High-thermal-conductivity high-plasticity cast aluminum alloy and preparation method thereof

Abstract

The application discloses a high-thermal-conductivity high-plasticity cast aluminum alloy and a preparation method thereof. The alloy is composed of the following components in percentage by mass: Zn: 2.0-12.0 %, M: 0.3-3.0 %, B: 0.05-0.3 %, and the balance of Al and inevitable impurities, wherein M is at least one of La, Ce and Ca; the atomic percentage content ratio of Zn and M in the aluminum alloy is Zn / M >= 2; the aluminum alloy comprises a matrix phase and a eutectic phase; the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape. The application dopes Zn, Ce, La and Ca elements which have little influence on the thermal conductivity as main alloying elements in the Al matrix, controls the reasonable combination of Zn and Ce, La and Ca elements, ensures that the alloy has excellent casting performance, reduces the die sticking of the alloy in the die casting process through Fe and Mn, improves the strength of the alloy through Mg, Si and Cu elements, finally reasonably designs the components, and significantly improves the thermal conductivity and the elongation of the aluminum alloy which is not less than 10 %, and expands the application range of the aluminum alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cast aluminum alloy materials, and particularly relates to a high-thermal-conductivity high-plasticity cast aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Casting aluminum alloys have low density, high specific strength, good corrosion resistance and castability, and are widely used in aerospace, transportation, electronic communication and other fields. With the development and progress of science and technology, the heat generated by electronic products and communication equipment increases, and higher requirements are put forward for the heat dissipation performance of case, frame and shell materials. In the electronic communication industry, in order to ensure that the alloy has excellent castability to meet the forming requirements of complex and thin-walled parts, Al-Si series casting aluminum alloys are generally selected. However, due to the presence of a large amount of Si element in these alloys, the thermal conductivity of the alloy is low and the plasticity is poor. For example, the thermal conductivity of the widely used ADC12 die casting aluminum alloy is less than 96 W / (m.k), the tensile strength is less than 150 MPa, and the elongation is less than 3%. In order to improve the thermal conductivity of the casting aluminum alloy, researchers mainly optimize the design of Al-Si series alloys or develop new casting aluminum alloy series. For example, patent CN 109652685 B discloses a high-thermal-conductivity and high-corrosion-resistance casting aluminum alloy and a preparation method thereof, which is composed of the following components in percentage: 7-9% Si, 0.6-1.0% Fe, 0.2-0.6% Zn, 0.1-0.5% Co, 0.05%-0.15% B, 0.2-0.5% RE, 0.05-0.2% Sr, and the balance of Al. However, the thermal conductivity of the as-cast alloy is less than 160 W / (m.k). Patent CN 104264017 B discloses a high-thermal-conductivity die casting aluminum alloy and a preparation method thereof. The weight percentage of each component in the die casting aluminum alloy is as follows: 10.50-13.50% Si, 0.10-0.50% Co, 0.20-0.40% Fe, 0.01-0.05% Ti, 0.01-0.05% B, other impurities total amount and less than or equal to 0.2%, and the balance of aluminum. The thermal conductivity of the alloy can reach 190 W / (m.k), but the elongation is less than 4%. Patent CN 111378875 B discloses a high-thermal-conductivity and corrosion-resistant Al-RE-Y-Zr alloy suitable for gravity casting and a preparation method thereof, which contains the following elements in mass percentage: 5-16% RE, 0.1-7% Y, 0.5-0.8% Mg, 0.01-0.5% Zr, and the balance of Al elements and unavoidable impurity elements; wherein RE is at least one element of La and Ce. The casting Al REY alloy of the invention has a room temperature tensile strength of 175 MPa, a yield strength of 86 MPa or more, an elongation of 10% or more, and a thermal conductivity of 160 W / (m.K) or more after gravity casting, but the high cost of raw materials of the alloy is caused by the addition of a large amount of rare earth elements.Patent CN114672697 B discloses a new high-thermal-conductivity die-casting aluminum alloy and a preparation method thereof. According to mass percentage, the alloy comprises 1.5-2.5% Ni, 0.5-1.5% Fe, 0.5-1.0% Mg, 0.9-1.8% Zn, 0.1-0.3% B, unavoidable other impurities less than 0.3%, and the balance of Al. The tensile strength of the die-casting aluminum alloy of the invention is 197-209 MPa, and the thermal conductivity coefficient is 208.9-209.6 W / (m.K), but Ni is a strategic resource and is expensive, which is not suitable for large-scale application in the field of civil electronic products. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a high-thermal-conductivity high-plasticity cast aluminum alloy and a preparation method thereof. Zn, Ce, La and Ca elements which have little effect on thermal conductivity are doped in an Al matrix as main alloying elements, and reasonable matching of Zn and Ce, La and Ca elements is controlled to form network-shaped Al-M-Zn eutectic phase in the structure, so as to ensure that the alloy has excellent casting performance. In addition, Fe and Mn are added to reduce die sticking of the alloy during die casting, Mg and Si and Cu elements are added to improve the strength of the alloy, and a small amount of B element is added to refine the grains. Finally, the thermal conductivity of the cast aluminum alloy obtained by reasonable design of components and through gravity casting or die casting and heat treatment can reach more than 200 W / (m.K), and the elongation is not less than 10%.

