Aluminum alloy, preparation method thereof and application of aluminum alloy in preparation of hardware products

Abstract

The invention relates to the technical field of aluminum alloys, in particular to an aluminum alloy, a preparation method of the aluminum alloy and application of the aluminum alloy in preparation of hardware products. The aluminum alloy comprises the following chemical elements in percentage by mass: 0.45%-0.80% of Si; 0.08% to 0.85% of Cu; 5.0% to 6.0% of Zn; 1.8% to 2.2% of Mg; 0.05% to 0.15% of Cr; 0.01% to 0.25% of Mn; 0.15% to 0.6% of Ti; 0.03%-0.05% of a rare earth element; and the balance of Al and inevitable impurities. According to the aluminum alloy, the tensile strength, the yield strength, the Vickers hardness and the ductility of the aluminum alloy are improved by optimizing the components and the content of the components and exerting the mutual synergistic effect of the components, so that the aluminum alloy has good strength and toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum alloy and a preparation method thereof and application thereof in the preparation of hardware products. Background Art

[0002] With the rapid development of science and technology and industrial economy in recent years, the demand for aluminum alloys has increased day by day, and the application fields of aluminum alloys have gradually increased. Among them, aluminum alloys have been widely used in 3C electronic equipment and automobile parts. However, in the fields of aviation and aerospace, the strength and toughness of aluminum alloys in related technologies are poor, which is difficult to meet their application needs, resulting in further restrictions on their application. Summary of the invention

[0003] The invention provides an aluminum alloy and a preparation method thereof and application in the preparation of hardware products. The aluminum alloy has good strength and toughness, so that its application is more extensive.

[0004] A first aspect of the present invention provides an aluminum alloy comprising the following chemical elements in mass percentage:

[0005] Si, 0.45% to 0.80%;

[0006] Cu, 0.08%~0.85%;

[0007] Zn, 5.0%-6.0%;

[0008] Mg, 1.8%-2.2%;

[0009] Cr, 0.05%~0.15%;

[0010] Mn, 0.01%~0.25%;

[0011] Ti, 0.15%~0.6%;

[0012] Rare earth elements, 0.03% to 0.05%;

[0013] The balance is Al and inevitable impurities.

[0014] In some embodiments of the present invention, the following chemical elements are included in mass percentage:

[0015] Si, 0.55%-0.7%;

[0016] Cu, 0.10%~0.53%;

[0017] Zn, 5.2%-5.8%;

[0018] Mg, 1.8%-2.0%;

[0019] Cr, 0.08%~0.12%;

[0020] Mn, 0.06%~0.20%;

[0021] Ti, 0.2%-0.5%;

[0022] Rare earth elements, 0.035% to 0.045%;

[0023] The balance is Al and inevitable impurities.

[0024] In some embodiments of the present invention, the rare earth element includes yttrium and / or scandium.

[0025] In some embodiments of the present invention, the following chemical elements are also included in mass percentage:

[0026] Zr, 0.05%~0.1%;

[0027] Sr, 0.01%~0.08%.

[0028] In some embodiments of the present invention, the following chemical elements are also included in mass percentage:

[0029] Zr, 0.06%~0.09%;

[0030] Sr, 0.03%~0.07%.

[0031] In some embodiments of the present invention, the aluminum alloy includes a precipitation phase, and the average grain size of the precipitation phase is less than 60 μm.

[0032] In some embodiments of the present invention, the aluminum alloy satisfies any one or more of the following conditions:

[0033] (I) Yield strength σs ≥ 430 MPa;

[0034] (II) Tensile strength σb ≥ 450 MPa;

[0035] (III) Vickers hardness ≥ 150 HV;

[0036] (IV) Elongation δ≥13%.

[0037] The second aspect of the present invention provides a method for preparing the aluminum alloy according to any one of the embodiments of the first aspect of the present invention, comprising:

[0038] A melting step, heating and melting the raw material of the aluminum alloy and stirring it evenly to obtain an aluminum alloy melt;

[0039] A refining step, in which the aluminum alloy melt is mixed with a refining agent under protective atmosphere conditions, and subjected to refining, degassing and impurity removal to obtain a refined aluminum alloy melt;

[0040] The casting process is to die-cast the refined aluminum alloy melt in a vacuum mold to obtain an ingot;

[0041] A heat treatment step, performing a solution heat treatment on the ingot to obtain a heat-treated ingot;

[0042] The aging process is to perform extrusion aging treatment on the ingot after heat treatment to obtain an aluminum alloy, wherein the aluminum alloy includes the following chemical elements by mass percentage: Si, 0.45% to 0.80%; Cu, 0.08% to 0.85%; Zn, 5.0% to 6.0%; Mg, 1.8% to 2.2%; Cr, 0.05% to 0.15%; Mn, 0.01% to 0.25%; Ti, 0.15% to 0.6%; rare earth elements, 0.03% to 0.05%; the balance is Al and inevitable impurities.

