High-strength, high-thermal-conductivity and high-toughness aluminum alloy and preparation method thereof

Abstract

The invention discloses a high-strength, high-thermal-conductivity and high-toughness aluminum alloy and a preparation method thereof. The high-strength, high-thermal-conductivity and high-toughness aluminum alloy comprises the following element components in percentage by mass: 0.5-2% of Fe, 0-12% of Si, 0.05-0.4% of Mg, 0.02-0.3% of Ca, Zr, Ni, Bi, Er and B in total content, less than 0.005% of Mn, Cr, Ti and V in total content, and the balance of Al. Comprising Al13Fe4 phases with the number density larger than or equal to 2 * 10 < 12 > / m < 2 > or Al5FeSi phases with the number density larger than or equal to 1.5 * 10 < 12 > / m < 2 >. Through accurate control of one or more elements of Mg, Ca, Zr, Ni, Bi, Er and B, the number density of a Fe-containing phase is improved, the strengthening effect of the Fe-containing phase is higher, the Fe-containing phase is refined, and the toughness and heat conduction comprehensive performance of the alloy are improved; on the basis of controlling the Fe-containing phase, the heat conductivity of the alloy is not reduced, and the high-strength and high-heat-conductivity performance of the alloy is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy, in particular to a high-strength high-thermal-conductivity high-toughness aluminum alloy and a preparation method thereof. BACKGROUND

[0002] At present, the technology of high-strength high-thermal-conductivity aluminum alloy mainly breaks through the inherent contradiction between strength and thermal conductivity along two paths. The first path is to realize the comprehensive performance improvement through multi-element alloying and advanced forming process, the core of which is to strengthen the matrix through the synergistic effect of multiple elements under the premise of ensuring good castability. For example, patent CN120796789A adopts semi-solid die casting technology, and the tensile strength and thermal conductivity of the aluminum alloy are improved by adding copper, molybdenum, scandium and other elements; patent CN114855036A controls the content of silicon, iron, manganese and rare earth elements to make the cast aluminum alloy have high thermal conductivity and good strength and toughness. The second path is more focused on the direct regulation and utilization of harmful phases, especially the iron-containing phase. Since iron is a common and harmful impurity in aluminum alloy, it is easy to form a brittle phase that penetrates the matrix and seriously damages the mechanical properties. Therefore, many technologies are committed to changing the morphology of these iron-containing phases. For example, electric pulse treatment or adding manganese, rare earth and other composite modifiers is used to convert harmful needle-shaped iron phases into spherical or Chinese characters to reduce their harm, and even attempt to use them as heat-resistant strengthening phases.

[0003] However, the existing technology still faces significant bottlenecks in achieving quantitative and standardized precise control of iron-containing phases. Most methods focus on "morphology improvement" of the phases, but have limited ability to precisely control key micro parameters such as phase type, number density, size distribution, etc., resulting in large performance fluctuations. For example, patent CN119979976A mentions using Al 13 Fe4 phases to improve heat resistance, but precise control of their volume fraction and distribution is still a problem. This limits the use of Fe-containing phases to provide synergistic performance of aluminum alloy strength and toughness and thermal conductivity, and new Fe-containing phase feature precise control technology needs to be developed to achieve high strength and toughness and high thermal conductivity of aluminum alloy, and to realize the technical upgrade of "active design and utilization" of Fe-containing phases. SUMMARY

[0004] The present application provides a high-strength high-thermal-conductivity high-toughness aluminum alloy and a preparation method thereof, which innovatively designs the alloy composition, precisely controls trace elements, effectively increases the number density of Fe-containing phases, makes the strengthening effect stronger, refines the iron-containing phases, improves the toughness of the alloy, and realizes the high strength and high thermal conductivity of the alloy based on the control of the Fe-containing phases without reducing the thermal conductivity of the alloy, thereby obtaining a high-strength high-thermal-conductivity high-toughness aluminum alloy.

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a high-strength, high-thermal-conductivity, and high-toughness aluminum alloy, comprising the following elemental components by mass percentage: Fe 0.5-2%, Si 0-12%, Mg 0.05-0.4%, Ca, Zr, Ni, Bi, Er, and B total content of 0.02-0.3%, Mn, Cr, Ti, and V total content of less than 0.005%, with the balance being Al.

