Heat-resistant aluminum alloy material as well as preparation method and application thereof

Abstract

The invention discloses a heat-resistant aluminum alloy material and a preparation method and application thereof, and belongs to the technical field of additive manufacturing aluminum alloy materials. The heat-resistant aluminum alloy material comprises the following components in percentage by mass: 0.5-6% of Fe, 0.5-6% of Cr, 0.5-3% of Ti, less than or equal to 2% but not equal to 0 of Mn, less than or equal to 2% but not equal to 0 of Sc, less than or equal to 2% but not equal to 0 of Zr and the balance of Al and inevitable impurities. By optimizing the component proportion, the preparation method and the like, in the microstructure of the heat-resistant aluminum alloy material, the interior of the heat-resistant aluminum alloy material is of a bimodal grain structure, the boundary of a molten pool is mainly isometric crystals, the center of the molten pool is columnar crystals, and an icosahedron nanometer quasi-crystal phase and an intermetallic compound strengthening phase are further distributed on the boundary of the molten pool and the center of the molten pool in a dispersed mode; the problems that when a traditional aluminum alloy material is used for additive manufacturing forming, hot cracks or macroscopic cracks occur, and the mechanical property of a formed product is poor are fundamentally solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of additive manufacturing of aluminum alloys, and particularly relates to a heat-resistant aluminum alloy material and a preparation method and application thereof. BACKGROUND

[0002] Lightweight is the core demand for realizing the "double carbon" goal in the field of aerospace, and aluminum alloy, as a representative of lightweight structural materials, is favored by the industry. Additive manufacturing can realize net shaping of parts according to digital models, and thus becomes the preferred preparation process for lightweight structure manufacturing. At present, the low-altitude economy is increasingly developed, and aircraft are constantly pursuing performance improvement, so the demand for small and high-performance engines is increasingly strong. There is an urgent need for heat-resistant aluminum alloys for additive manufacturing that can serve at 300-400℃ for a long time, replacing high-density traditional metal materials.

[0003] At present, the additive manufacturing aluminum alloys that have achieved wide commercial application are limited to a few aluminum-silicon alloys such as AlSi12 and AlSi10Mg, while traditional high-strength aluminum alloys such as 2-series and 7-series are prone to serious thermal cracking under the complex thermal stress environment of additive manufacturing due to their wide solidification interval. In addition, traditional high-strength aluminum alloys rely on nano-precipitated phase aging strengthening, and at 300-400℃ high temperature, the precipitated phase coarsens due to rapid diffusion of solute atoms and Ostwald ripening effect, resulting in a sharp decrease in strength. In addition, the thermal influence zone caused by layer-by-layer solidification in additive manufacturing leads to phase coarsening, and the high temperature gradient brings about a large thermal stress, so the traditional heat-resistant aluminum alloy materials usually have poor formability, and when they are used for additive manufacturing, they are prone to metallurgical defects such as thermal cracking or macroscopic cracking, resulting in very poor mechanical properties, which cannot be directly applied to additive manufacturing technology, which also causes the predicament that there is no lightweight additive manufacturing aluminum alloy material available at 300-400℃ temperature range. Therefore, it is urgent to develop high-strength heat-resistant aluminum alloy powder suitable for additive manufacturing to improve the performance of aluminum alloy formed products.

[0004] Chinese patent CN118880132A discloses a high-ductility Al-Mg alloy powder material for additive manufacturing, a preparation method and application thereof. The Al-Mg alloy powder material uses elements such as Mg, Mn, Zr, Ti, Ce and Si, and forms Al3Zr, Al3Ti and Al3(Ce,Zr) nano-dispersed phases and Mg2Si strengthening phases in combination with the laser additive manufacturing process. The prepared aluminum alloy has a yield strength of 500 MPa or more and an elongation of 12.5%. Chinese patent CN118773489A discloses a heat-resistant high-strength aluminum alloy and a preparation method thereof. The aluminum alloy is prepared by combining gas atomization screening and additive manufacturing, and uses elements such as Mn, Sc, Zr and Nd to form intermetallic compounds, thereby improving the high-temperature mechanical properties of the aluminum alloy. However, the mechanical properties of the above aluminum alloys at high temperature still have a large room for improvement. SUMMARY

[0005] The application aims to provide a heat-resistant aluminum alloy material and a preparation method thereof to solve the problems of thermal cracks or macroscopic cracks, and poor mechanical properties of the formed product when the conventional aluminum alloy material is used for additive manufacturing.

[0006] To solve the above problems, the application is implemented by the following scheme: Firstly, the application provides a heat-resistant aluminum alloy material, the components of the heat-resistant aluminum alloy material include, in mass percentage: 0.5-6% of Fe, 0.5-6% of Cr, 0.5-3% of Ti, ≤2% but not 0 of Mn, ≤2% but not 0 of Sc, ≤2% but not 0 of Zr, the balance of Al and inevitable impurities.

[0007] Further, in the microstructure of the heat-resistant aluminum alloy material, the internal part presents a bimodal grain structure, the molten pool boundary is mainly equiaxed crystal, the molten pool center is columnar crystal, and the molten pool boundary and the molten pool center are also dispersedly distributed with quasicrystal and intermetallic compound strengthening phase. Further, the elongation of the heat-resistant aluminum alloy material is ≥10% at 300-400℃.

