A kind of light-weight heat-resistant aluminum alloy manufactured by additive manufacturing and preparation method thereof

Abstract

The present invention relates to an additive manufacturing lightweight heat-resistant aluminum alloy and a preparation method thereof. The heat-resistant aluminum alloy, in terms of mass fraction percentage, comprises the following components: Ni 0.5 - 10%, Mg 3 - 8%, Zr 0.4 - 1.8%, Ti 0.5 - 10%, B 0.2 - 4.5%, and the balance is Al and inevitable impurity elements; and the mass ratio of Ti to B is 2 - 2.22; the heat-resistant aluminum alloy contains Al3Zr, TiB2 and Al3Ni eutectics. The product of the present invention is obtained by laser additive manufacturing. By adding specific proportions of Ti and B to the Al-Mg alloy, through the synergistic effect among the precipitation phases with low coarsening rate, nano / micron-sized ceramic particles and heat-resistant eutectics, the high volume fraction of heat-resistant phases pin the grain boundaries, thereby improving the high-temperature performance of the alloy. The component design of the present invention is reasonable, the preparation process is simple and controllable, the obtained product has excellent performance, and is convenient for industrial application.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing of metal alloy materials, and particularly to a lightweight heat-resistant aluminum alloy for additive manufacturing and a preparation method thereof. Background Art

[0002] Aluminum alloys and their composite materials (aluminum-based materials) have a series of advantages such as low density and high specific strength, and are widely used in the fields of aerospace, transportation, and military industry. The demand for high-strength heat-resistant aluminum alloys and their composite materials in practical applications has been growing rapidly. Aerospace has been committed to achieving weight reduction design for the fuselage and propulsion system, which is usually achieved by relying on lightweight materials and topology optimization structure design. Additive manufacturing is of great significance for the lightweight design and manufacturing of hot-end components in the aerospace field. At present, aluminum alloys are difficult to meet the service requirements of actual working conditions in terms of high-temperature mechanical properties, especially for aerospace components with harsh application environments. Therefore, there is an urgent need to develop new lightweight high-temperature-resistant aluminum alloys for additive manufacturing.

[0003] In the prior art, the patent application CN117600493A relates to a preparation method of an additive manufacturing heat-resistant aluminum alloy, which includes the following steps: S1: Using AlSi10Mg alloy powder as the base material; the modified powder materials are one or more of Al-Ce master alloy powder, Al-Sc master alloy powder, Al-Zr master alloy powder, Al-Fe master alloy powder, Al-V master alloy powder, Al-Ag master alloy powder, Al-Cu master alloy powder, Al-Si master alloy powder, Al-Mn master alloy powder, Al-Mg master alloy powder, Al-Ti master alloy powder, Al-Ni master alloy powder, Al-Cr master alloy powder, Al-Zn master alloy powder, Al-Ti-C master alloy powder; the base material and the modified powder materials have the same particle size; S2: Selecting one or more of the modified powder materials with different alloy components and different masses and uniformly mixing them with the AlSi10Mg alloy powder, and the mixing time is not less than 5 hours; S3: Preparing a dense heat-resistant aluminum alloy by changing the laser power, laser scanning speed, and laser scanning spacing. Summary of the Invention

[0004] In order to further improve the comprehensive performance of the additive manufacturing heat-resistant aluminum alloy, the present invention designs a high-quality lightweight heat-resistant aluminum alloy for additive manufacturing containing Al 3 Zr, TiB 2 and Al 3 Ni eutectic.

[0005] The present invention relates to an additive manufacturing lightweight heat-resistant aluminum alloy, which, in terms of mass fraction percentage, comprises the following components: Ni 0.5 - 10%, Mg 3 - 8%, Zr 0.4 - 1.8%, Ti 0.5 - 10%, B 0.2 - 4.5%, and the balance is Al and inevitable impurity elements (such as Fe, Si), wherein the mass percentage of the impurity elements is less than or equal to 0.1%;

[0006] Moreover, in the above-mentioned additive manufacturing lightweight heat-resistant aluminum alloy, the mass ratio of Ti to B is 2 - 2.22;

[0007] The additive manufacturing lightweight heat-resistant aluminum alloy contains Al 3 Zr, TiB 2 and Al 3 Ni eutectic.