[0006] Existing technologies lack precise control over the quantity density of the Fe-containing phase, resulting in limited strengthening effects. This invention, through innovative alloy composition design and precise control of the addition of one or more elements from Mg, Ca, Zr, Ni, Bi, Er, and B, effectively increases the quantity density of the Fe-containing phase, enhancing its strengthening effect. Furthermore, it achieves high strength and high thermal conductivity without reducing the alloy's thermal conductivity while controlling the Fe-containing phase. In addition, this invention refines the Fe-containing phase and reduces the grain size of the iron-containing phase through the design of one or more trace alloying elements from Mg, Ca, Zr, Ni, Bi, Er, and B, simultaneously improving the alloy's strength, toughness, and thermal conductivity.

[0007] Furthermore, the aluminum alloy contains alloy grains: when the Si content is <0.1%, the Fe phase in the alloy is Al. 13 Fe4 phase; when the Si element content is >0.1%, the Fe phase in the alloy is Al5FeSi phase. Preferably, when the Si element content is ≥0.1%, the mass percentage of Si is preferably 5-12%, more preferably 8-12%.

[0008] Furthermore, the Al 13 Fe4 phase abundance density ≥ 2 × 10 12 / m 2 .

[0009] Furthermore, the number density of the Al5FeSi phase is ≥1.5×10⁻⁶. 12 / m 2 .

[0010] Furthermore, in the aluminum alloy, the proportion of grains with a diameter d < 10 μm is 40-60%, the proportion of grains with a diameter 10 μm ≤ d < 20 μm is 20-30%, and the proportion of grains with a diameter 20 μm ≤ d < 40 μm is 10-30%.

[0011] Furthermore, the aluminum alloy has a yield strength ≥160MPa, tensile strength ≥300MPa, elongation ≥8%, and thermal conductivity ≥185W / m·K. The aluminum alloy possesses excellent high strength, high toughness, and high thermal conductivity, far exceeding the comprehensive strength, toughness, and thermal conductivity of traditional cast aluminum alloy materials.

[0012] The second aspect of the present application provides a preparation method of the high-strength high-thermal-conductivity high-toughness aluminum alloy of the first aspect, wherein the cooling rate of the aluminum alloy melt during solidification is 50-500 K / s, high-cooling-rate casting conditions are used, and the alloy grains are further optimized, so that the comprehensive performance of strength, toughness and thermal conductivity of the alloy is further improved.

[0013] Further, the aluminum alloy is prepared by extrusion or high-pressure casting.

[0014] Further, after the aluminum alloy melt is solidified, the aluminum alloy is heated to 400-500 DEG C for heat treatment.

[0015] Further, the heating rate is 10-20 DEG C / min, and the heat treatment time is 0.5-3 h.

[0016] The present application has the following beneficial effects:

[0017] The present application effectively improves the number density of the Fe-containing phase by accurately controlling the addition of one or more elements of Mg, Ca, Zr, Ni, Bi, Er and B, so that the strengthening effect is stronger.

[0018] The present application does not reduce the thermal conductivity of the alloy on the basis of controlling the Fe-containing phase, and realizes the high-strength high-thermal-conductivity performance of the alloy.

[0019] The present application refines the Fe-containing phase by designing a plurality of trace alloying elements, and simultaneously improves the strength, toughness and thermal conductivity of the alloy.

[0020] The present application contains Al 13 The Fe4 phase or Al5FeSi phase alloy grain, and the number of alloy grains is as high as 2*10 12 / m 2 The yield strength of the alloy is greater than or equal to 160 MPa, the tensile strength is greater than or equal to 300 MPa, the elongation is greater than or equal to 8%, and the thermal conductivity is greater than or equal to 185 W / m*K. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is the microstructure morphology diagram of the aluminum alloy obtained in example 1 of the present application;

[0023] Figure 2 is the microstructure morphology diagram of the aluminum alloy obtained in example 2 of the present application;

[0024] Figure 3Figure 1 is a microstructure morphology diagram of the aluminum alloy obtained in Embodiment 3 of the present application. DETAILED DESCRIPTION

