CN110079714B - Non-heat-treatment-strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy and preparation method thereof - Google Patents

Non-heat-treatment-strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy and preparation method thereof Download PDF

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CN110079714B
CN110079714B CN201910458305.XA CN201910458305A CN110079714B CN 110079714 B CN110079714 B CN 110079714B CN 201910458305 A CN201910458305 A CN 201910458305A CN 110079714 B CN110079714 B CN 110079714B
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magnesium
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CN110079714A (en
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彭立明
袁灵洋
郑飞燕
陆珂伟
周定贤
陈海平
杨小亮
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Shanghai Jiaotong University
Shanghai E Propulsion Auto Technology Co Ltd
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Shanghai E Propulsion Auto Technology Co Ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making alloys
    • C22C1/02Making alloys by melting
    • C22C1/026Alloys based on aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making alloys
    • C22C1/02Making alloys by melting
    • C22C1/03Making alloys by melting using master alloys
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making alloys
    • C22C1/06Making alloys with the use of special agents for refining or deoxidising
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/06Alloys based on aluminium with magnesium as the next major constituent

Abstract

The invention discloses a non-heat treatment reinforced high-strength high-toughness die-casting aluminum-magnesium-copper alloy and a preparation method thereof, wherein the alloy comprises the following components in percentage by weight: 4.5 to 7.5 percent of Mg; 0.6 to 0.9 percent of Mn, 0.5 to 1.5 percent of Cu, 0.1 to 0.2 percent of Ti, 0.004 to 0.006 percent of Be and 0.01 to 0.2 percent of RE; the sum of the total amount of other impurities is less than or equal to 0.4 percent, and the balance is Al. During preparation, strengthening element Cu is introduced, and Cu is mainly taken as second phase Al2The presence of CuMg (S phase) in the tissue; the RE element is added to refine the Al2CuMg phase, so that high strength is obtained and sufficient elongation is obtained at the same time. The alloy can be obtained in a die-casting state: the yield strength is 180-200MPa, the tensile strength is 310-330MPa, and the elongation is 6-10 percent; the die-casting alloy has the characteristics of high strength and high toughness in a die-casting state, and can realize good die-casting performance.

Description

Non-heat-treatment-strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy and preparation method thereof
Technical Field
The invention relates to the technical field of metal materials, in particular to a non-heat-treatment reinforced high-strength high-toughness die-casting aluminum-magnesium-copper alloy and a preparation method thereof.
Background
In recent years, with the rapid development of industries such as automobiles, aerospace and the like, the requirements on the performance of materials for automobiles and aerospace are more severe. In addition, due to social pressure of energy conservation, emission reduction, environmental pollution and the like, light weight is required as a development strategy. Therefore, in the automobile and aerospace industries, higher strength is required for part design, and high elongation and excellent impact toughness are required for deformation in order to achieve the weight reduction. Most die-cast aluminum alloys have moderate strength and poor toughness (elongation < 5%), such as conventional die-cast aluminum alloys like ADC12, a380, etc. In recent years, in order to meet the market demand, the development of high-strength and high-toughness die-cast aluminum alloys, such as Silafot-36 alloy (patent publication No. US6364970B1) developed by the Germany Rhein company, has been receiving more attention, and the alloy has good mechanical properties. However, the alloy needs special high vacuum die casting, and then T6 heat treatment (solution treatment and artificial aging) strengthening is carried out to meet the requirement of improving the comprehensive mechanical property of the casting. The whole process flow is lengthened due to the high vacuum and heat treatment process, the cost consumption is high, the casting is easy to deform due to the solid solution treatment, the subsequent shape correction treatment is needed, and the yield is low. In addition, the die-casting Al-Mg alloy has attracted much attention because of its excellent mechanical properties, and a non-heat-treated reinforced high-toughness die-casting Al-Mg-Mn alloy (patent publication No. CN104805322A) has been developed by Shanghai communications university, which