[0008] The optimized composition of the additive manufacturing lightweight heat-resistant aluminum alloy, in terms of mass percentage, is: Ni is 1 - 8%, Mg is 3 - 8%, Zr is 0.5 - 1.4%, Ti is 0.5 - 8%, B is 0.2 - 3.2%, and the balance is Al and inevitable impurity elements (such as Fe, Si).

[0009] After further optimization, the composition of the additive manufacturing lightweight heat-resistant aluminum alloy, in terms of mass percentage, is: Ni is 2 - 5%, Mg is 3 - 8%, Zr is 0.5 - 1.4%, Ti is 0.5 - 6%, B is 0.2 - 2.8%, and the balance is Al and inevitable impurity elements (such as Fe, Si).

[0010] In the present invention, in order to ensure that the product has relatively excellent elongation performance and excellent mechanical strength at room temperature and high temperature (such as 200°C - 300°C), the optional solutions include: the composition of the lightweight heat-resistant aluminum alloy, in terms of mass percentage, is: Ni is 3 - 8%, Mg is 5.5 - 6.5%, Zr is 1.1 - 1.3%, Ti is 3 - 6%, B is 1.2 - 2.8%, and the balance is Al and inevitable impurity elements (such as Fe, Si). This of course includes a series of solutions such as Ni being 3.5 - 7.5%, Mg being 5.5 - 6.5%, Zr being 1.1 - 1.3%, Ti being 3 - 5%, and B being 1.3 - 2.3%.

[0011] In the present invention, in order to ensure that the product has good mechanical strength and excellent elongation performance at room temperature and high temperature (such as 200°C to 300°C), the solution includes: the composition of the lightweight heat-resistant aluminum alloy is as follows by mass percentage: Ni is 1 to 2%, Mg is 5.5 to 6.5%, Zr is 0.4 to 1.3%, Ti is 3 to 6%, B is 1.2 to 2.8%, and the balance is Al and inevitable impurity elements (Fe, Si), etc. This of course includes a series of solutions where Ni is 1 to 1.5%, Mg is 5.5 to 6.5%, Zr is 0.4 to 1.2%, Ti is 3 to 5%, and B is 1.3 to 2.3%.

[0012] The present invention also provides a preparation method of an additive manufacturing lightweight heat-resistant aluminum alloy, which includes the following steps:

[0013] Using aluminum alloy powder as raw material, through additive manufacturing, a heat-resistant aluminum alloy is obtained; during additive manufacturing, the laser power is controlled at 200 to 350 W, the scanning speed is 350 to 1320 mm / s, the scanning spacing is 30 to 200 μm, and the scanning layer thickness is 20 to 70 μm;

[0014] The aluminum alloy powder, by mass fraction percentage, includes the following components: Ni 0.5 to 10%, Mg 3 to 8%, Zr 0.4 to 1.8%, Ti 0.5 to 10%, B 0.2 to 4.5%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than or equal to 0.1%;

[0015] And in the above lightweight heat-resistant aluminum alloy, the mass ratio of Ti to B is 2 to 2.22;

[0016] The particle size of the aluminum alloy powder is 10 to 100 μm.

[0017] The present invention also provides a preparation method of an additive manufacturing lightweight heat-resistant aluminum alloy, and the aluminum alloy powder is prepared by the following process:

[0018] Weigh each raw material according to the designed ratio, first heat it to melt the aluminum ingot at 700 - 720°C, skim the surface oxidation slag, then raise the temperature to 750 - 780°C, add Al-Ni and Al-TiB 2 master alloys, lower the temperature to 730 - 750°C, then add Al-Zr and Al-Mg master alloys, wrap the refining agent with aluminum foil, press it into the aluminum melt through a bell jar, keep the refining temperature at 720 - 750°C, let it stand for 10 - 30 min after the refining is completed, skim the slag and then pour to obtain an ingot; melt the ingot and atomize it into powder to obtain 10 - 100 μm aluminum alloy powder.

[0019] Further preferably: add Al-Ni and Al-TiB when the temperature is raised to 750 - 760°C2 The master alloy is cooled to 730 - 740 °C, then master alloys of Al-Zr and Al-Mg are added, the refining temperature is controlled at 730 - 740 °C, and after refining, it is left standing for 15 - 25 min.

[0020] The present invention also provides a method for preparing the above-mentioned lightweight heat-resistant aluminum alloy, which comprises the following steps: the gas atomization powder-making temperature is 800 - 950 °C, the powder particle size is 10 - 100 μm, and the powder particle size is further preferably 10 - 70 μm.