[0043] In some embodiments of the present invention, in the melting process, the heating and melting temperature is 700°C to 850°C.

[0044] In some embodiments of the present invention, the die casting process satisfies at least one of the following conditions:

[0045] (I) Temperature is 600°C to 550°C;

[0046] (II) The temperature of the vacuum mold is 250°C to 300°C.

[0047] The third aspect of the present invention provides an application of the aluminum alloy described in any embodiment of the first aspect of the present invention or the aluminum alloy prepared by the preparation method described in any embodiment of the second aspect of the present invention in the preparation of hardware products.

[0048] The aluminum alloy provided by the present invention, its preparation method and application in the preparation of hardware products, improve the tensile strength, yield strength, Vickers hardness and elongation of the aluminum alloy by optimizing the components and their contents and exerting the synergistic effect between them, so that the aluminum alloy has good strength and toughness.

[0049] The above description is only an overview of the technical solution of this specification. In order to more clearly understand the technical means of this specification, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of this specification more obvious and easy to understand, the specific implementation methods of this specification are listed below. DETAILED DESCRIPTION

[0050] Unless otherwise specified, the terms used in the present invention have the commonly understood meanings that are generally understood by those skilled in the art.

[0051] Unless otherwise specified, the values ​​of the parameters mentioned in the present invention can be measured by various test methods commonly used in the art, for example, they can be measured according to the test methods given in the embodiments of the present invention.

[0052] A first aspect of the present invention provides an aluminum alloy comprising the following chemical elements in mass percentage:

[0053] Si, 0.45% to 0.80%;

[0054] Cu, 0.08%~0.85%;

[0055] Zn, 5.0%-6.0%;

[0056] Mg, 1.8%-2.2%;

[0057] Cr, 0.05%~0.15%;

[0058] Mn, 0.01%~0.25%;

[0059] Ti, 0.15%-0.6%;

[0060] Rare earth elements, 0.03% to 0.05%;

[0061] The balance is Al and inevitable impurities.

[0062] In some embodiments of the present invention, the following chemical elements are included in mass percentage:

[0063] Si, 0.55%-0.7%;

[0064] Cu, 0.10%~0.53%;

[0065] Zn, 5.2%-5.8%;

[0066] Mg, 1.8%-2.0%;

[0067] Cr, 0.08%~0.12%;

[0068] Mn, 0.06%~0.20%;

[0069] Ti, 0.2%-0.5%;

[0070] Rare earth elements, 0.035% to 0.045%;

[0071] The balance is Al and inevitable impurities.

[0072] The aluminum alloy provided by the present invention improves the tensile strength, yield strength, Vickers hardness and elongation of the aluminum alloy by optimizing the components and their contents and exerting the synergistic effect between them, so that the aluminum alloy has good strength and toughness.

[0073] The following is a detailed introduction to the chemical elements contained in aluminum alloys and their contents.

[0074] (Si: 0.45% to 0.80%)

[0075] The Si content within a suitable range can improve the fluidity of the alloy melt and the strength of the aluminum alloy. Therefore, in the technical solution of the present invention, the Si content is set within a range of 0.45% to 0.80%.

[0076] Exemplarily, the content of Si element can be, but is not limited to, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80% or a range consisting of any two of the above values.

[0077] (Cu: 0.08% to 0.85%)

[0078] When the content of Cu element is within a suitable range, it is not only easy to be enriched on the surface of the workpiece during the heating process to form an oxide layer (i.e., CuO layer) with good compactness, but also helps to strengthen the strength of the aluminum alloy through solid solution, so that the high temperature oxidation resistance and strength of the aluminum alloy can be further enhanced. Therefore, in the technical solution of the present invention, the content of Cu element is set in the range of 0.08% to 0.85%.

[0079] For example, the content of Cu element may be, but is not limited to, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82%, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85% or a range consisting of any two of the above values.