has as-cast mechanical properties: the yield strength is 150-160MPa, the tensile strength is 260-280MPa, and the elongation is 10-15%. The German Rhine company developed a Magsimal-59 alloy (patent publication No. EP0853133B1) whose standard tensile bar properties were about 160MPa in yield strength, 12-15% in elongation, and about 300MPa in tensile strength. The two die-casting Al-Mg alloy patents have excellent elongation, but are limited to single Al-Mg alloy strengthening mode and lower yield strength. However, with the increasing trend of the strategy of weight reduction, the performance requirements, especially the strength requirements, of the die-cast aluminum alloy for the vehicle body structural member are higher and higher. For example, automobile companies have proposed that the properties of die-cast aluminum alloys for shock towers of structural members of automobile bodies need to satisfy yield strength >180MPa, tensile strength >320MPa, and elongation > 8%, and that castings have the mechanical properties in the die-cast state. However, in the existing die-casting aluminum alloy, a suitable material is difficult to find. For die cast Al-Si systems, the lack of elongation and the need for heat treatment enhancements limit their use in automotive body structural members. However, for die-cast Al-Mg alloy, the Al-Mg alloy has good strength and excellent elongation in an as-cast state, and the Al-Mg alloy is more likely to obtain the die-cast aluminum alloy with high strength and high toughness by certain means without heat treatment. Therefore, developing a non-heat-treated high-strength high-toughness die-casting Al-Mg alloy, and researching the preparation and die-casting process thereof so as to meet the increasingly-improved actual use requirements of high-quality high-performance aluminum alloy die castings in the automobile industry, and the Al-Mg alloy becomes one of the targets pursued in the die-casting field.
Disclosure of Invention
The invention aims to provide a non-heat-treatment strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy and a preparation method thereof under the background of the prior art. On the premise of ensuring that the alloy has good casting performance, the non-heat-treated casting has excellent comprehensive mechanical properties, thereby meeting the performance requirements of vehicle body structural parts, in particular large thin-wall vehicle body structural parts.
In order to achieve the purpose, the invention discovers that the introduction of a strengthening element Cu can have obvious influence on the structure and the performance of the die-casting aluminum-magnesium alloy in long-term die-casting aluminum alloy research. It is noted that in general, al-mg-cu alloys are mainly used for wrought alloy applications. This is because a coarse Al2CuMg second phase is generated during the casting process of the aluminum-magnesium-copper alloy, and therefore, the performance of the alloy needs to be regulated and controlled by a T6 heat treatment process at a later stage. In die-cast Al — Mg alloys, however, Cu is generally present as an impurity element, which is closely related to the die-casting process. Because the gas entrapment phenomenon is serious due to high-speed filling of the melt under the conventional die-casting condition, T6 heat treatment cannot be carried out (the bubbling is prevented from influencing the performance), and the alloy performance cannot be regulated. Therefore, the Cu element has little application in die-casting Al-Mg alloys. The invention mainly aims to illustrate the influence of the Cu element on the structure and the performance of the Al-Mg alloy under the die casting condition. In order to solve the problem that the added Cu element can generate a coarse Al2CuMg phase, the invention creatively introduces the RE element to refine the Al2CuMg phase, thereby obtaining a fine Al2CuMg phase. A great deal of previous experiments prove that Y, Er in rare earth elements and Ce can be used as active elements to enrich and hinder the second phase interface of Al2CuMg in die-cast aluminum-magnesium-copper alloyThe growth of the phases and thus the size and shape of the phases changes. The composite addition of Cu/RE enables the formation of fine Al in the as-cast structure2A CuMg phase. Along with this, a small amount of Cu element is dissolved in the matrix to produce fine Al2The second phase of the CuMg phase strengthens the solid solution strengthening generated by Cu element solid dissolved in the matrix, thereby improving the strength of the alloy. On the premise of ensuring excellent casting performance, the mechanical property of the die-casting aluminum-magnesium-copper alloy can be greatly improved, and the comprehensive mechanical properties of high strength and high toughness with both strength and shaping are obtained.
