Aluminum alloy comprehensive alterant and preparation method thereof

Abstract

The invention provides an aluminum alloy comprehensive alterant and a preparation method thereof. The alterant comprises an Al matrix, TiCx seed crystals and a second phase located in the Al matrix, the second phase comprises Al and a transition metal element, the TiCx seed crystals comprise first TiCx seed crystals with a submicron scale and second TiCx seed crystals with a nanometer scale, at least a part of the first TiCx seed crystals are dispersed in the Al matrix, at least a part of the second TiCx seed crystals are dispersed in the Al matrix, at least a part of the second TiCx seed crystals are dispersed in the Al matrix, at least a part of the second TiCx seed crystals are dispersed in the Al matrix, and at least a part of the second TiCx seed crystals are dispersed in the Al matrix. At least a part of the second TiCx seed crystal is coated with the second phase, and x is smaller than 1. The modifier can modify a Fe-rich phase in the Fe-containing aluminum alloy and refine an alpha-Al phase.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal materials, and particularly relates to an aluminum alloy comprehensive modifier and a preparation method thereof. BACKGROUND

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

[0003] In addition, the above-mentioned aluminum alloys are also widely used in tooling fixtures and lightweight structural components that need to bear high loads in the fields of rail transportation, high-end molds and mechanical equipment. The high strength and good forming performance of the above-mentioned aluminum alloys meet the dual requirements of lightweight and durability in the industrial field.

[0004] Grain refinement is usually used to improve the strength and toughness of the alloy and improve the casting quality of the alloy. For example, Al-5Ti-1B intermediate alloy can be used to refine the α-Al grains in the aluminum alloy to improve the mechanical properties thereof.

[0005] However, as the requirements for the mechanical properties of the aluminum alloy become higher and higher, it is expected that the microstructure of the aluminum alloy can be further improved, for example, it is expected that the α-Al grains can be further refined. Therefore, the means for further refining the α-Al grains in the aluminum alloy are also being continuously researched.

[0006] In addition, it is more worth noting that the aluminum alloy inevitably contains Fe elements, especially under the background that the amount of recycled aluminum is increasing. The Fe element usually exists in the form of Fe-rich phase, and the morphology of the Fe-rich phase is usually long strip or large block, which will have an adverse effect on the performance. For example, it will cause the corrosion resistance to decrease, the mechanical properties to deteriorate, and especially the fatigue performance to decrease. Therefore, it is also expected to reduce the size of the Fe-rich phase in the aluminum alloy to reduce the adverse effect of the Fe-rich phase on the performance. SUMMARY

[0007] The purpose of the present application is to provide a modifier capable of modifying the Fe-rich phase in the aluminum alloy containing Fe elements and a preparation method thereof.

[0008] Another purpose of the present application is to provide a modifier capable of refining α-Al and modifying the Fe-rich phase and a preparation method thereof.

[0009] According to one aspect of the present application, a modifier is provided, which comprises an Al matrix, TiC x seeds and a second phase in the Al matrix, the second phase comprising Al and a transition metal element, the TiC xseed crystals comprise a first TiC having a sub-micron scale x seed crystals and a second TiC having a nano-scale x seed crystals, the first TiC x at least a portion of the seed crystals are dispersed in the Al matrix, the second TiC x at least a portion of the seed crystals are coated by the second phase, wherein x satisfies x < 1.

[0010] Optionally, the transition group metal elements comprise at least one of Mn, Cr, and V.

[0011] Optionally, a plurality of the second TiC is coated in a single second phase. x seed crystals.

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

[0013] Optionally, the first TiC x seed crystals have a scale between 100 nm and 600 nm, the second TiC x seed crystals have a scale less than 100 nm.

[0014] Optionally, the first TiC x seed crystals and the second TiC x seed crystals are both in-situ grown.

[0015] Optionally, based on 100 wt.% of the modifier, TiC x 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 the at least one of Mn, Cr, and V is less than or equal to 0.9 wt.%. Based on 100 wt.% of the modifier, the mass percentage of a single element of 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 application, there is provided a method for preparing a modifier, the method comprising: preparing an Al-Ti alloy melt; adding an aluminum alloy containing sub-micron Al4C3 to the Al-Ti alloy melt to obtain a first melt after holding at 1100-1250 °C for 3-15 min; reducing the temperature to 1000-1150 °C, adding an aluminum alloy containing nano-scale Al4C3 to the first melt, applying stirring for 2-10 min to obtain a second melt; and adding an aluminum alloy containing transition group metal elements to the second melt, and pouring after reducing the temperature to 800-930 °C.

