CN113862523A - Al-Mn series die-casting alloy and preparation method and application thereof - Google Patents
Al-Mn series die-casting alloy and preparation method and application thereof Download PDFInfo
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Abstract
An Al-Mn series die-casting alloy and a preparation method and application thereof, belonging to the technical field of die-casting alloys. The Al-Mn series die casting alloy comprises the following components in percentage by mass: 1.2 to 2.1 percent of Mn, 0.9 to 1.6 percent of Si, 0.4 to 1.5 percent of Mg, 0.25 to 1.2 percent of Cu which is not equal to 0.25 percent, less than or equal to 0.5 percent of Zn, less than or equal to 0.5 percent of Ti, less than or equal to 0.5 percent of Cr, less than or equal to 0.5 percent of Zr, less than or equal to 0.3 percent of Fe, 0 to 0.5 percent of rare earth elements, 0 to 0.5 percent of Sr, and the balance of Al and inevitable impurities, wherein the total content of the inevitable impurities is less than or equal to 1.0 percent. The Al-Mn series die casting alloy has the advantages that through the adjustment of components, the alloy components are positioned near a eutectic point, so that the Al-Mn series die casting alloy has good fluidity and is an alloy with high strength, high heat conductivity, die casting performance and anodic oxidation performance.
Description
Technical Field
The invention belongs to the technical field of die-casting alloys, and particularly relates to an Al-Mn series die-casting alloy and a preparation method and application thereof.
Background
Aluminum alloys are increasingly used as exterior parts of 3C electronic products. The production process can be roughly classified into a full CNC (numerically controlled machine) machining process and a die casting process. Appearance parts of high-end products are mainly manufactured by a CNC (computerized numerical control) machining process, and are bright and attractive in appearance through anodic oxidation. But CNC processing cost is high, and production efficiency is low; the die casting process has high production efficiency and low cost, but appearance parts produced by the die casting process cannot be subjected to anodic oxidation, and the surface of the die casting process is mostly coated with paint by baking, so that the die casting process is not as bright and vivid as the anodic oxidation surface.
The anodic oxidation process of aluminum alloy is a surface treatment method which takes the aluminum alloy as an anode and inert electrodes such as lead plates as a cathode in a proper electrolyte and passes current to make the surface of the aluminum alloy lose electrons to form an oxide film with larger thickness. It is composed of the steps of aluminum matrix dissolution, ion migration in solution, electrode discharge, oxidation reaction (film formation) and the like. Therefore, the anodic oxidation performance of the aluminum alloy is closely related to alloy elements, and a good anodic oxidation effect can be obtained only by specific aluminum alloy. As appearance parts of products such as mobile phones and the like, the appearance parts are required to have not only brilliant and attractive appearance, but also high strength and plasticity, so that defects such as pits, scratches and the like are not easy to appear on the surfaces of the parts, and the appearance quality is influenced. The medium and high strength aluminum alloys which can be anodized at present are mainly 6000 series and 7000 series alloys. 6000 series alloy is mainly used for appearance parts of full CNC processing. However, 6000 series alloys are medium strength alloys, and the strength cannot completely meet the requirements of high-end products, so 7000 series alloys with higher strength are used for some products, and the cost is higher. Currently, the most widely used Al — Si based casting alloys, such as ADC12, have excellent fluidity, but have poor anodic oxidation due to the high Si content. Therefore, the appearance parts produced by the die casting process at present cannot be anodized. Today, mainframe factory designers are often faced with a difficult choice: if a brilliant and appealing look with a high-grade impression is desired, only a full CNC machining process can be selected, with the result that high machining costs have to be paid. If high production rates and low costs are chosen, die casting is chosen, as a result of which a relatively inexpensive and rigid appearance must be accepted.