Accordingly, the purpose of the invention is realized by the following technical scheme:
the invention relates to a non-heat treatment reinforced high-strength high-toughness die-casting aluminum-magnesium-copper alloy, which comprises the following components in percentage by weight: 4.5-7.5 wt.% Mg, 0.6-0.9 wt.% Mn, 0.5-1.5 wt.% Cu, 0.1-0.2 wt.% Ti, 0.004-0.006 wt.% Be, 0.01-0.2 wt.% RE; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The RE element is selected from Y, Ce or Er element.
The invention also relates to a preparation method of the non-heat treatment strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy, which comprises the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Cu intermediate alloy, Al-RE intermediate alloy and Al-Be intermediate alloy to 240 ℃ for drying treatment;
2) smelting: firstly melting pure aluminum, then heating to 780 ℃ of 760-;
3) refining: heating the melt with qualified alloy components to 700-720 ℃, introducing argon with refining agent powder into the melt for powder spraying and refining, deslagging and degassing;
4) and when the melt reaches the casting temperature, carrying out alloy ingot casting operation or die-casting molding process operation.
In step 2), the covering agent sprinkled on the surface of the melt is MgCl2+ KCl mixed solvent, and MgCl2The weight ratio of the KCl to the KCl is 1: 0.5-2.
The refining agent adopted in the step 3) is aluminum oxide or zinc oxide, and the adding amount of the refining agent is 0.8-1.5% of the weight of the furnace burden.
And 3) standing and performing stokehole component analysis after the refining is finished and the stirring is uniform, detecting the component content of the alloy melt, and supplementing or diluting the melt with the content deviation to enable the components to reach preset values.
The standing time is 20-30 min.
The casting temperature in step 4) is 680-710 ℃.
In the step 4), the range of the injection speed adopted by the die-casting forming process is 2-3 m/s.
In the step 4), the casting pressure (pressurization) range adopted by the operation of the die-casting forming procedure is 80-120 Mpa.
Compared with the prior art, the invention has the following beneficial effects:
the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy prepared by the invention has important industrial application value. The die-casting aluminum-magnesium-copper alloy obtains yield strength under the die-casting condition: 180-200MPa, tensile strength 310-330MPa and elongation of 6-10% (conventional die-casting YL302 alloy, as-cast tensile strength 220MPa and elongation 2%), can realize good die-casting performance, and greatly meets the application requirements of large thin-wall body structural members in the automobile industry.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic view of SEM tissue observation; wherein (a) represents a B1 casting; (b) represents a B2 casting; (c) represents a B3 casting; (d) represents a B4 casting; (e) represents a B5 casting; (f) represents a B6 casting; (g) represents a B7 casting; (h) representing a B8 casting.
Detailed Description
The non-heat-treated reinforced high-strength die-cast aluminum-magnesium-copper alloy and the preparation process thereof provided by the present invention are further described in the following with reference to examples in order to make the advantages and features of the present invention more easily understood by those skilled in the art, but not to limit the application scope of the present invention.
Example 1
The embodiment relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-silicon alloy which comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; be:0.005 wt.%; 0.8 wt.% Cu; 0.15 wt.% Er; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and the die casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy comprise the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy and Al-5Be intermediate alloy to 200 ℃, and drying;
2) smelting: melting pure aluminum, heating to 760 ℃, adding Al-50Cu intermediate alloy, cooling to 740 ℃ after the intermediate alloy is melted, adding Al-10Mn, Al-10Er and Al-10Ti intermediate alloy for melting, cooling to 690 ℃ after the melting is finished, and spraying a covering agent (containing no Na ions and having the density of a solvent) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The injection speed is 2m/s, and the casting pressure is 110 MPa. The die used in the production process is a die-casting test bar die, and the obtained casting is marked as B1.
