High-performance aluminum alloy die casting material and preparation method thereof

Abstract

This invention relates to the field of aluminum alloy materials technology, specifically to a high-performance aluminum alloy die-casting material and its preparation method, comprising the following components by weight percentage: Si: 6.0–10.0 wt.%; Mg: 2.0–3.5 wt.%; Zn: 1.0–1.5 wt.%; Cu: 0.5–0.8 wt.%; Mn: 0.2–0.5 wt.%; RE: 0–1.0 wt.%; Ti: 0.1–0.2 wt.%; Sr: 0.01–0.03 wt.%; the balance being Al and unavoidable impurities, wherein the Fe element in the impurities is ≤0.15 wt.%, the total amount of impurity elements is ≤0.3 wt.%, and RE is a rare earth element. It is prepared through processes such as alloy melt smelting, die casting, and T6 heat treatment. This material possesses excellent die-casting properties and superior mechanical properties, meeting the performance requirements of various automotive parts. Its yield strength is 210–240 MPa; tensile strength is 300–350 MPa; and elongation is 6–10 wt.%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy materials, and particularly relates to a high-performance aluminum alloy die casting material and a preparation method thereof. BACKGROUND

[0002] In order to ensure the safe driving of an automobile, the automobile industry has very strict requirements on the mechanical properties of parts. Generally, automobile parts must have high strength and good plasticity. High strength can prevent automobile parts from being severely deformed to cause failure of the automobile parts during service; good plasticity can prevent automobile parts from suddenly breaking to cause disasters during service.

[0003] A high-performance structural part casting aluminum alloy and a preparation method thereof are provided in a Chinese patent with the authorized publication number CN115125420B. The aluminum alloy includes the following components by mass percentage: Si: 6.0% to 8.5%, Mg: 0.05% to 0.40%, Cu: 0.50% to 0.85%, Cr: 0.20% to 0.60%, Er: 0.01% to 0.10%, Mn: 0.45% to 0.75%, Zn: 0.1% to 3.0%, V: 0.04% to 0.14%, Ni: 0.01% to 0.1%, Ba≤0.1%, Y≤0.1%, Fe≤0.16%, and the balance is Al. The test results of the scheme are as follows:

[0004] Yield strength (MPa) Tensile strength (MPa) Elongation (%) Example 1 215.8 300.22 9.21 Example 2 203.2 296.41 9.96 Example 3 211.89 290.91 8.99 Example 4 208.67 295.45 8.03 Example 5 212.92 296.78 7.96

[0005] The preparation method provided by the present application can achieve excellent mechanical properties of the aluminum alloy without solid solution heat treatment, meeting the use requirements. However, the mechanical properties of the aluminum alloy obtained by the above technical scheme cannot meet the strength requirements of automobile parts.

[0006] Therefore, the prior art still needs to be improved in view of the above deficiencies. SUMMARY

[0007] The present application aims to provide a high-performance aluminum alloy die casting material and a preparation method thereof to overcome the deficiencies of the prior art.

[0008] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0009] The application provides a high-performance aluminum alloy die-casting material, which comprises the following components in percentage by weight: Si: 6.0-10.0 wt.%; Mg: 2.0-3.5 wt.%; Zn: 1.0-1.5 wt.%; Cu: 0.5-0.8 wt.%; Mn: 0.2-0.5 wt.%; RE: 0-1.0 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.03 wt.%; and the balance of Al and inevitable impurities, wherein the content of Fe in the impurities is less than or equal to 0.15 wt.%, and the total content of impurities is less than or equal to 0.3 wt.%, and the RE is a rare earth element.

[0010] According to the above scheme, the RE is one or more of La, Ce, Y and Gd.

[0011] The application provides a preparation method of the high-performance aluminum alloy die-casting material.

[0012] 1) ingredients are prepared according to the chemical composition of the alloy, and the Si, Zn, Cu, Mn, RE, Ti and Sr are added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti and Al-Sr intermediate alloys, and the Al and Mg are added in the form of pure Al and pure Mg;

[0013] 2) the pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE and Al-Ti are added to a smelting furnace for heating and melting, the melting temperature is 750-780 DEG C, and after the alloy liquid is completely melted, the pure Mg is added for melting, and the uniform alloy liquid is obtained after stirring;

[0014] 3) the refining agent is added to the prepared alloy liquid for refining the alloy liquid, and after the refining is completed, the alloy liquid is subjected to slag removal treatment and then transferred to a transfer ladle;

[0015] 4) the alloy liquid in the transfer ladle is subjected to degassing treatment;

[0016] 5) the alloy liquid in the transfer ladle is poured into a machine-side furnace of a die-casting machine, and the Al-Sr intermediate alloy is added for melting and stirring uniformly;

[0017] 6) the temperature of the alloy liquid in the machine-side furnace of the die-casting machine is adjusted to 680-700 DEG C, and the alloy liquid is subjected to die-casting;

[0018] 7) the die-casting formed material is subjected to T6 heat treatment.