[0021] The present invention also provides a method for preparing the above-mentioned lightweight heat-resistant aluminum alloy, which comprises the following steps: the alloy powder is subjected to additive manufacturing to prepare the above-mentioned lightweight heat-resistant aluminum alloy.

[0022] The substrate used in the above additive manufacturing process is an Al-Ni alloy, the substrate preheating temperature is 55 - 220 °C, and the laser process parameters are: the laser power is 200 - 350 W, the scanning rate is 350 - 1320 mm / s, the scanning spacing is 30 - 200 μm, and the scanning layer thickness is 20 - 70 μm.

[0023] The further preferred process parameters are: the substrate preheating temperature is 70 - 160 °C, and the laser process parameters are: the laser power is 235 - 330 W, the scanning rate is 600 - 1200 mm / s, the scanning spacing is 70 - 150 μm, and the scanning layer thickness is 30 - 70 μm.

[0024] The further preferred process parameters are: the substrate preheating temperature is 70 - 130 °C, and the laser process parameters are: the laser power is 235 - 330 W, the scanning rate is 800 - 1200 mm / s, the scanning spacing is 70 - 120 μm, and the scanning layer thickness is 30 - 70 μm. This of course includes the scheme where the substrate preheating temperature is 70 - 90 °C, the laser process parameters are: the laser power is 280 - 330 W, the scanning rate is 900 - 1200 mm / s, the scanning spacing is 70 - 120 μm, and the scanning layer thickness is 30 - 60 μm.

[0025] The above scheme of the present invention has the following advantages:

[0026] The lightweight heat-resistant aluminum alloy of the present invention adds appropriate amounts of Zr, Ti, B, and Ni elements on the basis of the Al-Mg series alloy. Among them, the addition of an appropriate amount of Zr element can generate nano-scale precipitation phases Al 3 Zr, the addition of specific mass percentages of Ti and B can generate high-temperature stable nano / sub-micron TiB 2 ceramic particles, and the addition of Ni can form heat-resistant Al with a high volume fraction (10 - 30%) 3 Ni eutectic. The high-temperature resistant Al 3Zr, TiB 2 and Al 3 The eutectic of Ni can act synergistically to pin the grain boundaries together, enabling the alloy to obtain good high-temperature resistance and meet the requirements for heat-resistant parts in the fields of aerospace, military, etc.

[0027] The heat-resistant aluminum alloy of the present invention uses additive elements with relatively low costs, which can significantly reduce production costs and meet the requirements of industrial production applications. And the purpose of improving the high-temperature resistance of the alloy is achieved through the design of multi-level high-temperature-resistant particles.

[0028] The preparation method of the present invention adopts additive manufacturing. Utilizing the high cooling rate of additive manufacturing, the eutectic structure of Al 3 Ni is refined, and parts can be directly formed.

[0029] The as-printed Al-Mg lightweight aluminum alloy obtained in the present invention has good strength and plasticity. By adding Zr elements with low solid solubility and low solid-state diffusion coefficient, high-temperature-resistant precipitation phases are formed, high-melting-point TiB 2 ceramic particles, and high-volume high-temperature-resistant eutectic phase Al 3 Ni pin the grain boundaries, playing a role in enhancing the high-temperature resistance. Description of the Drawings

[0030] Figure 1 It is the microstructural diagram of Example 2;

[0031] Figure 2 It is the hardness curve diagram of the alloys prepared in Examples 1-3 and Comparative Examples 1, 3, and 4 of the present invention after long-term thermal exposure at 370 °C;

[0032] Figure 3 It is the microstructural diagram of Example 2 aged at 370 °C for 8 h.

[0033] It can be seen from Figure 1 that there are nanoscale Al 3 Zr precipitation phases, nano / microscale TiB 2 ceramic particles, and high-volume fraction of Al 3 Ni eutectic in the product.

[0034] It can be seen from Figure 2 that the hardness of Examples 1-3 after 200 h of thermal exposure is still equivalent to that at room temperature, and the hardness value after their long-term thermal exposure is higher than that of Comparative Examples 1, 3, and 4, proving that the three high-temperature-resistant particles have a synergistic effect in enhancing the high-temperature resistance of the alloy.

[0035] It can be seen from Figure 3 that there are Al 3 Zr precipitation phases and TiB 2Ceramic particles, and a high volume fraction of Al 3 Ni is distributed at the grain boundaries, and no obvious growth in the grain size and precipitate size is found. Specific embodiments

[0036] The present invention will be further described in detail below mainly in combination with specific embodiments and the accompanying drawings.

