Patent Application
20220195563
This application claims priority to Chinese Patent Application No. 201910293278.5 filed by BYD Co., Ltd. on Apr. 12, 2019, and entitled DIE-CAST ALUMINUM ALLOY AND PREPARATION METHOD AND USE THEREOF.
The present disclosure relates to the field of aluminum alloys, and in particular, to a die-cast aluminum alloy and a preparation method and use thereof.
Al—Mg alloys for die casting have been approved by customers due to good mechanical properties and corrosion resistance thereof. However, magnesium is relatively active and is easily oxidized and burnt during casting. The oxidized and burnt residue entering the product affects the mechanical properties of the alloy, resulting in large fluctuation and poor stability in product performance, and cracking in the subsequent preparation of an alloy die casting. Therefore, the Al—Mg alloys for die casting are subject to certain restrictions in use. Specifically, for example, the ADC6 aluminum alloy is easily oxidized and burnt to cause slagging during casting, which affects the comprehensive performance of the product and limits the scope of application of the product.
To overcome the defects in the related art, this disclosure provides a die-cast aluminum alloy and a preparation method thereof. The die-cast aluminum alloy has good mechanical properties, stability, and die-casting formability.
According to a first aspect of this disclosure, a die-cast aluminum alloy is provided. Based on the total mass of the die-cast aluminum alloy, the die-cast aluminum alloy includes: 4-9 wt % of Mg; 1.6-2.8 wt % of Si; 1.1-2 wt % of Zn; 0.5-1.5 wt % of Mn; 0.1-0.3 wt % of Ti; 0.009-0.05 wt % of Be; the balance of Al; and less than 0.2 wt % of inevitable impurities.
According to an embodiment of this disclosure, based on the total mass of the die-cast aluminum alloy, the die-cast aluminum alloy includes: 5-7 wt % of Mg; 1.6-2.5 wt % of Si; 1.1-1.4 wt % of Zn; 0.6-1.0 wt % of Mn; 0.1-0.3 wt % of Ti; 0.01-0.022 wt % of Be; the balance of Al; and less than 0.2 wt % of inevitable impurities.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the mass ratio of Zn to Be is (60-140):1.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the mass ratio of Mg to Zn is (4.5-5):1, and the mass ratio of Si to Zn is (1.5-2):1.
According to an embodiment of this disclosure, based on the total mass of the die-cast aluminum alloy, among the inevitable impurities, the content of each of the Cu, Ni, Cr, Zr, Ag, Sr, and Sn impurities is independently less than 0.1%, and the content of Fe is less than 0.15%.
According to an embodiment of this disclosure, the die-cast aluminum alloy includes a Mg2Si phase, a MgZn2 phase, an Al6Mn phase, and a TiAl2 phase.
According to an embodiment of this disclosure, for the die-cast aluminum alloy, the tensile strength is not less than 350 MPa, the elongation is not less than 4%, and the relative standard deviation of the tensile strength is not greater than 10%.
According to an embodiment of this disclosure, for the die-cast aluminum alloy, the tensile strength is 350-390 MPa, the elongation is 6-9%, and the relative standard deviation of the tensile strength is 5-8%.
According to a second aspect of this disclosure, a method for preparing the foregoing die-cast aluminum alloy is provided, including: smelting an aluminum-containing material in a smelting furnace, adding a silicon-containing material, a manganese-containing material, a zinc-containing material, a magnesium-containing material, a beryllium-containing material, and a titanium-containing material for smelting after the aluminum-containing material is melted, subjecting the mixed materials to refining and degassing and then casting to obtain an aluminum alloy ingot, and melting and die-casting the aluminum alloy ingot, to obtain the die-cast aluminum alloy according to the first aspect of this disclosure.
In some embodiments, the smelting temperature of the aluminum-containing material is 710-730° C., and the smelting temperature of the silicon-containing material, the manganese-containing material, the zinc-containing material, the magnesium-containing material, the beryllium-containing material, and the titanium-containing material is 680-710° C.
According to a third aspect of this disclosure, use of the die-cast aluminum alloy of this disclosure or a die-cast aluminum alloy obtained by using the method in computers, communication electronic products, or consumer electronic products.