The Al-Mn alloy has good anodic oxidation performance and good heat transfer performance. There are some commercial Al — Mn alloys, such as DM3 alloy, containing about 1.2% Mn and Co, which result in higher cost of the alloy and poor fluidity in the industry. The Chinese invention patent with the application number of 201910447015.5 discloses an anodized Al-Mn series cast aluminum alloy, which contains 2.0% of Mn, 0.7-1.2% of Co, 0.2-0.4% of Sc, 0.1-0.3% of Ti and the balance of Al, and shows that the tensile strength of the alloy is greatly improved according to the disclosed content, and the film obtained after anodization is thick, smooth in surface, uniform in color, attractive, and better in corrosion resistance, and is suitable for manufacturing the protective shell of a 3C electronic product. However, the alloy also contains Co and Sc, so that the cost of the alloy is greatly increased. On the other hand, simple Al — Mn alloys are non-heat treatment strengthened alloys, and do not form any strengthening phase during heat treatment. This determines that simple Al-Mn alloys cannot be high strength alloys. The Chinese patent with application number 2020106514606 discloses an anodized Al-Fe-Mn-Si-Mg die casting alloy which can be used for anodization and has strong age hardening effect, but the strength of the alloy does not reach the level of 6061 alloy, and the requirement of high-end products on strength cannot be completely met.
The fluidity of the alloy is one of the important indexes for evaluating the die casting performance of the aluminum alloy. If the fluidity of the alloy is insufficient, the defect of insufficient mold filling may be generated in the die-casting process, and particularly, appearance parts of 3C electronic products are all thin-walled parts, so that the problem of insufficient mold filling is easily generated in the die-casting process, and the requirement on the fluidity of the alloy is higher. On the other hand, another problem that easily occurs in the die casting process is die sticking. Namely, the casting is adhered to the surface of the mold after solidification, so that the mold is not easy to demould and is easy to damage. In order to prevent die sticking, the alloy is generally required to contain high Fe or Mn. Although 6000 series and 7000 series wrought aluminum alloys have good anodic oxidation performance and high mechanical property, the flowability of the alloys is poor, and the contents of Fe and Mn are strictly limited, so that the alloys are easy to stick to a die during die casting, and cannot be produced by the die casting process.
In conclusion, the die-casting aluminum alloy with excellent anodic oxidation performance and excellent mechanical property is developed, 3C product appearance parts which are comparable to CNC machining process production are produced by the die-casting process, and the die-casting aluminum alloy has important economic value and social value.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an Al-Mn series die-casting alloy and a preparation method and application thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention relates to an Al-Mn series die casting alloy, which comprises the following components in percentage by mass: 1.2 to 2.1 percent of Mn, 0.9 to 1.6 percent of Si, 0.4 to 1.5 percent of Mg, 0.25 to 1.2 percent of Cu which is not equal to 0.25 percent, less than or equal to 0.5 percent of Zn, less than or equal to 0.5 percent of Ti, less than or equal to 0.5 percent of Cr, less than or equal to 0.5 percent of Zr, less than or equal to 0.3 percent of Fe, 0 to 0.5 percent of rare earth elements, 0 to 0.5 percent of Sr, and the balance of Al and inevitable impurities, wherein the total content of the inevitable impurities is less than or equal to 1.0 percent.
After the time effect treatment of the Al-Mn series die-casting alloy, the tensile strength in the T6 state is 251-364MPa, the yield strength is 207-316MPa, the elongation is 7.9-15.9%, the thermal conductivity is 122-166W/m.K, and the anodic oxidation effect is evaluated by 5 minutes to reach 5 minutes.
The invention relates to a preparation method of an Al-Mn series die-casting alloy, which comprises the following steps:
step 1: preparation of
Preparing a Mn raw material, a Si raw material, a Mg raw material, a Cu raw material, a Zn raw material, a Ti raw material, a Cr raw material, a Zr raw material, a Fe raw material, a rare earth element raw material and an Al raw material according to the component ratio of the Al-Mn series die casting alloy; preparing a Sr alterant raw material Al-10 Sr;
step 2: melting
Heating and melting an Al raw material into an aluminum melt, adding a Mn raw material, a Si raw material, a Cu raw material, a Zn raw material, a Ti raw material, a Cr raw material, a Zr raw material, a Fe raw material and a rare earth element raw material into the aluminum melt according to the requirement of alloy components, adding a Mg raw material after all the raw materials are melted, and uniformly stirring to obtain an alloy melt; wherein, in the whole smelting process, the temperature is controlled to be 700-760 ℃;
and step 3: refining and modification
Adding a refining agent into the alloy melt for refining, then slagging off, and adding a Sr alterant raw material Al-10Sr for modification to obtain an aluminum alloy melt after modification;
and 4, step 4: post-treatment
Degassing the refined and modified aluminum alloy melt, standing for 15-60min at the temperature of 700-760 ℃ to precipitate or float impurities in the aluminum alloy melt, removing the impurities, and die-casting to obtain the Al-Mn series die-casting alloy.
