High-strength, high-toughness, and high-fatigue-resistance cast aluminum alloy and preparation method therefor

Abstract

The present invention relates to the field of aluminum alloy materials, and in particular to a high-strength, high-toughness, and high-fatigue-resistance cast aluminum alloy and a preparation method therefor. The matrix of the aluminum alloy comprises two or more nano-sized phases, and the elemental composition thereof comprises Al and any one or more of elements Si, Cu, and Mg, and one or more of Sn, Ag, Zn, In, and Hf. The alloy comprises two or more submicron-sized phases, and the elemental composition thereof comprises Al and any one or more of elements Fe, Mn, Cr, V, Zr, Ti ,and Mo, and any one or more of elements Cu, Ni, Y, Er, and Nb. The preparation method comprises performing non-isothermal+isothermal solution treatment and aging treatment on an aluminum alloy ingot. The cast aluminum alloy and the preparation method in the present invention achieve control over the number density and size of the nano-sized phases and submicron-sized strengthening phases, thereby enhancing the strength, toughness, and fatigue resistance of the alloy.

Description

High-toughness and high-fatigue-resistance cast aluminum alloy and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the field of aluminum alloy materials, and particularly relates to a high-toughness and high-fatigue-resistance cast aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Cast aluminum alloys are widely used in the fields of transportation, aerospace and automobiles due to their moderate strength, good fluidity, low cost and high production efficiency. In the field of automobile lightweighting, cast aluminum alloys are often used to prepare automobile body, wheel hub, oil tank, aluminum tank, machine cover plate, motor shell, steering knuckle and push-pull rod. In order to ensure the safety of the parts, the cast aluminum alloy is required to have high toughness and high fatigue resistance.

[0003] Chinese patent CN109266923A discloses a high-strength and high-fatigue-resistance Al-Cu-Mg-Si-Mn aluminum alloy and a processing method thereof. The alloy is obtained by adjusting the composition and heat treatment process to effectively control the number density of dispersed phases, the area percentage of coarse phases and the recrystallization area fraction, thereby obtaining an aluminum alloy with high strength and long fatigue life.

[0004] Chinese patent CN109295355A discloses an anti-fatigue and corrosion-resistant Al-Mg-Si-Cr aluminum alloy for rail transit and a preparation method thereof. The alloy is obtained by adjusting the composition, heat treatment and rolling process to obtain an aluminum alloy with high fatigue resistance.

[0005] However, the aluminum alloys and processing methods disclosed in the above patents and some other existing technologies are all about improving the fatigue resistance of Al-Cu, Al-Mg-Si and other deformation aluminum alloys. The fatigue resistance is achieved by means of recrystallization caused by plastic deformation processing. However, for cast aluminum alloys that do not undergo plastic deformation processing, how to simultaneously improve the toughness and fatigue resistance of the cast aluminum alloy is of great significance to the quality improvement of the cast aluminum alloy for automobiles.

[0006] SUMMARY

[0007] The present application aims to provide a high-toughness and high-fatigue-resistance cast aluminum alloy and a preparation method thereof to solve one or more technical problems in the prior art.

[0008] To achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0009] The present application provides a high-toughness and high-fatigue-resistance cast aluminum alloy, which comprises a matrix, at least two kinds of nanoscale phases and at least two kinds of submicron size phases.

[0010] The nanometer-sized phase has a size ranging from 1 to 50 nm;

[0011] The phase element composition of the nanometer-sized phase comprises Al, element Al and element A2; the element Al is selected from one or more of Si, Cu and Mg, and the element A2 is selected from one or more of Sn, Ag, Zn, In and Hf;

[0012] The phase element composition of the sub-micrometer-sized phase comprises Al, element B1 and element B2; the element B1 is selected from one or more of Fe, Mn, Cr, V, Zr, Ti and Mo, and the element B2 is selected from one or more of Cu, Ni, Y, Er and Nb.

[0013] Preferably, the two-dimensional morphology of the nanometer-sized phase is selected from one or more of long strip, polygon and sphere.

[0014] Preferably, in the high-strength and high-toughness high-fatigue-resistance cast aluminum alloy, the nanometer-sized phase and the matrix are in complete coherent relationship, and the crystal structure is selected from one or more of monoclinic structure, tetragonal structure, hexagonal structure and cubic structure.

