A conductive Al 2 O 3 / Al-based composite material and its preparation method

Abstract

The present invention discloses a conductive Al2O3 / Al-based composite material and a preparation method thereof. The content of alumina particles in the composite material is 0.1 to 0.5 wt.%, the total content of copper, zirconium and cerium is 0.34 to 2 wt.%, and the balance is aluminum. The preparation method is as follows: heating and melting a pure aluminum block to obtain an aluminum melt; adding an in-situ reaction powder preform into the aluminum melt for in-situ reaction, cooling after the reaction ends to obtain an aluminum-based melt; successively adding an aluminum-zirconium master alloy and an aluminum-cerium master alloy into the aluminum-based melt, stirring until completely melted to obtain a mixed melt; casting by a near-liquidus casting method to obtain an aluminum-based composite material ingot; performing solution treatment on the aluminum-based composite material ingot to obtain an aluminum-based composite material; and performing alternating treatment of rolling and aging on the aluminum-based composite material. The aluminum-based composite material of the present invention has both mechanical properties and electrical conductivity, and can solve the problem of low mechanical properties of existing aluminum wires.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum matrix composites. Specifically, it is a conductive Al 2 O 3 / Al matrix composite material and its preparation method. Background Art

[0002] Both copper and aluminum are high-quality conductor materials. Among them, copper materials have excellent electrical conductivity, good flexibility, excellent corrosion resistance, high ductility, and recyclability, and have always dominated the application of wires and cables. According to statistics, the content of copper in the earth's crust is about 0.01%, which belongs to scarce resources, while the content of aluminum in the earth's crust is about 7.45%, which is the most abundant metal in reserves. Its density is about 1 / 3 of that of copper, and its relative electrical conductivity is 63% IACS, and the price is only about 30% of that of pure copper. With the development direction of a conservation-oriented society advocated in China, "replacing copper with aluminum" is an inevitable trend. However, compared with copper wires, pure aluminum wires have the problem of low mechanical properties.

[0003] All-aluminum alloy stranded wire (AAAC), all of its strands are composed of homogeneous aluminum alloy wires, and has the advantages of high elongation rate, good corrosion resistance, and being convenient for recycling and reuse; its tensile strength is slightly lower than that of aluminum alloy stranded wire with steel core (AACSR), but its relative electrical conductivity is higher. The commonly used all-aluminum alloy stranded wire is medium-strength aluminum alloy stranded wire (such as LHA3), which complies with GB / T42042-2014. In the process indexes, the tensile strength of the single wire ≥235MPa, the electrical conductivity ρ20 ≥58.5% IACS at 20°C, and the elongation after fracture of the single wire after stranding >3.5%. With the expansion of the application demand of aluminum alloy, the mechanical requirements for conductive aluminum alloy are also getting higher and higher. Therefore, it is necessary to prepare conductive aluminum alloy with higher mechanical strength. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a conductive Al 2 O 3 / Al matrix composite material and its preparation method to solve the problem of low mechanical properties of existing aluminum wires.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A conductive Al 2 O 3 / Al-based composite material, the content of alumina particles is 0.1 - 0.5 wt.%, the total content of copper, zirconium and cerium is 0.34 - 2 wt.%, and the balance is aluminum. If the content of alumina particles is greater than 0.5 wt%, the casting is prone to cracking during subsequent rolling deformation, and too high a content has a greater impact on the electrical conductivity; an increase in the content of alumina particles means an increase in the content of copper element, which will make the composite material prone to cracking during rolling, while an increase in the content of zirconium and cerium will cause alloying elements not to be fully dissolved into the lattice points of the matrix during the solution treatment, thereby affecting the material properties.

[0007] The above-mentioned conductive Al 2 O 3 / Al-based composite material, the mass ratio of the three elements of copper, zirconium and cerium is (8 - 10):(1 - 2):1.