[0025] The technical solutions of the present application will be described clearly and completely below in combination with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0026] To solve the above technical problems, the present embodiment relates to a high-strength high-thermal-conductivity high-toughness aluminum alloy, which comprises the following element components in percentage by mass: Fe 0.5-2%, Si 0-12%, Mg 0.05-0.4%, total content of Ca, Zr, Ni, Bi, Er, B 0.02-0.3%, total content of Mn, Cr, Ti, V elements less than 0.005%, and the balance of Al. The present embodiment aims at the problem that the quantity density of Fe-containing phase is not accurately controlled in the prior art, resulting in limited strengthening effect. Through innovative design of alloy components, accurate control of addition of one or more elements of Mg, Ca, Zr, Ni, Bi, Er, B effectively improves the quantity density of Fe-containing phase, so that the strengthening effect is stronger. On the basis of controlling the Fe-containing phase, the thermal conductivity of the alloy is not reduced, and high-strength high-thermal-conductivity performance of the alloy is realized. In addition, the present application refines the Fe-containing phase through design of one or more trace alloying elements of Mg, Ca, Zr, Ni, Bi, Er, B, reduces the grain size of the Fe-containing phase, and synchronously improves the strength, toughness and thermal conductivity of the alloy.

[0027] As a preferred embodiment, the aluminum alloy comprises alloy grains: when the content of Si element is <0.1%, the Fe-containing phase in the alloy is Al4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 13 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 13 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 12 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 2 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 12 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al 2 4Fe4 phase; when the content of Si element is >0.1%, the Fe-containing phase in the alloy is Al5FeSi phase. Preferably, when the content of Si element is ≥0.1%, the mass percentage of Si is preferably 5-12%, and more preferably 8-12%. The Al

[0028] The yield strength of the aluminum alloy is greater than or equal to 160 MPa, the tensile strength is greater than or equal to 300 MPa, the elongation is greater than or equal to 8%, and the thermal conductivity is greater than or equal to 185 W / m·K. The aluminum alloy has excellent high strength, high toughness and high thermal conductivity, which far exceeds the comprehensive performance of traditional cast aluminum alloy materials in strength, toughness and thermal conductivity.

[0029] Another embodiment provides a preparation method of the high-strength high-thermal-conductivity high-toughness aluminum alloy described in the above embodiments. The cooling rate of the aluminum alloy melt during solidification is 50-500 K / s. The aluminum alloy is prepared by extrusion or high-pressure casting. After the aluminum alloy melt is solidified, the temperature is raised to 400-500 DEG C for heat treatment. The temperature raising rate is 10-20 DEG C / min, and the heat treatment time is 0.5-3 h. The alloy grain is further optimized by using the high cooling rate casting condition, so as to further improve the comprehensive performance of the alloy in strength, toughness and thermal conductivity.

[0030] Embodiment 1

[0031] This embodiment relates to a high-strength high-thermal-conductivity high-toughness aluminum alloy and a preparation method thereof. The aluminum alloy contains the following elements in percentage by mass: Fe 0.51%, Si 8%, Mg 0.15%, Ca 0.05%, Zr 0.08%, B 0.08%, and the total content of Mn, Cr, Ti and V elements is less than 0.004%, and the balance is Al.

[0032] The high-strength high-thermal-conductivity high-toughness aluminum alloy of this embodiment is prepared by high-pressure die casting process. The aluminum alloy melt is solidified at a cooling rate of about 300 K / s, and then heat treated at 450 DEG C for 2 hours (temperature raising rate is 15 DEG C / min).

[0033] The microstructure of the aluminum alloy obtained in this embodiment is shown in Figure 1 The high number density of Al5FeSi phase (about 2.0 x 10 12 / m 2 ) is formed, and the phase size is mostly in the range of 1-3 μm. In the aluminum alloy, the number proportion of the alloy grain size less than 10 μm is 40%, the number proportion of the grain size in the range of 10 μm≤d<20 μm is 30%, and the number proportion of the grain size in the range of 20 μm≤d<40 μm is 30%. The alloy obtained in this embodiment shows balanced comprehensive performance: the yield strength is about 170 MPa, the tensile strength is 315 MPa, the elongation is 9%, and the thermal conductivity is 188 W / (m·K).

[0034] Embodiment 2

[0035] The embodiment relates to a high-strength high-thermal-conductivity high-toughness aluminum alloy and a preparation method thereof, and the aluminum alloy comprises the following element components in percentage by mass: Fe 0.68%, Si 10.22%, Mg 0.11%, Ni 0.08%, Er 0.05%, Bi 0.03%, Ca 0.02%, B 0.08%, and the total content of Mn, Cr, Ti and V is less than 0.005%, and the rest is Al.