[0008] Further, the tensile strength of the heat-resistant aluminum alloy material is >260MPa and the yield strength is >220MPa at 300℃; the tensile strength of the heat-resistant aluminum alloy material is >180MPa and the yield strength is >160MPa at 350℃.

[0009] Further, the components of the heat-resistant aluminum alloy material further include 0.2-4.0% of Ce.

[0010] Further, the components of the heat-resistant aluminum alloy material include: 0.2-2.0% of Mn, 0.2-1.5% of Sc, and 0.2-1.5% of Zr.

[0011] Preferably, the microstructure of the heat-resistant aluminum alloy material contains 20-40vol% of dispersedly distributed icosahedral nanometer quasicrystal phase.

[0012] Further, the application provides a preparation method of the heat-resistant aluminum alloy material, including the following steps: S1, putting the heat-resistant aluminum alloy raw material powder into a 3D printing device for laser melting printing process; S2, high-temperature stress annealing.

[0013] Further, the laser power in the laser melting printing process is 200-400W, the scanning speed is 600-2000mm / s, and the scanning interval is 0.06-0.18mm.

[0014] Further, the heating rate in the stress relief annealing process is 5-15℃ / min, the holding temperature is 200-400℃, and the holding time is 2-10h.

[0015] Further, the Hall flow rate of the heat-resistant aluminum alloy raw powder is ≤130s / 50g, and the sphericity is ≥0.85.

[0016] Further, the preparation process of the heat-resistant aluminum alloy raw powder is: (1) raw material smelting; (2) atomization powdering; (3) powder screening; wherein the raw material smelting temperature is 1000-1300℃, and the atomization gas pressure is 2.0-3.0MPa.

[0017] Further, the particle size range of the heat-resistant aluminum alloy raw powder is 15-53μm.

[0018] Further, the application also provides the application of the heat-resistant aluminum alloy material in additive manufacturing.

[0019] The beneficial effects of the application are:

[0020] (1) The Al alloy composition of the application is mainly alloyed with transition group (Fe, Cr, Ti, etc.) elements and rare earth (Sc, Zr, Ce, etc.) elements, the rapid solidification characteristics of additive manufacturing are used to inhibit the coarse AlFe needle-shaped precipitated phase, the limit solid solubility of alloy elements is improved, and a sufficient number of high-temperature heat-resistant dispersion strengthening phases are formed in the aluminum matrix, such as Al 13 (Cr, Fe) 2-4 intermetallic compound; the Al3(Sc, Zr) coherent nano precipitated phase is precipitated on the surface of the primary strengthening phase by using the rare earth elements Sc and Zr, the coarsening and dissolution of the structure at high temperature are inhibited, and the cracking, poor mechanical strength and other problems of traditional aluminum alloy in the additive manufacturing process are fundamentally solved.

[0021] (2) The aluminum alloy material obtained by the specific component formula and the specific preparation method has a refined bimodal grain structure inside, the melt pool boundary is equiaxed crystal, and the melt pool center is columnar crystal, the fine equiaxed crystal inhibits crack propagation and cooperates with the columnar crystal to improve the strength and plasticity of the alloy; a large number of quasicrystal and intermetallic compound strengthening phases are dispersedly distributed in the melt pool boundary and center, which endows the heat-resistant alloy material with excellent high-temperature performance.

[0022] (3) The heat-resistant alloy material of the present application has a tensile strength of >260 MPa, a yield strength of >220 MPa, and an elongation of ≥10% at 300°C; and a tensile strength of >180 MPa, a yield strength of >160 MPa, and an elongation of ≥10% at 350°C; and has low performance anisotropy.

[0023] (4) The aluminum alloy material used for additive manufacturing in this application has excellent mechanical properties such as excellent formability, no cracks, high strength, and high heat resistance, which can meet the industrial demand for high-strength, heat-resistant, lightweight, and complex structure aluminum alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : Scanning electron microscope image of the heat-resistant aluminum alloy raw material powder of Example 2.

[0025] Figure 2 : Optical microscope image of the heat-resistant aluminum alloy material of Example 2.

[0026] Figure 3 : Scanning electron microscope image of the heat-resistant aluminum alloy material of Example 2.

[0027] Figure 4 : Phase distribution diagram of the aluminum alloy material of Example 2.

[0028] Figure 5 : High temperature tensile test stress-strain curve of aluminum alloy material in Example 3.

[0029] Figure 6 : High temperature tensile test stress-strain curve of the aluminum alloy material of Example 4.

[0030] Figure 7 : Example 2 Heat-resistant strengthening phase morphology and distribution diagram of aluminum alloy material. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] A heat-resistant aluminum alloy material comprises, in percentage by mass, 0.5-6% of Fe, 0.5-6% of Cr, 0.5-3% of Ti, ≤2% but not 0 of Mn, ≤2% but not 0 of Sc, ≤2% but not 0 of Zr, and the balance being Al and unavoidable impurities.

