CN118028664A - Renewable heat-resistant high-fatigue cast aluminum alloy and preparation method and application thereof - Google Patents

Renewable heat-resistant high-fatigue cast aluminum alloy and preparation method and application thereof Download PDF

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CN118028664A
CN118028664A CN202410296915.5A CN202410296915A CN118028664A CN 118028664 A CN118028664 A CN 118028664A CN 202410296915 A CN202410296915 A CN 202410296915A CN 118028664 A CN118028664 A CN 118028664A
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aluminum alloy
cast aluminum
alloy
solution treatment
phase
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梁帅
陈来
朱慧颖
陈小村
张海
李震
王东涛
李振宇
闫炫杰
周威虎
张波
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Weiqiao Suzhou Lightweight Research Institute Co ltd
Suzhou University
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Weiqiao Suzhou Lightweight Research Institute Co ltd
Suzhou University
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/02Alloys based on aluminium with silicon as the next major constituent
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/02Making non-ferrous alloys by melting
    • C22C1/026Alloys based on aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/002Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/043Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with silicon as the next major constituent

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Continuous Casting (AREA)

Abstract

The invention discloses a renewable heat-resistant high-fatigue cast aluminum alloy, a preparation method and application thereof, wherein the cast aluminum alloy comprises Al, si, cu, mg, mn, ti, cr, sr and unavoidable impurities, and the impurities comprise Fe and other impurities except Fe; during preparation, each component is mixed, melted and refined to prepare an aluminum alloy cast ingot, and then the aluminum alloy cast ingot is subjected to solution treatment, quenching and cooling and aging treatment; the aluminum alloy disclosed by the invention has the characteristics of simple formula, high tolerance to impurity elements, especially iron, low thermal cracking property, heat resistance and high fatigue resistance, can meet the requirements of level grade and even upgrade use of high-quality recycled aluminum alloy existing in a large amount, can be recycled, reduces carbon emission, can be used at a higher service temperature, and is simple in formula and relatively low in raw material cost.

Description

Renewable heat-resistant high-fatigue cast aluminum alloy and preparation method and application thereof
The invention relates to a casting aluminum alloy, which is a divisional application of China patent application with the application date of 2024, 01 month and 03, the application number of 2024100038341 and the name of 'a preparation method and application'.
Technical Field
The invention relates to the technical field of cast aluminum alloy, in particular to a renewable heat-resistant high-fatigue aluminum-silicon alloy and a preparation method thereof, and particularly relates to a renewable heat-resistant high-fatigue cast aluminum alloy which is low in carbon equivalent and suitable for a working condition of thermal mechanical coupling, and particularly relates to a renewable heat-resistant high-fatigue cast aluminum alloy and a preparation method and application thereof.
Background
In recent years, with the development of aerospace and automobile industry, the requirements on energy conservation and emission reduction are more and more strict. The aluminum-silicon cast alloy has wide application in transportation and manufacturing due to the advantages of low density, excellent strength, good casting performance, wear resistance, heat conduction and the like; among them, various engine cases, speed reducer cases, accessory transmission cases, which are chassis structural members and power transmission device parts of aircrafts, passenger cars, commercial vehicles, are increasingly manufactured from aluminum-silicon series cast alloys to achieve weight reduction. However, in practice, since engines face complex and severe operating environments, engine power densities are increasing, and therefore, next generation materials for manufacturing engines and transmissions need to not only withstand service temperatures up to 250 ℃ but also have good fatigue properties.
Mg and Cu are commonly added to al—si alloys at present, and normal temperature mechanical properties are improved by forming Mg 2Si、Al2 Cu, Q phases and metastable phases thereof, including a356.2 alloy, a319 alloy, a380 alloy, ZL114A alloy, ZL702A alloy, and the like; however, at higher service temperatures, these alloys rapidly thicken the strengthening phase and significantly decrease the high temperature strength.
Meanwhile, compared with the original aluminum ingot, the level use and even the upgrading use of the renewable high-quality recovered aluminum with higher impurity element content can greatly reduce the carbon emission and meet the development direction of green low-carbon aluminum. Therefore, the high-efficiency utilization of the renewable aluminum is realized, the thermal stability and fatigue performance of the cast aluminum alloy are improved, but the current cast aluminum alloy has higher requirements on impurity elements such as impurity Fe content and must be controlled at a lower level, otherwise, better mechanical properties are difficult to obtain, and the problems of flat use and even upgrading use of the renewable high-quality recycled aluminum with higher impurity element content are solved.
For example, patent application CN114774741a discloses a heat-resistant cast aluminum alloy in which Fe is not more than 0.12% in the impurity elements and the sum of other impurity elements is not more than 0.2%; on one hand, the requirement of low impurity element content limits the use of high-quality recovered aluminum, and on the other hand, the heat-resistant phase is single in type by only increasing the Al 3Zr,Al3 (ZrV) nanometer heat-resistant phase. The invention patent application JP5344527B2 adds Fe and Ni elements to form Ni-rich compounds such as epsilon-Al 3Ni,δ-Al3CuNi,γ-Al7Cu4Ni,T-Al9 FeNi and the like to improve the high temperature performance of the alloy, and the existence of Ni in the Al-Si alloy neutralizes Fe and reduces the tendency of forming Fe-rich beta-Al 5 FeSi needle-shaped phases, and the distribution state of net shape and semi-net shape is favorable for the high temperature strength of the alloy. However, by forming a phase between Ni and Cu, the Cu content in the alpha-Al matrix is reduced, thereby reducing precipitation hardening, and the presence of a more brittle phase is detrimental to the fatigue strength of the alloy. In general, the existing disclosed cast aluminum-silicon alloy can not meet the requirements of heat resistance and high fatigue, the types of heat-resistant phases are still single, the number density is low, and the use of high-quality recovered aluminum is limited by the low impurity element content.
In addition, the prior patent CN115261682B discloses a cast aluminum alloy and a preparation method, wherein the matrix of the aluminum alloy comprises more than one submicron dispersed phase, the grain boundary of the aluminum alloy comprises more than one micron second phase, the size range of the submicron dispersed phase is 20-1000nm, the components comprise more than two arbitrary kinds of Al, fe, mn, cr, zr, mo, ti, cu, ni, co, Y, V, sc elements, and the number density of the submicron dispersed phase is within the range of 10 15-1020/m3; the size range of the micron-sized second phase is between 1 and 20 mu m, and the components comprise more than two of Al, fe, mn, cr, zr, mo, ti, cu, ni, co, Y, V, sc elements; the aluminum alloy comprises :Si 4-17%、Mg 0.1-1%、Fe 0.1-0.5%、Mn 0.1-0.5%、Cr 0.1-0.5%、Zr 0.1-0.5%、Mo 0.1-0.5%、Ti 0.1-0.5%、Cu 0.1-2%、Ni 0.1-1%、Co 0.1-0.5%、Y 0.1-0.5%、V 0.1-0.5%、Sc 0.1-0.5%, of Al and the balance of Al. The patent suggests that the aluminum alloy has a non-shear strengthening phase and high fatigue performance, but the formula is known to be complex, the first formula has at least 15 alloy components, the complex components lead to a narrower process window of the alloy, and particularly for sand castings and thick and large parts, due to slower cooling speed, primary multi-element intermetallic compounds are easy to form, so that the alloy performance is damaged; second, it must also contain a more expensive metal such as nickel, which is costly; thirdly, the cast aluminum alloy must include a plurality of expensive rare earth elements for collocation, so that the cast aluminum alloy in the patent has the disadvantages of high preparation cost, complex formula and adverse industrial application.