[0036] The high-strength high-thermal-conductivity high-toughness aluminum alloy in the embodiment is prepared through a high-pressure die casting process, the aluminum alloy melt is solidified at a cooling rate of about 52 K / s, and then is subjected to heat treatment at 480 DEG C for 1 hour (the heating rate is 10 DEG C / min).

[0037] The microstructure of the aluminum alloy obtained in the embodiment is shown in the drawing. Figure 2 The addition of Ni and Er promotes the formation of high-density Al5FeSi phases, and Bi and Ca effectively modify the eutectic silicon phases to make them spheroidized. The microstructure is characterized by high-density Al5FeSi phases (about 2.1 x 10 12 / m 2 ) and the phase size ranges from 2 to 4 microns. The number proportion of the aluminum alloy grain size in the range of less than 10 microns is 60%, the number proportion of the grain size in the range of 10 microns <= d < 20 microns is 20%, and the number proportion of the grain size in the range of 10 microns <= d < 20 microns is 20%. The yield strength of the alloy in the embodiment reaches 172 MPa, the tensile strength reaches 319 MPa, the elongation reaches 9.8%, the thermal conductivity is improved to 188 W / (m*K), and excellent matching of strength, toughness and thermal conductivity is achieved.

[0038] Embodiment 3

[0039] The embodiment relates to a high-strength high-thermal-conductivity high-toughness aluminum alloy and a preparation method thereof, and the aluminum alloy comprises the following element components in percentage by mass: Fe 1.8%, Mg 0.37%, Zr 0.11%, Ca 0.08%, Bi 0.05%, Er 0.02%, B 0.03%, Si 0.03%, and the total content of Mn, Cr, Ti and V is less than 0.003%, and the rest is Al.

[0040] The high-strength high-thermal-conductivity high-toughness aluminum alloy in the embodiment is prepared through a high-pressure die casting process, the aluminum alloy melt is solidified at a cooling rate of about 390 K / s, and then is subjected to heat treatment at 400 DEG C for 2 hours (the heating rate is 20 DEG C / min).

[0041] The microstructure of the aluminum alloy obtained in the embodiment is shown in the drawing. Figure 3 The alloy forms high-number-density Al 13 Fe4 phases (about 2.8 x 10 12 / m2 ), the number proportion of the alloy grain size in the range of 10 pm≤d<20 pm is 25%, and the number proportion of the alloy grain size in the range of 20 pm≤d<40 pm is 25%. The alloy exhibits balanced comprehensive performance: the yield strength is about 174 MPa, the tensile strength reaches 311 MPa, the elongation is 10%, and the thermal conductivity is 189 W / (m·K), which meets the performance target set by the patent. In the alloy, the fine and dispersed Al 13 Fe4 phase provides the basis for strengthening, and the pure aluminum matrix guarantees the heat conduction path. Therefore, the alloy realizes high strength and high thermal conductivity performance, and is suitable for application scenarios with extreme requirements for heat dissipation efficiency.

[0042] Comparative Example 1

[0043] The comparative example relates to an aluminum alloy and a preparation method thereof, which comprises the following element components in percentage by mass: Fe 0.65%, Si 7.56%, Mg 0.21%, and the balance being Al.

[0044] The aluminum alloy of the comparative example is prepared by a high-pressure die casting process, and the aluminum alloy melt is solidified at a cooling rate of about 100 K / s, and then is subjected to a heat treatment at 400°C for 2 hours (heating rate 20°C / min). Under this process, the alloy forms Al5FeSi phase with a number density of 1.0×10 12 / m 2 , and the phase size is in the range of 20-30 pm. The yield strength of the alloy is about 130 MPa, the tensile strength reaches 265 MPa, the elongation is 7%, and the thermal conductivity is 170 W / (m·K). It can be seen that without the precise control of one or more of Ca, Zr, Ni, Bi, Er, and B, the number of Al5FeSi phase is greatly reduced, the phase size is greatly increased, and the strength, toughness, and thermal conductivity of the obtained alloy are all reduced to different degrees.

[0045] Comparative Example 2

[0046] The comparative example relates to an aluminum alloy and a preparation method thereof, which comprises the following element components in percentage by mass: Fe 2.6%, Mg 0.37%, Si 0.03%, and the balance being Al.