[0033] The heat-resistant aluminum alloy material of the present application is an Al-Fe-Cr-Ti system aluminum alloy, and the effects of each element are as follows: Fe: cooperates with Cr to form a quasicrystal phase, which is the core element of the quasicrystal structure in the Al-Fe-Cr-Ti system aluminum alloy, improves the high-temperature strength of the alloy, inhibits grain coarsening, and maintains the stability of the quasicrystal phase at high temperatures; but is limited to solid solution in the Al matrix, and excessive use will precipitate coarse needle-shaped Al 13 Fe4 phase, resulting in cracks in the alloy, increased porosity, and decreased density. Within the content range of 0.5-6%, Fe and Cr can form a good match, balancing the strength and density of the aluminum alloy.

[0034] Cr: cooperates with Fe to stabilize the quasicrystal structure and reduce lattice distortion. Low diffusion rate slows down phase transformation at high temperatures, delaying the decomposition of quasicrystals into stable intermetallic compounds. Cr can form a dense chromium oxide layer in a high-temperature environment, improving oxidation resistance. When the amount is too small, the grain boundary segregation is weak, and 0.5-6% is the best dosage range of Cr.

[0035] Ti: as a strong nucleating agent, generates Al3Ti intermetallic compounds with excellent high-temperature stability, promotes non-uniform nucleation of Al, significantly refines quasicrystal phase particles, reduces thermal cracks, improves strength and toughness, and improves the high-temperature strength and hardness of the alloy. However, when the amount is too much, it will lead to coarsening of Al3Ti particles and thus reduce the strength of the alloy.

[0036] The above three elements in the aluminum alloy interact with each other, collectively affecting the microstructure of the Al-Fe-Cr-Ti system aluminum alloy matrix, and improving its mechanical strength.

[0037] Further, in the microstructure of the heat-resistant aluminum alloy material, the internal structure presents a bimodal grain structure, the melt pool boundary is mainly equiaxed crystal, the melt pool center is columnar crystal, and the melt pool boundary and melt pool center are also dispersedly distributed with icosahedral quasicrystals and intermetallic compound strengthening phases.

[0038] The bimodal grain structure in the heat-resistant aluminum alloy material has excellent strength and plasticity synergy; the columnar crystal can reduce the number of grain boundaries, reduce the probability of pores or un-melted defects, and provide higher tensile strength. The equiaxed crystal has higher hardness, can synergize with the soft columnar crystal to delay strain localization and improve the elongation of the alloy. In addition, the staggered distribution of columnar crystals and equiaxed crystals can hinder crack propagation and improve the fatigue performance of the alloy. A multi-level defense strengthening system is constructed in the aluminum alloy material of the present application, the equiaxed crystal acts as a crack barrier, the columnar crystal is a load channel, the icosahedral quasicrystal improves the high-temperature performance of the alloy, and the dispersion strengthening hinders the dislocation movement, improves the yield strength, and also plays a role with the intermetallic compound strengthening phase to provide extreme environmental stability and mechanical strengthening. The existence and distribution of the above structure can ensure that the elongation of the aluminum alloy is ≥10%, the tensile strength of the heat-resistant aluminum alloy material is >260 MPa at 300℃, and the yield strength is >220 MPa; the tensile strength of the heat-resistant aluminum alloy material is >180 MPa at 350℃, and the yield strength is >160 MPa.

[0039] Preferably, the heat-resistant aluminum alloy material contains 20-40vol% of dispersed icosahedral nanometer quasicrystal phase in the microstructure. The icosahedral nanometer quasicrystal phase is a hard phase that hinders dislocation movement, and the coherent interface between the quasicrystal and the matrix has high coherence, which can effectively delay crack initiation and is beneficial to the mechanical strength of the alloy; and due to its high nucleation rate, it forms a dispersed distribution and has high thermal stability (430℃ decomposition), which is a very excellent high-temperature strengthening phase. The formation of icosahedral nanometer quasicrystal depends on the composition design and preparation process of the Al-Fe-Cr-Ti system aluminum alloy. The relative amount of the above-mentioned Fe, Cr, Ti elements in Al can form a specific stoichiometric ratio range to promote the formation of nanometer quasicrystals. If the stoichiometric ratio deviates, too many crystal phases (such as Al 13 Fe4) will be precipitated; and on the preparation process side, specific melt holding temperature and cooling process must be matched to ensure that the alloy contains a dispersed nanometer quasicrystal phase.

[0040] Further, the tensile strength of the heat-resistant aluminum alloy material is >260 MPa at 300℃, and the yield strength is >220 MPa; the tensile strength of the heat-resistant aluminum alloy material is >180 MPa at 350℃, and the yield strength is >160 MPa.

[0041] Further, the composition of the heat-resistant aluminum alloy material further includes 0.2-4.0% of Ce. Adding Ce element can remove O / S impurities and reduce alloy surface pores on one hand; on the other hand, it can be adsorbed on the grain boundary to reduce the interface energy and promote the growth of equiaxed crystals; it can also form high-melting-point intermetallic compounds such as AlCe with Al matrix to improve high-temperature strength.

[0042] Further, the heat-resistant aluminum alloy material comprises 0.2-2.0% of Mn, 0.2-1.5% of Sc, and 0.2-1.5% of Zr.

