阅读说明：本技术 一种压铸铝合金及其制备方法和应用 (Die-casting aluminum alloy and preparation method and application thereof ) 是由 李运春 郭强 任又平 谢勇亮 于 2019-04-12 设计创作，主要内容包括：本发明涉及铝合金领域,尤其涉及一种压铸铝合金及其制备方法和应用。以重量百分含量计,本发明所述压铸铝合金包含：Mg 4％-9％,Si 1.6％-2.8％,Zn 1.1％-2％,Mn 0.5％-1.5％,Ti 0.1％-0.3％,Be 0.009％-0.05％,以及铝和不可避免杂质,杂质总量＜0.2％。通过上述技术方案,本发明提供的压铸铝合金具有良好的力学性能、稳定性和压铸成型性。(The invention relates to the field of aluminum alloys, in particular to a die-casting aluminum alloy and a preparation method and application thereof. The die-casting aluminum alloy comprises the following components in percentage by weight: 4 to 9 percent of Mg, 1.6 to 2.8 percent of Si, 1.1 to 2 percent of Zn, 0.5 to 1.5 percent of Mn, 0.1 to 0.3 percent of Ti, 0.009 to 0.05 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent. Through the technical scheme, the die-casting aluminum alloy provided by the invention has good mechanical property, stability and die-casting formability.)

1. A die cast aluminum alloy, comprising, in weight percent: 4 to 9 percent of Mg, 1.6 to 2.8 percent of Si, 1.1 to 2 percent of Zn, 0.5 to 1.5 percent of Mn, 0.1 to 0.3 percent of Ti, 0.009 to 0.05 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

2. The die-cast aluminum alloy of claim 1, comprising: 5 to 7 percent of Mg, 1.6 to 2.5 percent of Si, 1.1 to 1.4 percent of Zn, 0.6 to 1.0 percent of Mn, 0.1 to 0.3 percent of Ti, 0.01 to 0.022 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

3. The die-cast aluminum alloy of claim 1, wherein a Zn to Be ratio in the die-cast aluminum alloy is (60-140): 1.

4. the die-cast aluminum alloy according to claim 1, wherein a ratio of Mg to Zn in the die-cast aluminum alloy is (4.5-5): 1; the ratio of Si to Zn is (1.5-2): 1.

5. the die-cast aluminum alloy according to claim 1, wherein the die-cast aluminum alloy contains less than 0.1% of Cu, Ni, Cr, Zr, Ag, Sr, and Sn as individual impurities and less than 0.15% of Fe as an impurity.

6. The die-cast aluminum alloy of claim 1, comprising Mg therein₂Si phase, MgZn2 phase, Al₆Mn phase and TiAl₂And (4) phase(s).

7. The die-casting aluminum alloy according to claim 1, wherein the die-casting aluminum alloy has a tensile strength of 350MPa or more, an elongation of 4% or more, and a relative standard deviation of the tensile strength of 10% or less.

8. The aluminum die-casting alloy as recited in claim 1, wherein the aluminum die-casting alloy has a tensile strength of 350-390Mpa, an elongation of 6-9%, and a relative standard deviation of the tensile strength of 5-8%.

9. The preparation method of the die-casting aluminum alloy is characterized by comprising the following steps of: according to the component proportion of the die-casting aluminum alloy, firstly adding an aluminum-containing material into a smelting furnace, after the aluminum-containing material is melted, 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 into the smelting furnace for smelting, then carrying out refining degassing treatment, then carrying out casting to obtain an aluminum alloy ingot, and carrying out melt die-casting molding on the aluminum alloy ingot to obtain the die-casting aluminum alloy as claimed in any one of claims 1 to 8.

10. The method for producing a die-cast aluminum alloy according to claim 9, wherein the temperature for melting the aluminum-containing material is 710 ℃ to 730 ℃; 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 ℃.

11. Use of the aluminum die-casting alloy according to any one of claims 1 to 8 in a computer, a communication electronic product or a consumer electronic product.

Technical Field

The invention relates to the field of aluminum alloys, in particular to a die-casting aluminum alloy and a preparation method and application thereof.

Background

The Al-Mg alloy for die casting is accepted by customers because of good mechanical property and corrosion resistance, but magnesium is more active and is easy to oxidize and burn during casting, and oxidation burning residues enter products to influence the mechanical property of the alloy, so that the product performance has large fluctuation and poor stability, and the problem of cracking is easy to occur during subsequent preparation of alloy die castings, therefore, the Al-Mg alloy for die casting is limited in application. Specifically, for example: ADC6 aluminum alloy, its easy oxidation burning loss slagging scorification when casting influences the comprehensive properties of product, and the range of application is not wide.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a die-casting aluminum alloy and a preparation method thereof, and the die-casting aluminum alloy has good mechanical property, stability and die-casting formability.