[0019] According to the above scheme, the weight ratio of the refining agent added in step 3) is 1.0-2.5 ‰, and the refining time is 10-30 min.

[0020] According to the above scheme, the degassing treatment in step 4) is carried out by using nitrogen or argon, the temperature of the alloy liquid is 700-720℃, the degassing time is 30-40min, the flow rate of nitrogen or argon during degassing is 10-25L / min, the gas outlet pressure is 0.4-0.5MPa, and the rotation speed of the degassing rotor is 250-450r / min.

[0021] According to the above scheme, since the Sr element is easy to burn, the Al-Sr intermediate alloy should be supplemented every 3-4h during die casting in step 5).

[0022] According to the above scheme, the pressure of die casting in step 6) is 60-80MPa, the injection speed is 30-50m / s, and the mold temperature is 200-280℃.

[0023] According to the above scheme, the specific process of T6 heat treatment in step 6) is to first carry out solid solution treatment, the temperature of the solid solution treatment is 500-550℃, and the time is 30-40min, and then carry out aging treatment, the temperature of the aging treatment is 160-180℃, and the time is 120-180min.

[0024] The beneficial effects of the present application are:

[0025] (1) The high-performance aluminum alloy die casting material provided by the present application has good die casting performance and excellent mechanical properties, and can meet the requirements of various automobile parts on material performance. The yield strength of the material is 210-240MPa, the tensile strength is 300-350MPa, and the elongation is 6-10wt.%.

[0026] (2) The excellent mechanical properties of the high-performance aluminum alloy die casting material provided by the present application come from the mutual cooperation and interaction of various chemical elements constituting the material.

[0027] The 6.0-10.0 wt.% Si element gives the material good flowability, and the material can fill the mold smoothly in the die casting process; the 2.0-3.5 wt.% Mg element is the main source of the strengthening phase of the material, and the Mg element and the Si element can form Mg2Si strengthening phase in the T6 heat treatment process, which significantly improves the yield strength and tensile strength of the material, and the content of the Mg element should be strictly controlled; the 1.0-1.5 wt.% Zn element can combine with the Mg element in the alloy to generate MgZn2 strengthening phase, which enhances the mechanical properties of the alloy. The 0.5-0.8 wt.% Cu element can enhance the mechanical properties of the material on the one hand, and can improve the corrosion resistance of the material on the other hand; the 0.2-0.5 wt.% Mn element can weaken the adverse effect of the Fe element on the plasticity of the alloy, and is also beneficial to the demolding of the die casting material; the 0-1.0 wt.% RE element can enhance the mechanical properties of the material, and in addition, the RE element can react with oxygen in the air during the preparation of the alloy to purify the solution; the 0.1-0.2 wt.% Ti element can refine the grains of the alloy, and at the same time, can improve the strength and plasticity of the material; the 0.01-0.03 wt.% Sr element plays a modification role, changes the morphology of the Si phase in the alloy, and significantly improves the plasticity of the material. The content of the impurity Fe element in the alloy should not be more than 0.15 wt.%, otherwise, the plasticity of the material will be affected to a certain extent.

[0028] (3) The high-performance aluminum alloy die casting material provided by the application has a very obvious solid solution + aging strengthening effect due to the addition of a high content of Mg element (2.0-3.5 wt.%), and the strength of the material will be significantly increased after T6 heat treatment. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a microstructure picture of the material obtained in Example 1 China;

[0030] Figure 2 is a microstructure picture of the material obtained in Example 1 China;

[0031] Figure 3 is a microstructure picture of the material obtained in Example 1 China;

[0032] Figure 4 is a microstructure picture of the material obtained in Example 1 China. DETAILED DESCRIPTION

[0033] The technical solutions of the application will be described below in combination with examples.