[0043] Mn participates in the formation of icosahedral quasicrystal phase, improves the heat resistance and corrosion resistance of the alloy, and can also form AlMnCe high-melting-point intermetallic compounds with Ce, but too high content of Mn will lead to a decrease in the density of the alloy. Sc and Zr can both refine the grain size of the structure, promote the coherent nanometer precipitates such as Al3(Sc, Zr), inhibit dynamic recrystallization, and improve the high-temperature strength of the alloy; however, too high content of Sc will cause coarse Al3Sc to easily gather into crack sources, thereby reducing the plasticity of the alloy; and too high content of Zr will cause the brittle Al3Zr phase to coarsen, with the size reaching the micron level, which is not conducive to the elongation of the alloy. In the alloy material of the present application, there are multiple element interactions and synergistic regulation effects, such as the formation of Al3(Sc, Zr) by Sc / Zr, the promotion of Al3(Ti, Zr) precipitation by Ti, and the common refinement of the grain size; Sc has a high cost, and the combined addition of Ti to form Al3(Sc, Ti) can take into account the grain refinement and strengthening effects, and reduce the amount of Sc, but too high content of Ti will increase the proportion of Ti in Al3(Sc, Ti), reduce the pinning ability, and decrease the tensile strength of the alloy. Therefore, controlling the content of Sc in the system to be 0.2-1.5%, the content of Zr to be 0.2-1.5%, and the content of Ti to be 0.5-3% can exhibit the most excellent synergistic effect, effectively refine the grain size, inhibit harmful phases, optimize precipitated strengthening phases, and the like to improve the mechanical properties of the aluminum alloy.

[0044] Further, the present application provides a preparation method of a heat-resistant aluminum alloy material, comprising the following steps: S1, placing heat-resistant aluminum alloy raw material powder into a 3D printing device for laser melting printing process; S2, high-temperature stress annealing.

[0045] Further, in the laser melting printing process, the preheating temperature of the substrate is 50-200°C, the laser power is 200-400W, the scanning speed is 600-2000mm / s, and the scanning interval is 0.06-0.18mm.

[0046] The addition of Sc, Zr, Mn, Ce and other elements in Al-Fe-Cr-Ti aluminum alloy matrix can optimize alloy performance through grain refinement, harmful phase inhibition and high-temperature stability improvement. However, the effect of these elements is highly dependent on additive manufacturing process parameters, as they directly affect the thermal behavior of the molten pool (temperature gradient, cooling rate, thermal cycle) and element distribution. Among them, laser power directly affects the molten pool temperature and heat input, thereby regulating the solubility of elements and phase formation kinetics. At low power, due to the high reflectivity of aluminum alloy powder to infrared laser, Sc / Zr cannot fully dissolve and diffuse, the amount of Al3(Sc, Zr) precipitates decreases and the distribution is uneven, and Mn is difficult to fully diffuse, resulting in an increase in coarse Al6Mn phase. At high power, Al3(Sc, Zr) precipitates coarsen, and the evaporation of some elements leads to a deviation from the designed value. Scanning speed affects element segregation tendency and grain morphology by dominating the cooling rate and temperature gradient of the molten pool; at low scanning speed, the temperature gradient is large, columnar crystal epitaxial growth dominates, the heterogeneous nucleation of Sc / Zr is inhibited, and the thermal crack sensitivity is high; at a proper high scanning speed, the cooling rate increases, promoting the synergistic deformation of the bimodal grain structure and improving the elongation of the alloy; but too high scanning speed will exacerbate the non-equilibrium solidification of the melt, leading to element segregation and reducing the overall performance of the alloy. The scanning interval determines the thermal accumulation effect of the interlayer remelting area, thereby affecting the diffusion uniformity of elements and the size, number and distribution of strengthening phases in different regions of the molten pool. A scanning interval of 0.06-0.18 mm can maximize the forming efficiency of the aluminum alloy while ensuring the dimensional accuracy and density of the formed parts.

[0047] Further, the heating rate in the stress relief annealing process is 5-15℃ / min, the holding temperature is 200-400℃, and the holding time is 2-10h. Low heating rate will lead to grain coarsening of Al3(Sc, Zr), Al3Ti, etc., becoming a crack source, but at high heating rate, the residual stress in the alloy is not completely eliminated, increasing the risk of service deformation. The holding temperature determines the phase equilibrium state and grain boundary structure reconstruction. If the holding temperature is too low, the residual stress cannot be completely eliminated, and the alloy part is prone to deformation; if the temperature is too high, the strengthening phase will coarsen and the grain structure will grow, reducing the strength of the alloy. Only with appropriate heating rate, holding temperature and time can residual stress elimination and nanophase stability be achieved simultaneously.

[0048] Further, the Hall flow rate of the heat-resistant aluminum alloy raw powder is ≤130 s / 50g, and the sphericity is ≥0.85. A Hall flow rate of ≤130 s / 50g can ensure efficient powder laying and high density, avoiding un-melted defects; a sphericity of ≥0.85 can improve laser absorption rate and composition uniformity, and inhibit cracks and pores.