Through the foregoing technical solutions, the die-cast aluminum alloy provided by this disclosure contains the foregoing components with limited contents, which can have good mechanical properties, stability, and die-casting formability.
Additional aspects and advantages of this disclosure will be given in the following description, some of which will become apparent from the following description or may be learned from practices of this disclosure.
The foregoing additional aspects and advantages of this disclosure will become apparent and comprehensible from the following descriptions of the embodiments with reference to the accompanying drawings.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to include values that are close to the ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and the individual point values, and the individual point values can be combined with one another to yield one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed herein.
According to a first aspect of this disclosure, a die-cast aluminum alloy is provided. Based on the total mass of the die-cast aluminum alloy, the die-cast aluminum alloy includes: 4-9 wt % of Mg; 1.6-2.8 wt % of Si; 1.1-2 wt % of Zn; 0.5-1.5 wt % of Mn; 0.1-0.3 wt % of Ti; 0.009-0.05 wt % of Be; the balance of Al; and less than 0.2 wt % of inevitable impurities. For example, the content of Mg is 4 wt %, 4.1 wt %, . . . , 8.9 wt %, or 9 wt %; the content of Si is 1.6 wt %, 1.7 wt %, . . . , 2.7 wt %, or 2.8 wt %; the content of Zn is 1.1 wt %, 1.2 wt %, . . . , 1.9 wt %, or 2 wt %; the content of Mn is 0.5 wt %, 0.6 wt %, . . . , 1.4 wt %, or 1.5 wt %; the content of Ti is 0.1 wt %, 0.11 wt %, . . . , 0.29 wt %, or 0.3 wt %; and the content of Be is 0.009 wt %, 0.01 wt %, 0.049 wt %, or 0.05 wt %.
The die-cast aluminum alloy provided by this disclosure has good mechanical properties, stability, and die-casting formability. This is because the cooperation between elements Mg, Si, Zn, Mn, Ti, and Be with specific contents in this disclosure balances various properties of the alloy, thereby obtaining the die-cast aluminum alloy with excellent comprehensive performance.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Mg in percentage by mass is 5-7%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Mg in percentage by mass is 6%.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Si in percentage by mass is 1.6-2.5%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Si in percentage by mass is 1.7-2.4%. According to another specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Si in percentage by mass is 2.2%.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Zn in percentage by mass is 1.1-1.4%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Zn in percentage by mass is 1.2%.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Mn in percentage by mass is 0.6-1.0%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Mn in percentage by mass is 0.7%.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Ti in percentage by mass is 0.1-0.25%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Ti in percentage by mass is 0.15%.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the content of Be in percentage by mass is 0.01-0.022%. According to a specific embodiment of this disclosure, in the die-cast aluminum alloy, the content of Be in percentage by mass is 0.015%.
To further improve the mechanical properties, stability, and die-casting formability of the die-cast aluminum alloy, in an embodiment of this disclosure, based on the total mass of the die-cast aluminum alloy, the die-cast aluminum alloy includes: 5-7 wt % of Mg; 1.6-2.5 wt % of Si; 1.1-1.4 wt % of Zn; 0.6-1.0 wt % of Mn; 0.1-0.3 wt % of Ti; 0.01-0.022 wt % of Be; the balance of Al; and less than 0.2 wt % of inevitable impurities.
In this disclosure, the die-cast aluminum alloy contains Mg, Si, and Zn within the foregoing content ranges, which can achieve a good solid solution strengthening effect, and Mg can be combined with Si and Zn to form the Mg2Si phase and the MgZn2 phase to achieve a precipitation strengthening effect, which ensures the toughness (the toughness refers to that the alloy has both good tensile strength and elongation) of the alloy product. In the die-cast aluminum alloy of this disclosure, if the content of Mg or Si is excessively low, the toughening effect of the alloy cannot be ensured, and the mechanical properties are poor; if the content of Mg is excessively high, the alloy is easily oxidized to cause slagging, and the plasticity and toughness of the alloy decrease; and if the content of Si is excessively high, the alloy is likely to precipitate a brittle elemental silicon phase, which also causes the plasticity and toughness of the alloy to decrease. In addition, it can be seen from
In this disclosure, a melt refers to a state in which a substance that was originally a solid at room temperature becomes a liquid at a high temperature. Specifically, in this disclosure, the melt refers to that the metal raw material is melted into a molten state (liquid) in the process of preparing the die-cast aluminum alloy.