[0047] The aluminum alloy of the comparative example is prepared by a high-pressure die casting process, and the aluminum alloy melt is solidified at a cooling rate of about 100 K / s, and then is subjected to a heat treatment at 400°C for 2 hours (heating rate 20°C / min). Under this process, the alloy forms Al 13 Fe4 phase with a number density of 1.0×10 12 / m 2, the size of the phase is in the range of 20-30 μm. The yield strength of the alloy is about 131 MPa, the tensile strength reaches 250 MPa, the elongation is 7%, and the thermal conductivity is 171 W / (m·K). It can be seen that without the precise control of one or more of Ca, Zr, Ni, Bi, Er, and B, Al 13 The number of Fe4 phases is greatly reduced, and the size of the phase is greatly increased, and the strength, toughness and thermal conductivity of the obtained alloy are all reduced to different degrees.

[0048] In summary, through the innovative design of the alloy composition, the number density of the Fe-containing phase is effectively increased by precisely controlling the addition of one or more of Mg, Ca, Zr, Ni, Bi, Er, and B, so that the strengthening effect is stronger; the thermal conductivity of the alloy is not reduced on the basis of controlling the Fe-containing phase, and the high-strength and high-thermal-conductivity performance of the alloy is realized; the Fe-containing phase is refined by designing multiple trace alloying elements, and the strength, toughness and thermal conductivity of the alloy are simultaneously improved; the aluminum alloy contains Al 13 Fe4 phase or Al5FeSi phase alloy grains, and the number of alloy grains is as high as 2×10 12 / m 2 , the yield strength of the alloy is ≥160 MPa, the tensile strength is ≥300 MPa, the elongation is ≥8%, and the thermal conductivity is ≥185 W / m·K.

[0049] In the present application, unless otherwise specified, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like used in the present application indicate the orientation or positional relationship only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application; the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present patent can be understood according to the specific circumstances.

[0050] The present application has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that the technical solutions and embodiments of the present application can be variously replaced, modified or improved without deviating from the spirit and scope of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

Claims

1. A high-strength, high-thermal-conductivity, high-toughness aluminum alloy, characterized by comprising, in mass %, The aluminum alloy comprises the following components by mass percentage: Fe 0.5-2%, Si 0-12%, Mg 0.05-0.4%, total content of Ca, Zr, Ni, Bi, Er and B 0.02-0.3%, total content of Mn, Cr, Ti and V less than 0.005%, and the balance of Al.

2. The high-strength, high-thermal conductivity, high-toughness aluminum alloy of claim 1, wherein, The aluminum alloy contains a Fe-containing phase: when the content of Si element is <0.1%, the Fe-containing phase in the alloy is Al4FeSi 13 Fe4phase; when the content of Si element is ≥0.1%, the Fe-containing phase in the alloy is Al5FeSi phase.

3. The high-strength, high-thermal conductivity, high-toughness aluminum alloy of claim 2, wherein, The Al 13 Fe4phase number density ≥ 2 x 10 12 / m 2 .

4. The high-strength, high-thermal conductivity, high-toughness aluminum alloy of claim 2, wherein The number density of the Al5FeSi phase is ≥ 1.5 x 10 12 / m 2 .

5. The high-strength, high-thermal conductivity, high-toughness aluminum alloy of claim 1, wherein In the aluminum alloy, the number of grains with a grain size d < 10 μm accounts for 40-60%, the number of grains with a grain size 10 μm ≤ d < 20 μm accounts for 20-30%, and the number of grains with a grain size 20 μm ≤ d < 40 μm accounts for 10-30%.

6. The high-strength, high-thermal conductivity, high-toughness aluminum alloy of claim 1, wherein The aluminum alloy has a yield strength ≥ 160 MPa, a tensile strength ≥ 300 MPa, an elongation ≥ 8%, and a thermal conductivity ≥ 185 W / m·K.

7. A method of producing the high-strength, high-thermal conductivity, high-toughness aluminum alloy according to any one of claims 1 to 6, characterized by, The cooling rate of the aluminum alloy melt during solidification is 50-500 K / s.

8. The method of producing a high-strength, high-thermal conductivity, high-toughness aluminum alloy according to claim 7, wherein The aluminum alloy is prepared by extrusion or high-pressure casting.

9. The method of producing a high-strength, high-thermal conductivity, high-toughness aluminum alloy according to claim 7, wherein After the solidification of the aluminum alloy melt, the aluminum alloy is heated to 400-500 ℃ for heat treatment.

10. The method of producing a high-strength, high-thermal conductivity, high-toughness aluminum alloy according to claim 7, wherein The heating rate is 10-20 ℃ / min, and the heat treatment time is 0.5-3 h.

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