[0080] (Zn: 5.0% to 6.0%) and (Mg: 1.8% to 2.2%)

[0081] Zn and Mg, respectively, within appropriate ranges, can work synergistically to improve the tensile strength, hardness and fluidity of the workpiece. Therefore, in the technical solution of the present invention, the Zn element content is set in the range of 5.0% to 6.0%, and the Mg element content is set in the range of 1.8% to 2.2%.

[0082] Exemplarily, the content of Zn element can be, but is not limited to, 5.0%, 5.1%, 5.2%, 5.22%, 5.24%, 5.26%, 5.28%, 5.3%, 5.32%, 5.34%, 5.36%, 5.38%, 5.4%, 5.42%, 5.44%, 5.46%, 5.48%, 5.5%, 5.52%, 5.54%, 5.56%, 5.58%, 5.6%, 5.62%, 5.64%, 5.66%, 5.68%, 5.7%, 5.72%, 5.74%, 5.76%, 5.78%, 5.8%, 5.9%, 6.0% or a range consisting of any two of the above values.

[0083] Exemplarily, the content of Mg element may be, but is not limited to, 1.8%, 1.82%, 1.84%, 1.86%, 1.88%, 1.9%, 1.92%, 1.94%, 1.96%, 1.98%, 2%, 2.1%, 2.2% or a range consisting of any two of the above values.

[0084] (Cr: 0.05% to 0.15%)

[0085] The Cr content within a suitable range can improve the strength, toughness and corrosion resistance of the aluminum alloy. Therefore, in the technical solution of the present invention, the Cr content is set within a range of 0.05% to 0.15%.

[0086] Exemplarily, the content of Cr element may be, but is not limited to, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15% or a range consisting of any two of the above values.

[0087] (Mn: 0.01%~0.25%)

[0088] The Mn element can improve the strength and elongation of the aluminum alloy within a suitable range. Therefore, in the technical solution of the present invention, the content of the manganese element is set within a range of 0.01% to 0.25%.

[0089] Exemplarily, the content of Mn element can be, but is not limited to, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25% or a range consisting of any two of the above values.

[0090] (Ti: 0.15%~0.6%)

[0091] The Ti element within a suitable range can refine the grain size in the aluminum alloy and improve the elongation of the aluminum alloy. Therefore, in the technical solution of the present invention, the titanium content is set within a range of 0.15% to 0.6%.

[0092] For example, the content of Ti element may be, but is not limited to, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6% or a range consisting of any two of the above values.

[0093] Rare earth elements (0.03% to 0.05%)

[0094] Rare earth elements within a suitable range can help improve the strength and toughness of aluminum alloys. Therefore, in the technical solution of the present invention, the content of rare earth elements is set within a range of 0.03% to 0.05%.

[0095] In some embodiments, the rare earth element includes yttrium and / or scandium.

[0096] Exemplarily, the content of rare earth elements can be, but is not limited to, 0.03%, 0.031%, 0.032%, 0.033%, 0.034%, 0.035%, 0.036%, 0.037%, 0.038%, 0.039%, 0.04%, 0.041%, 0.042%, 0.043%, 0.044%, 0.045%, 0.046%, 0.047%, 0.048%, 0.049%, 0.05% or a range consisting of any two of the above values.

[0097] (Zr: 0.05% ~ 0.1%) and (Sr: 0.01% ~ 0.08%).

[0098] When the Zr and Sr elements are within a suitable range, the grain of the material can be refined, the grain structure inside the metallographic structure can be more uniform, and the glossiness can be higher, which not only improves the aesthetics of the material, but also enhances the corrosion resistance and toughness of the material. Therefore, in the technical solution of the present invention, the zirconium content is set in the range of 0.05% to 0.1%, and the strontium content is set in the range of 0.01% to 0.08%.

[0099] For example, the content of Zr element may be, but is not limited to, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1% or a range consisting of any two of the above values.

[0100] For example, the content of Sr element may be, but is not limited to, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08% or a range consisting of any two of the above values.

[0101] In some embodiments of the present invention, the aluminum alloy includes a precipitation phase, and the average grain size of the precipitation phase is less than 60 μm.

[0102] In some embodiments of the present invention, the aluminum alloy satisfies any one or more of the following conditions:

[0103] (I) Yield strength σs ≥ 430 MPa;

[0104] (II) Tensile strength σb ≥ 450 MPa;

[0105] (III) Vickers hardness ≥ 150 HV;

[0106] (IV) Elongation δ≥13%.