Disclosure of Invention
The invention aims to overcome one or more defects in the prior art, and provides an improved renewable heat-resistant high-fatigue cast aluminum alloy which has the advantages of simple formula, high tolerance to impurity elements, particularly iron, low heat cracking property and heat-resistant high-fatigue property, can meet the requirements of the level and even upgrade of high-quality recycled aluminum alloy existing in a large amount, can be recycled, reduces carbon emission, and can be used at a higher service temperature.
The invention also provides a preparation method of the cast aluminum alloy.
The invention also provides an application of the cast aluminum alloy in preparing an automobile chassis structural member, an engine or a transmission device, wherein the automobile chassis structural member, the engine or the transmission device can bear service temperature of 250 ℃ and has good fatigue performance, and the cast aluminum alloy can meet the requirement.
In order to achieve the above purpose, the invention adopts a technical scheme that:
A cast aluminum alloy comprising Al, si, cu, mg, mn, ti and unavoidable impurities, in particular, cr, sr and X 1, the X 1 being Sn and/or In, the impurities comprising Fe and other impurities than Fe;
The content of elements contained in :Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Sr 0.005%-0.04%,X1% by mass of the cast aluminum alloy is 0.001% -0.2% each independently, fe is less than or equal to 0.5%, the total of other impurities except Fe is not more than 0.2%, and the content of Al is adjusted to make the total amount of the aluminum alloy be 100%;
In the process of preparing the cast aluminum alloy, mixing, melting and refining the components, then preparing an aluminum alloy cast ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy cast ingot; the solid solution treatment is carried out at the temperature of 250-550 ℃ and in multiple stages, the temperatures among the multiple stages are sequentially increased according to the sequence of treatment, the multiple stages are at least three stages, and the first-stage solid solution treatment in the multiple stages is carried out at the temperature of 250-350 ℃.
The invention provides another technical scheme that: a cast aluminum alloy comprising Al, si, cu, mg, mn, ti and unavoidable impurities, in particular, cr and Sr, the impurities comprising Fe and other impurities than Fe;
:Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Sr 0.005%-0.04%,Fe% or less of the cast aluminum alloy, the total of other impurities except Fe is not more than 0.2%, and the content of Al is adjusted to 100% of the total amount of the aluminum alloy;
In the process of preparing the cast aluminum alloy, mixing, melting and refining the components, then preparing an aluminum alloy cast ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy cast ingot; the solid solution treatment is carried out at the temperature of 250-550 ℃ and in multiple stages, the temperatures among the multiple stages are sequentially increased according to the sequence of treatment, the multiple stages are at least three stages, and the first-stage solid solution treatment in the multiple stages is carried out at the temperature of 250-350 ℃.
The invention provides another technical scheme that: a cast aluminum alloy comprising Al, si, cu, mg, mn, ti and unavoidable impurities, in particular, cr and Sr, the impurities comprising Fe and other impurities than Fe;
The total content of :Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Sr 0.005%-0.04%,Fe% or less, other impurities except Fe in the cast aluminum alloy is not more than 0.2%, and the content of Al is adjusted to be 100% of the total content of the aluminum alloy.
According to some preferred aspects of the present invention, the ratio of the addition amount of Cu to the addition amount of Mg in the cast aluminum alloy is 1.2 to 6.
According to some preferred aspects of the present invention, mg comprises 0.25% to 0.5% by mass of the cast aluminum alloy.
According to some preferred aspects of the present invention, the cast aluminum alloy comprises 0.1% -0.5% of Fe in mass percent.
According to some specific aspects of the invention, the needle-shaped beta-Fe phase in the alloy structure of the cast aluminum alloy accounts for less than 5% of the total area of the Fe phase, and even the complete elimination of the needle-shaped beta-Fe phase can be achieved.
According to some specific aspects of the invention, when the solution treatment is carried out, a Cu-containing phase and a Mg-containing phase are respectively dissolved into an alpha-Al matrix of an alloy structure, and a Q' metastable phase is separated out in the aging treatment process;
after the solution treatment and before the aging treatment, the alloy structure of the intermediate includes an α -Al (Fe, mn, cr) Si dispersed phase.
In some embodiments of the invention, the cast aluminum alloy further comprises Zr, and after the solution treatment and before the aging treatment, the alloy structure of the intermediate comprises a (Al, si) 3 (Zr, ti) dispersed phase.
According to some preferred aspects of the present invention, zr is 0.05% -0.3% in mass% in the cast aluminum alloy.
In some embodiments of the invention, the cast aluminum alloy further comprises X 2, the X 2 is a combination of one or more selected from Mo, V, Y, and Er.
According to some preferred aspects of the present invention, the cast aluminum alloy contains the elements of X 2 in an amount of 0.01% to 0.3% each independently, in terms of mass%.
According to some preferred and specific aspects of the invention, the solution treatment is carried out at 250-540 ℃.
In some preferred embodiments of the present invention, the solution treatment comprises the following steps performed in sequence:
primary solid solution treatment: preserving heat at 250-350 ℃;
and (3) secondary solid solution treatment: preserving heat at 370-470 ℃;
three-stage solid solution treatment: preserving heat at 490-510 ℃;
Four-stage solid solution treatment: preserving heat at 520-540 ℃.
In some preferred embodiments of the invention, the solution treatment embodiments include:
Primary solid solution treatment: heating the ingot from room temperature to 250-350 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-11h at 250-350 ℃;
And (3) secondary solid solution treatment: heating the alloy obtained by primary solution treatment from 250-350 ℃ to 370-470 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-13h at 370-470 ℃;
Three-stage solid solution treatment: heating the alloy obtained by the secondary solution treatment from 370-470 ℃ to 490-510 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-6h at 490-510 ℃;
Four-stage solid solution treatment: heating the alloy obtained by three-stage solution treatment from 490-510 ℃ to 520-540 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-12h at 520-540 ℃.
According to some specific aspects of the invention, the cast aluminum alloy has a charge length above 645mm at 700 ℃.
According to some specific aspects of the invention, after the aging treatment, the cast aluminum alloy has a tensile strength at room temperature of 360MPa or more and an elongation after break of 7.5% or more.