According to the actual use requirement, one of the heat treatment without heat treatment, the annealing heat treatment and the solid solution-aging heat treatment can be selected.
Wherein the annealing heat treatment process comprises the following steps: the prepared Al-Mn series die casting alloy is kept at the temperature of 400-560 ℃ for 0.5-10h, then is slowly cooled (the cooling speed is less than or equal to 100 ℃/h) to the temperature below 300 ℃, and is cooled in air.
Wherein the solid solution-aging heat treatment process comprises the following steps:
carrying out solid solution-aging heat treatment on the prepared Al-Mn series die-casting alloy, wherein the solid solution temperature is 490-560 ℃, and the solid solution time is 2-24 h; the aging temperature is 120-200 ℃, and the aging time is 1-15 h.
In the step 1, the raw material of Mn is selected from an aluminum-manganese intermediate alloy and/or a manganese additive; the raw material of Si is selected from metal silicon and/or aluminum-silicon intermediate alloy; mg ingot is selected as the raw material of Mg; the Cu raw material selects an aluminum-copper intermediate alloy or metallic copper, the Zn raw material selects a zinc ingot, the Ti raw material selects an aluminum-titanium intermediate alloy and/or a titanium additive, the Zr raw material selects an aluminum-zirconium intermediate alloy and/or a zirconium additive, the Cr raw material selects an aluminum-chromium intermediate alloy and/or a chromium additive, and the Fe raw material selects an aluminum-iron intermediate alloy and/or an iron additive; the raw material of the rare earth element is aluminum-rare earth intermediate alloy, and the raw material of the Al element is pure aluminum ingot.
In the step 1, the rare earth element may be one or more of cerium (Ce), lanthanum (La), scandium (Sc), yttrium (Y), gadolinium (Gd), neodymium (Nd), erbium (Er), and samarium (Sm). The aluminum-rare earth intermediate alloy can be an intermediate alloy of a single rare earth element and aluminum, or an intermediate alloy of a mixed rare earth element and aluminum.
In the above step 2, Al-10Sr, which is a raw material of Sr modifier, may be added in step 2 together with raw materials of other components except for the raw material of Al.
In the step 3, the refining agent with refining effect on the aluminum alloy is selected, such as RJ-1 refining agent, and the adding mass of the refining agent is 0.2-0.8% of the total mass of the alloy melt.
In the step 3, according to the requirement on the performance of the alloy, Sr can be optionally not added for modification. Therefore, the residual mass percentage of Sr in the alloy is 0-0.5%.
In the step 4, degassing is performed by introducing argon or nitrogen into the aluminum alloy melt after modification by using a degassing machine, wherein the flow of the argon or the nitrogen is 0.2-0.3m3/h。
An Al-Mn series die casting alloy is applied to an aluminum alloy die casting which needs to obtain a brilliant and attractive appearance through anodic oxidation and needs high strength, and can also be used as a high-strength and high-heat-conductivity aluminum alloy die casting.
The aluminum alloy die casting which needs to obtain a brilliant and attractive appearance through anodic oxidation and needs high strength is preferably one of a panel of a notebook computer, a panel of a keyboard and a shell of a mobile phone.