[0107] The second aspect of the present invention provides a method for preparing the aluminum alloy described in any one of the embodiments of the first aspect of the present invention, comprising:

[0108] S100, a melting process, heating and melting the raw material of the aluminum alloy and stirring it evenly to obtain an aluminum alloy melt;

[0109] S200, a refining step, mixing the aluminum alloy melt with a refining agent under a protective atmosphere, refining, degassing and removing impurities to obtain a refined aluminum alloy melt;

[0110] S300, a casting process, performing die-casting on the refined aluminum alloy melt in a vacuum mold to obtain an ingot;

[0111] S400, a heat treatment step, performing a solution heat treatment on the ingot to obtain a heat-treated ingot;

[0112] S500, an aging process, performing extrusion aging treatment on the ingot after the heat treatment to obtain an aluminum alloy, wherein the aluminum alloy includes the following chemical elements by mass percentage: Si, 0.45% to 0.80%; Cu, 0.08% to 0.85%; Zn, 5.0% to 6.0%; Mg, 1.8% to 2.2%; Cr, 0.05% to 0.15%; Mn, 0.01% to 0.25%; Ti, 0.15% to 0.6%; rare earth elements, 0.03% to 0.05%; the balance is Al and unavoidable impurities.

[0113] In some embodiments of the present invention, in the melting process, the heating and melting temperature is 700°C to 850°C.

[0114] In some embodiments of the present invention, the die casting process satisfies at least one of the following conditions:

[0115] (I) Temperature is 600°C to 650°C;

[0116] (II) The temperature of the vacuum mold is 250°C to 300°C.

[0117] The third aspect of the present invention provides an application of the aluminum alloy described in any embodiment of the first aspect of the present invention or the aluminum alloy prepared by the preparation method described in any embodiment of the second aspect of the present invention in the preparation of hardware products.

[0118] Below, the embodiment of the present invention is described. The embodiment described below is exemplary, is only used to explain the present invention, and cannot be interpreted as limiting the present invention. If no specific technology or conditions are indicated in the embodiment, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments is not indicated, they are all conventional products that can be obtained commercially.

[0119] Example 1

[0120] This embodiment provides a method for preparing an aluminum alloy, comprising:

[0121] Pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys are placed in a melting furnace at 740°C for melting, and electromagnetic stirring is performed during the process;

[0122] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0123] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 600° C. and the temperature of the vacuum mold is 250° C.;

[0124] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.15%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0125] Example 2

[0126] Pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys are placed in a smelting furnace at 750°C for melting, and electromagnetic stirring is performed during the process;

[0127] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0128] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 620° C. and the temperature of the vacuum mold is 280° C.;

[0129] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.60%; Cu, 0.57%; Zn, 5.2%; Mg, 2.1%; Cr, 0.15%; Mn, 0.18%; Ti, 0.2%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0130] Example 3

[0131] The preparation method of this embodiment is similar to that of Embodiment 1, except that the aluminum alloy includes the following chemical elements by mass percentage: Si, 0.71%; Cu, 0.61%; Zn, 5.7%; Mg, 1.9%; Cr, 0.10%; Mn, 0.15%; Ti, 0.25%; Y, 0.03%; the remainder is Al and unavoidable impurities.

[0132] Example 4

[0133] The preparation method of this embodiment is similar to that of Embodiment 1, except that the aluminum alloy includes the following chemical elements by mass percentage: Si, 0.76%; Cu, 0.80%; Zn, 6.0%; Mg, 2.2%; Cr, 0.09%; Mn, 0.25%; Ti, 0.5%; Y, 0.03%; the remainder is Al and unavoidable impurities.

[0134] Example 5

[0135] The preparation method of this embodiment is similar to that of Embodiment 1, except that the aluminum alloy includes the following chemical elements by mass percentage: Si, 0.80%; Cu, 0.85%; Zn, 5.2%; Mg, 1.8%; Cr, 0.07%; Mn, 0.22%; Ti, 0.21%; Y, 0.03%; the remainder is Al and unavoidable impurities.

[0136] Example 6

[0137] This embodiment provides a method for preparing an aluminum alloy, comprising:

[0138] Place pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum strontium alloys, aluminum zirconium alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys in a melting furnace at 740°C for melting, and perform electromagnetic stirring during the process;

[0139] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0140] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 600° C. and the temperature of the vacuum mold is 250° C.;

[0141] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.18%; Y, 0.03%; Zr, 0.1%; Sr, 0.05%; the balance is Al and unavoidable impurities.