[0015] Preferably, the size of the sub-micrometer-sized phase ranges from 50 to 500 nm; wherein the number proportion of the sub-micrometer-sized phase with a size ranging from 100 to 300 nm is 70 to 80%, and the number proportion of the sub-micrometer-sized phase with other size ranges is 20 to 30%.

[0016] Preferably, the sub-micrometer-sized phase and the matrix in the cast aluminum alloy are in coherent or semi-coherent relationship, and the crystal structure is selected from one or more of simple cubic structure, complex cubic structure, tetragonal structure, monoclinic structure and close-packed hexagonal structure.

[0017] Preferably, the two-dimensional morphology of the sub-micrometer-sized phase is selected from one or more of polygon, short rod and sphere.

[0018] Preferably, the number density of the sub-micrometer-sized phase is 10 13 -10 20 / m 3 .

[0019] Preferably, the high-toughness and high-fatigue-resistance cast aluminum alloy has the following components by weight fraction: Si 3-9%, Mg 0.1-0.7%, Fe 0.01-0.3%, Mn 0.01-0.5%, Cr 0.01-0.2%, Zr 0.01-0.3%, Mo 0.01-0.2%, Ti 0.01-0.1%, Cu 1%-4%, Ni 0.01-0.1%, Y 0.01-0.1%, V 0.01-0.1%, Sn 0.01-0.2%, Ag 0.01-0.5%, Zn 0.1-3%, In 0.01-0.1%, Hf 0.01-0.3%, Er 0.01-0.1%, Nb 0.01-0.1%, and the rest is Al.

[0020] The application also provides a preparation method of the high-toughness and high-fatigue-resistance cast aluminum alloy, comprising the following steps:

[0021] S1: after batching, melting and casting to obtain an aluminum alloy ingot; the components of the batching are as follows by weight fraction: Si 3-9%, Mg 0.1-0.7%, Fe 0.01-0.3%, Mn 0.01-0.5%, Cr 0.01-0.2%, Zr 0.01-0.3%, Mo 0.01-0.2%, Ti 0.01-0.1%, Cu 1%-4%, Ni 0.01-0.1%, Y 0.01-0.1%, V 0.01-0.1%, Sn 0.01-0.2%, Ag 0.01-0.5%, Zn 0.1-3%, In 0.01-0.1%, Hf 0.01-0.3%, Er 0.01-0.1%, Nb 0.01-0.1%, and the rest is Al;

[0022] S2: non-isothermal-isothermal solid solution treatment is performed on the aluminum alloy ingot; the method of the non-isothermal-isothermal solid solution treatment is as follows: the aluminum alloy ingot is placed to be heated from room temperature (25±5℃) to 450-500℃ at a heating rate of 10-30℃ per hour, and then is kept at 500-530℃ for 1-6h, and is treated by water quenching or air cooling;

[0023] S3: the aluminum alloy ingot after the non-isothermal-isothermal solid solution treatment in the step S2 is subjected to aging treatment to obtain the high-toughness and high-fatigue-resistance cast aluminum alloy; the method of the aging treatment is as follows: the aluminum alloy ingot after the non-isothermal-isothermal solid solution treatment in the step S2 is kept at 70-90℃ for 1-8h, is heated to 100-120℃, is kept at 100-120℃ for 1-6h, and is continuously heated to 160-200℃, and is kept at 160-200℃ for 1-6h to complete the aging treatment.

[0024] Preferably, in the step S1, the casting method is selected from any one of gravity differential pressure casting, high pressure differential pressure casting, extrusion differential pressure casting, low pressure differential pressure casting and differential pressure casting.

[0025] The alloy obtained by the application has a yield strength greater than or equal to 320 MPa, an elongation greater than or equal to 8%, a tensile strength greater than or equal to 400 MPa, and a high-cycle fatigue strength greater than or equal to 130 MPa (stress ratio of -1, cycle number greater than 10 7 ) times.