Example 2
The embodiment relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-silicon alloy which comprises the following components in percentage by weight: mg: 7.5 wt.%; 0.9 wt.% Mn; 0.2 wt.% Ti; be: 0.006 wt.%; 0.5 wt.% Cu; 0.2 wt.% Er; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and the die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy comprise the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy and Al-5Be intermediate alloy to 200 ℃, and drying;
2) smelting: melting pure aluminum, heating to 760 ℃, adding Al-50Cu intermediate alloy, cooling to 740 ℃ after the intermediate alloy is melted, adding Al-10Mn, Al-10Er and Al-10Ti intermediate alloy for melting, cooling to 690 ℃ after the melting is finished, and spraying a covering agent (containing no Na ions and having the density of a solvent) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The injection speed is 2m/s, and the casting pressure is 110 MPa. The die used in the production process is a die-casting test bar die, and the obtained casting is marked as B2.
Example 3
The embodiment relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-silicon alloy which comprises the following components in percentage by weight: mg:4.5 wt.%; 0.6 wt.% Mn; 0.1 wt.% Ti; be:0.004 wt.%; 1.5 wt.% Cu; 0.15 wt.% Er; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and the die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy comprise the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy and Al-5Be intermediate alloy to 200 ℃, and drying;
2) smelting: melting pure aluminum, heating to 760 ℃, adding Al-50Cu intermediate alloy, cooling to 740 ℃ after the intermediate alloy is melted, adding Al-10Mn, Al-10RE and Al-10Ti intermediate alloy for melting, cooling to 690 ℃ after the melting is finished, and spraying a covering agent (containing no Na ions and having the density of a solvent) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The injection speed is 2m/s, and the casting pressure is 110 MPa. The die used in the production process is a die-casting test bar die, and the obtained casting is marked as B3.
Comparative example 1
The comparative example relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy which comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; be:0.005 wt.%; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy comprises the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-10RE intermediate alloy and Al-5Be intermediate alloy to 200 ℃ and drying;
2) smelting: melting pure aluminum, heating to 740 deg.C, adding Al-10Mn, Al-10RE, and Al-10Ti intermediate alloy, melting, cooling to 690 deg.C, and spreading covering agent (containing no Na ion and having solvent density) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The die casting process parameters and die casting were the same as in example 1, and a casting B4 was obtained.
Comparative example 2
The comparative example relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy which comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; be:0.005 wt.%; 0.8 wt.% Cu; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy in the comparative example 2 comprises the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-RE intermediate alloy and Al-5Be intermediate alloy to 200 ℃ and drying;
2) smelting: melting pure aluminum, heating to 760 ℃, adding Al-50Cu intermediate alloy, cooling to 740 ℃ after the intermediate alloy is melted, adding Al-10Mn, Al-RE and Al-10Ti intermediate alloy for melting, cooling to 690 ℃ after the melting is finished, and spraying a covering agent (containing no Na ions and having solvent density) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The die casting process parameters and die casting were the same as in example 1, and a casting B5 was obtained.
Comparative example 3
The non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy in the comparative example 3 comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; 0.005 wt.% Be; 0.15 wt.% Er; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy in the comparative example 3 comprises the following steps:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy and Al-5Be intermediate alloy to 200 ℃, and drying;
2) smelting: melting pure aluminum, heating to 760 ℃, adding Al-50Cu intermediate alloy, cooling to 740 ℃ after the intermediate alloy is melted, adding Al-10Mn, Al-10Er and Al-10Ti intermediate alloy for melting, cooling to 690 ℃ after the melting is finished, and spraying a covering agent (containing no Na ions and having the density of a solvent) on the surface of the melt<2.7g/cm3) For a certain protection, pure Mg, Al-5Be master alloy is then added and pressed into the bottom region of the crucible for melting. After the materials are melted and stirred uniformly, standing and performing stokehole component analysis, detecting the component content of the alloy melt, and supplementing or diluting the melt with deviation in content to enable the components to reach the qualified range.