According to some specific aspects of the invention, after the aging treatment, the test conditions are: and the stress ratio R of the smooth sample is-1, and the cycle is 1000 ten thousand times, so that the fatigue strength of the cast aluminum alloy reaches more than 100 MPa.
According to some preferred aspects of the invention, the quench cooling is cooling to room temperature in water within 30 seconds.
In some embodiments of the invention, the aging treatment is incubation at 140-200 ℃ for 6-18h.
It is known that the use of recycled aluminum can lead to an increase in the content of alloying impurity elements, particularly Fe elements, and that the needle-like Fe phase formed after solidification can severely fracture the matrix; the aluminum alloy formula has the advantage of high impurity tolerance, particularly high Fe tolerance, so in practice, part of components including Al in the cast aluminum alloy can be fed through adding recycled aluminum alloy, and the recycled aluminum alloy is one or a combination of a plurality of Al-Si-Mg alloy, al-Si-Cu-Mg alloy and Al-Mn alloy, so that a large amount of high-quality recycled aluminum alloy can be recycled (i.e. regenerated) for even upgrading, and carbon emission is reduced.
The invention provides another technical scheme that: a method of producing the cast aluminum alloy described above, the method comprising:
According to the components, preparing materials, melting, refining, modifying and refining to prepare an aluminum alloy ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy ingot; the solid solution treatment is carried out at the temperature of 250-550 ℃ and in multiple stages, the temperatures among the multiple stages are sequentially increased according to the sequence of treatment, the multiple stages are at least three stages, and the first-stage solid solution treatment in the multiple stages is carried out at the temperature of 250-350 ℃.
In some embodiments of the invention, during the preparation of the cast aluminum alloy, the high-quality recovered aluminum alloy of Al-Si-Mg, al-Si-Cu, al-Si-Cu-Mg and Al-Mn can be melted first, surface scum is removed, component mushrooms are cast, components are measured, pure alloy or intermediate alloy of corresponding elements is adopted to adjust the alloy components to a target interval, slag is removed by refining, modification and refinement are carried out, standing and cooling are carried out, and the aluminum alloy cast ingot is prepared.
In order to further achieve the object of the present invention, it is preferable to control the melting temperature of the high-quality recycled aluminum alloy of Al-Si-Mg, al-Si-Cu-Mg, al-Mn to be 730-760 ℃.
Preferably, the refining slag removal is performed by adding a general-purpose refining agent by using a rotary argon blowing process.
Preferably, the refining agent is FL-228 type refining agent, and the addition amount of the refining agent is 0.05% -0.15% of the weight of the alloy melt.
Preferably, the refining is performed by using a TCB grain refiner, the addition amount of the refiner is 0.3% -0.8% of the weight of the alloy melt, the modification is performed by using an AlSr10 modifier, and the addition amount of the modifier is 0.005% -0.04% of the weight of the alloy melt.
In some embodiments of the invention, embodiments of preparing the cast aluminum alloy include:
1) High temperature melting of aluminum alloy: melting high-quality recovered aluminum alloy containing Al-Si-Mg, al-Si-Cu, al-Si-Cu-Mg, al-Mn and the like according to the component proportion requirement of the raw materials, controlling the melting temperature to be 730-760 ℃, and stirring for 1-10min until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements into the alloy melt prepared in the step 1) (note that pure Mg and optional X 1 are added, and aluminum foil is used for wrapping to reduce burning loss), controlling the treatment temperature to be 720-730 ℃, stirring for 1-10min until the components of the melt are uniform, continuously casting the component mushroom samples, and adjusting to a target component interval according to the test result;
4) And (3) refining and deslagging the melt: adding a general refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, refining and deslagging, controlling the treatment temperature to be 705-715 ℃, and standing for deslagging;
5) Modification and refinement: firstly adding AlSr10 modifier accounting for 0.005-0.04 percent of the weight of alloy melt; standing, adding a TCB grain refiner accounting for 0.3-0.8% of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting and forming the aluminum alloy melt;
7) Solution treatment: carrying out solid solution treatment on the alloy obtained in the step 6), which specifically comprises the following steps:
primary solid solution treatment: heating the alloy obtained by casting from room temperature to 250-350 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-11h at 250-350 ℃;
And (3) secondary solid solution treatment: heating the alloy obtained by primary solid solution from 250-350 ℃ to 370-470 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-13h at 370-470 ℃;
Three-stage solid solution treatment: heating the alloy obtained by the secondary solid solution from 370-470 ℃ to 490-510 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-6h at 490-510 ℃;
Four-stage solid solution treatment: heating the alloy obtained by three-stage solid solution from 490-510 ℃ to 520-540 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-12h at 520-540 ℃;
Quenching and cooling: placing the alloy obtained after the four-stage solution treatment in water for 30 seconds, and cooling to room temperature;
aging treatment: and (3) preserving the heat of the alloy obtained after quenching for 6-18h at 140-200 ℃.
Preferably, in step 1) or 3), the stirring time is 2-3min.
Preferably, in step 4) or 5), the standing time is 10-20min.
Preferably, in step 6), the casting method of the casting molding is gravity casting or pressure casting.
The invention provides another technical scheme that: the cast aluminum alloy is applied to the preparation of automobile chassis structural parts, engines or transmission devices.
According to the invention, a multistage solution treatment method with at least three stages of treatments sequentially increasing in temperature according to a sequential treatment sequence is adopted, so that Mg, si and Cu atom clusters can be formed at a relatively low temperature, the clusters can be used as nucleation base points of alpha-type disperse phases and Al 3 M (M can be Mn, cr, ti, mo, V, Y, er and the like) disperse phases, the dispersion degree of the disperse phases is increased, and the size of the disperse phases can be reduced due to the increase of nucleation positions;
Then under the relatively high temperature treatment of sequential increment, nucleation and growth of a disperse phase can be promoted to obtain a disperse phase with a certain volume fraction and a certain number density, and then theta phase and Q phase containing Cu are further promoted to be dissolved back to form a supersaturated solid solution, so that preparation is made for subsequent aging precipitation of a nano reinforced phase;
Finally, at the relatively highest temperature, the solid solubility of the Al matrix is further increased, the elements are uniformly distributed, the spheroidization of Si phase is promoted, the tearing effect of strip Si relative to the Al matrix is lightened, the stress concentration is reduced, and the plasticity of the alloy is further improved.