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

[0020] Optionally, the step of preparing the Al-Ti alloy melt comprises: melting Al and adding sponge Ti after heating to 780-820 °C.

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

[0022] Optionally, the method further comprises a step of performing gas refining on the alloy melt before pouring.

[0023] According to another aspect of the present application, there is provided a method for modifying an aluminum alloy containing Fe elements, the method comprising: melting the aluminum alloy containing Fe elements and heating to 700-750 °C to form a melt; adding the modifier as described above to the melt, and pouring after holding for 10-30 min.

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

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

[0026] According to another aspect of the present application, there is provided an aluminum alloy containing Fe elements modified by the modifier as described above.

[0027] According to another aspect of the present application, there is provided an aluminum alloy containing Fe elements modified by the modifier as described above.

[0028] Submicron TiC in the modifying agent according to the embodiment of the present application x Can fully refine α-Al and improve its morphology, increase strength and casting quality. Nano TiC in the modifying agent x (i.e., the second TiC x Seed) with nanometer scale can fully modify the Fe-rich phase, reduce its size and improve its morphology, thereby effectively improving corrosion resistance, mechanical properties and fatigue properties.

[0029] The preparation method of the modifying agent according to the embodiment of the present application is simple in process, green and environmentally friendly, and has wide industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the microstructure and EPMA analysis of the modifying agent according to the embodiment of the present application, wherein (a) is submicron TiC and nano TiC in the Mn-rich phase, and (b) is the surface scanning analysis of Al, Mn, Ti and C using EPMA.

[0031] Figure 2 is the SEM surface scanning analysis of the grain structure and Fe-rich phase of 7050 aluminum alloy before and after refinement modification, wherein (a), (a1) and (a2) are the SEM surface scanning analysis of the grain structure and Fe-rich phase of 7050 aluminum alloy before refinement modification; (b), (b1) and (b2) are the SEM surface scanning analysis of the grain structure and Fe-rich phase of 7050 aluminum alloy after refinement modification using 0.3wt% Al-5Ti-1B intermediate alloy; (c), (c1) and (c2) are the SEM surface scanning analysis of the grain structure and Fe-rich phase of 7050 aluminum alloy after refinement modification using 0.3wt% of the modifying agent of the present application. DETAILED DESCRIPTION

[0032] The following detailed description is provided to aid the reader in gaining a comprehensive understanding of the product, method described herein. However, various changes, modifications, and equivalents of the product, method described herein will be clear to those skilled in the art after understanding the content of the present disclosure. For example, the order of steps of the method described herein is only an example, and is not limited to the order set forth herein, but can be changed as will be clear after understanding the content of the present disclosure, except for steps that must occur in a specific order. In addition, the description of features known in the art can be omitted for the sake of more clarity and conciseness.

[0033] The features described herein can be implemented in different forms and should not be interpreted as being limited to the examples described herein. On the contrary, the examples described herein have been provided to merely show some of the many possible ways of implementing the product, method described herein, which will be clear after understanding the content of the present disclosure.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs when read in light of the entire disclosure. Terms such as, unless expressly so defined in this disclosure, shall be interpreted as having a meaning that is consistent with the meaning of the term in the context of the disclosure and not be interpreted in an idealized or overly formal sense.

[0035] It will be further understood that the terms "comprises" and / or "comprising," or "includes" and / or "including" when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. Therefore, unless explicitly described otherwise, the words "comprise," "comprising," "includes," "including," "have" or "having" will be understood to imply the inclusion of stated features but not to the exclusion of one or more other features, steps, operations, elements, and / or groups thereof.

[0036] Metallurgical agent According to an embodiment of the present disclosure, there is provided a modifier for an aluminum alloy containing an Fe element to achieve refinement of α-Al in the aluminum alloy and modification of an Fe-rich phase, i.e., further refinement of a grain size of α-Al and improvement of a morphology of the Fe-rich phase.

[0037] Figure 1 is a microstructure and EPMA analysis of the modifier according to an embodiment of the present disclosure, in which (a) is a submicron TiC and nano TiC in an Mn-rich phase, and (b) is a face scanning analysis of Al, Mn, Ti, and C using EPMA. As shown in Figure 1 The modifier according to an embodiment of the present disclosure can include an Al matrix, TiC x seed, and a second phase located in the Al matrix, the second phase can include Al and a transition metal element, TiC x seed can include a first TiC x seed and a second TiC x seed, the first TiC x seed, the second TiC x seed is coated by the second phase, wherein x satisfies x < 1.