[0026] Compared with the prior art, the technical scheme of the application has the following advantages:

[0027] The cast aluminum alloy and the preparation method of the application control the number density and size of nanoscale phases and submicron phases by controlling the alloy composition and the ratio, and the temperature and time of heat treatment in the preparation process, so that one or more nanoscale phases and submicron phases with certain density, size and crystal structure are formed in the crystal of the aluminum alloy, and the aluminum alloy has high strength and toughness and high fatigue performance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 is a schematic diagram of the alloy structure of Example 1 of the application;

[0029] Fig. 2 is a schematic diagram of the alloy structure of Example 2 of the application;

[0030] Fig. 3 is a schematic diagram of the alloy structure of Example 3 of the application. DETAILED DESCRIPTION

[0031] The application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the application and implement it, but the examples are not limiting to the application.

[0032] The mechanical properties (yield strength, elongation, tensile strength, etc.) of the metal materials described in the following examples are tested according to the following standards:

[0033] GB / T 228.1-2021 Metal Materials Tensile Test Part 1: Room Temperature Test Method;

[0034] The fatigue performance test standard is as follows:

[0035] GB / T3075-2020 Metal Material Fatigue Test Axial Force Control Method.

[0036] The element composition of the nano and sub-micron size phase described in the following embodiments is determined by Energy-dispersive X-ray spectroscopy (EDS), Electron energy-loss spectroscopy (EELS) or High Angle Angular Dark Field-Scanning Transmission Electron Microscopy (HAADF-STEM) of a transmission electron microscope (TEM) to determine the phase composition.

[0037] Embodiment 1

[0038] The embodiment discloses a high-toughness and high-fatigue-resistance cast aluminum alloy and a preparation method thereof. The aluminum alloy comprises the following components and their respective weight percentages: Si 4%, Mg 0.22%, Fe 0.21%, Mn 0.01%, Cr 0.18%, Zr 0.24%, Mo 0.07%, Ti 0.10%, Cu 1%, Ni 0.01%, Y 0.01%, V 0.07%, Sn 0.01%, Ag 0.01%, Zn 0.1%, In 0.01%, Hf 0.15%, Er 0.01%, Nb 0.01%, and the rest is Al.

[0039] The preparation method of the high-toughness and high-fatigue-resistance cast aluminum alloy based on the above components comprises the following steps:

[0040] (1) The above components are weighed and mixed to prepare the aluminum alloy, and then the aluminum alloy is melted and cast into an ingot by gravity casting;

[0041] (2) The aluminum alloy ingot is subjected to non-isothermal + isothermal solid solution treatment, which comprises:

[0042] The aluminum alloy ingot is placed in a heat treatment furnace, the ingot is heated from room temperature to 500 DEG C at a rate of 10 DEG C per hour, then held at 500 DEG C for 1 hour, then held at 520 DEG C for 3 hours, and then water quenched;

[0043] The alloy ingot after solid solution treatment is held at 70 DEG C for 8 hours, then heated to 100 DEG C for 6 hours, and then aged at 190 DEG C for 2 hours to obtain the final high-toughness and high-fatigue-resistance cast aluminum alloy.

[0044] The alloy structure obtained in this example is shown in Figure 1. It is found by microstructure observation that a large number of nanometer-sized phases and sub-micron-sized phases exist in the alloy matrix of this example. The nanometer-sized phases have a size range of 1-50 nm, and the phase element composition includes Al, Si, Cu, Mg, Sn, Ag, Zn, In and Hf elements. The two-dimensional morphology includes long strips, polygons and spheres, and the crystal structure includes monoclinic structure, tetragonal structure, hexagonal structure and cubic structure. The element composition of the sub-micron-sized phases includes Al, Fe, Mn, Cr, V, Zr, Ti, Mo and Cu, Ni, Y, Er and Nb elements. The size range of the sub-micron-sized phases is 50-500 nm, wherein the number proportion of the sub-micron-sized phases with a size range of 100-300 nm is 70%, and the number proportion of the sub-micron-sized phases with other size ranges is 30%. The sub-micron-sized phases have a coherent or semi-coherent relationship with the matrix, and the crystal structure includes simple cubic structure, complex cubic structure, tetragonal structure, monoclinic structure and close-packed hexagonal structure. The two-dimensional morphology of the sub-micron-sized phases includes polygons, short rods and spheres. The number density of the sub-micron-sized phases in the alloy is 10 14 / m 3 ;

[0045] It is tested that the yield strength of the alloy is 345 MPa, the elongation is 10.9%, the tensile strength is 418 MPa, and the high-cycle fatigue strength is 131 MPa (stress ratio is -1, and the cycle number is greater than 10 7 .