In this disclosure, the die-cast aluminum alloy contains Be within the foregoing content ranges, which can form an oxide film on the surface of an aluminum-magnesium alloy melt to prevent the melt from oxidation quickly and reduce slagging caused by oxidation of the melt. It can be seen from
In this disclosure, the die-cast aluminum alloy contains Mn within the foregoing content ranges, which can be combined with Al to form the Al6Mn phase to achieve a precipitation strengthening effect, further increasing the toughness of the alloy product, and Mn within the foregoing content ranges can alleviate die erosion during die-casting production and increase die life. In the aluminum alloy of this disclosure, if the content of Mn is excessively low, the toughening effect of the alloy is reduced, the mechanical properties are reduced, and die life is reduced; and if the content of Mn is excessively high, it is easy to precipitate a brittle phase, the plasticity is reduced, and the toughness of the alloy is reduced.
In this disclosure, the die-cast aluminum alloy contains Ti within the foregoing content ranges, which can be combined with Al to form the TiAl2 phase to achieve a grain refining effect, further increasing the toughness of the alloy product. In the aluminum alloy of this disclosure, if the content of Ti is excessively low, the grain refining and toughening effect of the alloy is reduced; and if the content of Ti is excessively high, a coarse brittle phase is likely to segregate, the plasticity is reduced, and the toughness of the alloy is reduced.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the mass ratio of Zn to Be is (60-140):1. For example, in the die-cast aluminum alloy, the mass ratio of Zn to Be is 60:1, 61:1, 139:1, or 140:1. In some embodiments, by conducting a large quantity of experiments that Zn and Be in the die-cast aluminum alloy that meet the foregoing ratio relationship can form a dense oxide film on the surface of an aluminum alloy (especially an aluminum-magnesium alloy) melt to better protect the melt from oxidation, resulting in reduced oxidation of the aluminum alloy melt, reduced slagging, and improved performance and stability of the die-cast product. The aluminum-magnesium alloy belongs to the system with severe oxidation slagging in the aluminum alloy. This disclosure can significantly reduce slagging in the alloy melt by properly adding Zn and Be with controlled addition amounts.
According to an embodiment of this disclosure, in the die-cast aluminum alloy, the mass ratio of Mg to Zn is (4.5-5):1, and the mass ratio of Si to Zn is (1.5-2):1. For example, in the die-cast aluminum alloy, the mass ratio of Mg to Zn is 4.5:1, 4.6:1, . . . , 4.9:1, or 5:1, and the mass ratio of Si to Zn is 1.5:1, 1.6:1, . . . , 1.9:1, or 2:1. Mg is easily combined with Zn and Si to form the Mg2Si phase and the MgZn2 phase to achieve a strengthening effect. In some embodiments, by conducting a large quantity of experiments that, when Mg, Zn, and Si in the die-cast aluminum alloy meet the foregoing ratio relationship, Mg can fully interact with Zn and Si to form precipitation strengthening phases, and excess Mg can further achieve a solid solution strengthening effect in the aluminum alloy matrix. Therefore, the die-cast aluminum alloy of this disclosure has a better toughness.
According to this disclosure, there are a small quantity of other metal elements in the die-cast aluminum alloy, including one, two, three, or more of Fe, Cu, Ni, Cr, Zr, Ag, Sr, and Sn, and the other metal elements are generally from impurities in the alloy raw material during the preparation of the alloy. Excessive impurity elements are likely to lead to a decrease in the elongation of the die-casting alloy and product cracking. Therefore, based on the total mass of the die-cast aluminum alloy, in the die-cast aluminum alloy of this disclosure, the content of impurity Fe is less than 0.15%, and the content of each of the Cu, Ni, Cr, Zr, Ag, Sr, and Sn impurities is independently less than 0.1%. According to a specific embodiment of this disclosure, based on the total mass of the die-cast aluminum alloy, in the die-cast aluminum alloy of this disclosure, the content of each of the Cu, Ni, Cr, Zr, Ag, Sr, and Sn impurities is independently less than 0.02%.