[0004] According to an aspect of the present application, the present application provides a high-thermal-conductivity high-plasticity cast aluminum alloy, comprising 2.0-12.0 wt% Zn, 0.3-3.0 wt% M (M is at least one of La, Ce and Ca), the balance of Al and unavoidable impurities.

[0005] In some embodiments, the M is Ca.

[0006] In some embodiments, the high-thermal-conductivity high-plasticity cast aluminum alloy can further comprise 0.05-0.3% B.

[0007] In some embodiments, the high-thermal-conductivity high-plasticity cast aluminum alloy can further comprise 0.1-1.2% Fe.

[0008] In some embodiments, the high-thermal-conductivity high-plasticity cast aluminum alloy can further comprise 0.2-0.8% Mn.

[0009] In some embodiments, the high-thermal-conductivity high-plasticity cast aluminum alloy can further comprise 0.3-1.0% Mg and 0.2-3.0% Si.

[0010] In some embodiments, the high-thermal-conductivity high-plasticity cast aluminum alloy can further include 0.1-3.0% of Cu.

[0011] According to another aspect of the present application, the present application further provides a preparation method of the high-thermal-conductivity high-plasticity cast aluminum alloy, comprising the following steps:

[0012] a. Raw material preparation: quantitatively configure Al ingot, Zn ingot, Mg ingot and Al-Ce, Al-La, Al-Si, Al-Ca, Al-Fe, Al-Mn and Al-Cu intermediate alloy raw materials according to the mass percentage;

[0013] b. Melting: after preheating the pit-type crucible, load the Al ingot, melt the Al ingot by increasing the temperature, then increase the temperature to 720℃, add the intermediate alloy in batches, melt and fully stir; decrease the temperature to 700℃, then add the Mg ingot and Zn ingot, melt and fully stir to be uniform, remove the slag, and obtain the alloy melt;

[0014] c. Refining: introduce Ar gas for refining treatment at 700℃ for 30 min;

[0015] d. Casting: after the refining is completed, stand for 1 h, remove the surface dross, then pour into ingot by gravity or perform die casting to obtain the high-thermal-conductivity high-plasticity gravity cast aluminum alloy or the die cast aluminum alloy.

[0016] The present application further provides a heat treatment method of the high-thermal-conductivity high-plasticity cast aluminum alloy, comprising:

[0017] 1) the gravity cast aluminum alloy obtained in the step d is kept at 350-420℃ for 0.5-2 h, then increased to 490-560℃ for 3-10 h for solid solution treatment, water-quenched to room temperature, kept at 115-220℃ for 5-20 h for aging treatment, and the gravity cast aging-state aluminum alloy is obtained;

[0018] 2) the die cast aluminum alloy obtained in the step d is kept at 115-180℃ for 1-8 h for aging treatment, and the die cast aging-state aluminum alloy is obtained.

[0019] The present application has the following advantages over the prior art:

[0020] (1) by controlling the content of Zn element to be between 2.0-12.0%, and by the matching of Zn with Ce, La and Ca, the total content of Ce, La and Ca is controlled to be between 0.3-3.0%, and the atomic percentage ratio of Zn / M is kept to be greater than or equal to 2, so that the main second phase in the alloy structure is the network-distributed Al-M-Zn ternary phase, the thermal brittleness caused by Zn is reduced, the solidification interval of the alloy is shortened, and the casting performance is improved.

[0021] (2) Secondly, controlling the content of Zn element can reduce the melting point of the alloy and improve the casting fluidity.