[0008] The above-mentioned conductive Al 2 O 3 Preparation method of the above-mentioned conductive Al

[0009] Step (1), heating and melting a pure aluminum block to obtain an aluminum melt;

[0010] Step (2), adding an in-situ reaction powder preform to the aluminum melt for in-situ reaction, and after the reaction is completed, cooling down to obtain an aluminum-based melt;

[0011] Step (3), adding an aluminum-zirconium master alloy and an aluminum-cerium master alloy to the aluminum-based melt in sequence, stirring to make the two master alloys completely melt and mix evenly to obtain a mixed melt;

[0012] Step (4), casting the mixed melt by near-liquidus casting method to obtain an aluminum-based composite ingot;

[0013] Step (5), performing solution treatment on the aluminum-based composite ingot to obtain an aluminum-based composite material;

[0014] Step (6), performing secondary alternating treatment of rolling and aging on the aluminum-based composite material, that is, obtaining the conductive Al 2 O 3 / Al-based composite material.

[0015] The above-mentioned conductive Al 2 O 3 Preparation method of the above-mentioned conductive Al

[0016] The above-mentioned conductive Al2 O 3 Preparation method of conductive Al

[0017] The above-mentioned conductive Al 2 O 3 / Al matrix composite material, in step (2), the preparation method of the in-situ reaction powder preform is as follows: mix aluminum powder and copper oxide powder and grind them to obtain a mixed powder; use a powder press to press the mixed powder into an in-situ reaction powder preform. Aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; if the particle size of the aluminum powder or copper oxide powder is too large, the size of the alumina particles generated by the reaction will be relatively large, resulting in a weakened strengthening effect on the composite material; the mass ratio of copper oxide powder to aluminum powder is 1:4 - 5; the grinding time is 1 - 1.5 h; after grinding, the particle size of the mixed powder is 5 - 20 μm (the aluminum powder is 5 - 20 μm after grinding, and the CuO powder is 5 - 10 μm); during pressing, the forming pressure is 10 - 12 MPa, and the pressure holding time is 3 - 5 min; the in-situ reaction powder preform is a disc shape. When the size of the preform is too large or the block is too thick, when added to the pure aluminum melt, the outermost reactant powder rapidly heats up to the reaction temperature and starts to react. At this time, through the transfer of heat, the internal reactants do not reach the reaction temperature, while the outermost reactant powder has started the in-situ reaction. The heat released by the in-situ reaction will, on the one hand, cause the temperature of the aluminum liquid around the block to rise rapidly, and on the other hand, the heat released will cause the temperature of the unreacted reactant powder inside the block to rise, and the speed of the in-situ reaction will also be faster, and the reaction will be more intense; moreover, a too thick preform means an increase in reactants, that is, more heat will be released by the reaction. The aluminothermic reaction belongs to a thermal explosion reaction, its reaction rate is relatively fast and the reaction is extremely intense. The increase in reactants will exacerbate the intensity of the reaction, resulting in explosion and splashing of the aluminum liquid.

[0018] The above-mentioned conductive Al 2 O 3 / Al matrix composite material, in step (3), the mass fraction of zirconium element in the aluminum-zirconium master alloy is 10 wt.%, and the mass fraction of cerium element in the aluminum-cerium master alloy is 10 wt.%; in step (4), the preheating temperature of the mold before casting is 300 - 320 °C, and the casting temperature is 660 - 680 °C.

[0019] The above-mentioned conductive Al 2 O 3 / Al matrix composite material, in step (5), the conditions for solution treatment are: directly place the aluminum matrix composite ingot in an environment of 400 °C and keep it warm for 1 h, and then perform water quenching with normal temperature water.

[0020] The above-mentioned conductive Al 2 O 3 / Al-based composite material preparation method. In step (6), the secondary alternating treatment process of rolling and aging is as follows:

[0021] Perform one-time room-temperature rolling on the aluminum-based composite material at room temperature, with a deformation amount of 75-85%;

[0022] Perform primary aging treatment on the aluminum-based composite material after one-time rolling at 160 °C for 8 h;

[0023] Perform secondary room-temperature rolling on the aluminum-based composite material after primary aging treatment, with a deformation amount of 60-70%;

[0024] Perform secondary aging treatment on the aluminum-based composite material after secondary rolling at 150 °C for 8 h.