[0049] Further, the preparation process of the heat-resistant aluminum alloy raw material powder comprises the following steps: (1) raw material smelting; (2) atomization powder preparation; and (3) powder screening, wherein the raw material smelting temperature is 1000-1300℃, and the atomization gas pressure is 2.0-3.0MPa.

[0050] Further, the particle size of the heat-resistant aluminum alloy raw material powder ranges from 15 to 53μm.

[0051] Further, the application also provides the application of the heat-resistant aluminum alloy material in additive manufacturing.

[0052] Embodiment 1 The heat-resistant aluminum alloy material comprises the following components in percentage by mass: 0.5-6% of Fe, 0.5-6% of Cr, 0.5-3% of Ti, the balance of Al and inevitable impurities.

[0053] Preferably, it also comprises 0.2-4.0% of Ce, 0.2-2.0% of Mn, 0.2-1.5% of Sc and 0.2-1.5% of Zr.

[0054] The embodiment also provides a preparation method of the heat-resistant aluminum alloy material, comprising the following steps: S1, drawing a part model to be printed on a three-dimensional design software, adding support to the three-dimensional model, slicing, and putting the heat-resistant aluminum alloy raw material powder into a 3D printing device for selective laser melting (SLM) printing process; wherein the SLM laser is 1000nm-1100nm infrared light, the substrate preheating temperature is 50-200℃, the laser power is 200-400W, the scanning speed is 600-2000mm / s, the scanning interval is 0.06-0.18mm, and the layer thickness is 0.03-0.06mm.

[0055] S2, high-temperature stress annealing, specifically, heating at a heating rate of 5-15℃ / min to 200-400℃ for heat preservation, and the heat preservation time is 2-10h, and then furnace cooling or air cooling is performed after the end.

[0056] The preparation process of the heat-resistant aluminum alloy raw material powder comprises the following steps: (1) raw material smelting: putting all the component metal raw materials of the heat-resistant aluminum alloy material into a crucible of a vacuum induction furnace for smelting, and the smelting temperature is 1000-1300℃; (2) atomization powder preparation: transferring the smelted metal melt into an atomization barrel, replacing the air in the atomization barrel with argon gas, and performing atomization powder preparation, and the gas pressure is 2.0-3.0Mpa; (3) Powder screening: Powder screening: Use 250 mesh and 550 mesh screens to perform ultrasonic vibration screening and grading on the atomized metal powder to obtain alloy raw material powder with a powder size range of 15-53μm; The Hall flow rate of the heat-resistant aluminum alloy raw material powder is ≤130 s / 50g, and the sphericity is ≥0.85.

[0057] Example 2 This embodiment provides a heat-resistant aluminum alloy material. The components of the heat-resistant aluminum alloy material include, by mass percentage, 1% Fe, 4% Cr, 3% Ti, and the balance being Al and unavoidable impurities.

[0058] This embodiment also provides a method for preparing the heat-resistant aluminum alloy material, comprising the following steps: S1. Draw the part model to be printed on the 3D design software, add supports and slice the 3D model, and place the heat-resistant aluminum alloy raw material powder into the 3D printing equipment for selective laser melting (SLM) printing process; the SLM laser is 1000nm infrared light, the substrate preheat temperature is 130℃, the laser power is 330W, the scanning speed is 1400mm / s, the scanning pitch is 0.09mm, and the layer thickness is 0.03mm.

[0059] S2. High-temperature stress relief annealing, specifically heating to 260°C at a heating rate of 10°C / min and holding for 3 hours, followed by air cooling; the density of the prepared heat-resistant aluminum alloy material is 99.2%.

[0060] The preparation process of the heat-resistant aluminum alloy raw material powder is as follows: (1) Raw material smelting: Place all the component metal raw materials of the heat-resistant aluminum alloy material in a crucible of a vacuum induction furnace for smelting at a smelting temperature of 1100°C; (2) Atomization powder making: The molten metal is transferred into the atomization barrel after smelting, and argon gas is passed through the atomization barrel to replace the air in the atomization barrel for atomization powder making. The gas pressure is 2.6 MPa; (3) Powder screening: Powder screening: The atomized metal powder is subjected to ultrasonic vibration screening and classification using 250-mesh and 550-mesh sieves to obtain alloy raw material powder with a powder particle size range of 15-53 μm (D10 is 20.09 μm; D50 is 35.63 μm; D90 is 56.17 μm); The Hall flow rate of the heat-resistant aluminum alloy raw material powder is 121s / 50g, and the sphericity is 0.87.

[0061] Attachment Figure 1 This is a scanning electron microscope image of the raw material powder. It can be seen from the image that the raw material powder prepared in this application is a spherical powder.

[0062] Fig. 1 is an optical microscope image of a printed state corrosion metallograph of an aluminum alloy material of the present application, and Fig. 2 is a scanning electron microscope image of the printed state corrosion metallograph of the aluminum alloy material of the present application, from which it can be seen that the aluminum alloy material prepared in the present application does not have defects such as cavities, welds, cracks, etc. Figure 2 Fig. 3 is a phase distribution diagram of the aluminum alloy material of the present application, from which it can be seen that the aluminum alloy material has a refined bimodal grain structure, the molten pool boundary is an equiaxed crystal region, the molten pool center is a columnar crystal region, and a large number of quasicrystals and intermetallic compound strengthening phases are dispersedly distributed in the molten pool boundary and center. Figure 3 Fig. 4 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 2 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center. Fig. 5 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 3 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center.