The Al-Mn series die-casting alloy, the preparation method and the application thereof have the beneficial effects that:
the research shows that the element Sr is Al6Fe、Al6Mn、Al6(FeMn) and All5(MnFe)3Si2And the effective alterant of the intermetallic compound phase can greatly refine the intermetallic compound phase. The components of the alloy are near the eutectic components, so that the alloy has good fluidity and is suitable for die-casting production. The alloy is added with high content of alloying elements of Si, Mg and Cu. When the alloy is solidified, partial Si, Mg and Cu are dissolved into the matrix in a solid mode, and the solid solution strengthening effect of the alloy is improved; si combines with Fe and Mn to form All5(MnFe)3Si2An intermetallic compound phase. The remaining Si combines with the remaining Mg to form Mg2Si phase, Cu forms Al with Al and Mn12CuMn2Phase and form Al with Mg2CuMg phases, which are formed during solidification and which are completely melted back into the aluminum matrix during solution treatment and subsequently strengthened during ageing to form the Mg phase2Si、Al2Cu and Al2The CuMg is precipitated. The strengthening phases have very strong aging strengthening effect, and the mechanical property of the alloy is greatly improved after solid solution and aging. On the other hand, the size of these phases is of the order of nanometers, and does not destroy the anodic oxidation properties of the alloy. Sr to All5(MnFe)3Si2The phase of intermetallic compounds is changed and refined, and the damage of the relative mechanical property of the intermetallic compounds is greatly reduced, so that the alloy of the invention realizes the great improvement of the mechanical property on the premise of keeping good fluidity and anode oxidizing property.
The Al-Mg-Si alloy improves the alloy strength by strengthening the phase Mg2 Si. When the ratio of Mg to Si content Mg/Si is 1.73, Mg and Si form Mg2Si completely. However, the alloy of the present invention contains high Mn, and Mg and Si cannot completely form Mg2Si at an Mg/Si ratio of 1.73, and a large excess of Mg is present. Studies have shown that a large amount of Si combines with Fe, Mn and Al to form All5(MnFe)3Si2Si is consumed and thus not enough Si forms Mg2Si with Mg, resulting in Mg excess, which is not in accordance with the present theory.
It is generally believed that the element Cu has a strengthening effect in the aluminum alloy. In the Al-Cu alloy, the Cu content is more than 3.5 percent, so that stronger aging strengthening effect can be obtained. According to the invention, a small amount of Cu is added, and the Cu is combined with Al and Mg to form an Al2CuMg strengthening phase, so that the negative influence caused by excess Mg is solved, the alloy is further strengthened, and the strength is improved. The alloy composition of the invention avoids the damage of harmful relative mechanical properties and promotes the precipitation of strengthening phases.
Drawings
FIG. 1 is a metallographic structure diagram of a die casting alloy prepared in example 5;
fig. 2 is a metallographic structure diagram of a die casting alloy prepared in example 14.
Fig. 3 is a metallographic structure diagram of the die-cast alloy prepared in comparative example 1.
Detailed Description
The present invention will be described in further detail with reference to examples.
In the description of the present invention, it is to be noted that those who do not specify specific conditions in the examples are performed according to conventional conditions or conditions recommended by manufacturers; the reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below; the embodiment of the invention provides an Al-Mn series die casting alloy, and the Al-Mn series die casting alloy and the preparation method thereof are explained in detail through the following specific embodiment; each example was a 100kg Al-Mn series die casting alloy.
The aluminum ingot selected in the embodiment of the invention can be Al99.70 in the aluminum ingot for remelting of 2017, which is the national standard GB/T1196, and can also be a scrap remelting aluminum ingot; when Mn element is added, Al-10Mn intermediate alloy or 75Mn agent (aluminum-manganese alloy additive with Mn mass content of 75%) is selected; when adding Si element, selecting Al-30Si intermediate alloy; when Mg element is added, metal magnesium is selected; when Zn element is added, metal zinc is selected; when adding Cu element, selecting Al-50Cu intermediate alloy or metallic copper; when adding Ti, selecting Al-10Ti intermediate alloy or 75Ti agent (Al-Ti alloy additive with Ti mass content of 75%); when Zr is added, Al-10Zr intermediate alloy and/or 75Zr agent (Al-Zr alloy additive with Zr mass content of 75%) is selected, when Cr is added, Al-10Cr intermediate alloy and/or 75Cr agent (Al-Cr alloy additive with Cr mass content of 75%) is selected, when Fe element is added, Al-10Fe intermediate alloy or 75Fe agent (Al-Fe alloy additive with Fe mass content of 75%) is selected, when rare earth element is added, Al-10Re intermediate alloy is selected, and the rare earth element Re can be one or a mixture of more of cerium (Ce), lanthanum (La), scandium (Sc), yttrium (Y), gadolinium (Gd), neodymium (Nd), erbium (Er), samarium (Sm) and the like. The Al-10Re intermediate alloy can be an intermediate alloy of a single rare earth element and aluminum, or an intermediate alloy of a mixed rare earth element and aluminum. .