[0022] (3) Generally, Ca element is considered as an impurity element in Al alloy, which reduces the castability of the aluminum alloy. However, the present application finds that, after Zn and Ca elements with reasonable components are adopted, the combination of Zn and Ca in the alloy can not only reduce the adverse effects of Ca element on the fluidity and solidification shrinkage and other casting defects of the aluminum alloy, but also form Al-M-Zn ternary phase similar to La and Ce, so that the addition of La and Ce can be reduced or even replaced, and the cost of the alloy is significantly reduced.

[0023] (4) By adjusting the contents of Fe, Mn, Mg, Si and Cu elements, the die casting performance and strength of the alloy can be improved when the contents are in a suitable component range.

[0024] (5) The present application adopts a targeted heat treatment process, which can further improve the thermal conductivity and strength matching of the gravity casting and die casting aluminum alloy, and expand the application range thereof. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The microstructure of the gravity casting aluminum alloy (a) and the die casting aluminum alloy (b) of Example 1 of the present application.

[0026] Figure 2 The microstructure of the as-cast alloy of Example 5 of the present application. DETAILED DESCRIPTION

[0027] The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0028] Example 1: Preparation of Al-5Zn-2La-0.15B alloy

[0029] (1) Prepare pure Al ingot, pure Zn ingot, Al-La and Al-B intermediate alloy, and mix them according to the above alloy component ratio;

[0030] (2) After preheating the crucible, put the pure Al ingot into the crucible, heat to melt the Al ingot, then heat to 720℃, add Al-La and Al-B intermediate alloy, melt and stir thoroughly; cool to 700℃, then add pure Zn ingot, melt and stir thoroughly, remove slag, and obtain the alloy melt;

[0031] (3) Blow Ar gas for 30 min at 700℃ for refining treatment, and obtain the castable melt;

[0032] (4) After refining, the alloy melt was kept for 1 h, and then the surface scum was removed. A part of the alloy melt was poured into a preheated metal mold at 200℃ by gravity casting to obtain a gravity cast aluminum alloy. Another part of the alloy melt was subjected to cold-chamber die casting to obtain a die cast aluminum alloy.

[0033] (5) The gravity cast alloy was kept at 360℃ for 1 h, and then heated to 508℃ for 5 h, and then quenched to room temperature by water cooling. The gravity cast alloy was aged at 120℃ for 15 h to obtain a gravity cast aged alloy. The die cast alloy was aged at 150℃ for 3 h to obtain a die cast aged alloy.

[0034] The Zn / La atomic ratio of the Al-5Zn-2La-0.15B alloy prepared in the example is 5.27. The microstructure of the gravity cast alloy is shown in (a), and the microstructure of the die cast alloy is shown in (b). The second phase of both the alloys is a network-shaped Al-La-Zn ternary phase. Figure 1 Figure 1 The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in the example are shown in Table 1, and the properties of the die cast aluminum alloy are shown in Table 2.

[0035] Example 2: Preparation of Al-5Zn-1La-0.5Ca-0.15B alloy

[0036] The Zn / (La+Ca) atomic ratio of the Al-5Zn-1La-0.5Ca-0.15B alloy prepared in the example is 3.89, and the preparation process is basically the same as that of Example 1, wherein the Al-Ca and Al-La intermediate alloys are added at the same time. The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in the example are shown in Table 1, and the properties of the die cast aluminum alloy are shown in Table 2.

[0037] Example 3: Preparation of Al-10Zn-1.5La-1Ca-0.8Fe-0.15B alloy

[0038] The Zn / (La+Ca) atomic ratio of the Al-10Zn-1.5La-1Ca-0.8Fe-0.15B alloy prepared in the example is 4.26, and the preparation process is basically the same as that of Example 1, wherein the Al-Ca, Al-Fe and Al-La intermediate alloys are added at the same time. The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in the example are shown in Table 1, and the properties of the die cast aluminum alloy are shown in Table 2.

[0039] Example 4: Preparation of Al-8Zn-0.8La-1.2Ce-1Ca-0.8Mg-1.2Si-0.8Fe-0.15B alloy

[0040] ​(1) Prepare pure Al ingot, pure Zn ingot, pure Mg ingot, Al-La, Al-Ce, Al-Ca, Al-Si, Al-Fe and Al-B intermediate alloy, and proportion according to the above alloy composition ratio;

[0041] (2) After preheating the well-type crucible, the pure Al ingot is loaded, the Al ingot is melted after heating, and then the temperature is raised to 720℃, the Al-La, Al-Ce, Al-Si, Al-Fe and Al-B intermediate alloy is added, and the alloy is fully stirred after melting; The temperature is lowered to 700℃, then the pure Mg ingot and the pure Zn ingot are added, and the alloy is fully stirred after melting to be uniform, and the slag is removed to obtain an alloy melt;

[0042] (3) Ar gas is introduced for refining treatment at 700℃ for 30min to obtain a castable melt;

[0043] (4) After the refining is completed, the surface dross is removed after standing for 1h, and then a part of the alloy melt is poured into a preheated 200℃ metal mold by gravity casting to obtain a gravity cast aluminum alloy; another part of the melt is subjected to cold chamber die casting to obtain a die cast aluminum alloy.