[0037] Example 1

[0038] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically as follows:

[0039] (1) A lightweight heat-resistant aluminum alloy, which includes the following components, all in mass fraction percentages: Ni is 1%, Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0040] (2) Take raw materials according to the designed composition. First, control the temperature of the resistance furnace at 700 - 720 °C and heat until the pure aluminum ingot melts. After skimming the surface oxidation slag, raise the temperature to 760 °C, add Al-Ni and Al-TiB 2 master alloys. Cool down to 740 °C, then add Al-Zr and Al-Mg master alloys. Wrap the refining agent with aluminum foil and press it into the aluminum melt through a bell jar. Keep the refining temperature at 735 °C. After the refining is completed, let it stand for 20 min, skim the slag and then cast to obtain an ingot; melt the ingot and atomize it into powder by gas to obtain 30 - 70 μm aluminum alloy powder;

[0041] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 310 W, scanning speed is 1100 mm / s, scanning pitch is 100 μm, and scanning layer thickness is 30 μm.

[0042] (4) Subject the above-obtained samples (as-printed state) to high-temperature tensile tests at 200 °C and 300 °C respectively. The tensile strengths at 200 °C and 300 °C are 357 MPa and 231 MPa respectively.

[0043] The hardness of the as-printed products is detected after thermal exposure at 370 °C for 200 h, and the results are shown in Figure 2 .

[0044] Example 2

[0045] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically as follows:

[0046] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentage: Ni is 3.5%, Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0047] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace to be heated at 700 - 720 °C until the pure aluminum ingot melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, cooling to 735 °C, and then adding Al-Zr and Al-Mg master alloys. Wrap the refining agent with aluminum foil and press it into the aluminum melt through a bell. Keep the refining temperature at 735 °C, let it stand for 20 min after the refining is completed, skim the slag and then pour to obtain an ingot.

[0048] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1100 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0049] (4) Tensile tests of the above obtained samples are carried out at 200 °C and 300 °C respectively, and the tensile strengths at 200 °C and 300 °C are 385 MPa and 259 MPa respectively.

[0050] The hardness of the as-printed product is detected after thermal exposure at 370 °C for 200 h, and the results are shown in Figure 2 .

[0051] The as-printed product is solution-treated at 370 °C for 8 h, and its microstructure is shown in Figure 3 .

[0052] Example 3

[0053] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically:

[0054] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentage: Ni is 7.5%, Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0055] (2) The present invention also provides a method for preparing the above-mentioned lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace at 700-720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, cooling to 735 °C, and then adding Al-Zr and Al-Mg master alloys. Wrap the refining agent with aluminum foil and press it into the aluminum melt through a bell. Keep the refining temperature at 735 °C. After the refining is completed, let it stand for 20 min, skim the slag and then cast to obtain an ingot.

[0056] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 290 W, scanning speed is 1000 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0057] (4) Subject the above-obtained samples to high-temperature tensile tests at 200 °C and 300 °C respectively. The tensile strengths at 200 °C and 300 °C are 397 MPa and 278 MPa respectively.

[0058] Detect the hardness of the as-printed product after heat exposure at 370 °C for 200 h. The results are shown in Figure 2 .

[0059] Example 4

[0060] This example provides a lightweight heat-resistant aluminum alloy and a method for preparing the same, specifically:

[0061] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentages: Ni is 5%, Mg is 6%, Zr is 1.2%, Ti is 3%, B is 1.35%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0062] (2) The present invention also provides a method for preparing the above-mentioned lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace at 700-720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, cooling to 730 °C, and then adding Al-Zr and Al-Mg master alloys. Wrap the refining agent with aluminum foil and press it into the aluminum melt through a bell. Keep the refining temperature at 735 °C. After the refining is completed, let it stand for 20 min, skim the slag and then cast to obtain an ingot.

[0063] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 320 W, scanning speed is 1000 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0064] (4) The above-obtained samples were subjected to high-temperature tensile tests at 200 °C and 300 °C respectively, and the tensile strengths at 200 °C and 300 °C were 386 MPa and 266 MPa respectively.