In the embodiment of the invention, the degassing is carried out by introducing argon into the added aluminum water by using a degassing machine, wherein the flow of the argon is 0.2-0.3m3/h。
In the embodiment of the invention, the residual mass percent of Sr in the aluminum alloy melt after modification is 0-0.5% due to the addition of the modifier.
In the embodiment of the invention, the three-helix fluidity tester is adopted to measure the fluidity of the Al-Mn series die-casting alloy, the Al-Mn series die-casting alloy melt is poured into the metal die of the three-helix fluidity tester, and the total flowing length of the molten aluminum in the three helices in the metal die is measured. The temperature has an important influence on the fluidity, and in order to compare the fluidity of the examples, the melt casting temperature was uniformly set to 725 ℃.
Example 1
Al-Mn based die casting alloy whose components and mass percentages of the components are shown in Table 1.
A preparation method of Al-Mn series die casting alloy comprises the following steps:
preparing an aluminum ingot and alloy raw materials, heating and melting the aluminum ingot to form an aluminum melt, then adding 75Mn agent, Al-30Si, Al-50Cu and 75Fe agent into the aluminum melt, adding Mg raw materials after all the raw materials are melted, and stirring uniformly after all the raw materials are melted to form an alloy melt; wherein, in the whole smelting process, the temperature is controlled to be 725 ℃;
adding an RJ-1 refining agent into the alloy melt for refining treatment; the adding amount of the refining agent is 0.4 percent of the total weight of the alloy melt; then adding an Al-10Sr alterant into the alloy melt for modification treatment to obtain the modified aluminum alloy melt; the addition amount of the Al-10Sr alterant is 0.10 percent of the residual mass percent of Sr in the aluminum alloy melt after the alteration;
removing gas from the aluminum alloy melt after modification, slagging off, standing for 30min, pouring a small amount of melt into a triple-spiral fluidity testing die, then die-casting the rest melt into a die-casting piece with the wall thickness of 5mm, and then carrying out T6 treatment (solid solution and aging, the specific process is shown in Table 1) on the die-casting piece to obtain the Al-Mn series die-casting alloy;
the prepared Al-Mn series die-casting alloy product is subjected to tensile property test and thermal conductivity test, and the tensile property and the thermal conductivity are shown in Table 1 in a T6 state; the results of the flowability tests (total length of the melt flowing in the triple helix) are also given in Table 1.
Examples 2 to 11 were the same as example 1 in the solid solution-aging state (T6 state) preparation method of the Al — Mn die casting alloy, except that the Al — Mn die casting alloy used was different in composition and ratio, that Cr, Ti, Zr, rare earth elements, and the like were added in some examples, that the heat treatment process was different, and that the composition and performance statistics are shown in table 1.
Comparing example 5 with example 6 and example 7 with example 8, example 6 is the example 5 with 0.2% of the rare earth element Ce added thereto, and example 8 is the example 7 with 0.2% of the rare earth element La added thereto. The result shows that the mechanical property of the alloy is further improved by adding the rare earth element. Except for Ce and La. Other rare earth elements including, but not limited to, scandium (Sc), yttrium (Y), gadolinium (Gd), neodymium (Nd), erbium (Er), samarium (Sm) and the like can achieve good strengthening effects.
