the modifier according to embodiments of the present invention x It can effectively refine α-Al and improve its morphology, thereby enhancing strength and casting quality. The modifier contains nano-TiC. x (i.e., a second TiC with nanoscale) x Seed crystals can fully metamorphose the Fe-rich phase, reduce its size and improve its morphology, thereby effectively improving corrosion resistance, mechanical properties and fatigue performance.

[0091] The method for preparing the degrading agent according to embodiments of the present invention is simple, environmentally friendly, and has broad prospects for industrial application.

[0092] While this disclosure has been described in conjunction with what is now considered to be actual embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Rather, it is intended to cover various variations and equivalents that are included within the spirit and scope of the appended claims.

Claims

1. A degrading agent, characterized in that, The modifier includes an Al matrix and TiC. x Seed crystals and a second phase located in the Al matrix, the second phase comprising Al and transition metal elements, the TiC x The seed crystal contains a first TiC with a submicron scale. x Seed crystals and second TiC with nanoscale x Seed crystal, the first TiC x At least a portion of the seed crystals are dispersed in the Al matrix, and the second TiC x At least a portion of the seed crystal is coated with the second phase, wherein x satisfies x < 1. The transition metal element includes at least one of the three elements Mn, Cr, and V.

2. The degrading agent according to claim 1, characterized in that, A single second phase is coated with multiple second TiCs x Seed crystal.

3. The degrading agent according to claim 1, characterized in that, The modifier is used in an aluminum alloy containing Fe, the aluminum alloy comprising α-Al and a Fe-rich phase, wherein the first TiC x Seed crystals are used to refine the α-Al in the aluminum alloy, and the second TiC x Seed crystals are used to modify Fe-rich phases.

4. The deteriorating agent according to claim 1, characterized in that, The first TiC x The seed crystal size is between 100nm and 600nm, and the second TiC x The size of the seed crystal is less than 100 nm.

5. The degrading agent according to claim 1, characterized in that, The first TiC x Seed crystals and the second TiC x All seed crystals are generated in situ.

6. The degrading agent according to claim 1, characterized in that, Based on 100 wt.% of the aforementioned modifier, TiC x The seed crystals have a mass percentage of 0.1 wt.% to 5 wt.%.

7. The degrading agent according to claim 1, characterized in that, Based on 100 wt.% of the modifier, the total mass percentage of at least one of the three elements Mn, Cr, and V is less than or equal to 0.9 wt.%. Based on 100 wt.% of the modifier, the mass percentage of each of the three elements Mn, Cr, and V is less than or equal to 0.3 wt.%.

8. The degrading agent according to claim 1, characterized in that, x satisfies 0.7≤x≤0.

9.

9. A method for preparing a deteriorating agent, characterized in that, The preparation method includes: Preparation of Al-Ti alloy melt; An aluminum alloy containing submicron-sized Al4C3 was added to the Al-Ti alloy melt, and the melt was held at 1100℃-1250℃ for 3 min-15 min to obtain the first melt. The temperature was lowered to 1000℃-1150℃, and an aluminum alloy containing nanoscale Al4C3 was added to the first melt. The mixture was stirred for 2 min-10 min to obtain the second melt. An aluminum alloy containing transition metal elements is added to the second melt, and the temperature is lowered to 800℃-930℃ before casting. The aluminum alloy containing transition metal elements includes at least one of Al-Mn, Al-Cr, and Al-V.

10. The method for preparing the deteriorating agent according to claim 9, characterized in that, The melt temperature when aluminum alloys containing nanoscale Al4C3 are added is lower than the melt temperature when aluminum alloys containing submicron-scale Al4C3 are added. The aluminum alloy containing submicron-scale Al4C3 and the aluminum alloy containing nanoscale Al4C3 are Al-C alloys.

11. The method for preparing the deteriorating agent according to claim 9, characterized in that, The steps for preparing the Al-Ti alloy melt include: melting Al and heating it to 780℃-820℃, then adding sponge Ti.

12. The method for preparing the deteriorating agent according to claim 9, characterized in that, The preparation method also includes a step of refining the alloy melt by blowing air before casting.

13. A method for modifying an aluminum alloy containing Fe, characterized in that, The degradation method includes: The Fe-containing aluminum alloy is melted and heated to 700°C to 750°C to form a melt; The modifier according to any one of claims 1 to 8 is added to the melt, and the melt is kept at a constant temperature for 10 to 30 minutes before casting.

14. The deterioration method according to claim 13, characterized in that, Based on the 100 wt.% Fe-containing aluminum alloy, the amount of the modifier added is 0.05-1.0 wt.%.

15. The deterioration method according to claim 13, characterized in that, The aluminum alloys containing Fe are Al-Zn-Mg-Cu, Al-Cu, and Al-Mg-Si aluminum alloys.

16. An aluminum alloy containing Fe, wherein the Fe-containing aluminum alloy is an Al-Zn-Mg-Cu system, an Al-Cu system, or an Al-Mg-Si system aluminum alloy, and the modification method of the Fe-containing aluminum alloy includes: The Fe-containing aluminum alloy is melted and heated to 700°C to 750°C to form a melt; The modifier according to any one of claims 1 to 8 is added to the melt, and after holding at a temperature for 10 to 30 minutes, it is cast. Based on 100 wt.% of the Fe-containing aluminum alloy, the amount of the modifier added is 0.05-1.0 wt.%.

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