[0038] Hereinafter, the modifier according to an embodiment of the present disclosure will be described in detail. The modifier according to an embodiment of the present disclosure can include TiC x seed, wherein x satisfies x < 1. That is, TiC x seed has a C vacancy. As shown in Figure 1 in which a region in which Ti and C are enriched is TiC x seed, TiC xThe seed crystals are white and have an overall granular morphology.

[0039] In addition to containing TiC, the modifier according to embodiments of the present invention is also a modifier. 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 Mn-containing second phase 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.

[0040] 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.

[0041] 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 xThe seed crystals can be dispersed in the Al matrix, and the at least one second TiC x The seed crystals are coated by the second phase. As shown in Figure 1 A single second phase can coat multiple second TiC x seed crystals, for example, a single second phase can coat at least two, at least three, or at least four second TiC x seed crystals. In addition, the first TiC x seed crystals can not be coated by the second phase, for example, they can be dispersed in the Al matrix apart from the second phase, or can be in contact with the second phase in the Al matrix.

[0042] According to embodiments of the present application, the first TiC x seed crystals and the second TiC x seed crystals are both in-situ formed. The two different scale TiC x seed crystals are formed in-situ by reacting Ti with two different scale Al4C3 x seed crystals and the second TiC x seed crystals have clean and good bonding interfaces with the Al matrix.

[0043] According to embodiments of the present application, the mass percentage of TiC x seed crystals can be 0.1 wt.% - 5% wt.%. For example, the mass percentage of TiC x seed crystals can be 0.5 wt.% - 4.5% wt.%, 1.0 wt.% - 4.0% wt.%, 1.5 wt.% - 3.5% wt.% or 2.0 wt.% - 3.0% wt.%.

[0044] TiC x seed crystals, the first TiC x seed crystals and the second TiC x seed crystals is not particularly limited, but can be adjusted as needed.

[0045] According to embodiments of the present application, the total mass percentage of Mn, Cr, V is less than or equal to 0.9 wt.% based on 100 wt.% of the modifier. That is, regardless of whether the transition metal elements are specifically selected as one, two or three of Mn, Cr, V, the total mass percentage of them is controlled to be less than or equal to 0.9 wt.% (based on 100 wt.% of the modifier).

[0046] According to embodiments of the present application, preferably, the mass percentage of a single element among Mn, Cr, V is less than or equal to 0.3 wt.% based on 100 wt.% of the modifier.

[0047] 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.

[0048] 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.%.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Figure 2 (b), (b1), and (b2) in the figure represent the grain structure and Fe-rich phase-rich phase SEM surface scanning 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.). xinterface properties change, when a modifier is added to the aluminum alloy melt, the second phase rich in transition group metal elements dissolves, the interface modified nano TiC x is released, the Fe-rich phase nucleates at part of the nano TiC x interface, at the same time, the remaining nano TiC x will also hinder the growth of the Fe-rich phase, thereby playing a modification effect on the Fe-rich phase.

[0057] Although the above describes the 7050 aluminum alloy containing Fe elements as an example, the modifier according to the embodiments of the present application can also be applied to other aluminum alloys containing Fe elements.

[0058] According to the embodiments of the present application, the x in the TiC x When x satisfies 0.7≤x≤0.9, the refining and modification effects will be more excellent.

[0059] Process for preparing a metallurgical agent The preparation method of the modifier according to the embodiments of the present application can include: preparing an Al-Ti alloy melt; adding an aluminum alloy containing sub-micron Al4C3 to the Al-Ti alloy melt to obtain a first melt by maintaining at 1100-1250°C for 3-15 min; reducing the temperature to 1000-1150°C, adding an aluminum alloy containing nano Al4C3 to the first melt, applying stirring for 2-10 min to obtain a second melt; and adding an aluminum alloy containing transition group metal elements to the second melt, and pouring after reducing the temperature to 800-930°C.

[0060] First, an Al-Ti alloy melt is prepared. The step of preparing the Al-Ti alloy melt can include: melting Al and heating to 780-820°C, then adding sponge Ti until complete reaction to form an Al-Ti alloy melt. However, the method of preparing the Al-Ti alloy melt is not limited thereto, for example, the Al-Ti alloy melt can also be obtained by directly melting an Al-Ti alloy.