[0065] Example 5

[0066] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically:

[0067] (1) A lightweight heat-resistant aluminum alloy, which includes the following components, all in mass fraction percentages: Ni is 1%, Mg is 6%, Zr is 0.4%, Ti is 3%, B is 1.35%, and the balance is Al and unavoidable impurity elements (Fe, Si), etc., where the mass percentage of impurity elements is less than 0.1%;

[0068] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which includes the following steps: controlling the temperature of the resistance furnace to 700 - 720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, cooling to 730 °C, then adding Al-Zr and Al-Mg master alloys, wrapping the refining agent with aluminum foil, and pressing it into the aluminum melt through a bell jar, keeping the refining temperature at 730 °C, standing for 20 min after the refining is completed, skimming the slag and then casting to obtain an ingot.

[0069] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 325 W, scanning speed is 1100 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0070] (4) The above-obtained samples were subjected to high-temperature tensile tests at 200 °C and 300 °C respectively, and the tensile strengths at 200 °C and 300 °C were 332 MPa and 225 MPa respectively; the elongation rates at 200 °C and 300 °C were 19.7% and 23.4% respectively. In the present invention, when the printed product is at 300 °C, the elongation rate shown is higher than that shown at 200 °C.

[0071] Example 6

[0072] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically:

[0073] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentage: Ni is 7.5%, Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0074] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace to heat to the melting of pure aluminum ingots at 700 - 720 °C, skimming the surface oxidation slag, then heating to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, cooling to 735 °C, then adding Al-Zr and Al-Mg master alloys, wrapping the refining agent with aluminum foil, pressing it into the aluminum melt through a bell, keeping the refining temperature at 735 °C, standing for 20 min after the refining is completed, skimming the slag and then casting to obtain ingots.

[0075] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 330 W, scanning speed is 600 mm / s, scanning pitch is 100 μm, and scanning layer thickness is 30 μm.

[0076] (4) The obtained samples are respectively subjected to high-temperature tensile tests at 200 °C and 300 °C, and the tensile strengths at 200 °C and 300 °C are 390 MPa and 272 MPa respectively.

[0077] Comparative Example 1 (without Ni)

[0078] This example provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically:

[0079] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentage: Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0080] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace to heat to the melting of pure aluminum ingots at 700 - 720 °C, skimming the surface oxidation slag, then heating to 760 °C, adding Al-TiB 2 master alloys, cooling to 735 °C, then adding Al-Zr and Al-Mg master alloys, wrapping the refining agent with aluminum foil, pressing it into the aluminum melt through a bell, keeping the refining temperature at 735 °C, standing for 20 min after the refining is completed, skimming the slag and then casting to obtain ingots.

[0081] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1000 mm / s, scanning pitch is 100 μm, and scanning layer thickness is 30 μm.

[0082] (4) The above-obtained samples were subjected to high-temperature tensile tests at 200 °C and 300 °C respectively, and the tensile strengths at 200 °C and 300 °C were 155 MPa and 60 MPa respectively.

[0083] The hardness of the as-printed product was measured after thermal exposure at 370 °C for 200 h, and the results are shown in Figure 2 .

[0084] Comparative Example 2 (without TiB 2 )

[0085] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentages: Ni is 3.5%, Mg is 6%, Zr is 1.2%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0086] (2) The present invention also provides a method for preparing the above lightweight heat-resistant aluminum alloy, which comprises the following steps: controlling the temperature of the resistance furnace to 700-720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding an Al-Ni master alloy, lowering the temperature to 735 °C, adding Al-Zr and Al-Mg master alloys, wrapping the refining agent with aluminum foil, pressing it into the aluminum melt through a bell jar, keeping the refining temperature at 735 °C, standing for 20 min after the refining is completed, skimming the slag and then casting to obtain an ingot.

[0087] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1100 mm / s, scanning pitch is 100 μm, and scanning layer thickness is 30 μm.

[0088] (4) The above-obtained samples were subjected to high-temperature tensile tests at 200 °C and 300 °C respectively, and the tensile strengths at 200 °C and 300 °C were 179 MPa and 72 MPa respectively.

[0089] Comparative Example 3 (without Zr)

[0090] (1) A lightweight heat-resistant aluminum alloy, which comprises the following components, all in mass fraction percentages: Ni is 3.5%, Mg is 6%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0091] (2) The present invention also provides a method for preparing the above lightweight heat-resistant aluminum alloy, which includes the following steps: controlling the temperature of the resistance furnace at 700 - 720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, adding Al-Ni and Al-TiB 2 master alloys, lowering the temperature to 735 °C, then adding Al-Mg master alloy, wrapping the refining agent with aluminum foil, and pressing it into the aluminum melt through a bell jar. The refining temperature is maintained at 735 °C. After the refining is completed, let it stand for 20 min, skim the slag and then pour to obtain an ingot.