In a first aspect of the present invention, there is provided a die-cast aluminum alloy comprising, in weight percent: 4 to 9 percent of Mg, 1.6 to 2.8 percent of Si, 1.1 to 2 percent of Zn, 0.5 to 1.5 percent of Mn, 0.1 to 0.3 percent of Ti, 0.009 to 0.05 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

Preferably, the die-cast aluminum alloy includes: 5 to 7 percent of Mg, 1.6 to 2.5 percent of Si, 1.1 to 1.4 percent of Zn, 0.6 to 1.0 percent of Mn0.1 to 0.3 percent of Ti, 0.01 to 0.022 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

Preferably, the ratio of Zn to Be in the die-cast aluminum alloy is (60-140): 1.

preferably, the ratio of Mg to Zn in the die-cast aluminum alloy is (4.5-5): 1; the ratio of Si to Zn is (1.5-2): 1.

preferably, the content of Cu, Ni, Cr, Zr, Ag, Sr and Sn single impurities in the die-casting aluminum alloy is less than 0.1%, and the content of Fe impurities is less than 0.15%.

Preferably, the die-cast aluminum alloy includes Mg therein₂Si phase, MgZn₂Phase, Al₆Mn phase and TiAl₂And (4) phase(s).

Preferably, the tensile strength of the die-casting aluminum alloy is more than or equal to 350MPa, the elongation is more than or equal to 4 percent, and the relative standard deviation of the tensile strength is less than or equal to 10 percent.

Preferably, the die-casting aluminum alloy has the tensile strength of 350-390MPa, the elongation of 6-9% and the relative standard deviation of the tensile strength of 5-8%.

In a second aspect of the present invention, a method for producing a die-cast aluminum alloy is provided, which includes the steps of: according to the component proportion of the die-casting aluminum alloy, firstly adding an aluminum-containing material into a smelting furnace, after the aluminum-containing material is melted, 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 into the smelting furnace for smelting, then carrying out refining degassing treatment, casting to obtain an aluminum alloy ingot, and carrying out melting die-casting molding on the aluminum alloy ingot to obtain the die-casting aluminum alloy of the first aspect of the invention.

Preferably, the temperature for smelting the aluminum-containing material is 710-730 ℃; 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 ℃.

In a third aspect of the invention, there is provided a use of the die-cast aluminum alloy of the invention in a computer, a communication electronic product, or a consumer electronic product.

Through the technical scheme, the die-casting aluminum alloy provided by the invention contains the components with the limited content, and has good mechanical property, stability and die-casting formability.

Drawings

Fig. 1 shows XRD patterns of die-cast aluminum alloys obtained in example 1.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect of the present invention, there is provided a die-cast aluminum alloy comprising, in weight percent: 4 to 9 percent of Mg, 1.6 to 2.8 percent of Si, 1.1 to 2 percent of Zn, 0.5 to 1.5 percent of Mn, 0.1 to 0.3 percent of Ti, 0.009 to 0.05 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

The die-casting aluminum alloy provided by the invention has excellent mechanical property, stability and die-casting formability, and various properties of the alloy are balanced by adopting the mutual matching of various elements of Mg, Si, Zn, Mn, Ti and Be with specific contents, so that the die-casting aluminum alloy with excellent comprehensive properties is obtained.

In one embodiment of the invention, the mass percentage of Mg is 5-7%.

In a preferred embodiment of the present invention, the Mg content is 6% by mass.

In one embodiment of the invention, the mass percentage of Si is 1.6-2.5%.

In a preferred embodiment of the present invention, the Si content is 1.7% to 2.4% by mass.

In a preferred embodiment of the present invention, the Si content is 2.2% by mass.

In one embodiment of the invention, the mass percentage of Zn is 1.1-1.4%.

In a preferred embodiment of the present invention, the mass percentage of Zn is 1.2%.

In one embodiment of the invention, the mass percentage of Mn is 0.6% to 1.0%.

In a preferred embodiment of the present invention, the Mn content is 0.7% by mass.

In one embodiment of the invention, the mass percentage of Ti is 0.1-0.25%.

In a preferred embodiment of the present invention, the Ti content is 0.15% by mass.

In one embodiment of the invention, the Be content is 0.01-0.022 wt%.

In a preferred embodiment of the present invention, the content of Be is 0.015% by mass.