According to an embodiment of this disclosure, the die-cast aluminum alloy includes a Mg2Si phase, a MgZn2 phase, an Al6Mn phase, and a TiAl2 phase. This disclosure contains the foregoing crystal phases, which can effectively increase the mechanical properties of the alloy.
According to an embodiment of this disclosure, for the die-cast aluminum alloy, the tensile strength is not less than 350 MPa, the elongation is not less than 4%, and the relative standard deviation of the tensile strength is not greater than 10%. In this disclosure, the relative standard deviation is the value obtained by dividing a standard deviation by a corresponding average value and multiplying 100%. The relative standard deviation can reflect the stability of product performance. The smaller the relative standard deviation is, the more stable the product performance is. According to a specific embodiment of this disclosure, for the die-cast aluminum alloy, the tensile strength is 350-390 MPa, the elongation is 6-9%, and the relative standard deviation of the tensile strength is 5-8%.
According to a second aspect of this disclosure, a method for preparing the foregoing die-cast aluminum alloy is provided, including the following steps: according to the foregoing composition ratio of the die-cast aluminum alloy, first smelting an aluminum-containing material in a smelting furnace, adding a silicon-containing material, a manganese-containing material, a zinc-containing material, a magnesium-containing material, a beryllium-containing material, and a titanium-containing material for smelting after the aluminum-containing material is melted, subjecting the mixed materials to refining and degassing and then casting to obtain an aluminum alloy ingot, and melting and die-casting the aluminum alloy ingot, to obtain the die-cast aluminum alloy according to the first aspect of this disclosure.
In this disclosure, the aluminum-containing material, the magnesium-containing material, the silicon-containing material, the zinc-containing material, the manganese-containing material, the titanium-containing material, and the beryllium-containing material may be materials that can provide various elements required for preparing the die-cast aluminum alloy of this disclosure, or may be alloys or pure metals containing the foregoing elements, as long as the composition of the aluminum alloy obtained after the added aluminum alloy raw material is smelted is within the foregoing range. According to a specific embodiment of this disclosure, the aluminum alloy raw material may include a pure Al or Al alloy, a pure Mg or Mg alloy, a pure Si or Si alloy, a pure Zn or Zn alloy, a pure Mn or Mn alloy, a pure Ti or Ti alloy, and a pure Be or Be alloy. According to another specific embodiment of this disclosure, the aluminum alloy raw material includes a pure Al, a pure Mg, an Al—Si alloy, a pure Zn, an Al—Mn alloy, an Al—Ti alloy, and an Al—Be alloy.
According to the method for preparing the die-cast aluminum alloy in this disclosure, the smelting condition is 700-750° C. of the smelting temperature. According to a specific embodiment of this disclosure, the smelting temperature of the aluminum-containing material is 710-730° C., such as 710° C., 711° C., . . . , 729° C., or 730° C.; and the smelting temperature of the silicon-containing material, the manganese-containing material, the zinc-containing material, the magnesium-containing material, the beryllium-containing material, and the titanium-containing material is 680-710° C., such as 680° C., 681° C., . . . , 709° C., or 710° C.
According to the method for preparing the die-cast aluminum alloy in this disclosure, the refining includes adding a refining agent into the molten metal and stirring to implement refining and degassing, the refining agent is at least one of hexachloroethane, zinc chloride, manganese chloride, and potassium chloride, and the refining temperature is 720-740° C., such as 720° C., 721° C., . . . , 739° C., or 740° C.
According to the method for preparing the die-cast aluminum alloy in this disclosure, the casting temperature is 680-720° C., such as 680° C., 681° C., . . . , 719° C., or 720° C.
According to the method for preparing the die-cast aluminum alloy in this disclosure, the die-casting is to remelt the aluminum alloy ingot at 680-720° C. (such as 680° C., 681° C., . . . , 719° C., or 720° C.) into an aluminum alloy liquid, pour a certain amount of the aluminum alloy liquid into a pressure chamber of a die-casting machine, and then inject the aluminum alloy liquid into a metal die by using an injection hammer to form a product.