For example, in the above-mentioned solution treatment process of the preferred four-stage solution treatment, the first-stage solution treatment may form clusters of Mg and Si atoms, which may serve as nucleation sites for the α -type dispersed phase and the Al 3 M (M may be Mn, cr, ti, mo, V, Y, er, etc.) dispersed phase, and the increase in the nucleation sites may also reduce the size of the dispersed phase;
the secondary solid solution treatment can promote nucleation and growth of a dispersed phase, and a dispersed phase with a certain volume fraction and number density is obtained;
the three-stage solid solution treatment can further promote equal dissolution of theta phase and Q phase containing Cu, and form supersaturated solid solution for preparing subsequent aging precipitation nano reinforced phase, and the solid solution temperature and time are selected by fully considering the inoculation, nucleation and growth of the phase.
The four-stage solid solution treatment can further increase the solid solubility of the Al matrix, lead the elements to be uniformly distributed, promote the spheroidization of Si phase, lighten the tearing effect of strip Si relative to the Al matrix, reduce the stress concentration and further improve the plasticity of the alloy. The solid solution temperature is too high, the alloy has the risk of overburning, and the upper limit is preferably determined to be 540 ℃ in consideration of low control accuracy of the industrial furnace temperature.
In the invention, quenching cooling can maintain the vacancy concentration during solution treatment and obtain supersaturated solid solution; the aging treatment can promote the dispersion and precipitation of the theta ' phase, the theta ' phase and the Q ' phase which are coherent or semi-coherent with the matrix, thereby further improving the room temperature/medium temperature strength of the alloy.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
The invention is based on the problems that the existing cast aluminum-silicon alloy can not meet the heat-resistant high-fatigue requirement, the heat-resistant phase is single, the number density is lower, the content of low impurity elements limits the use of high-quality recovered aluminum, the formula is complex, the cost is higher and the like, through a great deal of experimental research, the invention surprisingly finds that the alloy system of Al-Si-Cu-Mg-Mn-Cr is adopted, the addition of each component is controlled, the high tolerance of impurity elements, especially Fe, can be realized, the morphology of Fe phase can be regulated, the Fe phase is changed into a block shape, the adverse effect of a primary Fe phase can be reduced, and meanwhile, the Fe element dissolved in a matrix is converted into a beneficial dispersed phase through a solution treatment process, so that the alloy system of the invention can adopt recovered material ingots (80-90)% of the material ingots used in the invention can be from secondary high-quality recovered materials, including A356.2 alloy, A319 alloy, A380 alloy, ZL114A alloy, ZL702A alloy and the like), and the like, and is suitable for the flat grade even upgrading and use of the recovered material ingots, and the cost is saved; further, after Sn and/or In elements are added into the system, the Sn and/or In elements can be found to be rapidly diffused and preferentially combined with vacancies, so that the nucleation density of a disperse phase is further increased, the disperse phase is more finely and uniformly distributed, and the temperature resistance, the mechanical property and the like are improved; in particular, compared with the prior patent CN115261682B, the invention omits most elements, particularly expensive metal or rare earth elements, not only does not basically reduce the high-temperature strength and fatigue performance of the alloy, but also greatly improves the thermal cracking of the alloy, the reduction of the thermal cracking is beneficial to the molding of castings with complex shapes by the alloy, in addition, the cost is greatly saved, and the invention is suitable for industrial mass production.
Drawings
FIG. 1 is a metallographic structure diagram of an alloy of comparative example 1;
FIG. 2 is a metallographic structure diagram of the alloy of example 1 of the present invention;
FIG. 3 is a graph of the diffuse phase structure of the alloy of example 1 of the present invention;
FIG. 4 is a graph showing the results of the mold-filling test of the alloy of example 2 of the present invention;
FIG. 5 is a graph showing the results of thermal cracking tests of the alloy of example 2 of the present invention;
FIG. 6 is a graph of the diffuse phase structure of the alloy of example 2 of the present invention;
FIG. 7 is a diffuse phase structure diagram of the alloy of example 3 of the present invention;
FIG. 8 is a graph of the diffuse phase structure of the alloy of example 5 of the present invention;
FIG. 9 is a diffuse phase structure diagram of the alloy of example 6 of the present invention;
FIG. 10 is a graph showing the dispersion phase distribution of the alloy of example 6 of the present invention.
Detailed Description
The main conception of the invention is that: 1) The hypoeutectic Al-Si alloy has the advantages of small solid-liquid crystallization temperature range, good fluidity and feeding property, good casting performance, lower production cost, almost no casting crack, low thermal expansion coefficient, good corrosion resistance and stability, good wear resistance and cutting processability, and therefore, the alloy is widely applied. Although Al-Si series alloy has a plurality of advantages, the strength and hardness of the alloy are low, so that the application of the alloy in heat-resistant high-fatigue castings is limited; further, mg is added to the alloy system, in practice, the room temperature solid solubility of Mg in the α -Al matrix is 0.34% and at the eutectic temperature is 14.9%, so that the strength and hardness of the alloy can be improved by solid solution strengthening and aging strengthening. Practice shows that the addition amount of Mg in the aluminum-silicon alloy cannot be too much, the brittle phase A1 3Mg2 is formed by too high content, a matrix is split, the mechanical property is reduced, the higher the silicon content is, the magnesium content of the alloy is correspondingly reduced, and the mass content of Mg is controlled to be not higher than 0.5% and not lower than 0.1%; meanwhile, cu is further added, the solubility of Cu in an Al matrix at room temperature is 0.2%, and the solid solubility is 5.65% at the eutectic temperature of 548 ℃, so that the Cu atoms with larger size are dissolved in the Al solid solution to cause serious lattice distortion, prevent dislocation movement, increase the shear stress of sliding movement, form solid solution strengthening and improve the strength of the alloy; in the alloy of the present system, which is capable of forming a theta (Al 2 Cu) phase, al 2 Cu dissolves into the alpha solid solution upon solution treatment, and precipitates a theta', theta "metastable phase or a theta stable phase during aging, which can hinder the movement of dislocations, improve tensile strength, hardness, fatigue strength and high temperature strength, and in particular, in the present system, in addition to forming the strengthening phases Al 2 Cu and Mg 2 Si, al 2 CuMg, Q phase (Al 5Cu2Mg8Si6), W phase (Al xMg5Si4 Cu) are easily formed, which are higher in strength and heat resistance than other aluminum-silicon alloys; when Cu and Mg in the alloy composition are further controlled to be in proper contents, a Q (Al 5Cu2Mg8Si6 or Al 4Mg5Si4 Cu) reinforced phase is formed, and the reinforced effect is better than that of Al 2 Cu and Mg 2 Si. The Q phase is a quaternary alloy phase, the atom bonding strength of the multi-element alloy is higher than that of the binary alloy, and the more elements are, the more the heat resistance of the alloy is improved, and the high-temperature performance of the alloy is improved.