In order to further improve the mechanical properties, stability and die-casting formability of the die-casting aluminum alloy, a preferred embodiment of the present invention is a die-casting aluminum alloy comprising: 5 to 7 percent of Mg, 1.6 to 2.5 percent of Si, 1.1 to 1.4 percent of Zn, 0.6 to 1.0 percent of Mn, 0.1 to 0.3 percent of Ti, 0.01 to 0.022 percent of Be, aluminum and inevitable impurities, wherein the total amount of the impurities is less than 0.2 percent.

In the invention, the die-casting aluminum alloy contains Mg, Si and Zn within the content range, so that the die-casting aluminum alloy has good solid solution strengthening effect, and Mg can be combined with Si and Zn to form Mg₂Si phase, MgZn₂The phase plays a role in precipitation strengthening, and the obdurability of the alloy product is ensured (the obdurability means that the alloy simultaneously has good tensile strength and extensionRate). The content of Mg or Si in the die-casting aluminum alloy is too low, the strengthening and toughening effect of the alloy cannot be guaranteed, and the mechanical property is low; if the content of Mg is too high, the oxidation slagging is easy, the plasticity and the toughness of the alloy are reduced, if the content of Si is too high, a brittle simple substance silicon phase is easy to precipitate, and the plasticity and the toughness of the alloy are also reduced. Moreover, as can be seen from fig. 1, the die-casting aluminum alloy of the present invention contains zinc oxide, and Zn forms a layer of oxide film on the surface of the aluminum-magnesium alloy melt to prevent the melt from being oxidized too fast; if the Zn content is too high, a low-melting-point brittle phase is easily precipitated, the plasticity is reduced, and the toughness of the alloy is reduced.

In the present invention, the melt means a state in which a substance which is originally solid at normal temperature is changed into liquid at high temperature. Specifically, the melt in the present invention means that the metal raw material is changed into a molten state (liquid) by the melting treatment in the process of preparing the die-cast aluminum alloy.

In the invention, the die-casting aluminum alloy contains Be within the content range, so that a layer of oxide film can Be formed on the surface of the aluminum-magnesium alloy melt, the melt is prevented from being oxidized too fast, and the oxidation and slagging of the melt are reduced, and as can Be seen from figure 1, the die-casting aluminum alloy obviously contains beryllium oxide. If the content of Be in the aluminum alloy is too low, the oxidation protection of the alloy melt is weakened, the melt slag is more, and the fluctuation of mechanical properties is increased; when the content of Be is too high, the grains tend to Be coarse, the plasticity tends to Be reduced, and the toughness of the alloy tends to Be lowered.

In the present invention, the die-cast aluminum alloy contains Mn in the above-mentioned content range, and can be combined with Al to form Al₆The Mn phase plays a role in precipitation strengthening, the toughness of the alloy product is further improved, and the Mn in the content range can relieve die erosion in die-casting production and prolong the service life of the die. If the Mn content in the aluminum alloy is too low, the strengthening and toughening effect of the alloy is reduced, the mechanical property is reduced, and the service life of a die is reduced; if the Mn content is too high, a brittle phase is easily precipitated, the plasticity is reduced, and the toughness of the alloy is lowered.

In the invention, the die-casting aluminum alloy contains Ti within the content range, and can be combined with Al to form TiAl₂The phase plays a role in refining grains, and further enhances the toughness of the alloy product. If the content of Ti in the aluminum alloy is too low, the grain-refining strengthening and toughening effects of the alloy are reduced; if the Ti content is too high, it is likely to segregate to form a coarse brittle phase, resulting in a decrease in plasticity and a decrease in toughness of the alloy.

According to the present invention, preferably, the weight ratio of Zn to Be in the die-cast aluminum alloy is (60-140): 1. through a large number of experimental trials, the inventor of the invention finds that Zn and Be in the die-casting aluminum alloy meet the proportional relationship, a layer of compact oxide film can Be formed on the surface of an aluminum alloy (especially an aluminum-magnesium alloy) solution, the effect of protecting the solution from oxidation can Be better achieved, the oxidation of the aluminum alloy solution is reduced, slagging is also reduced, the performance and the performance stability of the die-cast product are improved, the aluminum-magnesium alloy belongs to a system with serious oxidation slagging in the aluminum alloy, and the invention can obviously reduce the slagging phenomenon in the alloy solution by adding the elements of zinc and beryllium reasonably and controlling the addition amount of the elements.