[0092] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1100 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0093] (4) The above-obtained samples are respectively subjected to high-temperature tensile tests at 200 °C and 300 °C, and the tensile strengths at 200 °C and 300 °C are 183 MPa and 79 MPa respectively.

[0094] Comparative Example 4 (without TiB 2 and Ni)

[0095] (1) A lightweight heat-resistant aluminum alloy, which includes the following components, all in mass fraction percentages: Mg is 6%, Zr is 1.2%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of the impurity elements is less than 0.1%;

[0096] (2) The present invention also provides a method for preparing the above lightweight heat-resistant aluminum alloy, which includes the following steps: controlling the temperature of the resistance furnace at 700 - 720 °C to heat the pure aluminum ingot until it melts, skimming the surface oxidation slag, then raising the temperature to 760 °C, lowering the temperature to 735 °C, then adding Al-Zr and Al-Mg master alloys, wrapping the refining agent with aluminum foil, and pressing it into the aluminum melt through a bell jar. The refining temperature is maintained at 735 °C. After the refining is completed, let it stand for 20 min, skim the slag and then pour to obtain an ingot.

[0097] (3) The substrate used in the above additive manufacturing process is an Al-Mg alloy, the preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1100 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0098] (4) The above-obtained samples are respectively subjected to high-temperature tensile tests at 200 °C and 300 °C, and the tensile strengths at 200 °C and 300 °C are 117 MPa and 33 MPa respectively.

[0099] Comparative Example 5

[0100] This embodiment provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically as follows:

[0101] (1) A lightweight heat-resistant aluminum alloy, which includes the following components, all in mass fraction percentages: Ni is 7.5%, Mg is 6%, Zr is 1.2%, Ti is 5%, B is 2.25%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of impurity elements is less than 0.1%;

[0102] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which includes the following steps: Control the temperature of the resistance furnace to heat to the melting of pure aluminum ingots at 700 - 720 °C. After skimming the surface oxidation slag, raise the temperature to 760 °C, add Al-Ni, Al-TiB 2 master alloys, cool down to 735 °C, then add Al-Zr and Al-Mg master alloys. Wrap the refining agent with aluminum foil and press it into the aluminum melt through a bell jar. Keep the refining temperature at 735 °C, let it stand for 20 min after the refining is completed, skim the slag and then pour to obtain ingots.

[0103] (3) The substrate used in the above additive manufacturing process is an Al-Ni alloy, the substrate preheating temperature is 75 °C, and the laser process parameters are: laser power is 200 W, scanning speed is 1400 mm / s, scanning spacing is 100 μm, and scanning layer thickness is 30 μm.

[0104] (4) Tensile tests are carried out on the above obtained samples at 200 °C and 300 °C respectively. The tensile strengths at 200 °C and 300 °C are 191 MPa and 94 MPa respectively.

[0105] Comparative Example 6

[0106] This embodiment provides a lightweight heat-resistant aluminum alloy and its preparation method, specifically as follows:

[0107] (1) A lightweight heat-resistant aluminum alloy, which includes the following components, all in mass fraction percentages: Ni is 0.2%, Mg is 10%, Zr is 2%, Ti is 0.5%, B is 0.2%, and the balance is Al and inevitable impurity elements (Fe, Si), etc., where the mass percentage of impurity elements is less than 0.1%;

[0108] (2) The present invention also provides a preparation method of the above lightweight heat-resistant aluminum alloy, which includes the following steps: Control the temperature of the resistance furnace to heat to the melting of pure aluminum ingots at 700 - 720 °C. After skimming the surface oxidation slag, raise the temperature to 760 °C, add Al-Ni, Al-TiB 2The master alloy is cooled to 735 °C, and then master alloys of Al-Zr and Al-Mg are added. The refining agent is wrapped with aluminum foil and pressed into the aluminum melt through a bell jar. The refining temperature is maintained at 735 °C. After the refining is completed, it is left standing for 20 min. After skimming the slag, casting is carried out to obtain an ingot.