[0061] Then, the melt temperature is adjusted to 1100-1250°C, an aluminum alloy containing sub-micron Al4C3 is added and maintained for 3-15 min to obtain a first melt. Then, after reducing the temperature to 1000-1150°C, an aluminum alloy containing nano Al4C3 is added to the first melt, and stirring is applied for 2-10 min to obtain a second melt. According to the present application, by reacting Ti with Al4C3 as a carbon carrier to form TiC xSeed crystal. In addition, by adding Al4C3 of different sizes in two steps to react with Ti, sub-micron-sized Al4C3 is first used to react with Ti to form a first TiC x Seed crystal, and then nano-sized Al4C3 is used to react with Ti to form a second TiC x Seed crystal. If nano-sized Al4C3 is added first, nano-sized TiC x formed first will continue to grow, so the present application adds sub-micron-sized Al4C3 first and then adds nano-sized Al4C3, thereby obtaining TiC x Seed crystal modifier.

[0062] The holding temperature when adding the aluminum alloy containing sub-micron-sized Al4C3 is 1100-1250℃. If the reaction temperature is lower than 1100℃, the temperature is low and the reaction can not be carried out. If the reaction temperature is higher than 1250℃, the reaction temperature is too high and the TiC x size will become large and the oxidation of the aluminum alloy will be more serious. The holding time after adding the aluminum alloy containing sub-micron-sized Al4C3 is 3-15 min. If the holding time is less than 3 min, the reaction can not be sufficient. If the holding time is more than 15 min, the TiC x size can become large.

[0063] The temperature when adding the aluminum alloy containing nano-sized Al4C3 is lowered to 1000-1150℃. If the reaction temperature is lower than 1000℃, the temperature is low and the reaction can not be carried out. If the reaction temperature is higher than 1150℃, the reaction temperature is too high and the TiC x size will become large and the oxidation of the aluminum alloy will be more serious. In addition, the holding time after adding the aluminum alloy containing nano-sized Al4C3 is 2-10 min. If the holding time is less than 2 min, the reaction can not be sufficient. If the holding time is more than 10 min, the TiC x size can become large.

[0064] In addition, according to the embodiment of the present application, the melt temperature when adding the aluminum alloy containing nano-sized Al4C3 is lower than the melt temperature when adding the aluminum alloy containing sub-micron-sized Al4C3, so that nano-sized TiC is formed in cooperation with the nano-sized Al4C3 raw material. x Seed crystal.

[0065] According to embodiments of the present application, the aluminum alloy containing sub-micron Al4C3 and the aluminum alloy containing nano-scale Al4C3 can be Al-C alloys. By adding Al4C3 in the form of Al-C alloys, Al4C3 can be ensured to dissolve in the aluminum alloy more quickly to react with Ti, thereby improving the dissolution efficiency and reaction efficiency.

[0066] According to embodiments of the present application, after obtaining the second melt, the aluminum alloy containing transition group metal elements is added to the second melt, and the temperature is reduced to 800-930°C before pouring.

[0067] According to embodiments of the present application, the aluminum alloy containing transition group metal elements includes at least one of Al-Mn, Al-Cr, and Al-V. According to embodiments of the present application, by reducing the temperature to 800-930°C, the nano TiC generated by the reaction can interact with the clusters of transition group metal elements such as Mn, Cr, and V, and form a coating effect during the pouring and cooling process.

[0068] According to embodiments of the present application, the alloy melt can also be subjected to gas refining before pouring. Any gas refining method known in the art can be used to refine the alloy melt, and the present application does not make specific limitations in this regard.

[0069] Process for modifying an aluminum alloy containing Fe elements According to embodiments of the present application, a modification method of an aluminum alloy containing Fe elements can also be provided.

[0070] The modification method of the aluminum alloy containing Fe elements according to embodiments of the present application can include: melting the aluminum alloy containing Fe elements and heating to 700-750°C to form a melt; adding the modification agent as described above to the melt, and pouring after holding for 10-30 min.