[0034] Example 1

[0035] A high-performance aluminum alloy die casting material comprises the chemical composition shown in Table 1.

[0036] Table 1 Chemical composition (wt.%) of a high-performance aluminum alloy die casting material

[0037] Si Mg Zn Cu Mn RE Ti Sr Fe Example 1 6.25 2.56 1.20 0.58 0.25 0 0.12 0.01 0.08

[0038] The preparation process comprises the following steps:

[0039] 1) ingredients are prepared according to the chemical composition in Table 1, wherein Si, Zn, Cu, Mn, RE, Ti and Sr are added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti and Al-Sr intermediate alloys respectively, and Al and Mg are added in the form of pure Al and pure Mg;

[0040] 2) pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE and Al-Ti are added to a smelting furnace for heating and melting, the melting temperature is 750°C, after the alloy liquid is completely melted, pure Mg is added for melting, and the alloy liquid is stirred uniformly;

[0041] 3) 1.0‰ refining agent is added to the prepared alloy liquid for refining, the refining time is 15 min, and after the alloy liquid is treated by slagging, it is transferred to a transfer ladle;

[0042] 4) the alloy liquid in the transfer ladle is treated by degassing, the degassing process is: nitrogen or argon is used for degassing, the temperature of the alloy liquid is 700°C, the degassing time is 30 min, the flow rate of nitrogen or argon during degassing is 10 L / min, the gas outlet pressure is 0.4 MPa, and the rotation speed of the degassing rotor is 250 r / min;

[0043] 5) the alloy liquid in the transfer ladle is poured into the edge furnace of the die casting machine, Al-Sr intermediate alloy is added for melting and stirring uniformly, since Sr element is easy to burn, the Al-Sr intermediate alloy should be supplemented every 3-4 h during die casting;

[0044] 6) the temperature of the alloy liquid in the edge furnace of the die casting machine is adjusted to 700°C, and the alloy liquid is die cast, the die casting process is: pressure 60 MPa, injection speed 30 m / s, and mold temperature 250°C.

[0045] 7) the die cast material is subjected to T6 heat treatment, the specific process is: solid solution treatment temperature 500°C, time 40 min; aging treatment temperature 160°C, time 180 min.

[0046] Example 2

[0047] A high-performance aluminum alloy die casting material comprises the chemical composition shown in Table 2.

[0048] Table 2 Chemical composition (wt.%) of a high-performance aluminum alloy die casting material

[0049] Si Mg Zn Cu Mn RE Ti Sr Fe Example 2 8.20 3.28 1.35 0.60 0.20 0 0.15 0.012 0.06

[0050] The preparation process comprises the following steps:

[0051] 1) ingredients are prepared according to the chemical composition in Table 1, wherein Si, Zn, Cu, Mn, RE, Ti and Sr are added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti and Al-Sr intermediate alloys respectively, and Al and Mg are added in the form of pure Al and pure Mg;

[0052] 2) pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE and Al-Ti are added to a smelting furnace for heating and melting, the melting temperature is 750°C, after the alloy liquid is completely melted, pure Mg is added for melting, and the alloy liquid is stirred uniformly;

[0053] 3) 1.2‰ refining agent is added to the prepared alloy liquid for refining, the refining time is 25 min, and after the alloy liquid is treated by slagging, it is transferred to a transfer ladle;

[0054] 4) the alloy liquid in the transfer ladle is treated by degassing, the degassing process is: nitrogen or argon is used for degassing, the temperature of the alloy liquid is 720°C, the degassing time is 40 min, the flow rate of nitrogen or argon during degassing is 25 L / min, the gas outlet pressure is 0.4 MPa, and the rotation speed of the degassing rotor is 450 r / min;

[0055] 5) the alloy liquid in the transfer ladle is poured into the edge furnace of the die casting machine, Al-Sr intermediate alloy is added for melting and stirring, since Sr element is easy to burn, Al-Sr intermediate alloy should be added every 3-4 h during die casting;

[0056] 6) the temperature of the alloy liquid in the edge furnace of the die casting machine is adjusted to 700°C, and the alloy liquid is die cast, the die casting process is: pressure 80 MPa, injection speed 50 m / s, and mold temperature 280°C.

[0057] 7) the die cast material is subjected to T6 heat treatment, the specific process is: solid solution treatment temperature is 520°C, time is 30 min; and aging treatment temperature is 180°C, time is 160 min.