[0025] The above-mentioned conductive Al 2 O 3 / Al-based composite material preparation method. In step (1), the purity of the pure aluminum block is greater than or equal to 99.996 wt.%, and the heating and melting temperature is 730 °C; in step (2), the in-situ reaction temperature is 900 °C, and the in-situ reaction time is 10-30 s (under this reaction condition, the intensity of the in-situ reaction is moderate, and it can make the alumina particles generated after the reaction uniformly disperse in the aluminum-based melt), and the temperature of the aluminum-based melt drops to 750 °C (adding the master alloy at this temperature can effectively reduce the burning loss of the master alloy and make zirconium and cerium quickly melt and disperse in the melt);

[0026] The preparation method of the in-situ reaction powder preform is as follows: Mix aluminum powder and copper oxide powder and grind them to obtain a mixed powder; Use a powder press to press the mixed powder into an in-situ reaction powder preform; The aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; The copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; The mass ratio of copper oxide powder to aluminum powder is 1:5 (under this ratio, the in-situ reaction can reduce the safety risk caused by overly violent reaction, and at the same time can make the alumina particles generated by the in-situ reaction uniformly disperse into the aluminum-based melt); The grinding time is 1 h; After grinding, the particle size of the mixed powder is 5-20 μm; During pressing, the forming pressure is 10 MPa, and the pressure holding time is 5 min; The in-situ reaction powder preform is in the shape of a round sheet;

[0027] In step (3), the mass fraction of zirconium element in the aluminum-zirconium master alloy is 10 wt.%, and the mass fraction of cerium element in the aluminum-cerium master alloy is 10 wt.%; in the mixed melt, the mass ratio of copper, zirconium and cerium elements is 9.4:1.5:1, and the content of alumina particles is 0.5 wt%; in step (4), the preheating temperature of the mold before casting is 300 °C, and the casting temperature is 670 °C;

[0028] In step (5), the conditions for solution treatment are: directly placing the aluminum matrix composite ingot in an environment of 400 °C and holding for 1 h, and then quenching with normal temperature water; if the solution treatment temperature is too high or the treatment time is too long, it will cause grain growth and even overburning; however, if the solution treatment temperature is too low or the treatment time is too short, the alloying elements cannot be completely dissolved into the matrix and the ideal strengthening effect cannot be achieved;

[0029] In step (6), the secondary alternating treatment process of rolling and aging is as follows: performing one-time room temperature rolling on the aluminum matrix composite at room temperature, with a deformation amount of 80% (if the deformation amount of the first room temperature rolling is too large, it will cause cracking, but if it is too small, the strengthening effect will be insufficient); performing primary aging treatment on the aluminum matrix composite after one-time rolling at 160 °C for 8 h (if the aging temperature is too high or the aging time is too long, the precipitated phase or grains will grow, resulting in a decrease in material strength and an increase in toughness; if the aging temperature is low, the precipitated phase will not precipitate completely, and a longer aging time is required to achieve a better strengthening effect, which will increase the cost); performing secondary room temperature rolling on the aluminum matrix composite after primary aging treatment, with a deformation amount of 66.7%, the same as the deformation of the same room temperature rolling. If the deformation amount of the secondary room temperature rolling is too large, the composite material will also crack and the required tensile specimen cannot be obtained, while a smaller deformation has a limited effect on improving the strength of the composite material, and the strength improvement after secondary rolling is not obvious; performing secondary aging treatment on the aluminum matrix composite after secondary rolling at 150 °C for 8 h; secondary aging is to precipitate the elements that are not completely precipitated and dissolved in the matrix during primary aging; if the secondary aging temperature is too high or the aging temperature is too long, the second phase precipitated during primary aging will grow; if the aging temperature is too low or the time is too short, the alloying elements dissolved in the matrix are difficult to precipitate, and the strengthening effect on the matrix is weak.

[0030] The technical solution of the present invention has achieved the following beneficial technical effects:

[0031] 1. In the present invention, specific contents of alloying elements Cu, Zr and rare earth Ce elements are added to the conductive Al 2 O 3 / Al matrix composite material, which can effectively refine grains, and at the same time, the rare earth elements can also react with impurities to purify the matrix. The Zr element can inhibit Al 4 Cu 9The growth of the phase also prolongs the time for the composite material to reach peak aging. The Ce element precipitates in the form of the Al 8 Cu 4 Ce phase, showing a significant strengthening effect on the matrix.