[0063] Fig. 6 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 4 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center. Figure 4 Fig. 7 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 5 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center. Fig. 8 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 6 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center.

[0064] Fig. 9 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 7 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center. Figure 7 Fig. 10 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 8 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center. Fig. 11 is a heat-resistant strengthening phase morphology and distribution diagram of the aluminum alloy material of Example 9 of the present application, from which it can be seen that the heat-resistant strengthening phase of the aluminum alloy is distributed along the molten pool boundary and center.

[0065] Table 1 shows the high-temperature tensile mechanical property test results of the aluminum alloy material of Example 2 at 300℃ and 350℃, where X is parallel to the substrate direction, and Z is the deposition direction, i.e. perpendicular to the substrate direction, and the same applies below.

[0066] Table 1 High-temperature tensile mechanical property test results of the aluminum alloy material of Example 2 at 300℃ and 350℃

[0067] Example 3 The present example provides a heat-resistant aluminum alloy material, the components of which include, in mass percentage: 1% of Fe, 4% of Cr, 1% of Ti, 1% of Ce, 0.5% of Mn, 0.3% of Sc, 0.5% of Zr, the balance being Al and unavoidable impurities.

[0068] The present example also provides a preparation method of the heat-resistant aluminum alloy material, comprising the following steps: S1, draw the part model to be printed on a three-dimensional design software, add support to the three-dimensional model, slice, and put the heat-resistant aluminum alloy raw material powder into a 3D printing device for selective laser melting (SLM) printing process; wherein the SLM laser is 1000nm infrared light, the substrate preheating temperature is 130℃, the laser power is 350W, the scanning speed is 1600mm / s, the scanning interval is 0.09mm, and the layer thickness is 0.03mm.

[0069] S2, high-temperature stress annealing, specifically heating to 260℃ at a heating rate of 10℃ / min and holding for 3h, and then performing air cooling cooling; the prepared heat-resistant aluminum alloy material has a density of 99.5%.

[0070] The preparation process of the heat-resistant aluminum alloy raw material powder is as follows: (1) Raw material smelting: place all component metal raw materials of the heat-resistant aluminum alloy material in a crucible of a vacuum induction furnace for smelting, and the smelting temperature is 1050℃; (2) Atomization powdering: transfer the smelted metal melt into an atomization barrel, replace the air in the atomization barrel with argon, and perform atomization powdering, and the gas pressure is 2.7Mpa; (3) Powder screening: adopt 250-mesh and 550-mesh screens to perform ultrasonic vibration screening and grading treatment on the atomized metal powder, and obtain the alloy powder with a particle size range of 15-53μm (D10 is 19.52μm; D50 is 33.83μm; D90 is 57.21μm); The Hall flow rate of the heat-resistant aluminum alloy raw material powder is 115s / 50g, and the sphericity is 0.88.

[0071] The aluminum alloy material of the embodiment is subjected to high-temperature tensile mechanical property tests at 300℃ and 350℃, and the results of parallel measurement twice are shown in Table 2 below.

[0072] Table 2 High-temperature tensile mechanical property test results of the aluminum alloy material of Example 3 at 300℃ and 350℃

[0073] The stress-strain curve of the high-temperature tensile test of the aluminum alloy material of the embodiment is shown in the following figure. Figure 5

[0074] Example 4 The embodiment provides a heat-resistant aluminum alloy material, and components of the heat-resistant aluminum alloy material include, in mass percentage: 1% of Fe, 4% of Cr, 1% of Ti, 3% of Ce, 0.5% of Mn, 0.3% of Sc, 0.5% of Zr, and the balance of Al and inevitable impurities.

[0075] The embodiment also provides a preparation method of the heat-resistant aluminum alloy material, including the following steps: S1, draw a part model to be printed on a three-dimensional design software, add support to the three-dimensional model, slice, and put the heat-resistant aluminum alloy raw material powder into a 3D printing device for selective laser melting (SLM) printing process; wherein the SLM laser is 1000nm infrared light, the substrate preheating temperature is 130℃, the laser power is 350W, the scanning speed is 1600mm / s, the scanning interval is 0.09mm, and the layer thickness is 0.03mm.

[0076] ​S2, high temperature stress annealing, specifically, heating at a rate of 10℃ / min to 260℃, holding for 3h, and then air cooling; the density of the prepared heat-resistant aluminum alloy material is 99.5%.

[0077] The preparation process of the heat-resistant aluminum alloy raw powder is as follows: (1) Raw material smelting: place all component metal raw materials of the heat-resistant aluminum alloy material in a crucible of a vacuum induction furnace for smelting, and the smelting temperature is 1050℃; (2) Atomization powdering: transfer the smelted metal melt into an atomization barrel, replace the air in the atomization barrel with argon, and perform atomization powdering, and the gas pressure is 2.7Mpa; (3) Powder screening: adopt 250-mesh and 550-mesh screens to perform ultrasonic vibration screening and grading treatment on the atomized metal powder, and obtain alloy powder with a particle size range of 15-53μm (D10 is 19.68μm; D50 is 34.35μm; D90 is 56.63μm); The Hall flow rate of the heat-resistant aluminum alloy raw powder is 126s / 50g, and the sphericity is 0.88.