[0044] (5) The gravity cast alloy is aged at 380℃ for 1h, then the temperature is raised to 550℃ for 4h, and then water quenching is performed to room temperature, and aging is performed at 150℃ for 10h to obtain a gravity cast aged alloy; the die cast alloy is aged at 180℃ for 2h to obtain a die cast aged alloy.

[0045] The Zn / (La+Ce+Ca) atomic ratio of the Al-8Zn-0.8La-1.2Ce-1Ca-0.8Mg-1.2Si-0.8Fe-0.15B alloy of the present embodiment is 3.11. The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in the present embodiment are shown in Table 1, and the performance of the die cast aluminum alloy is shown in Table 2.

[0046] Example 5: Preparation of Al-8Zn-1Ca-2Cu-0.5Mn-0.15B alloy

[0047] (1) Prepare pure Al ingot, pure Zn ingot, Al-Ca, Al-Cu, Al-Mn and Al-B intermediate alloy, and proportion according to the above alloy composition ratio;

[0048] (2) After preheating the well-type crucible, the pure Al ingot is loaded, the Al ingot is melted after heating, and then the temperature is raised to 720℃, the Al-La, Al-Ce, Al-Ca, Al-Si, Al-Fe and Al-B intermediate alloy is added, and the alloy is fully stirred after melting; The temperature is lowered to 700℃, then the pure Mg ingot and the pure Zn ingot are added, and the alloy is fully stirred after melting to be uniform, and the slag is removed to obtain an alloy melt;

[0049] (3) Ar gas is introduced for refining treatment at 700℃ for 30min to obtain a castable melt;

[0050] (4) After refining, the alloy melt was poured into a preheated metal mold at 200℃ by gravity casting to obtain a gravity cast aluminum alloy, and another part of the melt was subjected to cold chamber die casting to obtain a die cast aluminum alloy.

[0051] (5) The gravity cast alloy was aged at 380℃ for 1h, then heated to 530℃ for 5h, water quenched to room temperature, and aged at 200℃ for 12h to obtain a gravity cast aged alloy; the die cast alloy was aged at 210℃ for 1h to obtain a die cast aged alloy.

[0052] The Zn / Ca atomic ratio of the Al-8Zn-1Ca-2Cu-0.5Mn-0.15B alloy in the example is 4.90, Figure 2 The SEM microstructure of the as-cast alloy is shown, and the energy spectrum analysis results show that the network eutectic phase mainly contains Al, Zn and Ca elements, and is determined as an Al-Ca-Zn ternary phase. The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in the example are shown in Table 1, and the performance of the die cast aluminum alloy is shown in Table 2.

[0053] Example 6: Preparation of Al-11Zn-2.6Ca alloy

[0054] (1) Prepare pure Al ingot, pure Zn ingot and Al-Ca intermediate alloy, and prepare according to the above alloy composition ratio;

[0055] (2) After preheating the pit crucible, the pure Al ingot is loaded, the Al ingot is melted by heating, and then the temperature is raised to 720℃, the Al-Ca intermediate alloy is added, and after melting, it is fully stirred; the temperature is lowered to 700℃, then the pure Zn ingot is added, and after melting, it is fully stirred and uniformly distributed, and the slag is removed to obtain an alloy melt;

[0056] (3) Ar gas is introduced for 30min at 700℃ for refining treatment to obtain a castable melt;

[0057] (4) After refining, the alloy melt is poured into a preheated metal mold at 200℃ by gravity casting to obtain a gravity cast aluminum alloy, and another part of the melt is subjected to cold chamber die casting to obtain a die cast aluminum alloy.

[0058] (5) The gravity cast alloy is aged at 360℃ for 1h, then heated to 540℃ for 1h, water quenched to room temperature, and aged at 150℃ for 10h to obtain a gravity cast aged alloy; the die cast alloy is aged at 180℃ for 30min to obtain a die cast aged alloy.