[0032] 2. The conductive Al 2 O 3 / Al-based composite material prepared by the method of the present invention maintains a relatively high strength while ensuring good electrical conductivity of the material. This benefits from the role of precipitates with different sizes under the secondary rolling and aging alternating processing technology. In addition, the in-situ generated Al 2 O 3 particles have excellent stability and extremely high hardness. Although they will slightly reduce the electrical conductivity of the composite material, they can effectively improve the strength of the as-cast composite material. Moreover, during the processing, no phase transformation or size change will occur, so the processing process will not affect its strengthening effect on the composite material. Finally, under the refinement effect of the in-situ particles and the secondary alternating process on the precipitates, while ensuring the electrical conductivity of the material, the strength of the Al 2 O 3 / Al-based composite material can be greatly improved.

[0033] 3. By adjusting the content of each alloy element in the Al 2 O 3 / Al-Cu-Zr-Ce composite material and the content of Al 2 O 3 particles, and through a specific secondary alternating treatment process, the Cu, Zr, and Ce elements dissolved in the matrix are precipitated as second phases with nano-scale and sub-micron-scale sizes. Under the action of this process, the composite material can have a relatively high strength while slightly improving the electrical conductivity of the material. It is measured that the Al 2 O 3 / Al-based composite material prepared by the present invention has excellent performance, with a tensile strength exceeding 300 MPa and a relative electrical conductivity higher than 58% IACS, which can meet the performance requirements of the industry for aluminum alloy stranded wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic flow chart of the secondary alternating treatment in the embodiment of the present invention;

[0035] Figure 2a TEM image (striped) of alumina particles in the Al 2 O 3 / Al-based composite material in the embodiment of the present invention;

[0036] Figure 2b TEM image of the Al 2 O 3TEM image of alumina particles (irregular blocky shape) in Al-based composites;

[0037] Figure 2c Figure 2a The circular area in the figure corresponds to the energy spectrum diagram;

[0038] Figure 3a Al in the embodiment of the present invention 2 O 3 TEM image of Al-based composites (microscopic morphology of Al 4 Cu 9 phase and Al 8 Cu 4 Ce phase);

[0039] Figure 3b Al in the embodiment of the present invention 2 O 3 TEM image of Al-based composites (electron diffraction pattern);

[0040] Figure 4a Al in the embodiment of the present invention 2 O 3 TEM image of Al-based composites (microscopic morphology of Al 3 Zr phase and Al 8 Cu 4 Ce phase);

[0041] Figure 4b Al in the embodiment of the present invention 2 O 3 TEM image of Al-based composites (EDS layer image);

[0042] Figure 4c Al in the embodiment of the present invention 2 O 3 TEM image of Al-based composites (high-resolution image);

[0043] Figure 4d Figure 4c Electron diffraction pattern after Fourier transform;

[0044] Figure 5a Variation trend of the tensile strength of the composites prepared in the embodiments and comparative examples of the present invention under different states;

[0045] Figure 5b Variation trend of the elongation of the composites prepared in the embodiments and comparative examples of the present invention under different states;

[0046] Figure 5c Variation trend of the relative electrical conductivity of the composites prepared in the embodiments and comparative examples of the present invention under different states. Detailed implementation manners

[0047] Example

[0048] The preparation method of the conductive Al 2 O 3 / Al-based composite material comprises the following steps:

[0049] Step (1): Heat and melt a pure aluminum block to obtain an aluminum melt; the purity of the pure aluminum block is greater than or equal to 99.996 wt.%, and the heating and melting temperature is 730 °C;

[0050] Step (2): Add an in-situ reaction powder preform to the aluminum melt and carry out an in-situ reaction at 900 °C for 20 s. After the reaction ends, cool down to 750 °C to obtain an aluminum-based melt;

[0051] The preparation method of the in-situ reaction powder preform is as follows: Mix aluminum powder and copper oxide powder and grind them to obtain a mixed powder; use a bench-top powder press (FY-24) to press the mixed powder into a circular sheet of the in-situ reaction powder preform; the aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; the copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; the mass ratio of the copper oxide powder to the aluminum powder is 1:5; the grinding time is 1 h; after grinding, the particle size of the mixed powder is 5 - 20 μm; when pressing, the forming pressure is 10 MPa, and the pressure holding time is 5 min;