2) By adding Mn, cr and Ti microelements, alpha-type dispersion phases with large number density and rod-like/plate-like Al 3 M (M can be Mn, cr, ti, mo, V, Y, er and the like) heat-resistant dispersion phases can be formed in the alloy, and the research shows that the strength of the alloy containing transition metal is greatly dependent on the size and the shape of the formed intermetallic phase; mn and Cr elements have low diffusion rate, so that the alloy still keeps precipitation strengthening effect at high temperature, the solid solubility in an aluminum matrix is very low, primary intermetallic compounds are inevitably formed when the addition amount is excessive, and the intermetallic compounds are unfavorable to the mechanical properties of the alloy, therefore, the content of Mn is preferably controlled to be 0.05-0.4%, the content of Cr is preferably controlled to be 0.05-0.3%, and the content of Ti is preferably controlled to be 0.05-0.3%.
3) Further, in the invention, zr element or X 2 element (one or a combination of more selected from Mo, V, Y and Er) can be further added on the basis of the above, and the elements can also realize the effect of keeping the alloy precipitation strengthening at high temperature, so that alpha-type dispersed phase with large number density of block morphology and Al 3 M-type heat-resistant dispersed phase with rod/plate morphology are formed in the alloy, and the formation of primary intermetallic compounds which are unfavorable for mechanical properties is reduced by controlling the addition amount.
The above-described aspects are further described below in conjunction with specific embodiments; it should be understood that these embodiments are provided to illustrate the basic principles, main features and advantages of the present invention, and that the present invention is not limited by the scope of the following embodiments; the implementation conditions employed in the examples may be further adjusted according to specific requirements, and the implementation conditions not specified are generally those in routine experiments.
All starting materials are commercially available or prepared by methods conventional in the art, not specifically described in the examples below. Comparative example 1:
Comparative example 1 used the common alloy a356.2+0.5% cu for active accessory case housings.
The preparation method comprises the following steps:
(1) The raw materials of the alloy are from the common alloy A356.2+0.5% Cu of the casing of the active accessory casing, and the mass ratio range of the components is as follows: si 6-7.5%, cu:0.4 to 0.6 percent, 0.30 to 0.45 percent of Mg, less than or equal to 0.2 percent of Ti, less than or equal to 0.12 percent of Fe, less than or equal to 0.05 percent of Mn, less than or equal to 0.05 percent of Zn and the balance of Al;
(2) The specific smelting steps of the alloy comprise:
The weighed a356.2 alloy and pure Cu wire were melted at 720 ℃. After all the components are melted, stirring is carried out for 2min, so that the components are uniform, and standing and heat preservation are carried out for 10min. Casting a mushroom sample, and externally adding an F-228 general type refining agent into an alloy melt to refine and deslagging by adopting a rotary blowing argon method after the components are qualified. The addition amount of the refining agent is 0.15 percent of the weight of the alloy melt. Standing for 5min after treatment, cooling to 700 ℃, slagging off, and casting and forming. The casting process used was gravity casting, and the melt was cast into a metal mold preheated to 200 ℃ to prepare castings. The heat treatment process for ingot casting comprises the following steps: preserving heat for 8 hours at 535 ℃ and 6 hours of water quenching and aging at 170 ℃, and sampling from an ingot after cooling for tissue observation and performance test.
The charging property, thermal cracking property, and mechanical properties at normal temperature and high temperature of the alloy prepared in this example are shown in table 1.
Comparative example 2:
Comparative example 2 further increases the Cu, mg content.
The method comprises the following specific steps:
(1) The raw materials of the alloy are from the common alloy A356.2+0.5% Cu of the casing of the active accessory casing, and the mass ratio range of the components is as follows: 6.5 to 7.5 percent of Si, cu:0.9 to 1.1 percent of Mg, 0.9 to 1.1 percent of Ti, less than or equal to 0.2 percent of Fe, less than or equal to 0.12 percent of Mn, less than or equal to 0.05 percent of Zn and the balance of Al;
(2) The specific smelting steps of the alloy comprise:
The weighed a356.2 alloy and pure Cu wire were melted at 720 ℃. After all melting, adding pure Mg blocks wrapped by aluminum foil, manually stirring for 2min to make the components uniform, standing and preserving heat for 10min. Casting a mushroom sample, and externally adding an F-228 general type refining agent into an alloy melt to refine and deslagging by adopting a rotary blowing argon method after the components are qualified. The addition amount of the refining agent is 0.15 percent of the weight of the alloy melt. Standing for 5min after treatment, cooling to 700 ℃, slagging off, and casting and forming. The casting process used was gravity casting, and the melt was cast into a metal mold preheated to 200 ℃ to prepare castings. The heat treatment process for ingot casting comprises the following steps: preserving heat at 500 ℃ for 4 hours and 535 ℃ for 6 hours, quenching with water and preserving heat at 170 ℃ for 8 hours, cooling, sampling from cast ingot, and carrying out tissue observation and performance test.
The charging property, thermal cracking property, and mechanical properties at normal temperature and high temperature of the alloy prepared in this example are shown in table 1.
Comparative example 3:
comparative example 3 used a common alloy for active engine heads, alloy grade ZL702A.
The method comprises the following specific steps:
(1) The raw materials of the alloy are from widely used ZL702A alloy, and the mass ratio range of the components is as follows: 6.0 to 8.0 percent of Si, cu:1.3 to 1.8 percent of Mg, 0.3 to 0.5 percent of Ti:0.1 to 0.25 percent, less than or equal to 0.25 percent of Fe, less than or equal to 0.15 percent of Mn, less than or equal to 0.05 percent of Zn, and the balance of Al;
(2) The specific smelting steps of the alloy comprise:
The weighed ZL702A alloy was melted at 720 ℃. After all the components are melted, stirring is carried out for 2min, so that the components are uniform, and standing and heat preservation are carried out for 10min. And a rotary argon blowing method is adopted, and a F-228 general type refining agent is externally added into the alloy melt for refining and deslagging. The addition amount of the refining agent is 0.15 percent of the weight of the alloy melt. Standing for 5min after treatment, cooling to 700 ℃, slagging off, and casting and forming. The casting process used was gravity casting, and the melt was cast into a metal mold preheated to 200 ℃ to prepare castings. The heat treatment process for ingot casting comprises the following steps: preserving heat for 8 hours at 535 ℃ and 6 hours of water quenching and aging at 170 ℃, and sampling from an ingot after cooling for tissue observation and performance test.
The charging property, thermal cracking property, and mechanical properties at normal temperature and high temperature of the alloy prepared in this example are shown in table 1.
Example 1:
The example provides a cast aluminum alloy and a preparation method thereof, wherein the cast aluminum alloy comprises the following components in percentage by mass: 7% of Si, 0.5% of Cu, 0.4% of Mg, 0.3% of Mn, 0.2% of Cr, 0.08% of Ti, 0.02% of Sr, 0.4% of Fe, 0.05% of Sn, and the balance of Al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements (taking care of pure Mg and aluminum foil for wrapping when Sn is added, reducing burning loss) into the alloy melt prepared in the step 1), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting a mushroom sample, and measuring the components of the alloy until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: heat preservation at 275 ℃ for 7h+390 ℃ for 3h+500 ℃ for 4h+530 ℃ for 4h;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
Aging treatment: preserving heat for 13h at 180 ℃.