[0046] Example 2

[0047] The high-strength and high-toughness cast aluminum alloy disclosed in this example and the preparation method thereof have the following components and weight percentages: Si 7%, Mg 0.1%, Fe 0.15%, Mn 0.25%, Cr 0.2%, Zr 0.3%, Mo 0.01%, Ti 0.05%, Cu 1.7%, Ni 0.1%, Y 0.023%, V 0.1%, Sn 0.07%, Ag 0.37%, Zn 1.65%, In 0.051%, Hf 0.01%, Er 0.053%, Nb 0.049%, and the rest is Al.

[0048] The preparation method of the high-strength and high-toughness cast aluminum alloy based on the above components includes the following steps:

[0049] (1) The aluminum alloy is dosed and melted to obtain a cast ingot by extrusion casting;

[0050] (2) The aluminum alloy cast ingot is subjected to non-isothermal + isothermal solid solution treatment, including:

[0051] The aluminum alloy ingot is placed in a heat treatment furnace, the ingot is heated from room temperature 25℃ to 450℃ at a rate of 14℃ per hour, then held at 450℃ for 8h, then held at 525℃ for 6h, and after completion, air cooling treatment is performed;

[0052] The alloy ingot after solution treatment is held at 90℃ for 1h, then heated to 105℃ for 4.5h, and then continues to be heated to 160℃ for 6h for aging treatment, to obtain the final high strength and toughness high fatigue resistance cast aluminum alloy.

[0053] The alloy microstructure obtained in this example is shown in Figure 2. It is found by microstructure observation that there are a large number of nanometer-sized phases and sub-micron-sized phases in the alloy matrix of this example. The nanometer-sized phases have a size range of 1-50nm, and the phase element composition includes Al, Si, Cu, Mg, Sn, Ag, Zn, In and Hf elements. The two-dimensional morphology includes long strips, polygons and spheres, and the crystal structure includes monoclinic structure, tetragonal structure, hexagonal structure and cubic structure. The element composition of the sub-micron-sized phases includes Al, Fe, Mn, Cr, V, Zr, Ti, Mo and Cu, Ni, Y, Er and Nb elements. The size range of the sub-micron-sized phases is 50-500nm, of which the number proportion of the sub-micron-sized phases with a size range of 100-300nm is 75%, and the number proportion of the sub-micron-sized phases with other size ranges is 25%. The sub-micron-sized phases have a coherent or semi-coherent relationship with the matrix, and the crystal structure includes simple cubic structure, complex cubic structure, tetragonal structure, monoclinic structure and close-packed hexagonal structure. The two-dimensional morphology of the sub-micron-sized phases includes polygons, short rods and spheres. The number density of the sub-micron-sized phases in the alloy is 10 16 / m 3 ;

[0054] Test results show that the yield strength of the alloy is 350MPa, the elongation is 10%, the tensile strength is 421MPa, and the high-cycle fatigue strength is 135MPa (stress ratio is -1, and the cycle number is greater than 10 7 .

[0055] Example 3

[0056] The high strength and toughness high fatigue resistance cast aluminum alloy and its preparation method disclosed in this example have the following components and weight percentages: Si 9%, Mg 0.33%, Fe 0.25%, Mn 0.12%, Cr 0.15%, Zr 0.21%, Mo 0.16%, Ti 0.06%, Cu 2.6%, Ni 0.02%, Y 0.71%, V 0.01%, Sn 0.16%, Ag 0.13%, Zn 0.91%, In 0.03%, Hf 0.05%, Er 0.025%, Nb 0.31%, and the rest is Al.

[0057] The preparation method of the high-toughness high-fatigue-resistance cast aluminum alloy based on the above components comprises the following steps:

[0058] (1) The aluminum alloy is prepared, melted, and cast into ingots by high-pressure casting;

[0059] (2) The aluminum alloy ingot is subjected to non-isothermal + isothermal solid solution treatment, comprising:

[0060] The aluminum alloy ingot is placed in a heat treatment furnace, the ingot is heated from room temperature to 460℃ at a rate of 20℃ / h, then held at 460℃ for 4h, then held at 510℃ for 4h, and then water quenched after completion;

[0061] The alloy ingot after solid solution treatment is held at 76℃ for 6h, then heated to 120℃ for 1h, then continuously heated to 175℃ for 5h for aging treatment, to obtain the final high-toughness high-fatigue-resistance cast aluminum alloy.