[0052] Step (3): Immediately add an aluminum-zirconium master alloy with a zirconium element mass fraction of 10 wt.% and an aluminum-cerium master alloy with a cerium element mass fraction of 10 wt.% to the 750 °C aluminum-based melt, stir to completely melt and mix the two master alloys evenly to obtain a mixed melt; in the mixed melt, the mass ratio of the three elements of copper, zirconium, and cerium is 9.4:1.5:1;

[0053] Step (4): Cast the mixed melt by the near-liquidus casting method. The preheating temperature of the mold before casting is 300 °C, and the casting temperature is 670 °C to obtain an aluminum-based composite ingot;

[0054] Step (5): Carry out solution treatment on the aluminum-based composite ingot. The conditions for the solution treatment are: directly place the aluminum-based composite ingot in an environment of 400 °C and keep it warm for 1 h, and then carry out water quenching to obtain an aluminum-based composite material;

[0055] Step (6): Carry out a two-stage alternating treatment of rolling and aging on the aluminum-based composite material, that is, the conductive Al 2 O 3 / Al-based composite material; the secondary alternating treatment process of rolling and aging is as follows: the Al-based composite material is subjected to one-time room-temperature rolling at room temperature with a deformation amount of 80%; the Al-based composite material after one-time rolling is subjected to primary aging treatment at 160 °C for 8 h; the Al-based composite material after primary aging treatment is subjected to secondary room-temperature rolling with a deformation amount of 66.7%; the Al-based composite material after secondary rolling is subjected to secondary aging treatment at 150 °C for 8 h (see Figure 1 ).

[0056] After secondary aging, the morphology of Al 2 O 3 / Al-Cu-Zr-Ce composite material is shown in 2 O 3 . It can be seen from the figure that the in-situ formed massive Al Figures 2a to 2c O 2 O 3 particles have a size of 1-2 μm and are embedded in the aluminum matrix. The TEM images of the Al 2 O 3 / Al-Cu-Zr-Ce composite material after secondary aging are shown in Figure 3a and Figure 3b and Figures 4a to 4d . It can be seen from Figure 3a and Figure 3b that the nearly spherical Al 4 Cu 9 phases precipitated during the aging process are distributed around the elliptical Al 8 Cu 4 Ce phases. The size of the Al 4 Cu 9 phase is less than 100 nm, and the size of the Al 8 Cu 4 Ce phase is about 0.2-0.3 μm; it can be seen from Figures 4a to 4d that the spherical particles Al 3 Zr phases precipitated during the aging process are distributed around the elliptical Al 8 Cu 4 Ce phases. The size of the Al 3 Zr phase is only a few nanometers and is pinned around the Al 8 Cu 4 Ce phase during the precipitation process, hindering the growth of the Al 8 Cu 4 Ce phase. The size of the Al 8 Cu 4 Ce phase is between 0.1 μm and 0.3 μm.

[0057] The conductive Al 2 O 3In the Al-based composite material: the content of alumina particles is 0.5 wt.%, the content of copper is 0.94 wt.%, the content of zirconium is 0.15 wt.%, the content of cerium is 0.1 wt.%, and the balance is aluminum. This conductive Al 2 O 3 / Al-based composite material has good comprehensive properties. Its tensile strength at room temperature is 305 MPa, the elongation at room temperature is 25.3%, and the electrical conductivity at room temperature is 58.6% IACS, indicating that the conductive Al 2 O 3 / Al-based composite material prepared by the preparation method of this embodiment takes into account both mechanical properties and electrical properties.