[0059] The Zn / Ca atomic ratio of the Al-11Zn-2.6Ca alloy of this example is 2.58. The tensile strength, elongation and thermal conductivity of the gravity cast aluminum alloy prepared in this example are shown in Table 1, and the properties of the die cast aluminum alloy are shown in Table 2.

[0060] Table 1 Properties of the gravity cast aluminum alloy of each example

[0061]

[0062]

[0063] Table 2 Properties of the die cast aluminum alloy of each example

[0064]

[0065] The above application is only some embodiments of the present application. For those skilled in the art, several variations and improvements can be made without departing from the concept created by the present application, which are all within the scope of protection of the present application.

Claims

1. A high thermal conductive high plasticity cast aluminum alloy, characterized by comprising, in mass %, The alloy composition comprises, by mass percent: Zn: 2.0-12.0%, M: 0.3-3.0%, the balance being Al and inevitable impurities, wherein M is Ca, The atomic percentage ratio of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape, The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The thermal conductivity of the gravity casting aluminum alloy in a cast state is 180-205 W / (m.K), the tensile strength is not less than 200 MPa, and the elongation is not less than 10%; The thermal conductivity of the die casting aluminum alloy in a cast state is 175-205 W / (m.K), the tensile strength is not less than 280 MPa, and the elongation is not less than 10%; The thermal conductivity of the aged gravity casting aluminum alloy is 190-210 W / (m.K), the tensile strength is not less than 250 MPa, and the elongation is not less than 15.0%; 2. A high thermal conductive high plasticity cast aluminum alloy, characterized by comprising, in mass %, The thermal conductivity of the aged die casting aluminum alloy is 185-210 W / (m.K), the tensile strength is not less than 310 MPa, and the elongation is not less than 10%. The alloy composition comprises, by mass percent: Zn: 2.0-12.0%, M: 0.3-3.0%, B: 0.05-0.3%, the balance being Al and inevitable impurities, wherein M is Ca, The atomic percentage ratio of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape, The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The thermal conductivity of the gravity casting aluminum alloy in a cast state is 180-205 W / (m.K), the tensile strength is not less than 200 MPa, and the elongation is not less than 10%; The thermal conductivity of the die casting aluminum alloy in a cast state is 175-205 W / (m.K), the tensile strength is not less than 280 MPa, and the elongation is not less than 10%; The thermal conductivity of the aged gravity casting aluminum alloy is 190-210 W / (m.K), the tensile strength is not less than 250 MPa, and the elongation is not less than 15.0%; 3. A high thermal conductive high plasticity cast aluminum alloy, characterized by comprising, in mass %, The thermal conductivity of the aged die casting aluminum alloy is 185-210 W / (m.K), the tensile strength is not less than 310 MPa, and the elongation is not less than 10%. The alloy composition comprises, by mass percent: Zn: 2.0-12.0%, M: 0.3-3.0%, B: 0.05-0.3%, Fe: 0.1-1.2%, the balance being Al and inevitable impurities, wherein M is Ca, The atomic percentage ratio of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape, The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The gravity casting aluminum alloy has a thermal conductivity of 180-205 W / (m.K) in a cast state, a tensile strength of not less than 200 MPa and an elongation of not less than 10%; The die casting aluminum alloy has a thermal conductivity of 175-205 W / (m.K) in a cast state, a tensile strength of not less than 280 MPa and an elongation of not less than 10%; The aged gravity casting aluminum alloy has a thermal conductivity of 190-210 W / (m.K), a tensile strength of not less than 250 MPa and an elongation of not less than 15.0%; The aged die casting aluminum alloy has a thermal conductivity of 185-210 W / (m.K), a tensile strength of not less than 310 MPa and an elongation of not less than 10%.

4. A high thermal conductive high plasticity cast aluminum alloy, characterized by comprising, in mass %, The alloy composition comprises, in mass percentage, Zn: 2.0-12.0%, M: 0.3-3.0%, B: 0.05-0.3%, Fe: 0.1-1.2%, Mn: 0.2-0.8%, the balance of Al and inevitable impurities, wherein M is Ca, The ratio of the atomic percentage of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, and the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape; The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The gravity casting aluminum alloy has a thermal conductivity of 180-205 W / (m.K) in a cast state, a tensile strength of not less than 200 MPa and an elongation of not less than 10%; The die casting aluminum alloy has a thermal conductivity of 175-205 W / (m.K) in a cast state, a tensile strength of not less than 280 MPa and an elongation of not less than 10%; The aged gravity casting aluminum alloy has a thermal conductivity of 190-210 W / (m.K), a tensile strength of not less than 250 MPa and an elongation of not less than 15.0%; The aged die casting aluminum alloy has a thermal conductivity of 185-210 W / (m.K), a tensile strength of not less than 310 MPa and an elongation of not less than 10%.