3) Refining: heating the melt with qualified alloy components to 720 ℃, introducing nitrogen with the pressure of 0.2MPa into the melt, bringing refining agent (salt solvent without Na ions) powder with the weight of 0.8 percent of the total weight of the melt, and then continuously introducing the gas for 10min to remove slag and remove gas. Then standing for a period of time, and performing a stokehold composition analysis test again. After the components are qualified, high-pressure casting is carried out at the temperature of 690-700 ℃. The die casting process parameters and die casting were the same as in example 1, and a casting B6 was obtained.
Comparative example 4
The comparative example relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-silicon alloy which comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; be:0.005 wt.%; 0.8 wt.% Cu; 0.15 wt.% Nd; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and the die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy of the comparative example are basically the same as those of the example 1; casting B7 was obtained.
Comparative example 5
The comparative example relates to a non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-silicon alloy which comprises the following components in percentage by weight: mg: 6.5 wt.%; 0.7 wt.% Mn; 0.15 wt.% Ti; be:0.005 wt.%; 0.8 wt.% Cu; 0.15 wt.% La; the sum of the other impurities is less than or equal to 0.4 wt.%, and the balance is Al.
The preparation and the die-casting process of the non-heat treatment reinforced high-strength and high-toughness die-casting aluminum-magnesium-copper alloy of the comparative example are basically the same as those of the example 1; casting B8 was obtained.
The castings B1, B2, B3, B4, B5, B6, B7 and B8 prepared in the above examples 1, 2 and 3 and comparative examples 1 to 5, respectively, were subjected to microstructure observation, and the microstructures were as shown in FIG. 1. The structural comparison of B1, B2 and B3 shows that the addition of Cu causes Al in the alloy2A CuMg phase. Further, SEM-EDS energy spectrum analysis revealed that the addition of Cu dissolved Cu element in the matrix. Al in B1, B2 and B3 alloy2The quantitative analysis data of the content of the CuMg phase and the content of Cu dissolved in the matrix are shown in Table 1. According to the observation of the structure of B1-B3, the introduction of the Cu element ensures that an Al2CuMg phase appears in the alloy, and meanwhile, part of the Cu element is dissolved in the matrix. The comparison of B1 with B5 shows that Al in B1 tissue2The CuMg phase is more finely dispersed, and Al in the B5 alloy structure without the Er element2The CuMg phase is coarse and is in a net distribution. Comparing the alloy compositions of B1, B7 and B8, Al in the B7 and B8 alloys2The CuMg phase is also coarser than that of B1 alloy and is in a net distribution, which shows that Al in the unrefined structure is not refined by adding La and Nd rare earth elements2A CuMg phase. Generally speaking, Cu/RE (Er, Y, Ce) elements are introduced into the B1 alloy, so that Al in a matrix is caused to be contained2The CuMg phase is dispersed, and the texture characteristic ensures that the alloy has excellent mechanical property.
Table 1, Cu content in solid solution in B1, B2, B3 alloy matrix and Al in alloy structure2Content of CuMg
Tensile mechanical property tests were performed on the B1, B2, B3, B4, B5, B6, B7 and B8 castings, and the test results are shown in table 2. Comparing the mechanical properties of B1, B2 and B3 castings, the strength castings of the alloy are obviously improved along with the addition of Cu content, the elongation rate correspondingly shows a descending trend, but the casting still has higher elongation rate, so the casting can be called as non-heat-treated high-strength high-toughness die-casting aluminum alloy. The highest elongation was obtained for the B4 and B6 castings without Cu addition, but the casting strength was lower. In the B5 cast product, Cu element was added, but no Er was added, and the secondary phase structure was coarse, so the elongation was low. Further, by comparing the tensile properties of the castings B1, B4, B5 and B6, it can be seen that the castings B4/B6 without the addition of Cu element have lower strength, which is consistent with the fact described in the background of the invention, and the addition of Er element alone does not produce a large change in the alloy properties. In contrast, B1 showed a decrease in alloy elongation when Cu was added alone, but no Er was added, as compared to B5. Comparing the mechanical properties of B1 with those of B7 and B8 castings shows that the strength and the elongation of the B7 and B8 alloys added with Nd and La rare earth elements are lower than those of B1 alloys (added with Er rare earth). In conclusion, the die-casting Al-Mg alloy has the characteristics of high strength and high toughness in a non-heat treatment state by adding the Cu element and the RE element (Y, Er and Ce).