[0058] Comparative Example 1

[0059] The preparation method of the conductive Al 2 O 3 / Al-based composite material in this comparative example includes the following steps:

[0060] Step (1): Heat and melt the pure aluminum block to obtain an aluminum melt; the purity of the pure aluminum block is greater than or equal to 99.996 wt.%, and the heating and melting temperature is 800 °C;

[0061] Step (2): Add an in-situ reaction powder preform to the aluminum melt and carry out an in-situ reaction at 900 °C for 30 s. After the reaction is completed, cool down to 750 °C to obtain an aluminum-based melt;

[0062] The preparation method of the in-situ reaction powder preform is as follows: Mix and grind aluminum powder and copper oxide powder to obtain a mixed powder; use a bench-top powder press (FY-24) to press the mixed powder into a circular in-situ reaction powder preform; the aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; the copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; the mass ratio of copper oxide powder to aluminum powder is 1:1.5; the grinding time is 1 h; after grinding, the particle size of the mixed powder is 5 - 20 μm; during pressing, the forming pressure is 10 MPa, and the pressure holding time is 5 min;

[0063] Step (3): Immediately add an aluminum-zirconium master alloy with a mass fraction of zirconium element of 10 wt.% to the 750 °C aluminum-based melt, stir to completely melt and mix the master alloy evenly to obtain a mixed melt; in the mixed melt, the mass ratio of copper to zirconium is 9.4:1.5;

[0064] Step (4): Cast the mixed melt by the near-liquidus casting method. The preheating temperature of the mold before casting is 300 °C, and the casting temperature is 670 °C to obtain an aluminum-based composite material ingot;

[0065] ​Step (5): Perform solution treatment on the aluminum matrix composite ingot. The conditions for solution treatment are as follows: directly place the aluminum matrix composite ingot in an environment of 400 °C and hold for 1 h, then perform water quenching to obtain the aluminum matrix composite;

[0066] Step (6): Perform secondary alternating treatment of rolling and aging on the aluminum matrix composite, that is, obtain the conductive Al 2 O 3 / Al matrix composite. The process of secondary alternating treatment of rolling and aging is as follows: perform primary room-temperature rolling on the aluminum matrix composite at room temperature with a deformation amount of 80%; perform primary aging treatment on the aluminum matrix composite after primary rolling at 160 °C for 8 h; perform secondary room-temperature rolling on the aluminum matrix composite after primary aging treatment with a deformation amount of 66.7%; perform secondary aging treatment on the aluminum matrix composite after secondary rolling at 150 °C for 8 h.

[0067] In the conductive Al 2 O 3 / Al matrix composite prepared in this comparative example: the content of alumina particles is 0.5 wt.%, the content of copper is 0.94 wt.%, the content of zirconium is 0.15 wt.%, and the balance is aluminum. The room-temperature tensile strength of this conductive Al 2 O 3 / Al matrix composite is 221 MPa, the room-temperature elongation is 30.9%, and the room-temperature conductivity is 60.9% IACS.

[0068] Comparative Example 2

[0069] The preparation method of the conductive Al 2 O 3 / Al matrix composite in this comparative example includes the following steps:

[0070] Step (1): Heat and melt pure aluminum blocks to obtain an aluminum melt; the purity of the pure aluminum blocks is greater than or equal to 99.996 wt.%, and the temperature for heat melting is 660 °C;

[0071] Step (2): Add an in-situ reaction powder preform to the aluminum melt and perform an in-situ reaction at 900 °C for 10 s. After the reaction is completed, cool down to obtain an aluminum matrix melt; the content of copper in the aluminum matrix melt is 0.94 wt%;

[0072] The preparation method of the in-situ reaction powder preform is as follows: mix aluminum powder and copper oxide powder and grind to obtain a mixed powder; use a bench-top powder press (FY-24) to press the mixed powder into a circular sheet In-situ reaction powder preform; the aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; the copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; the mass ratio of the copper oxide powder to the aluminum powder is 1:1.5; the grinding time is 1 h; after grinding, the particle size of the mixed powder is 5 - 20 μm; during pressing, the forming pressure is 10 MPa and the pressure holding time is 5 min;

[0073] Step (3), casting the aluminum-based melt by the near-liquidus casting method. Before casting, the preheating temperature of the mold is 300 °C, and the casting temperature is 670 °C to obtain an aluminum-based composite ingot;

[0074] Step (4), performing solution treatment on the aluminum-based composite ingot. The conditions for solution treatment are: directly placing the aluminum-based composite ingot in an environment of 400 °C and holding for 1 h, and then performing water quenching to obtain an aluminum-based composite;