Examples 5, 12 and 13 have the same alloy composition and the same casting method, except for the heat treatment state. Example 5 is the T6 state, example 12 is the O state (annealed state, specifically by solutionizing at 530 ℃ for 6h, then cooling to 260 ℃ at a cooling rate of 30 ℃/h, then air cooling), and example 13 is the F state (prepared state, without any heat treatment). The state is different, the microstructure of the alloy is different, and the mechanical property and the thermal conductivity are completely different. In the T6 state (peak aging state), the alloy has the highest mechanical property but lower thermal conductivity; in the O state, the mechanical property of the alloy is lower, but the thermal conductivity is highest; in the F state, the alloy is not subjected to heat treatment, and the mechanical property and the thermal conductivity of the alloy are lower. The alloy system of the invention is heat treatment strengthened. The heat treatment process has an important influence on the mechanical properties and physical properties of the alloy. The heat treatment process is different, so that the alloy performance difference is huge, and in actual use, a proper state needs to be selected according to the actual application requirement.
Example 14
The alloy composition and preparation method were the same as example 5 except that example 14 contained no Sr. Compared with example 5, the mechanical properties were reduced and the anodic oxidation effect was slightly inferior. The reason for this is that in example 14, the Mn-rich Fe-rich intermetallic compound phase was not refined by Sr, and whether or not the modification treatment was carried out was selected in accordance with actual requirements.
FIG. 1 is a microstructure of example 5, and 1(a) is an as-cast structure; and 1(b) is a structure after solution treatment. The as-cast structure includes a Mn-rich phase (Al)l5(MnFe)3Si2) AlCuMn phase (Al)12CuMn2) Should also contain Mg2Si phase and Al2The CuMg phase is also dark under the microscope and is not well resolved. After solution treatment, Al12CuMn2、Mg2Si phase and Al2The CuMg phases have melted back into the matrix, leaving only All5(MnFe)3Si2There is no meltback. FIG. 2 shows the as-cast structure of example 14, and shows coarse intermetallic compound phases in the solidification structure of example 14. The intermetallic compound phase is significantly coarse compared to fig. 1. These phases are high temperature phases and are difficult to melt back into the matrix during solution treatment, which damages the mechanical properties and anodic oxidation effect of the alloy.
Comparative example 1
The alloy composition and preparation method were the same as example 5 except that the Cu content in comparative example 1 was only 0.25%. The mechanical properties and thermal conductivity are also shown in table 1. The mechanical properties are greatly reduced compared to example 5. Example 5 shows that the addition of higher Cu in the alloy greatly improves the mechanical properties of the alloy without damaging the oxidizing property of the anode, and the fluidity of the melt is not significantly reduced. The alloy has the advantages of die-casting performance, high anodic oxidation performance and mechanical property, and high Mn content in the alloy, so that the demolding performance of the alloy is ensured, and the anodic-oxidizable high-strength die-casting aluminum alloy is formed. But the addition of Cu lowers the thermal conductivity of the alloy.
Cu has a strong tendency to segregate and tends to form eutectic phases in the final solidification region. The alloy of the invention contains high Mn, Si and Mg, and also contains a certain amount of Fe. During solidification, these elements may all form different intermetallic phases with Cu. Such as Al-Mn-Cu to form Al12CuMn2Phase, Al-Fe-Cu forms Al7Cu2Fe phase, Al-Cu-Mg to form Al2CuMg phase, Al-Mg-Cu-Si forming Al4CuMg5Si4And (4) phase(s). These are the common intermetallic phases in aluminum alloys and have different effects on the mechanical properties of aluminum alloys. Such as Al7Cu2The Fe phase can not be melted back into the matrix through solution treatment, and has stronger destructive effect on mechanical properties; al (Al)12CuMn2Phase, Al2The CuMg phase is melted back into the matrix during the solution treatment, and is precipitated in a nanometer size during the aging treatment, thereby playing a role in strengthening. Al-Mn-Mg-Si-Cu is a very complex five-element alloy, no phase diagram can be referred to at present, and the phase diagram can only be explored through a large number of experiments.