5. A high thermal conductivity high ductility cast aluminum alloy characterized by comprising, in mass %, The alloy composition comprises, in mass percentage, Zn: 2.0-12.0%, M: 0.3-3.0%, B: 0.05-0.3%, Fe: 0.1-1.2%, Mn: 0.2-0.8%, Mg: 0.3-1.0%, Si: 0.2-3.0%, the balance of Al and inevitable impurities, wherein M is Ca, The ratio of the atomic percentage of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, and the eutectic phase is an Al-M-Zn ternary phase distributed in a network shape; The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The gravity casting aluminum alloy has a thermal conductivity of 180-205 W / (m.K) in a cast state, a tensile strength of not less than 200 MPa, and an elongation of not less than 10%; The die casting aluminum alloy has a thermal conductivity of 175-205 W / (m.K) in a cast state, a tensile strength of not less than 280 MPa, and an elongation of not less than 10%; The aged gravity casting aluminum alloy has a thermal conductivity of 190-210 W / (m.K), a tensile strength of not less than 250 MPa, and an elongation of not less than 15.0%; The aged die casting aluminum alloy has a thermal conductivity of 185-210 W / (m.K), a tensile strength of not less than 310 MPa, and an elongation of not less than 10%.

6. A high thermal conductivity high ductility cast aluminum alloy characterized by comprising, in mass %, The alloy composition comprises, in percentage by mass: Zn: 2.0-12.0%, M: 0.3-3.0%, B: 0.05-0.3%, Fe: 0.1-1.2%, Mn: 0.2-0.8%, Mg: 0.3-1.0%, Si: 0.2-3.0%, Cu: 0.1-3.0%, and the balance of Al and inevitable impurities, wherein M is Ca, The atomic percentage ratio of Zn and M in the aluminum alloy is Zn / M≥2, the high-thermal-conductivity casting aluminum alloy comprises a matrix phase and a eutectic phase, and the eutectic phase is an Al-M-Zn ternary phase in a network distribution; The casting aluminum alloy is a gravity casting aluminum alloy, a die casting aluminum alloy, an aged gravity casting aluminum alloy or an aged die casting aluminum alloy; The gravity casting aluminum alloy has a thermal conductivity of 180-205 W / (m.K) in a cast state, a tensile strength of not less than 200 MPa, and an elongation of not less than 10%; The die casting aluminum alloy has a thermal conductivity of 175-205 W / (m.K) in a cast state, a tensile strength of not less than 280 MPa, and an elongation of not less than 10%; The aged gravity casting aluminum alloy has a thermal conductivity of 190-210 W / (m.K), a tensile strength of not less than 250 MPa, and an elongation of not less than 15.0%; The aged die casting aluminum alloy has a thermal conductivity of 185-210 W / (m.K), a tensile strength of not less than 310 MPa, and an elongation of not less than 10%.

7. A method of producing a high thermal conductivity cast aluminum alloy according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) raw material preparation: quantitatively configuring raw materials according to the mass percentage, wherein the raw materials at least comprise Al ingot, Zn ingot, Al-M intermediate alloy and Al-B intermediate alloy; (2) melting: preheating a pit crucible, loading the Al ingot, melting the Al ingot by heating, heating to 720 ℃, adding other raw materials in batches, melting, fully stirring, skimming, and obtaining an alloy melt; (3) refining: introducing Ar gas for refining treatment at 700 ℃ for 30 min; (4) casting: after the refining is completed, standing for 1 h, removing the surface dross, and then performing gravity casting into an ingot or die casting, to obtain a high-thermal-conductivity high-plasticity gravity casting aluminum alloy or a die casting aluminum alloy; 8. The method for preparing a high thermal conductivity cast aluminum alloy according to claim 7, characterized in that, The obtained gravity casting aluminum alloy is heat treated at 350-420 DEG C for 0.5-2 h, then heated to 490-560 DEG C for 3-10 h for solid solution treatment, water quenched to room temperature, and then aged at 115-220 DEG C for 5-20 h to obtain an aged gravity casting aluminum alloy; The obtained die casting aluminum alloy is aged at 115-180 DEG C for 1-8 h to obtain an aged die casting aluminum alloy.

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