[0075] Step (5), performing a two-stage alternating treatment of rolling and aging on the aluminum-based composite, that is, obtaining the conductive Al 2 O 3 / Al-based composite material; the process of the two-stage alternating treatment of rolling and aging is as follows: performing primary room-temperature rolling on the aluminum-based composite at room temperature with a deformation amount of 80%; performing primary aging treatment on the aluminum-based composite after primary rolling at 160 °C for 8 h; performing secondary room-temperature rolling on the aluminum-based composite after primary aging treatment with a deformation amount of 66.7%; performing secondary aging treatment on the aluminum-based composite after secondary rolling at 150 °C for 8 h.

[0076] In the conductive Al 2 O 3 / Al-based composite material prepared in this comparative example: the content of alumina particles is 0.5 wt.%, the content of copper is 0.94 wt.%, and the balance is aluminum. The room-temperature tensile strength of this conductive Al 2 O 3 / Al-based composite material is 149 MPa, the room-temperature elongation is 16.6%, and the room-temperature conductivity is 61.3% IACS.

[0077] When the addition amount of Zr element is 0.15 wt%, Zr exists in the composite material in the form of L12-type Al 3 Zr phase or Zr 6 Al 7 Cu 16 phase, and Cu exists in the form of Al 4 Cu 9 phase. Among them, the Al 3 Zr phase and Al 4 Cu 9 phase in Zr 6 Al7 Cu 16 precipitates around the phase. At this time, the size of the precipitated phase is smaller than that of a single Al 3 Zr phase, Al 4 Cu 9 phase. The addition of Zr element can prolong the time for the composite material to reach peak aging and significantly improve the elongation of the material. When the addition amount of Ce element is 0.1 wt%, Ce exists in the composite material in the form of Al 8 Cu 4 Ce, with a size of about 0.1 - 0.5 μm. There will be Al 3 Zr phase and Al 4 Cu 9 phase precipitates. Compared with the case without Ce addition, the size of the precipitated phase decreases significantly, from sub-micron level to nano-level. In addition, the addition of Ce element can accelerate the precipitation rate of the second phase.

[0078] Obviously, the above embodiments are only examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the claims of this patent application.

Claims

1. A method for preparing a conductive Al 2 O 3 / Al-based composite material It is characterized in that it includes the following steps: Step (1): Heat and melt a pure aluminum block to obtain an aluminum melt; Step (2): Add an in-situ reaction powder preform to the aluminum melt for in-situ reaction. After the reaction ends, cool down to obtain an aluminum-based melt; In Step (2), the preparation method of the in-situ reaction powder preform is: mix aluminum powder and copper oxide powder and grind them to obtain a mixed powder; use a powder press to press the mixed powder into an in-situ reaction powder preform; Step (3): Sequentially add an aluminum-zirconium master alloy and an aluminum-cerium master alloy to the aluminum-based melt, stir to completely melt and mix the two master alloys evenly to obtain a mixed melt; Step (4): Cast the mixed melt by the near-liquidus casting method to obtain an aluminum-based composite ingot; Step (5): Perform solution treatment on the aluminum-based composite ingot to obtain an aluminum-based composite; Step (6), perform secondary alternating treatment of rolling and aging on the aluminum matrix composite material, and then the conductive Al 2 O 3 / Al matrix composite material is obtained; Conductive Al 2 O 3 / Al-based composite material: the content of alumina particles is 0.1-0.5 wt.%, the total content of copper, zirconium and cerium is 0.34-2 wt.%, and the balance is aluminum; the mass ratio of the three elements of copper, zirconium and cerium is (8-10):(1-2):

1.

2. The preparation method of the conductive Al 2 O 3 / Al-based composite material according to claim 1 It is characterized in that In Step (1), the purity of the pure aluminum block is greater than or equal to 99.996 wt.%, and the temperature of heat melting is 660 - 800 °C; in Step (2), the temperature of in-situ reaction is 900 - 920 °C, the time of in-situ reaction is 10 - 30 s, and the temperature of the aluminum-based melt drops to 740 - 750 °C.