[0062] The microstructure of the alloy obtained in this embodiment is shown in Figure 3. It is found through microstructure observation that a large number of nanoscale phases and sub-micron phases exist in the alloy matrix of this embodiment, wherein the nanoscale phases have a size range of 1-50nm, the phase element composition includes Al, Si, Cu, Mg, Sn, Ag, Zn, In and Hf elements, the two-dimensional morphology includes long strips, polygons and spheres, and the crystal structure includes monoclinic structure, tetragonal structure, hexagonal structure and cubic structure; the element composition of the sub-micron phases includes Al, Fe, Mn, Cr, V, Zr, Ti, Mo and Cu, Ni, Y, Er and Nb elements; the size range of the sub-micron phases is 50-500nm, wherein the number proportion of the sub-micron phases with a size range of 100-300nm is 80%, and the number proportion of the sub-micron phases with other size ranges is 20%; the sub-micron phases have a coherent or semi-coherent relationship with the matrix, and the crystal structure includes simple cubic structure, complex cubic structure, tetragonal structure, monoclinic structure and close-packed hexagonal structure. The two-dimensional morphology of the sub-micron phases includes polygons, short rods and spheres. The number density of the sub-micron phases in the alloy is 10 18 / m 3 ;

[0063] Through testing, the yield strength of the alloy is 320MPa, the elongation is 12%, the tensile strength is 400MPa, and the high-cycle fatigue strength is 134MPa (stress ratio is -1, and the cycle number is greater than 10 7 ).

[0064] Comparative Example 1

[0065] Compared with the conventional Al-Si-Cu-Mg casting alloy, the components and weight percentages are as follows: Si 7%, Mg 0.5%, Fe 0.1%, Cu 3.0%, and the rest is Al.

[0066] The preparation method of the conventional casting aluminum alloy with the above components includes the following steps:

[0067] (1) The aluminum alloy is dosed, melted, and obtained by differential pressure casting to obtain an ingot;

[0068] (2) The aluminum alloy ingot is subjected to isothermal solid solution and aging treatment, including:

[0069] The aluminum alloy ingot is placed in a heat treatment furnace, and the ingot is kept at 490℃ for 12h, and after completion, water quenching treatment is performed;

[0070] The alloy ingot after solid solution treatment is kept at 1800℃ for 11h for aging treatment to obtain a casting aluminum alloy in an artificial aging state.

[0071] Tested, the yield strength of the alloy is 340MPa, the elongation is 5.6%, the tensile strength is 380MPa, and the high-cycle fatigue strength is 105MPa (stress ratio is -1, and the cycle number is greater than 10 7 ).

[0072] Effect evaluation 1

[0073] According to the performance results of Example 1, Example 2 and Example 3 compared with the comparative example, the alloy and process design of the patent can significantly improve the strength and toughness and fatigue resistance of the casting aluminum alloy material, and have obvious innovative effect.

[0074] The technical content and technical features of the present application have been disclosed as above, however, those skilled in the art can make various substitutions and modifications based on the teachings and disclosures of the present application without departing from the spirit of the present application, therefore, the protection scope of the present application should not be limited to the disclosed content of the examples, but should include various substitutions and modifications without departing from the present application, and is covered by the claims of the present patent application.

Claims

1. A high strength and toughness high fatigue performance cast aluminum alloy, characterized by, The high strength and toughness high fatigue performance cast aluminum alloy comprises a matrix, at least two nano-sized phases and at least two sub-micron-sized phases. The nano-sized phase has a size ranging from 1 nm to 50 nm. The phase element composition of the nano-sized phase comprises Al, element A1 and element A2; the element A1 is selected from one or more of Si, Cu and Mg, and the element A2 is selected from one or more of Sn, Ag, Zn, In and Hf. The phase element composition of the sub-micron-sized phase comprises Al, element B1 and element B2; the element B1 is selected from one or more of Fe, Mn, Cr, V, Zr, Ti and Mo, and the element B2 is selected from one or more of Cu, Ni, Y, Er and Nb.

2. The high strength, high fatigue performance cast aluminum alloy of claim 1 wherein, The two-dimensional morphology of the nano-sized phase is selected from one or more of long strip, polygon and sphere.