[0142] Example 7

[0143] This embodiment provides a method for preparing an aluminum alloy, comprising:

[0144] Place pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum strontium alloys, aluminum zirconium alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys in a melting furnace at 740°C for melting, and perform electromagnetic stirring during the process;

[0145] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0146] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 600° C. and the temperature of the vacuum mold is 250° C.;

[0147] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.18%; Y, 0.05%; Zr, 0.1%; Sr, 0.05%; the balance is Al and unavoidable impurities.

[0148] Example 8

[0149] This embodiment provides a method for preparing an aluminum alloy, comprising:

[0150] Place pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum strontium alloys, aluminum zirconium alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys in a melting furnace at 740°C for melting, and perform electromagnetic stirring during the process;

[0151] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0152] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 600° C. and the temperature of the vacuum mold is 250° C.;

[0153] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.18%; Sc, 0.05%; Zr, 0.1%; Sr, 0.05%; the balance is Al and unavoidable impurities.

[0154] Example 9

[0155] This embodiment provides a method for preparing an aluminum alloy, comprising:

[0156] Place pure aluminum ingots, aluminum silicon alloys, aluminum copper alloys, aluminum manganese alloys, aluminum strontium alloys, aluminum zirconium alloys, aluminum titanium alloys, magnesium ingots, aluminum zinc alloys, and aluminum chromium alloys in a melting furnace at 740°C for melting, and perform electromagnetic stirring during the process;

[0157] Introduce carrier gas nitrogen and refining agent into the bottom of the smelting furnace, the refining agent includes 50% sodium nitrate, 10% graphite powder and 40% sodium chloride, degas for 20 minutes, let it stand for 10 minutes, and then skim the slag;

[0158] The refined aluminum alloy melt is die-casted in a vacuum mold to obtain an aluminum alloy ingot, wherein the die-casting temperature is 600° C. and the temperature of the vacuum mold is 250° C.;

[0159] The aluminum alloy ingot is subjected to solution heat treatment and aging treatment to obtain an aluminum alloy, wherein the temperature of the solution heat treatment is 300°C and the time is 2 hours; the temperature of the aging treatment is 150°C and the time is 10 hours; the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.18%; Y, 0.03%; Sc, 0.02%; Zr, 0.1%; Sr, 0.05%; the balance is Al and unavoidable impurities.

[0160] Comparative Example 1

[0161] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.1%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0162] Comparative Example 2

[0163] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.4%; Cu, 0.9%; Zn, 7.0%; Mg, 2.5%; Cr, 0.05%; Mn, 0.20%; Ti, 0.65%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0164] Comparative Example 3

[0165] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.01%; Mn, 0.20%; Ti, 0.15%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0166] Comparative Example 4

[0167] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.18%; Mn, 0.20%; Ti, 0.15%: the balance is Al and unavoidable impurities.

[0168] Comparative Example 5

[0169] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Ti, 0.15%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0170] Comparative Example 6

[0171] The difference between the comparative example and the embodiment 1 is that the aluminum alloy includes the following chemical elements in mass percentage: Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.3%; Ti, 0.15%; Y, 0.03%; the balance is Al and unavoidable impurities.

[0172] Comparative Example 7

[0173] Si, 0.55%; Cu, 0.24%; Zn, 5.0%; Mg, 2.0%; Cr, 0.05%; Mn, 0.20%; Ti, 0.15%; the balance is Al and inevitable impurities.

[0174] The test results of the tensile strength, yield strength, Vickers hardness and elongation of the aluminum alloys in Examples 1 to 9 and Comparative Examples 1 to 7 are shown in Table 1.

[0175] Table 1 Test results of aluminum alloys of Examples 1 to 9 and Comparative Examples 1 to 7

[0176] Serial number Tensile strength σb Yield strength σs Vickers hardness Elongation δ Example 1 462MPa 432MPa 159HV 13.2％ Example 2 481MPa 454MPa 165HV 15.4％ Example 3 476MPa 447MPa 161HV 14.1％ Example 4 528MPa 485MPa 184HV 18.7％ Example 5 557MPa 502MPa 197HV 20.9％ Example 6 482MPa 446MPa 160HV 14.5％ Example 7 484MPa 451MPa 168HV 16.4％ Example 8 491MPa 455MPa 170HV 15.0％ Example 9 502MPa 463MPa 176HV 17.3％ Comparative Example 1 404MPa 362MPa 135HV 6.9％ Comparative Example 2 361MPa 301MPa 112HV 9.2％ Comparative Example 3 443MPa 415MPa 142HV 11.2％ Comparative Example 4 438MPa 407MPa 137HV 10.4％ Comparative Example 5 373MPa 332MPa 122HV 7.7％ Comparative Example 6 415MPa 380MPa 129HV 8.5％ Comparative Example 7 411MPa 392MPa 131HV 8.8％

[0177] According to Table 1, Example 1 ～ 9 and Comparative Example 1 ～ 7, it can be seen that the aluminum alloy provided by the present invention improves the tensile strength, yield strength, Vickers hardness and elongation of the aluminum alloy by optimizing the components and their contents and exerting the synergistic effect between them, so that the aluminum alloy has good strength and toughness.