3. The preparation method of the conductive Al 2 O 3 / Al-based composite material according to claim 1 It is characterized in that The aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; the copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; the mass ratio of the copper oxide powder to the aluminum powder is 1:4 - 5; the grinding time is 1 - 1.5 h; after grinding, the particle size of the mixed powder is 5 - 20 μm; during pressing, the forming pressure is 10 - 12 MPa, and the pressure holding time is 3 - 5 min; the in-situ reaction powder preform is a circular sheet with a diameter of φ15 mm and a thickness of 2 mm.

4. The preparation method of the conductive Al 2 O 3 / Al-based composite material It is characterized in that In Step (3), the mass fraction of zirconium element in the aluminum-zirconium master alloy is 10 wt.%, and the mass fraction of cerium element in the aluminum-cerium master alloy is 10 wt.%; in Step (4), the preheating temperature of the mold before casting is 300 - 320 °C, and the casting temperature is 660 - 680 °C.

5. The preparation method of the conductive Al 2 O 3 / Al-based composite material It is characterized in that In Step (5), the conditions of solution treatment are: directly place the aluminum-based composite ingot in an environment of 400 °C and keep it warm for 1 h, and then perform water quenching with normal temperature water.

6. The preparation method of the conductive Al 2 O 3 / Al-based composite material according to claim 1 It is characterized in that In Step (6), the secondary alternating treatment process of rolling and aging is: Perform one-time room-temperature rolling on the aluminum-based composite at room temperature, and the deformation amount is 75 - 85%; Perform primary aging treatment on the aluminum-based composite after one-time rolling at 160 °C for 8 h; Perform secondary room-temperature rolling on the aluminum-based composite after primary aging treatment, and the deformation amount is 60 - 70%; Perform secondary aging treatment on the aluminum-based composite after secondary rolling at 150 °C for 8 h.

7. The preparation method of the conductive Al 2 O 3 / Al-based composite material according to claim 1 It is characterized in that In Step (1), the purity of the pure aluminum block is greater than or equal to 99.996 wt.%, and the temperature of heat melting is 730 °C; in Step (2), the temperature of in-situ reaction is 900 °C, the time of in-situ reaction is 20 s, and the temperature of the aluminum-based melt drops to 750 °C. The preparation method of the in-situ reaction powder preform is as follows: Mix aluminum powder and copper oxide powder and grind them to obtain a mixed powder; Use a powder press to press the mixed powder into an in-situ reaction powder preform; The aluminum powder passes through a 300-mesh sieve, and the purity of the aluminum powder is greater than or equal to 99.9 wt.%; The copper oxide powder passes through a 300-mesh sieve, and the purity of the copper oxide powder is greater than or equal to 99.9 wt.%; The mass ratio of copper oxide powder to aluminum powder is 1:5; The grinding time is 1 h; After grinding, the particle size of the mixed powder is 5 - 20 μm; During pressing, the forming pressure is 10 MPa, and the pressure holding time is 5 min; The in-situ reaction powder preform is a circular sheet with a diameter of φ15 mm and a thickness of 2 mm; In step (3), the mass fraction of zirconium element in the aluminum-zirconium master alloy is 10 wt.%, and the mass fraction of cerium element in the aluminum-cerium master alloy is 10 wt.%; In the molten mixture, the mass ratio of copper, zirconium and cerium is 9.4:1.5:1, and the content of alumina particles is 0.5 wt%; In step (4), the preheating temperature of the mold before casting is 300 °C, and the casting temperature is 670 °C; In step (5), the conditions for solution treatment are: Directly place the aluminum matrix composite ingot in an environment of 400 °C and keep it warm for 1 h, and then perform water quenching; In step (6), the secondary alternating treatment process of rolling and aging is: Perform primary room temperature rolling on the aluminum matrix composite at room temperature, and the deformation amount is 80%; Perform primary aging treatment on the aluminum matrix composite after primary rolling at 160 °C for 8 h; Perform secondary room temperature rolling on the aluminum matrix composite after primary aging treatment, and the deformation amount is 66.7%; Perform secondary aging treatment on the aluminum matrix composite after secondary rolling at 150 °C for 8 h.

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