[0078] The high-temperature tensile mechanical property of the aluminum alloy material of the present embodiment was tested at 300℃ and 350℃, and the results of parallel measurement twice are shown in Table 3 below.

[0079] Table 3 High-temperature tensile mechanical property test results of the aluminum alloy material of Example 4 at 300℃ and 350℃

[0080] The stress-strain curve corresponding to the high-temperature tensile test of the aluminum alloy material of the present embodiment is shown in Figure 2. Figure 6

[0081] Example 5 The present embodiment provides a heat-resistant aluminum alloy material, and the components of the heat-resistant aluminum alloy material include, in mass percentage: 6% of Fe, 4% of Cr, 1% of Ti, 0.2% of Ce, 0.5% of Mn, 0.3% of Sc, 0.5% of Zr, and the balance of Al and unavoidable impurities.

[0082] The present embodiment also provides a preparation method of the heat-resistant aluminum alloy material, which includes the following steps: ​S1, draw the part model that needs to be printed on the three-dimensional design software, add support to the three-dimensional model, slice, put the heat-resistant aluminum alloy raw material powder into the 3D printing equipment for selective laser melting (SLM) printing process; wherein the SLM laser is 1000nm infrared light, the substrate preheating temperature is 130℃, the laser power is 200W, the scanning speed is 600mm / s, the scanning interval is 0.06mm, and the layer thickness is 0.03mm.

[0083] S2, high-temperature stress annealing, specifically, heating at a rate of 5℃ / min to 200℃ and keeping for 10h, and then air cooling.

[0084] The preparation process of the heat-resistant aluminum alloy raw material powder is: (1) Raw material smelting: place all component metal raw materials of the heat-resistant aluminum alloy material in the crucible of the vacuum induction furnace for smelting, and the smelting temperature is 1000℃; (2) Atomization powdering: transfer the smelted metal melt into an atomization barrel, replace the air in the atomization barrel with argon, and perform atomization powdering, and the gas pressure is 2.5Mpa; (3) Powder screening: adopt 250 mesh and 550 mesh screens to perform ultrasonic vibration screening and grading treatment on the atomized metal powder, and obtain the alloy raw material powder with a powder particle size range of 15-53μm; The Hall flow rate of the heat-resistant aluminum alloy raw material powder is 129 s / 50g, and the sphericity is 0.88.

[0085] Example 6 The embodiment provides a heat-resistant aluminum alloy material, and components of the heat-resistant aluminum alloy material include, in percentage by mass: 6% of Fe, 1% of Cr, 1% of Ti, 0.2% of Ce, 2.0% of Mn, 1.0% of Sc, 0.5% of Zr, and the balance of Al and inevitable impurities.

[0086] The embodiment also provides a preparation method of the heat-resistant aluminum alloy material, and the preparation method comprises the following steps: S1, draw the part model that needs to be printed on the three-dimensional design software, add support to the three-dimensional model, slice, put the heat-resistant aluminum alloy raw material powder into the 3D printing equipment for selective laser melting (SLM) printing process; wherein the SLM laser is 1000nm infrared light, the substrate preheating temperature is 130℃, the laser power is 200W, the scanning speed is 600mm / s, the scanning interval is 0.06mm, and the layer thickness is 0.03mm.

[0087] S2, high-temperature stress annealing, specifically, heating at a rate of 5℃ / min to 200℃ and keeping for 10h, and then air cooling.

[0088] The preparation process of the heat-resistant aluminum alloy raw material powder is as follows: (1) Raw material smelting: place all component metal raw materials of the heat-resistant aluminum alloy material in a crucible of a vacuum induction furnace for smelting, and the smelting temperature is 1300℃; (2) Atomization powdering: transfer the smelted metal melt into an atomization barrel, replace the air in the atomization barrel with argon, and perform atomization powdering, and the gas pressure is 3.0Mpa; (3) Powder screening: adopt 250-mesh and 550-mesh screens to perform ultrasonic vibration screening and grading treatment on the atomized metal powder, and obtain the alloy raw material powder with a powder particle size range of 15-53μm; The Hall flow rate of the heat-resistant aluminum alloy raw material powder is 127s / 50g, and the sphericity is 0.87.

[0089] Comparative Example 1 The heat-resistant aluminum alloy material is basically the same as that in Example 3, except that the components of the heat-resistant aluminum alloy material include, by mass percentage, 1% of Mg, 4% of Cr, 1% of Ti, 1% of Ce, 0.5% of Mn, 0.3% of Sc, 2% of Zr, and the balance of Al and inevitable impurities.

[0090] Comparative Example 2 The heat-resistant aluminum alloy material is basically the same as that in Example 3, except that the components of the heat-resistant aluminum alloy material include, by mass percentage, 1% of Fe, 4% of Cr, 1% of Ti, 1% of Ce, 3% of Mn, 0.3% of Sc, 2% of Zr, and the balance of Al and inevitable impurities.