[0109] (3)The substrate used in the above additive manufacturing process is an Al-Ni alloy. The preheating temperature of the substrate is 75 °C, and the laser process parameters are: laser power is 300 W, scanning speed is 1100 mm / s, scanning pitch is 100 μm, and scanning layer thickness is 30 μm.

[0110] (4)The samples obtained above are subjected to high-temperature tensile tests at 200 °C and 300 °C respectively. The tensile strengths at 200 °C and 300 °C are 152 MPa and 52 MPa respectively.

[0111] The room-temperature tensile strength results of the printed alloys obtained in Examples 1-6 and Comparative Examples 1-6 are shown in Table 1:

[0112]

[0113] In summary, in the present invention, by adding specific proportions of Ni, Zr, Ti, and B elements to the Al-Mg alloy, optimizing the addition amounts of each element, and through further aging precipitation regulation, the synergistic effects among the precipitation phases, ceramic particles, and heat-resistant eutectics are fully utilized to sufficiently pin the grain boundaries, and a high-temperature heat-resistant aluminum alloy is obtained.

Claims

1. An additively manufactured lightweight heat-resistant aluminum alloy, characterized in that: The additively manufactured lightweight heat-resistant aluminum alloy is composed of the following components in terms of mass fraction percentage: Ni is 1-8%, Mg is 3-8%, Zr is 0.5-1.4%, Ti is 0.5-8%, B is 0.2-3.2%, and the balance is Al and unavoidable impurity elements, wherein the mass percentage of the impurity elements is less than or equal to 0.1%; And in the above-mentioned additively manufactured lightweight heat-resistant aluminum alloy, the mass ratio of Ti to B is 2 to 2.22; The additively manufactured lightweight heat-resistant aluminum alloy contains Al3Zr, TiB2 and Al3Ni eutectic; The additively manufactured lightweight heat-resistant aluminum alloy is prepared by the following process: Aluminum alloy powder is used as raw material to obtain additively manufactured lightweight heat-resistant aluminum alloy; during additive manufacturing, the laser power is controlled to be 200-350W, the scanning rate is 350-1320mm / s, the scanning interval is 30-200μm, and the scanning layer thickness is 20-70μm; the particle size of the aluminum alloy powder is 10-100μm.

2. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The additively manufactured lightweight heat-resistant aluminum alloy includes the following components, measured by mass fraction: 2-5% Ni, 3-8% Mg, 0.5-1.4% Zr, 0.5-6% Ti, 0.2-2.8% B, and the remainder Al and unavoidable impurity elements.

3. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The additively manufactured lightweight heat-resistant aluminum alloy includes the following components, measured by mass fraction: 3-8% Ni, 5.5-6.5% Mg, 1.1-1.3% Zr, 3-6% Ti, 1.2-2.8% B, and the remainder Al and unavoidable impurity elements.

4. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The additively manufactured lightweight heat-resistant aluminum alloy has the following components in percentage by mass: Ni is 1-2%, Mg is 5.5-6.5%, Zr is 0.4-1.3%, Ti is 3-6%, B is 1.2-2.8%, and the remainder is Al and unavoidable impurity elements.

5. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The aluminum alloy powder is prepared by the following process: Various raw materials are taken according to the designed composition, first heated at 700-720°C until the aluminum ingot is melted, and after removing the surface oxide slag, the temperature is raised to 750-780°C, and Al-Ni and Al-TiB2 intermediate alloys are added. The temperature is lowered to 730-750°C, and then Al-Zr and Al-Mg intermediate alloys are added. The refining agent is wrapped with aluminum foil and pressed into the aluminum melt through a bell jar. The refining temperature is maintained at 720-750°C. After the refining is completed, it is allowed to stand for 10-30 minutes, and the slag is removed before pouring to obtain an ingot; the ingot is melted and powdered by gas atomization to obtain 10-100μm aluminum alloy powder.

6. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 5, characterized in that: When the temperature rises to 750-760°C, add Al-Ni and Al-TiB2 master alloys, cool down to 730-740°C, then add Al-Zr and Al-Mg master alloys, control the refining temperature at 730-740°C, and let stand for 15-25 minutes after refining.

7. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The atomization powder making temperature is 800~950℃.

8. The additively manufactured lightweight heat-resistant aluminum alloy according to claim 1, characterized in that: The substrate preheating temperature is 70-160 °C, and the laser process parameters are: laser power is 235-330 W, scanning rate is 600-1200 mm / s, scanning spacing is 70-150 μm, and scanning layer thickness is 30-70 μm.

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