[0071] First, the aluminum alloy containing Fe elements is melted in, for example, a smelting furnace, and heated to 700-750°C (for example, 720-740°C) to form a melt. Then, the modification agent is added to the melt, and the α-Al is sufficiently refined and the Fe-rich phase is sufficiently modified after holding for 10-30 min. Finally, pouring is performed. According to embodiments of the present application, the addition amount of the modification agent can be 0.05-1.0 wt.%, based on 100 wt.% of the aluminum alloy containing Fe elements. For example, the addition amount of the modification agent can be 0.1-0.8 wt.%, 0.3-0.7 wt.%, or 0.4-0.6 wt.%, based on 100 wt.% of the aluminum alloy containing Fe elements.

[0072] According to an embodiment of the present application, the aluminum alloy containing Fe element can be an Al-Zn-Mg-Cu system, Al-Cu system, Al-Mg-Si system aluminum alloy. For example, the aluminum alloy containing Fe element can be a 7050 aluminum alloy. The composition of the 7050 aluminum alloy can be Al-6.8Zn-1.95Cu-2Mg-0.12Zr-0.03Ti-0.15Fe. However, the specific composition of the 7050 aluminum alloy can be adjusted in terms of element content according to the application field, and the present application does not specifically limit this. In addition, as described above, the aluminum alloy containing Fe element according to the embodiment of the present application can also be other series of aluminum alloys other than the Al-Zn-Mg-Cu system, Al-Cu system, Al-Mg-Si system aluminum alloy, as long as it has a Fe-rich phase therein, and the modification effect can be achieved by using the modifier according to the present application.

[0073] Aluminum alloy containing Fe elements According to an embodiment of the present application, an aluminum alloy containing Fe element modified by the above modifier can also be provided. As described above, the aluminum alloy containing Fe element can be an Al-Zn-Mg-Cu system, Al-Cu system, Al-Mg-Si system, etc.

[0074] Hereinafter, specific examples of the modifier and the preparation method thereof according to the embodiment of the present application will be described. However, it should be understood that the protection scope of the present application is not limited by these specific examples, but is limited by the technical solutions defined in the claims and their equivalent solutions.

[0075] Example 1 First, the raw materials required for preparing the modifier are prepared according to the mass percentage of 0.15wt.% of TiC in the 100wt.% of the modifier x The raw materials required for preparing the modifier are prepared according to the mass percentage of 0.15wt.% of TiC in the 100wt.% of the modifier

[0076] The pure aluminum is melted and heated to 900℃, and the titanium sponge is added until the reaction is complete. The temperature is adjusted to 1100℃, the Al-C intermediate alloy containing submicron Al4C3 is first added and reacted for 8min, then the temperature is reduced to 1000℃, the Al-C intermediate alloy containing nano Al4C3 is added, and reacted for 5min. Finally, the Al-Mn intermediate alloy is added, the temperature is reduced to 880℃, the nano TiC interacts with the Mn-rich clusters, and the coating effect is formed during the pouring and cooling process.

[0077] The microstructure and surface scanning analysis of the modifier prepared according to Example 1 are shown in Figure 1 .

[0078] Examples 2 to 6 Compared with Example 1, Examples 2 to 6 mainly differ in the mass percentage of TiC x , the mass percentage of transition group elements, the reaction temperature and reaction time after adding sub-micron or nano Al4C3, as shown in Table 1.

[0079] Table 1

[0080] By using EPMA analysis, in the modification agent prepared according to Examples 1 to 6, sub-micron TiC x crystals and nano TiC x crystals are formed, wherein the nano TiC x crystals are coated by the second phase containing the corresponding transition group metal elements.

[0081] In addition, the modification agent prepared by using the above Examples 1 to 6 is used to refine and modify 7050 aluminum alloy, wherein the refinement effect of α-Al is obvious, and the size of Fe-rich phase is obviously reduced, and the morphology is also changed from larger needle-like modification to smaller block, and obvious modification effect appears. Among them, the grain structure and Fe-rich phase morphology of 7050 aluminum alloy after being refined and modified by using the modification agent prepared by Example 1 are shown in (c), (c1) and (c2) of Figure 2 .

[0082] The modification agent and the preparation method thereof according to the embodiments of the present application can at least achieve the beneficial technical effects not limited to the following descriptions.

[0083] The sub-micron TiC x in the modification agent according to the embodiments of the present application can sufficiently refine α-Al and improve its morphology, and improve the strength and casting quality. The nano TiC x (in other words, the second TiC x crystals with nano scale) in the modification agent can sufficiently modify the Fe-rich phase, reduce its size and improve its morphology, thereby effectively improving the corrosion resistance, mechanical properties and fatigue properties.