[0091] Comparative Example 3 The heat-resistant aluminum alloy material is basically the same as that in Example 3, except that the components of the heat-resistant aluminum alloy material include, by mass percentage, 1% of Mg, 4% of Cr, 1% of Ti, 1% of Ce, 0.5% of Mn, 0.3% of Sc, 0.5% of Zr, and the balance of Al and inevitable impurities.

[0092] Comparative Example 4 The heat-resistant aluminum alloy material is basically the same as that in Example 3, except that the components of the heat-resistant aluminum alloy material include, by mass percentage, 1% of Fe, 4% of Cr, 1% of Ti, 1% of Nd, 0.5% of Mn, 0.3% of Sc, 0.5% of Zr, and the balance of Al and inevitable impurities.

[0093] Comparative Example 5 The heat-resistant aluminum alloy material is basically the same as that in Example 3, except that the laser power in S1 is 150W, and the scanning speed is 500mm / s.

[0094] Comparative Example 6 The same as Example 3, except that in S2, the temperature was raised to 500℃ at a rate of 3℃ / min, and the holding time was 10h, and then air cooling was performed after the end.

[0095] Comparative Example 7 The same as Example 3, except that the melting temperature was 1350℃, the atomization pressure was 3.5MPa, the Hall flow rate was not measured, and the sphericity was 0.8.

[0096] The mechanical properties of the above examples and comparative examples in the direction parallel to the substrate were statistically tested, and the results are shown in Table 4.

[0097] Table 4 Mechanical property test results of the aluminum alloy materials of the examples and comparative examples in the direction parallel to the substrate

[0098] Analysis: From the above table, it can be seen that the technical solutions of the aluminum alloy materials of Examples 2-6 have excellent forming properties, no cracks, high strength, high heat resistance, and other excellent mechanical strengths, which can well meet the needs of high-strength heat-resistant, lightweight, and complex-structure aluminum alloys in industry, and solve the problems of cracks and poor strength of traditional aluminum alloy materials in the additive manufacturing process.

[0099] It should be noted that in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0100] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements, and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A heat-resistant aluminum alloy material, characterized in that: The components of the heat-resistant aluminum alloy material include, by mass percentage, 0.5-6% Fe, 0.5-6% Cr, 0.5-3% Ti, ≤2% but not 0 Mn, ≤2% but not 0 Sc, ≤2% but not 0 Zr, and the balance being Al and unavoidable impurities; The microstructure of the heat-resistant aluminum alloy material presents a bimodal grain structure inside, the molten pool boundary is mainly equiaxed crystals, the molten pool center is columnar crystals, and quasicrystals and intermetallic compound strengthening phases are dispersed at the molten pool boundary and the molten pool center.

2. The heat-resistant aluminum alloy material according to claim 1, characterized in that: At 300°C, the tensile strength of the heat-resistant aluminum alloy material is greater than 260MPa, the yield strength is greater than 220MPa, and the elongation is ≥10%; at 350°C, the tensile strength of the heat-resistant aluminum alloy material is greater than 180MPa, the yield strength is greater than 160MPa, and the elongation is ≥10%.

3. The heat-resistant aluminum alloy material according to claim 1, characterized in that: The heat-resistant aluminum alloy material also includes 0.2-4.0% Ce.

4. The heat-resistant aluminum alloy material according to claim 1, characterized in that: The components of the heat-resistant aluminum alloy material include: 0.2-2.0% Mn, 0.2-1.5% Sc, and 0.2-1.5% Zr. The microstructure of the heat-resistant aluminum alloy material contains 20-40 vol% of dispersed icosahedral nano-quasi-crystalline phase.

5. The method for preparing a heat-resistant aluminum alloy material according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Place heat-resistant aluminum alloy raw material powder into a 3D printing device for laser melting printing; wherein the laser power is 200-400W, the scanning speed is 600-2000mm / s, and the scanning pitch is 0.06-0.18mm; S2. Stress relief annealing at high temperature.

6. The method for preparing the heat-resistant aluminum alloy material according to claim 5, characterized in that: In the stress relief annealing process, the heating rate is 5-15°C / min, the holding temperature is 200-400°C, and the holding time is 2-10h.

7. The method for preparing the heat-resistant aluminum alloy material according to claim 5, characterized in that: The Hall flow rate of the heat-resistant aluminum alloy raw material powder is ≤130 s / 50g, and the sphericity is ≥0.

85.

8. The method for preparing the heat-resistant aluminum alloy material according to claim 5 or 7, characterized in that: The preparation process of the heat-resistant aluminum alloy raw material powder is as follows: (1) raw material smelting; (2) atomization powder making; (3) powder screening; wherein the raw material smelting temperature is 1000-1300° C. and the atomization gas pressure is 2.0-3.0 MPa.

9. The method for preparing a heat-resistant aluminum alloy material according to claim 8, characterized in that: The particle size range of the heat-resistant aluminum alloy raw material powder is 15-53 μm.

10. Use of the heat-resistant aluminum alloy material according to any one of claims 1 to 4 in additive manufacturing.

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