The alloy in example 1 has the properties of hot-filling property, hot-cracking property, and mechanical properties at normal temperature and high temperature shown in Table 1.
Example 2:
The example provides a cast aluminum alloy and a preparation method thereof, wherein the cast aluminum alloy comprises the following components in percentage by mass: si7.5%, cu 1.8%, mg 0.35%, mn 0.3%, cr 0.2%, ti 0.08%, zr 0.1%, sr 0.03%, fe 0.3%, sn 0.1%, and the balance of Al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements (taking care of pure Mg and aluminum foil for wrapping when Sn is added, reducing burning loss) into the alloy melt prepared in the step 1), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting a mushroom sample, and measuring the components of the alloy until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: heat preservation at 275 ℃ for 7h+390 ℃ for 10h+500 ℃ for 4h+530 ℃ for 4h;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
Aging treatment: preserving heat for 13h at 180 ℃.
The alloy in example 2 has the properties of hot-filling property, hot-cracking property, and mechanical properties at normal temperature and high temperature shown in Table 1.
Example 3:
The example provides a cast aluminum alloy and a preparation method thereof, wherein the cast aluminum alloy comprises the following components in percentage by mass: si7.5%, cu 1.8%, mg 0.35%, mn 0.3%, cr 0.2%, ti 0.08%, zr 0.1%, sr 0.03%, fe 0.3%, sn 0.1%, and the balance of Al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements (taking care of pure Mg and aluminum foil for wrapping when Sn is added, reducing burning loss) into the alloy melt prepared in the step 1), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting a mushroom sample, and measuring the components of the alloy until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: preserving heat for 4h at 500 ℃ and 10h at 530 ℃;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
Aging treatment: preserving heat for 13h at 180 ℃.
The alloy in example 3 has the properties of hot-filling property, hot-cracking property, and mechanical properties at normal temperature and high temperature shown in Table 1.
Example 4:
The present example provides a cast aluminum alloy and a method for producing the same, wherein :Si 7%、Cu 0.5%、Mg 0.35%、Mn 0.2%、Cr 0.1%、Mo 0.1%、Zr 0.1%、Ti 0.1%、V 0.1%、Y 0.1%、Er 0.1%,Sr 0.02%,Fe 0.3%, of the cast aluminum alloy is, in mass percent, al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements into the alloy melt prepared in the step 1) (taking care of adopting aluminum foil for wrapping when pure Mg is added to reduce burning loss), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting the component mushroom sample, and measuring the alloy components until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: keeping the temperature at 250 ℃ for 11h+390 ℃ for 12h+500 ℃ for 4h+530 ℃ for 8h;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
Aging treatment: preserving heat for 13h at 180 ℃.
The alloy in example 4 has the properties of hot-filling property, hot-cracking property, and mechanical properties at normal temperature and high temperature shown in Table 1.
Example 5:
The present example provides a cast aluminum alloy and a method for producing the same, wherein :Si8.5%、Cu 2.0%、Mg 0.5%、Mn 0.4%、Cr 0.2%、Mo 0.2%、Zr 0.15%、Ti 0.3%、V 0.1%、Y 0.1%、Er 0.1%,Sn 0.05%,Sr 0.03%,Fe 0.4%, of the cast aluminum alloy is, in mass percent, al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements (taking care of pure Mg and aluminum foil for wrapping when Sn is added, reducing burning loss) into the alloy melt prepared in the step 1), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting a mushroom sample, and measuring the components of the alloy until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: preserving heat at 310 ℃ for 6 hours and at 410 ℃ for 8 hours and at 500 ℃ for 6 hours and at 530 ℃ for 4 hours;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
Aging treatment: preserving heat for 15h at 160 ℃.
The alloy in example 5 has the properties of hot-filling property, hot-cracking property, and mechanical properties at normal temperature and high temperature shown in Table 1.
Example 6:
The present example provides a cast aluminum alloy and a method for producing the same, wherein :Si 7%、Cu 1.5%、Mg 0.35%、Mn 0.2%、Cr 0.2%、Mo 0.2%、V 0.1%、Y 0.1%、Er 0.1%,Sn 0.05%,In 0.05%,Sr 0.025%,Fe 0.5%, of the cast aluminum alloy is, in mass percent, al and unavoidable impurities other than Fe.
The preparation method of the cast aluminum alloy comprises the following steps:
1) High temperature melting of aluminum alloy: according to the component proportion requirement of the raw material components, melting high-quality recovered aluminum alloy consisting of 30% of Al-Si-Mg,30% of Al-Si-Cu-Mg and 10% of Al-Mn, controlling the treatment temperature to 760 ℃, and stirring until the components are uniform;
2) Casting a component mushroom sample, and calculating the mass of supplementing corresponding alloy elements according to a test result;
3) Alloying an aluminum alloy melt: removing scum on the surface of the melt, adding pure alloy or intermediate alloy of corresponding elements (taking care of pure Mg, sn and In, adopting aluminum foil to wrap, reducing burning loss) into the alloy melt prepared In the step 1), controlling the treatment temperature to be 730 ℃, stirring until the components of the melt are uniform, continuously casting the component mushroom sample, and measuring the alloy components until the components are regulated to target components;
4) And (3) refining and deslagging the melt: adding an F-228 general type refining agent into the melt obtained in the step 3) by utilizing a rotary argon blowing process, wherein the adding amount of the refining agent is 0.15 percent of the weight of the alloy melt, refining and deslagging, controlling the treatment temperature to 710 ℃, and controlling the argon flow to 20L/min, refining time to 20min, and standing and deslagging;
5) Firstly adding AlSr10 modifier accounting for 0.03 percent of the weight of the alloy melt, standing for 10min, then adding TCB grain refiner accounting for 0.5 percent of the weight of the alloy melt, and skimming to obtain a target aluminum alloy melt;
6) Casting and forming: casting the melt into a metal mold preheated to 200 ℃ to prepare a casting;
7) The solid solution treatment parameters are as follows: preserving heat at 290 ℃ for 6 hours and 430 ℃ for 8 hours and 490 ℃ for 3 hours and 530 ℃ for 6 hours;
Quenching and cooling: water quenching (cooling to room temperature in water for 30 s);
aging treatment: preserving heat for 10h at 170 ℃.
The alloy in example 6 shows the charging property, thermal cracking property, and mechanical properties at normal temperature and high temperature as shown in table 1.
Performance test:
(1) A356.2+0.5% Cu alloy of comparative example 1 has a metallographic structure diagram shown in FIG. 1, most of the silicon phase is in fine particles of 1-3 mu m, a small amount of coarse particles of 5-10 mu m are arranged at the edge, fe phases are in different forms, and have needle shapes and block shapes, and the needle-shaped Fe phases can severely fracture a matrix, reduce the mechanical properties of the alloy and the like.