[0058] Example 3

[0059] A high-performance aluminum alloy die casting material comprises the chemical composition shown in Table 3.

[0060] Table 3 Chemical composition (wt.%) of a high-performance aluminum alloy die casting material

[0061] Si Mg Zn Cu Mn RE Ti Sr Fe Example 3 8.60 3.50 1.46 0.68 0.45 0 0.16 0.023 0.05

[0062] comprising the following preparation steps:

[0063] 1) according to the chemical composition of Table 1, the Si, Zn, Cu, Mn, RE, Ti, Sr are added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti, Al-Sr intermediate alloy respectively, and the Al and Mg are added in the form of pure Al and pure Mg;

[0064] 2) the pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti are added into a smelting furnace to heat and melt, the melting temperature is 760°C, after the alloy liquid is completely melted, the pure Mg is added to melt, and the uniform alloy liquid is obtained after stirring;

[0065] 3) 1.0‰ refining agent is added into the prepared alloy liquid, the alloy liquid is refined for 30 min, and after the slag removal treatment, the alloy liquid is transferred into a transfer ladle;

[0066] 4) the alloy liquid in the transfer ladle is subjected to degassing treatment, the degassing process is: nitrogen or argon is used for degassing, the temperature of the alloy liquid is 710°C, the degassing time is 30 min, the flow rate of nitrogen or argon is 15 L / min during degassing, the gas outlet pressure is 0.45 MPa, and the rotation speed of the degassing rotor is 250 r / min;

[0067] 5) the alloy liquid in the transfer ladle is poured into the edge furnace of the die casting machine, the Al-Sr intermediate alloy is supplemented and added, and is uniformly melted and stirred, since the Sr element is easy to burn, the Al-Sr intermediate alloy should be supplemented every 3-4 h during die casting;

[0068] 6) the temperature of the alloy liquid in the edge furnace of the die casting machine is adjusted to 680°C, and the alloy liquid is subjected to die casting, and the die casting process is: the pressure is 65 MPa, the injection speed is 35 m / s, and the mold temperature is 250°C.

[0069] 7) the die-cast material is subjected to T6 heat treatment, and the specific process is: the solution treatment temperature is 550°C, and the time is 30 min; the aging treatment temperature is 180°C, and the time is 120 min.

[0070] Example 4

[0071] A high-performance aluminum alloy die casting material, comprising the chemical composition shown in Table 4.

[0072] Table 4 Chemical composition (wt.%) of a high-performance aluminum alloy die casting material

[0073]

[0074]

[0075] The preparation steps include:

[0076] 1) The chemical composition is prepared according to Table 1, and the Si, Zn, Cu, Mn, RE, Ti, and Sr are added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti, and Al-Sr intermediate alloys, respectively, and the Al and Mg are added in the form of pure Al and pure Mg;

[0077] 2) The pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, and Al-Ti are added to a smelting furnace for heating and melting, and the melting temperature is 750°C. After the alloy liquid is completely melted, the pure Mg is added for melting, and the uniform alloy liquid is obtained after stirring;

[0078] 3) The 1.5‰ refining agent is added to the prepared alloy liquid for refining, and the refining time is 20 min. After the alloy liquid is treated by slagging, it is transferred to a transfer ladle;

[0079] 4) The alloy liquid in the transfer ladle is treated by degassing, and the degassing process is as follows: nitrogen or argon is used for degassing, the temperature of the alloy liquid is 710°C, the degassing time is 35 min, the flow rate of nitrogen or argon during degassing is 25 L / min, the gas outlet pressure is 0.5 MPa, and the rotation speed of the degassing rotor is 300 r / min;

[0080] 5) The alloy liquid in the transfer ladle is poured into the edge furnace of the die casting machine, and the Al-Sr intermediate alloy is added for melting and stirring. Since the Sr element is easily burned, the Al-Sr intermediate alloy should be supplemented every 3-4 h during die casting;

[0081] 6) The temperature of the alloy liquid in the edge furnace of the die casting machine is adjusted to 685°C, and the alloy liquid is die cast, and the die casting process is as follows: the pressure is 70 MPa, the injection speed is 50 m / s, and the mold temperature is 200°C.

[0082] 7) The die-cast material is subjected to T6 heat treatment, and the specific process is as follows: the solution treatment temperature is 550°C, and the time is 35 min; the aging treatment temperature is 160°C, and the time is 180 min.