According to a third aspect of this disclosure, use of the die-cast aluminum alloy of this disclosure or a die-cast aluminum alloy prepared by using the method of this disclosure in computers, communication electronic products, or consumer electronic products. According to an embodiment of this disclosure, the die-cast aluminum alloy of this disclosure is used in housings of 3C electronic products.
This disclosure is described with reference to the following specific examples. It is to be noted that these examples are merely illustrative and are not intended to limit this disclosure in any way.
An alloy raw material containing various elements was prepared according to the aluminum alloy composition shown in Table 1. A pure Al was put into a smelting furnace and smelted at 710-730° C. After the pure Al was melted, an Al—Si alloy, an Al—Mn alloy, a pure Zn, a pure Mg, an Al—Be alloy, and an Al—Ti alloy were added and smelted at 680-710° C., and stirred uniformly, to obtain a molten metal.
At 720-740° C., a refining agent was added into the molten metal for refining and degassing until the refining agent is fully reacted, then slag was removed to obtain an alloy liquid, and then the alloy liquid was cast to obtain an aluminum alloy ingot. The aluminum alloy ingot was remelted at 680-720° C. into an aluminum alloy liquid, a certain amount of the aluminum alloy liquid was poured into a pressure chamber of a die-casting machine, and then the aluminum alloy liquid was injected into a metal die by using an injection hammer to form a product, to obtain a die-cast aluminum alloy. The test result was shown in Table 2.
A die-cast aluminum alloy was prepared by using the same method as in the foregoing examples, except that an aluminum alloy raw material was prepared according to the composition shown in Table 1. The test result was shown in Table 2.
Performance Test
Aluminum alloy tensile test: Tensile test bars (diameter 6.4 mm, gauge length 50 mm) with different compositions were obtained by die-casting, the tensile test was carried out by using an electronic universal testing machine (model: CMT5105) according to GBT 228.1-2010 with a gauge length of 50 mm and a loading rate of 2 mm/min, and test data (tensile strength and elongation) was recorded. Six test bars were tested for each composition. The tensile strength and the elongation were average values of the six data. The relative standard deviation of the tensile strength was a ratio in percentage of a standard deviation of six tensile strength data to an average value.
Die-casting formability test: Aluminum alloys with different compositions were die-cast, if the composition had good fluidity and could easily fill up the cavity, and there was less slag on the surface of the melt, then the die-casting formability was evaluated as excellent; if the composition had average fluidity and required a relatively high pressure and speed to fill up the cavity, and there was less slag on the surface of the melt, then the die-casting formability was evaluated as good; and if the composition had average fluidity and required a relatively high pressure and speed to fill up the cavity, and there was much slag on the surface of the melt, then the die-casting formability was evaluated as poor.
It can be learned from Table 2 that the die-cast aluminum alloy of this disclosure has good mechanical properties (toughness), stability, and die-casting formability.
The preferred implementations of this disclosure arc described in detail above, but this disclosure is not limited to the specific details in the foregoing implementations. Various simple variations may be made to the technical solutions of this disclosure within the scope of the technical idea of this disclosure, and such simple variations shall all fall within the protection scope of this disclosure.
It should be further noted that the specific technical features described in the foregoing specific implementations may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, various possible combinations are not further described in this disclosure.
In addition, various different implementations of this disclosure may alternatively be combined randomly. Such combinations should also be considered as the content disclosed in this disclosure provided that these combinations do not depart from the concept of this disclosure.
In the descriptions of this specification, descriptions using reference terms “an embodiment”, “some embodiments”, “an example”, “a specific example”, or “some examples” mean that specific characteristics, structures, materials, or features described with reference to the embodiment or example are included in at least one embodiment or example of this disclosure. In this specification, schematic representations of the foregoing terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, different embodiments or examples described in this specification, as well as features of different embodiments or examples, may be integrated and combined by a person skilled in the art without contradicting each other.
Although the embodiments of this disclosure have been shown and described above, it can be understood that, the foregoing embodiments are exemplary and cannot be understood as limitation to this disclosure. A person of ordinary skill in the art can make changes, modifications, replacements, or variations to the foregoing embodiments within the scope of this disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201910293278.5 | Apr 2019 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2020/081413 | 3/26/2020 | WO | 00 |