3. The high strength, high fatigue performance cast aluminum alloy of claim 1 wherein, The nano-sized phase and the matrix in the high strength and toughness high fatigue performance cast aluminum alloy are in complete coherent relationship, and the crystal structure is selected from one or more of monoclinic structure, tetragonal structure, hexagonal structure and cubic structure.

4. The high strength, high fatigue performance cast aluminum alloy of claim 1 wherein, The sub-micron-sized phase has a size ranging from 50 nm to 500 nm; wherein the number proportion of the sub-micron-sized phase with a size ranging from 100 nm to 300 nm is 70% to 80%.

5. The high damage tolerance, high fatigue performance cast aluminum alloy of claim 1 wherein, The sub-micron-sized phase and the matrix in the cast aluminum alloy are in coherent or semi-coherent relationship, and the crystal structure is selected from one or more of simple cubic structure, complex cubic structure, tetragonal structure, monoclinic structure and close-packed hexagonal structure.

6. The high damage tolerance, high fatigue performance cast aluminum alloy of claim 1 wherein, The two-dimensional morphology of the sub-micron-sized phase is selected from one or more of polygon, short rod and sphere.

7. The high damage tolerance, high fatigue performance cast aluminum alloy of claim 1 wherein, The number density of the sub-micron sized phase is 10 13 -10 20 / m 3 .

8. The high damage tolerance, high fatigue performance cast aluminum alloy of claim 1 wherein, The high strength and toughness high fatigue performance cast aluminum alloy comprises the following components in terms of weight fraction: Si 3% to 9%, Mg 0.1% to 0.7%, Fe 0.01% to 0.3%, Mn 0.01% to 0.5%, Cr 0.01% to 0.2%, Zr 0.01% to 0.3%, Mo 0.01% to 0.2%, Ti 0.01% to 0.1%, Cu 1% to 4%, Ni 0.01% to 0.1%, Y 0.01% to 0.1%, V 0.01% to 0.1%, Sn 0.01% to 0.2%, Ag 0.01% to 0.5%, Zn 0.1% to 3%, In 0.01% to 0.1%, Hf 0.01% to 0.3%, Er 0.01% to 0.1%, Nb 0.01% to 0.1%, and the rest is Al.

9. A method of producing the high-strength high-toughness high-fatigue- property cast aluminum alloy according to any one of claims 1 to 8, characterized by, The method comprises the following steps: S1: melting and casting after batching to obtain an aluminum alloy ingot; the components of the batching are as follows in percentage by weight: Si 3-9%, Mg 0.1-0.7%, Fe 0.01-0.3%, Mn 0.01-0.5%, Cr 0.01-0.2%, Zr 0.01-0.3%, Mo 0.01-0.2%, Ti 0.01-0.1%, Cu 1%-4%, Ni 0.01-0.1%, Y 0.01-0.1%, V 0.01-0.1%, Sn 0.01-0.2%, Ag 0.01-0.5%, Zn 0.1-3%, In 0.01-0.1%, Hf 0.01-0.3%, Er 0.01-0.1%, Nb 0.01-0.1%, and the rest is Al; S2: non-isothermal-isothermal solid solution treatment is performed on the aluminum alloy ingot; the method of the non-isothermal-isothermal solid solution treatment is as follows: the aluminum alloy ingot is heated from room temperature to 450-500°C at a heating rate of 10-30°C per hour, and then is kept at 500-530°C for 1-6 hours, and is then water quenched or air cooled; S3: the aluminum alloy ingot after the non-isothermal-isothermal solid solution treatment in step S2 is subjected to aging treatment to obtain the high-strength and high-toughness and high-fatigue-resistance cast aluminum alloy; the method of the aging treatment is as follows: the aluminum alloy ingot after the non-isothermal-isothermal solid solution treatment in step S2 is kept at 70-90°C for 1-8 hours, is then heated to 100-120°C and kept at this temperature for 1-6 hours, and is then continuously heated to 160-200°C and kept at this temperature for 1-6 hours, and the aging treatment is completed.

10. The production method according to claim 9, wherein In step S1, the casting method is selected from any one of gravity differential pressure casting, high-pressure differential pressure casting, extrusion differential pressure casting, low-pressure differential pressure casting and differential pressure casting.

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