[0178] From the test comparison of Example 1 and Comparative Examples 3-4, it can be seen that when the mass fraction of Cr element is lower than or exceeds the range of 0.05%-0.15%, the strength and toughness of the aluminum alloy are significantly reduced. From the test results of Example 1 and Comparative Examples 5-6, it can be seen that when the mass fraction of Mn element is lower than or exceeds the range of 0.01%-0.25%, the strength and toughness of the aluminum alloy are also significantly reduced.

[0179] It can be seen from the test results of Example 1 and Example 7 that as the content of rare earth elements increases, the strength and toughness of the aluminum alloy also increase accordingly.

[0180] From the test results of Examples 7, 8 and 9, it can be seen that when rare earth elements of the same mass content are added to the aluminum alloy, Y can make the toughness of the aluminum alloy significantly stronger than Sc, and Sc can make the strength of the aluminum alloy higher than Y. When Y and Sc are added simultaneously, the strength and toughness of the aluminum alloy are significantly higher than those when Y and Sc are added alone.

[0181] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned experimental examples, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned experimental examples, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the experimental examples of the present invention.

Claims

1. An aluminum alloy, characterized in that: The following chemical elements are included in mass percentage: Si, 0.45% to 0.80%; Cu, 0.08%~0.85%; Zn, 5.0%-6.0%; Mg, 1.8%-2.2%; Cr，0.05％～0.15％； Mn, 0.01%~0.25%; Ti, 0.15%-0.6%; Rare earth elements, 0.03% to 0.05%; The balance is Al and inevitable impurities.

2. The aluminum alloy according to claim 1, characterized in that The following chemical elements are included in mass percentage: Si, 0.55%-0.7%; Cu, 0.10%~0.53%; Zn, 5.2%-5.8%; Mg, 1.8%-2.0%; Cr，0.08％～0.12％； Mn, 0.06%~0.20%; Ti, 0.2%-0.5%; Rare earth elements, 0.035% to 0.045%; The balance is Al and inevitable impurities.

3. The aluminum alloy according to claim 1 or 2, characterized in that: The rare earth element includes yttrium and / or scandium.

4. The aluminum alloy according to claim 1 or 2, characterized in that: The following chemical elements are also included in mass percentage: Zr，0.05％～0.1％； Sr，0.01％～0.08％。 5. The aluminum alloy according to claim 1, characterized in that The aluminum alloy includes a precipitated phase, and the average grain size of the precipitated phase is less than 60 μm.

6. The aluminum alloy according to claim 1, characterized in that The aluminum alloy satisfies any one or more of the following conditions: (I) Yield strength σs ≥ 430 MPa; (II) Tensile strength σb ≥ 450 MPa; (III) Vickers hardness ≥ 150 HV; (IV) Elongation δ≥13%.

7. A method for preparing the aluminum alloy according to any one of claims 1 to 6, characterized in that: include: A melting step, heating and melting the raw material of the aluminum alloy and stirring it evenly to obtain an aluminum alloy melt; A refining step, in which the aluminum alloy melt is mixed with a refining agent under protective atmosphere conditions, and subjected to refining, degassing and impurity removal to obtain a refined aluminum alloy melt; The casting process is to die-cast the refined aluminum alloy melt in a vacuum mold to obtain an ingot; A heat treatment step, performing a solution heat treatment on the ingot to obtain a heat-treated ingot; The aging step is to perform aging treatment on the ingot after the heat treatment to obtain an aluminum alloy.

8. The preparation method according to claim 7, characterized in that: In the melting step, the heating and melting temperature is 700°C to 850°C.

9. The preparation method according to claim 7, characterized in that: The die casting process satisfies at least one of the following conditions: (I) Temperature is 600°C to 550°C; (II) The temperature of the vacuum mold is 250°C to 300°C.

10. Use of the aluminum alloy according to any one of claims 1 to 6 or the aluminum alloy prepared by the preparation method according to any one of claims 7 to 9 in the preparation of hardware products.