[0083] The high-performance aluminum alloy die casting materials of Examples 1-4 are subjected to mechanical property tests in a greenhouse, and the test results are shown in Table 5.

[0084] Table 2 Mechanical properties of a high-performance aluminum alloy die casting material

[0085] Yield strength (MPa) Tensile strength (MPa) Elongation (%) Example 1 226 345 8.2 Example 2 218 315 9.8 Example 3 233 336 8.0 Example 4 240 346 9.0

[0086] As can be seen from Table 6, the high-performance aluminum alloy die-casting material provided in the embodiments of the present invention has excellent mechanical properties, and its yield strength and tensile strength are significantly improved compared with the existing aluminum alloys in the background art, which can meet the requirements of automotive parts.

[0087] Microstructure observations were conducted on the high-performance aluminum alloy die-casting materials of Examples 1-4. The observation results for Examples 1-4 are as follows: Figures 1-4 .

[0088] from Figures 1-4 It can be seen that the crystal grain diameter is generally less than 20 μm, the grain distribution is uniform, and the resulting high-performance aluminum alloy die-casting material has excellent mechanical properties.

[0089] The above description is only a preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of this patent application are included in the scope of this patent application.

Claims

1. A high performance aluminum alloy die casting material, characterized by, Comprise the following weight percentage of each component: Si: 6.0-10.0wt.%; Mg: 2.0-3.5wt.%; Zn: 1.0-1.5wt.%; Cu: 0.5-0.8wt.%; Mn: 0.2-0.5wt.%; RE: 0-1.0wt.%; Ti: 0.1-0.2wt.%; Sr: 0.01-0.03wt.%; the balance is Al and inevitable impurities, Wherein, the Fe element in the impurities ≤0.15wt.%, the total amount of impurity elements ≤0.3wt.%, the RE is a rare earth element; The preparation method of the high-performance aluminum alloy die casting material comprises the following steps: 1) according to the chemical composition of the alloy, the Si, Zn, Cu, Mn, RE, Ti, Sr is added in the form of Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti, Al-Sr intermediate alloy, and Al and Mg are added in the form of pure Al and pure Mg; 2) pure Al, Al-Si, Al-Zn, Al-Cu, Al-Mn, Al-RE, Al-Ti are added to the smelting furnace for heating and melting, the melting temperature is 750-780℃, after the alloy liquid is completely melted, pure Mg is added for melting, and the uniform alloy liquid is obtained after stirring; 3) refining agent is added to the prepared alloy liquid, the alloy liquid is refined, and after the refining is completed, the alloy liquid is subjected to slag removal treatment and then transferred to a transfer ladle; 4) the alloy liquid in the transfer ladle is subjected to degassing treatment; 5) the alloy liquid in the transfer ladle is poured into the edge furnace of the die casting machine, Al-Sr intermediate alloy is supplemented and added, and is uniformly melted and stirred; 6) the temperature of the alloy liquid in the edge furnace of the die casting machine is adjusted to 680-700℃, and the alloy liquid is subjected to die casting; 7) the die casting formed material is subjected to T6 heat treatment; In step 5), since the Sr element is easy to burn, the Al-Sr intermediate alloy should be supplemented every 3-4h during die casting.

2. The high-performance aluminum alloy die casting material of claim 1, wherein, The RE is one or more of La, Ce, Y, Gd rare earth elements.

3. The high-performance aluminum alloy die casting material of claim 1, wherein, In step 3), the weight ratio of the refining agent added is 1.0-2.5‰, and the refining time is 10-30min.

4. The high-performance aluminum alloy die casting material of claim 1, wherein, In step 4), the degassing treatment adopts nitrogen or argon degassing, the temperature of the alloy liquid is 700-720℃, the degassing time is 30-40min, the flow rate of nitrogen or argon during degassing is 10-25L / min, the gas outlet pressure is 0.4-0.5MPa, and the rotor speed is 250-450r / min.

5. The high-performance aluminum alloy die casting material of claim 1, wherein, In step 6), the pressure of die casting is 60-80MPa, the injection speed is 30-50m / s, and the mold temperature is 200-280℃.

6. The high-performance aluminum alloy diecasting material of claim 1, wherein In step 6), the specific process of T6 heat treatment is to first perform solid solution treatment, the solid solution treatment temperature is 500-550℃, and the time is 30-40min, and then perform aging treatment, the aging treatment temperature is 160-180℃, and the time is 120-180min.

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