FIG. 3 is a microstructure of comparative example 1, and 3(a) is an as-cast structure; and 3(b) is a structure after the solution treatment. As-cast structure having only Mn-rich phase (Al)l5(MnFe)3Si2) And Mg2A Si phase. No intermetallic compound phase containing Cu was found, indicating that Cu was dissolved in the matrix and no eutectic phase containing Cu was formed. After solution treatment, Mg2The Si phase has been melted back into the matrix, leaving only All5(MnFe)3Si2There is no meltback. By experimentIt was found that when the Cu content is 0.25% or less, Cu is present in Al as a solid solution, and only a solid solution strengthening effect is exhibited, and the strengthening effect is very limited, so that the mechanical properties are low. When the Cu content exceeds 0.25%, the aging strengthening effect of Cu is obviously enhanced, and a strengthening phase containing Cu is precipitated in the alloy.
On the other hand, it is considered that the addition of Cu is disadvantageous to the anodizing treatment, and the surface of the anodized part is discolored to affect the appearance. The invention leads the Cu element to form Al during solidification through reasonable component design12CuMn2The phase is melted back during solid solution and is precipitated in a nanometer size during aging treatment, so that the strengthening effect is achieved, and the negative influence on the anodic oxidation treatment is eliminated.
Comparative example 2
This comparative example is the alloy composition of ADC 12. The alloy is a die-cast aluminum alloy having excellent fluidity, which is recognized in the industry. The purpose of this comparison is to evaluate the fluidity of the alloy of the invention without subsequent treatment and performance testing of the alloy. It can be seen that the fluidity of example 5 of the present invention is 92% of that of the ADC12 alloy, so that the alloy of the present invention has good die casting properties. The fluidity of the molten alloy is closely related to the alloy composition. Generally, eutectic alloys have the best fluidity. Both hypoeutectic and hypereutectic alloys have reduced fluidity, and the farther the alloy composition is from the eutectic point, the poorer the fluidity. For the present invention, the alloy system is relatively complex and requires extensive research to determine its fluidity.
TABLE 1 composition ratio and Property parameter Table of Al-Mn series die-casting alloy prepared in the example of the present invention
In the above table, UST is tensile strength, YS is yield strength, El is elongation, and the anodizing effect is evaluated at 5 points, and the higher the point is, the better the anodizing effect is.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. An Al-Mn series die casting alloy is characterized in that the Al-Mn series die casting alloy comprises the following components by mass percent: 1.2 to 2.1 percent of Mn, 0.9 to 1.6 percent of Si, 0.4 to 1.5 percent of Mg, 0.25 to 1.2 percent of Cu which is not equal to 0.25 percent, less than or equal to 0.5 percent of Zn, less than or equal to 0.5 percent of Ti, less than or equal to 0.5 percent of Cr, less than or equal to 0.5 percent of Zr, less than or equal to 0.3 percent of Fe, 0 to 0.5 percent of rare earth elements, 0 to 0.5 percent of Sr, and the balance of Al and inevitable impurities, wherein the total content of the inevitable impurities is less than or equal to 1.0 percent.
2. The Al-Mn series die-casting alloy as recited in claim 1, wherein the Al-Mn series die-casting alloy has a tensile strength of 251-364MPa, a yield strength of 207-316MPa, an elongation of 7.9-15.9%, a thermal conductivity of 122-166W/m.K in T6 state after the time-effect treatment, and an anodic oxidation effect of 5 minutes.
3. The method for producing an Al-Mn-based die casting alloy according to claim 1 or 2, comprising the steps of:
step 1: preparation of
Preparing a Mn raw material, a Si raw material, a Mg raw material, a Cu raw material, a Zn raw material, a Ti raw material, a Cr raw material, a Zr raw material, a Fe raw material, a rare earth element raw material and an Al raw material according to the component ratio of the Al-Mn series die casting alloy; preparing a Sr alterant raw material Al-10 Sr;
step 2: melting
Heating and melting an Al raw material into an aluminum melt, adding a Mn raw material, a Si raw material, a Cu raw material, a Zn raw material, a Ti raw material, a Cr raw material, a Zr raw material, a Fe raw material and a rare earth element raw material into the aluminum melt according to the requirement of alloy components, adding a Mg raw material after all the raw materials are melted, and uniformly stirring to obtain an alloy melt; wherein, in the whole smelting process, the temperature is controlled to be 700-760 ℃;
and step 3: refining and modification
Adding a refining agent into the alloy melt for refining, then slagging off, and adding a Sr alterant raw material Al-10Sr for modification to obtain an aluminum alloy melt after modification;
and 4, step 4: post-treatment
Degassing the refined and modified aluminum alloy melt, standing for 15-60min at the temperature of 700-760 ℃ to precipitate or float impurities in the aluminum alloy melt, removing the impurities, and die-casting to obtain the Al-Mn series die-casting alloy.