According to the present invention, preferably, the ratio of Mg to Zn in said die-cast aluminum alloy is (4.5-5): 1; the ratio of Si to Zn is (1.5-2): 1. mg is easy to form Mg with Zn and Si₂Si phase, MgZn₂The inventors of the present invention have found through a large number of experimental trials that when Mg, Zn, and Si in the die-cast aluminum alloy satisfy the above proportional relationship, Mg can sufficiently react with Zn and Si to form a precipitation strengthening phase, and excess Mg can further exert a solid-solution strengthening effect in the aluminum alloy matrix, whereby the die-cast aluminum alloy of the present invention has more excellent toughness.

According to the invention, the die-cast aluminium alloy allows the presence of small amounts of other metallic elements, such as one, two or more of Fe, Cu, Ni, Cr, Zr, Ag, Sr, Sn, which are typically derived from impurities in the alloy raw materials when the alloy is prepared. Excessive impurity elements easily cause the problems of reduction of the elongation percentage of the die casting alloy, cracking of products and the like, so that the content of Fe impurities in the die casting aluminum alloy is less than 0.15 percent, and the content of single impurities of Cu, Ni, Cr, Zr, Ag, Sr and Sn is less than 0.1 percent, preferably less than 0.02 percent.

According to the present invention, preferably, Mg is included in the die-cast aluminum alloy₂Si phase, MgZn₂Phase, Al₆Mn phase and TiAl₂And (4) phase(s). The crystal phase contained in the invention can effectively increase the mechanical property of the alloy.

According to the invention, preferably, the tensile strength of the die-casting aluminum alloy is more than or equal to 350MPa, the elongation is more than or equal to 4%, and the relative standard deviation of the tensile strength is less than or equal to 10%. The relative standard deviation is a value obtained by dividing the standard deviation by the corresponding average value and multiplying 100%, and the relative standard deviation can reflect the stability of the performance of the product, wherein the smaller the relative standard deviation is, the more stable the performance of the product is. More preferably, the yield strength of the die-casting aluminum alloy is 350-390Mpa, the elongation is 6-9%, and the relative standard deviation of the tensile strength is 5-8%.

In a second aspect of the present invention, a method for producing a die-cast aluminum alloy is provided, which includes the steps of: according to the component proportion of the die-casting aluminum alloy, firstly adding an aluminum-containing material into a smelting furnace, after the aluminum-containing material is melted, 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 into the smelting furnace for smelting, then carrying out refining degassing treatment, casting to obtain an aluminum alloy ingot, and carrying out melting die-casting molding on the aluminum alloy ingot to obtain the die-casting aluminum alloy of the first aspect of the invention.

In the present invention, 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 capable of providing various elements required for preparing the die-casting aluminum alloy of the present invention, and may be alloys or pure metals containing the elements as long as the composition components in the aluminum alloy obtained by melting the added aluminum alloy raw material are within the above ranges. Preferably, the aluminum alloy feedstock may include pure Al or Al alloy, pure Mg or Mg alloy, pure Si or Si alloy, pure Zn or Zn alloy, pure Mn or Mn alloy, pure Ti or Ti alloy, and pure Be or Be alloy. More preferably, the aluminum alloy starting material includes pure Al, pure Mg, Al-Si alloy, pure Zn, Al-Mn alloy, Al-Ti alloy, and Al-Be alloy.

According to the preparation method of the die-casting aluminum alloy, preferably, the smelting conditions are as follows: the smelting temperature is 700 ℃ and 750 ℃. More preferably, the temperature for smelting the aluminum-containing material is 710-730 ℃; the temperature for smelting the materials containing silicon, manganese, zinc, magnesium, beryllium and titanium is 680-710 ℃.

According to the preparation method of the die-cast aluminum alloy, preferably, the refining comprises adding a refining agent into molten metal and stirring to realize refining degassing; the refining agent is at least one of hexachloroethane, zinc chloride, manganese chloride and potassium chloride, and the refining temperature is 720-740 ℃.

According to the preparation method of the die-casting aluminum alloy, the casting temperature is preferably 680-720 ℃.

According to the preparation method of the die-casting aluminum alloy, preferably, the die-casting is to remelt the aluminum alloy ingot into the aluminum alloy liquid at the temperature of 680-720 ℃, pour a certain amount of the aluminum alloy liquid into a pressure chamber of a die-casting machine, and press the aluminum alloy liquid into a metal mold through a jet hammer to form a product.

In a third aspect of the invention, there is provided a use of the die-cast aluminum alloy of the invention in a computer, a communication electronic product, or a consumer electronic product. Preferably, the die-cast aluminum alloy of the present invention is applied to a 3C electronic product housing.

The present invention will be described in detail below by way of examples.