Table 2, B1, B2, B3B5, B6, B7 and B8 mechanical properties of the cast pieces in tension
Group of Yield strength/MPa Tensile strength/MPa Elongation/percent
B1 187 314 8.7
B2 182 309 10.8
B3 203 321 7.1
B4 156 285 13.3
B5 183 297 5.2
B6 158 290 13.8
B7 173 303 6.1
B8 171 299 5.9
The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present invention or directly or indirectly applied to other related technical fields are included in the scope of the present invention.

Claims (6)

1. The non-heat treatment strengthened high-strength high-toughness die-casting aluminum-magnesium-copper alloy is characterized in that the die-casting aluminum-magnesium-copper alloy comprises the following components in percentage by weight: 4.5 to 7.5 percent of Mg, 0.6 to 0.9 percent of Mn, 0.5 to 1.5 percent of Cu, 0.1 to 0.2 percent of Ti, 0.004 to 0.006 percent of Be and 0.01 to 0.2 percent of RE; the sum of the other impurities is less than or equal to 0.4 percent, and the balance is Al; the RE element is selected from Y, Ce or Er element;
the non-heat-treatment reinforced high-strength high-toughness die-casting aluminum-magnesium-copper alloy is prepared by a method comprising the following steps of:
1) drying: preheating the prepared raw materials of pure aluminum, pure Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Cu intermediate alloy, Al-RE intermediate alloy and Al-Be intermediate alloy to 240 ℃ for drying treatment;
2) smelting: firstly melting pure aluminum, then heating to 780 ℃ of 760-;
3) refining: heating the melt with qualified alloy components to 700-720 ℃, introducing argon with refining agent powder into the melt for powder spraying and refining, deslagging and degassing;
4) when the melt reaches the casting temperature, the alloy ingot casting operation or the die-casting molding process operation can be carried out.
2. The non-heat-treated reinforced high-strength high-toughness die-cast aluminum-magnesium-copper alloy according to claim 1, wherein in the step 2), the covering agent sprayed on the surface of the melt is MgCl2+ KCl mixed solvent, and MgCl2The weight ratio of the KCl to the KCl is 1: 0.5-2.
3. The non-heat-treated reinforced high-strength high-toughness die-cast aluminum-magnesium-copper alloy as claimed in claim 1, wherein the refining agent used in the step 3) is aluminum oxide or zinc oxide, and the addition amount of the refining agent is 0.8-1.5% of the weight of the furnace burden.
4. The non-heat-treated reinforced high-strength high-toughness die-cast aluminum-magnesium-copper alloy as claimed in claim 1, wherein in the step 4), the casting temperature is 680-710 ℃.
5. The non-heat treated reinforced high strength and toughness die cast aluminum magnesium copper alloy as claimed in claim 1, wherein in step 4), the die casting process is operated at an injection speed in the range of 2-3 m/s.
6. The non-heat-treated reinforced high-strength high-toughness die-cast aluminum-magnesium-copper alloy as claimed in claim 1, wherein in the step 4), the die-casting molding process is operated at a casting pressure in the range of 80-120 Mpa.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102639733A (en) * 2009-07-24 2012-08-15 美铝公司 Improved 5xxx aluminum alloys and wrought aluminum alloy products made therefrom
CN108754256A (en) * 2018-07-16 2018-11-06 上海交通大学 Non-heat treated reinforcing high-strength and high ductility die casting aldray and preparation method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102639733A (en) * 2009-07-24 2012-08-15 美铝公司 Improved 5xxx aluminum alloys and wrought aluminum alloy products made therefrom
CN108754256A (en) * 2018-07-16 2018-11-06 上海交通大学 Non-heat treated reinforcing high-strength and high ductility die casting aldray and preparation method thereof

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