4. The method for producing an Al-Mn based die-cast alloy according to claim 3, wherein one of the heat treatment without heat treatment, the annealing heat treatment and the solution-aging heat treatment is further selected according to the actual use requirement;
the annealing heat treatment process comprises the following steps: the prepared Al-Mn series die-casting alloy is kept at the temperature of 400-560 ℃ for 0.5-10h, then is slowly cooled to the temperature below 300 ℃ at the cooling speed of less than or equal to 100 ℃/h, and is cooled in air;
the solid solution-aging heat treatment process comprises the following steps: carrying out solid solution-aging heat treatment on the prepared Al-Mn series die-casting alloy; the solid solution temperature is 490-560 ℃, and the solid solution time is 2-24 h; the aging temperature is 120-200 ℃, and the aging time is 1-15 h.
5. The method for preparing Al-Mn series die-casting alloy according to claim 3, wherein in the step 1, Mn is selected from an aluminum-manganese intermediate alloy and/or a manganese additive; the raw material of Si is selected from metal silicon and/or aluminum-silicon intermediate alloy; mg ingot is selected as the raw material of Mg; the Cu raw material selects an aluminum-copper intermediate alloy or metallic copper, the Zn raw material selects a zinc ingot, the Ti raw material selects an aluminum-titanium intermediate alloy and/or a titanium additive, the Zr raw material selects an aluminum-zirconium intermediate alloy and/or a zirconium additive, the Cr raw material selects an aluminum-chromium intermediate alloy and/or a chromium additive, and the Fe raw material selects an aluminum-iron intermediate alloy and/or an iron additive; the raw material of the rare earth element is aluminum-rare earth intermediate alloy, and the raw material of the Al element is pure aluminum ingot.
6. The method of producing an Al-Mn based die casting alloy according to claim 3, wherein in step 2, Al-10Sr, which is a modifier of Sr, is added or not added in step 2 together with raw materials of other components than the raw material of Al.
7. The method for producing an Al-Mn based die casting alloy according to claim 3, wherein in the step 3, the refining agent having a refining effect on the aluminum alloy is selected as the refining agent, and the addition amount of the refining agent is 0.2 to 0.8% by mass based on the total mass of the alloy melt.
8. The Al-Mn series die-casting alloy according to claim 3, wherein in the degassing in the step 4, argon or nitrogen is introduced into the aluminum alloy melt after the modification by using a degasser, and the flow rate of the argon or nitrogen is 0.2 to 0.3m3/h。
9. Use of the Al-Mn based die casting alloy according to claim 1 or 2, wherein the Al-Mn based die casting alloy is used as an aluminum alloy die casting requiring a brilliant appearance obtained by anodic oxidation and requiring high strength, or as a high-strength and high-heat-conductivity aluminum alloy die casting.
10. Use of the Al-Mn based die-casting alloy according to claim 9, wherein the aluminum alloy die-casting requiring achievement of brilliant and appealing appearance by anodic oxidation and high strength is one of a notebook computer panel, a keyboard panel, and a mobile phone case.
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| CN116676515A (en) * | 2023-06-02 | 2023-09-01 | 佛山市营鑫新材料有限公司 | Al-Mn-Zn-Ce die-casting anode alloy and preparation method and application thereof |
| CN117127064A (en) * | 2023-10-23 | 2023-11-28 | 中铝材料应用研究院有限公司 | Aluminum alloy material and preparation method thereof |
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