(2) The metallographic structure of the cast aluminum alloy prepared in example 1 is shown in fig. 2, wherein the needle-like Fe phase is substantially eliminated from the structure, and only the bulk Fe phase is present, which is beneficial for improving the alloy properties. As shown in figure 3, a large number of bright white fine dispersed disperse phases are distributed in the crystal, and the disperse phases can be used as strengthening phases, so that the deformation uniformity of the alloy is improved, the performance degradation caused by deformation concentration is avoided, and the high-temperature strength and the fatigue strength of the alloy can be remarkably improved.
(3) The cast aluminum alloy prepared in example 2 is shown in FIG. 4 as a result of the mold-filling test, and in FIG. 5 as a result of the thermal cracking test; it can be seen that the alloy has better mold-filling and hot cracking resistance, which is beneficial for forming castings with complex shapes. The submicron-sized dispersed phase structure of the cast aluminum alloy prepared in example 2 is shown in fig. 6, and a large number of bright white fine dispersed phases are distributed in the crystal, and the dispersed phases can serve as strengthening phases and are beneficial to improving the deformation uniformity of the alloy.
(4) As shown in fig. 7, the submicron-sized dispersed phase structure of the cast aluminum alloy prepared in example 3 is basically different from that of example 2 only in the process of solution treatment, example 2 is a specific solution treatment process of the present invention, and example 3 adopts a conventional solution treatment process, so that the number density of dispersed phase precipitation is obviously reduced. This shows that the solution treatment process of the present invention can greatly increase the number density of the dispersed phase compared with the conventional solution treatment process, and is favorable for improving the high temperature strength and fatigue strength of the alloy.
(5) The submicron-sized disperse phase structure of the cast aluminum alloy prepared in example 5 is shown in fig. 8, and it can be seen that the number density of the disperse phase is further improved after Mo, V, Y, er elements are further added.
(6) The submicron-order dispersed phase structure of the cast aluminum alloy prepared in example 6 is shown in fig. 9, and the distribution of the dispersed phase is shown in fig. 10; it can be seen that after Sn and In elements are added, the number density of the disperse phase is improved, and the distribution uniformity of the disperse phase can be improved.
(7) The charging property, thermal cracking property, and mechanical properties at normal temperature and high temperature of the cast aluminum alloys prepared in comparative examples 1 to 3 and examples 1 to 6 are shown in Table 1.
Wherein: the method for testing the filling performance comprises the following steps: a single spiral die is adopted to test fluidity, the die temperature is 200 ℃, and the casting temperature is 700 ℃; thermal cracking test method: carrying out alloy thermal cracking evaluation by adopting a thermal cracking constraint rod die, wherein the die temperature is 200 ℃ and the casting temperature is 730 ℃;
the test method of tensile strength at normal temperature and high temperature comprises the following steps: GB/T228-2021; the test method of elongation after break at normal temperature and high temperature comprises the following steps: GB/T228-2021;
method for testing fatigue strength: GB/T3075-2008.
TABLE 1
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As can be seen from Table 1, although the conventional alloy A356.2+0.5% Cu of the active accessory case housing of comparative example 1 is relatively good in thermal cracking property at the time of casting, it is poor in workability such as mold-filling property, particularly in mechanical property;
the common alloy A356.2+0.5% Cu of the casing of the other active accessory casing adopted in the comparative example 2 has poor casting performance as a whole and has poor mechanical properties compared with the comparative example 1;
The general alloy for the active engine heads used in comparative example 3, alloy No. ZL702A, had the worst overall properties among all comparative examples and examples.
In the invention, the casting performance is better, particularly the mechanical performance is remarkably improved, the tensile strength can reach more than 365MPa at room temperature, the elongation after fracture can reach more than 7.5%, and the fatigue resistance is more than 105 MPa; while still having excellent mechanical properties at higher temperatures, e.g. 150 ℃ and 250 ℃.
The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

Claims (22)

1. A cast aluminum alloy comprising Al, si, cu, mg, mn, ti, cr, sr and unavoidable impurities including Fe and other impurities other than Fe, characterized in that:
:Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Sr 0.005%-0.04%,Fe% or less of the cast aluminum alloy, the total of other impurities except Fe is not more than 0.2%, and the content of Al is adjusted to 100% of the total amount of the aluminum alloy;
In the process of preparing the cast aluminum alloy, mixing, melting and refining the components, then preparing an aluminum alloy cast ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy cast ingot; the solution treatment is carried out at 250-540 ℃ and in four stages, the temperature among the four stages is sequentially increased according to the sequence of treatment, the first-stage solution treatment in the four stages is carried out at 250-350 ℃, and in the first-stage solution treatment process, mg and Si atom clusters can be formed and serve as nucleation base points of alpha-type disperse phase and Al 3 M-type disperse phase, and M comprises Mn, cr or Ti.
2. A cast aluminum alloy comprising Al, si, cu, mg, mn, ti, cr, sr and unavoidable impurities including Fe and other impurities other than Fe, characterized in that:
:Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Sr 0.005%-0.04%,Fe% or less of the cast aluminum alloy, the total of other impurities except Fe is not more than 0.2%, and the content of Al is adjusted to 100% of the total amount of the aluminum alloy;
The preparation method of the cast aluminum alloy comprises the following steps: mixing, melting and refining the components, then preparing an aluminum alloy ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy ingot; wherein the solution treatment comprises the following steps in sequence:
Primary solid solution treatment: heat preservation is carried out at the temperature of 250-350 ℃, and in the primary solid solution treatment process, mg and Si atom clusters can be formed and used as nucleation base points of alpha-type disperse phase and Al 3 M-type disperse phase, wherein M comprises Mn, cr or Ti;
and (3) secondary solid solution treatment: preserving heat at 370-470 ℃;
three-stage solid solution treatment: preserving heat at 490-510 ℃;
Four-stage solid solution treatment: preserving heat at 520-540 ℃.
3. The cast aluminum alloy according to claim 1 or 2, characterized in that: embodiments of the solution treatment include:
Primary solid solution treatment: heating the aluminum alloy ingot from room temperature to 250-350 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-11h at 250-350 ℃;
And (3) secondary solid solution treatment: heating the alloy obtained by primary solution treatment from 250-350 ℃ to 370-470 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 3-13h at 370-470 ℃;
Three-stage solid solution treatment: heating the alloy obtained by the secondary solution treatment from 370-470 ℃ to 490-510 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-6h at 490-510 ℃;
Four-stage solid solution treatment: heating the alloy obtained by three-stage solution treatment from 490-510 ℃ to 520-540 ℃ at a heating rate of 1-10 ℃/min, and then preserving heat for 2-12h at 520-540 ℃.