[0084] The preparation method of the modification agent according to the embodiments of the present application has simple process, green and environmental protection, and wide industrial application prospect.

[0085] Although the present disclosure has been described in conjunction with the content presently considered to be practical embodiments, it should be understood that the present application is not limited to the disclosed embodiments. Rather, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A deteriorating agent characterized by, The modifier includes an Al matrix, TiC x a seed crystal and a second phase in the Al matrix, the second phase including Al and a transition group metal element, the TiC x the seed crystal includes a first TiC x the seed crystal and a second TiC x the seed crystal, the first TiC x at least a portion of the seed crystal is dispersed in the Al matrix, the second TiC x at least a portion of the seed crystal is coated by the second phase, wherein x satisfies x < 1.

2. The modifier according to claim 1, wherein The transition group metal element comprises at least one of Mn, Cr and V.

3. The modifier of claim 1, wherein A plurality of said second TiC is coated in a single said second phase x Seed crystals.

4. The modifier of claim 1, wherein The modifier is used for an aluminum alloy containing an Fe element, the aluminum alloy including α-Al and an Fe-rich phase, wherein the first TiC x The seed crystal is used for refining the α-Al in the aluminum alloy, the second TiC x The seed crystal is used for modifying the Fe-rich phase.

5. The modifier of claim 1, wherein said first TiC x crystals have a size between 100 nm and 600 nm, said second TiC x crystals have a size less than 100 nm.

6. The modifier of claim 1, wherein The first TiC x The seed crystal and the second TiC x Both the seed crystal and the second TiC are in-situ grown.

7. The modifier of claim 1, wherein TiC, based on 100 wt.% of the modifier x The mass percentage of the seed crystal is 0.1 wt.% - 5% wt.%.

8. The modifier of claim 2, wherein The total mass percentage of the at least one of Mn, Cr and V is less than or equal to 0.9wt.% based on 100wt.% of the modifier, The mass percentage of a single element of Mn, Cr and V is less than or equal to 0.3wt.% based on 100wt.% of the modifier.

9. The modifier of claim 1, wherein x satisfies 0.7≤x≤0.

9.

10. A method for producing a deteriorating agent, characterized by comprising the steps of: The preparation method comprises: preparing an Al-Ti alloy melt; adding an aluminum alloy containing sub-micron Al4C3 to the Al-Ti alloy melt, and holding at 1100℃-1250℃ for 3min-15min to obtain a first melt; reducing the temperature to 1000℃-1150℃, adding an aluminum alloy containing nano-scale Al4C3 to the first melt, and applying stirring for 2min-10min to obtain a second melt; adding an aluminum alloy containing a transition group metal element to the second melt, and pouring after reducing the temperature to 800℃-930℃.

11. The method for preparing the deteriorating agent according to claim 10, characterized in that, The melt temperature when adding the aluminum alloy containing nano-scale Al4C3 is lower than the melt temperature when adding the aluminum alloy containing sub-micron Al4C3, The aluminum alloy containing sub-micron Al4C3 and the aluminum alloy containing nano-scale Al4C3 are Al-C alloys.

12. The method for preparing the deteriorating agent according to claim 10, characterized in that, The step of preparing the Al-Ti alloy melt comprises melting Al and heating to 780℃-820℃ and then adding sponge Ti.

13. The method for preparing the deteriorating agent according to claim 10, characterized in that, The aluminum alloy containing a transition group metal element comprises at least one of Al-Mn, Al-Cr and Al-V.

14. The method for preparing the deteriorating agent according to claim 10, characterized in that, The preparation method further comprises a step of performing gas refining on the alloy melt before pouring.

15. A modification method of an aluminum alloy containing an Fe element, characterized by, The modification method comprises: melting the aluminum alloy containing the Fe element and heating to 700℃-750℃ to form a melt; adding the modifier according to any one of claims 1 to 9 to the melt, and pouring after holding for 10min-30min.

16. The method of claim 15, wherein The addition amount of the modifier is 0.05-1.0wt.% based on 100wt.% of the aluminum alloy containing the Fe element.

17. The method of claim 15, wherein the step of modifying comprises, The aluminum alloy containing the Fe element is an Al-Zn-Mg-Cu system, Al-Cu system or Al-Mg-Si system aluminum alloy.

18. An aluminum alloy containing the Fe element modified by the modifier according to any one of claims 1 to 9.

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