4. The cast aluminum alloy according to claim 1 or 2, characterized in that: the cast aluminum alloy also includes Zr, and after the solution treatment and before the aging treatment, the alloy structure of the intermediate includes a (Al, si) 3 (Zr, ti) dispersed phase.
5. The cast aluminum alloy as recited in claim 4 wherein: in the cast aluminum alloy, zr accounts for 0.05-0.3% by mass percent.
6. The cast aluminum alloy according to claim 1 or 2, characterized in that: the cast aluminum alloy further comprises X 2, wherein X 2 is one or a combination of a plurality of Mo, V, Y and Er; and, when the cast aluminum alloy includes X 2, the M also includes X 2.
7. The cast aluminum alloy as recited in claim 6 wherein: the content of the elements contained in the X 2 in the cast aluminum alloy is 0.01 to 0.3% each independently in terms of mass percent.
8. The cast aluminum alloy according to claim 1 or 2, characterized in that: the cast aluminum alloy further includes X 1, the X 1 being Sn and/or In.
9. The cast aluminum alloy as recited in claim 8 wherein: the content of the elements contained in the X 1 in the cast aluminum alloy is 0.001% -0.2% each independently in terms of mass percent.
10. The cast aluminum alloy according to claim 1 or 2, characterized in that: in the cast aluminum alloy, 0.25-0.5% of Mg, 0.1-0.5% of Fe and the ratio of the addition amount of Cu to the addition amount of Mg are 1.2-6.
11. The cast aluminum alloy according to claim 1 or 2, characterized in that: the acicular beta-Fe phase in the alloy structure of the cast aluminum alloy accounts for less than 5 percent of the total area of the Fe phase;
After the solution treatment and before the aging treatment, the alloy structure of the intermediate includes an α -Al (Fe, mn, cr) Si dispersed phase;
and when the solution treatment is carried out, the Cu-containing phase and the Mg-containing phase are respectively dissolved into an alpha-Al matrix of an alloy structure, and a Q' metastable phase is separated out in the aging treatment process.
12. The cast aluminum alloy according to claim 1 or 2, characterized in that: in the cast aluminum alloy, an alloy structure comprises an alpha-type dispersed phase with a block shape, an Al 3 M-type dispersed phase with a rod-shaped/plate-shaped shape, and a theta ' phase, a theta ' phase and a Q ' phase which are coherent or semi-coherent with a matrix, wherein the alpha-type dispersed phase comprises an alpha-Al (Fe, mn, cr) Si dispersed phase;
Wherein, the theta ' phase, the theta ' phase and the Q ' phase which are coherent or semi-coherent with the matrix are separated out after aging treatment.
13. The cast aluminum alloy according to claim 1 or 2, characterized in that: in the cast aluminum alloy, fe accounts for 0.3-0.5 percent by mass percent;
and in the cast aluminum alloy, part of components including Al are added by adding recycled aluminum alloy, wherein the recycled aluminum alloy is one or a combination of a plurality of Al-Si-Mg alloy, al-Si-Cu-Mg alloy and Al-Mn alloy.
14. The cast aluminum alloy according to claim 1 or 2, characterized in that: the filling length of the cast aluminum alloy at 700 ℃ is more than 645 mm.
15. The cast aluminum alloy according to claim 1 or 2, characterized in that: after the aging treatment, the tensile strength of the cast aluminum alloy at room temperature is more than 360MPa, and the elongation after fracture is more than 7.5%.
16. The cast aluminum alloy according to claim 1 or 2, characterized in that: after the aging treatment, the test conditions were: and the stress ratio R of the smooth sample is-1, and the cycle is 1000 ten thousand times, so that the fatigue strength of the cast aluminum alloy reaches more than 100MPa.
17. The cast aluminum alloy according to claim 1 or 2, characterized in that: the quenching and cooling are carried out by putting the steel into water and cooling to room temperature within 30s, and the aging treatment is carried out by preserving heat for 6-18h at 140-200 ℃.
18. A cast aluminum alloy comprising Al, si, cu, mg, mn, ti, cr, sr and unavoidable impurities including Fe and other impurities other than Fe, characterized in that:
The cast aluminum alloy further comprises Zr and X 2, wherein X 2 is one or a combination of a plurality of Mo, V, Y and Er;
The content of elements contained in :Si 6.5%-8.5%、Cu 0.5%-2.0%、Mg 0.1%-0.5%、Mn 0.05%-0.4%、Cr 0.05%-0.3%、Ti 0.05%-0.3%、Zr 0.05%-0.3%、Sr 0.005%-0.04%,X2 of the cast aluminum alloy is respectively and independently 0.01% -0.3%, the content of Fe is 0.3% -0.5%, the total content of other impurities except Fe is not more than 0.2%, and the content of Al is adjusted to be 100%;
In the process of preparing the cast aluminum alloy, mixing, melting and refining the components, then preparing an aluminum alloy cast ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy cast ingot; the solution treatment is carried out at 250-540 ℃ and in four stages, the temperature among the four stages is sequentially increased according to the sequence of treatment, the first-stage solution treatment in the four stages is carried out at 250-350 ℃, and in the first-stage solution treatment process, mg and Si atom clusters can be formed and serve as nucleation base points of alpha-type disperse phase and Al 3 M-type disperse phase, and M comprises Mn, cr, ti or X 2.
19. A method of producing the cast aluminum alloy of any one of claims 1-18, characterized by: the preparation method of the cast aluminum alloy comprises the following steps: according to the components, preparing materials, melting, refining, modifying and refining to prepare an aluminum alloy ingot, and carrying out solution treatment, quenching cooling and aging treatment on the aluminum alloy ingot; wherein the solution treatment comprises the following steps in sequence:
Primary solid solution treatment: heat preservation is carried out at the temperature of 250-350 ℃, and in the primary solid solution treatment process, mg and Si atom clusters can be formed and used as nucleation base points of alpha-type disperse phase and Al 3 M-type disperse phase, wherein M comprises Mn, cr or Ti;
and (3) secondary solid solution treatment: preserving heat at 370-470 ℃;
three-stage solid solution treatment: preserving heat at 490-510 ℃;
Four-stage solid solution treatment: preserving heat at 520-540 ℃.
20. Use of the cast aluminum alloy of any of claims 1-18 in thermomechanical coupling operating conditions.
21. The use according to claim 20, characterized in that: the working temperature of the thermomechanical coupling working condition can reach the service temperature of 250 ℃.
22. The use according to claim 20, characterized in that: an automotive chassis structural member, engine or transmission component made from the cast aluminum alloy of any one of claims 1-18 and used under said thermo-mechanical coupling conditions.
CN202410296915.5A 2024-01-03 2024-01-03 Renewable heat-resistant high-fatigue cast aluminum alloy and preparation method and application thereof Pending CN118028664A (en)

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