In-situ self-grown particle reinforced heat-resistant aluminum-rare earth alloy and preparation method thereof

Abstract

The application discloses an in-situ self-grown particle reinforced heat-resistant aluminum rare earth alloy and a preparation method thereof, and belongs to the field of metal material preparation. The application adds TiB2 particles and Mg, Zr and Zn in an aluminum-cerium alloy, so that multi-component reinforcing phases are formed in an alpha-Al matrix, and the grains are further refined, which not only improves the mechanical properties and ductility of the aluminum-cerium alloy at room temperature, but also enables the material to still maintain good tensile strength and excellent elongation in a thermal exposure environment. In addition, the method of the application generates TiB2 particles in-situ in a smelting process, cooperates with component design and selective laser melting additive manufacturing, and significantly improves the mechanical properties of the alloy.

Description

Technical Field

[0001] This invention relates to an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy and its preparation method; it belongs to the field of metal material preparation. Background Technology

[0002] With the development of selective laser melting (SLM) technology, the application of aluminum alloys in the manufacture of complex lightweight structural components has attracted widespread attention. Existing research indicates that Al-Ce-based alloys have established a substantial research foundation in the SLM field and demonstrate promising application prospects. On the one hand, Al-Ce alloys possess near-eutectic characteristics and a relatively narrow solidification range, thus exhibiting good adaptability to the rapid melting-solidification process of SLM; on the other hand, the Al formed in Al-Ce alloys… 11 Ce3 and related Ce-enriched intermetallic compounds have good thermal stability, which is beneficial for the material to maintain a fine and stable microstructure after forming.

[0003] However, existing Al-Ce alloys still suffer from problems during SLM forming, such as the need for further grain refinement, insufficient uniformity, and low plasticity. For example, Chinese patent application CN117230349A discloses a selective laser melting (SLM) high-strength and high-toughness aluminum-cerium-manganese-calcium heat-resistant aluminum alloy. By adding rare earth elements Ce, Ca, and Mn and using additive manufacturing, the volume fraction of intermetallic compounds is increased and the particles are refined. The resulting aluminum alloy has a room temperature strength greater than 450 MPa, but the room temperature elongation is only up to 13%. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the first objective of this invention is to provide an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy. By adding TiB2 particles and Mg, Zr, Zn, etc., to the aluminum-cerium alloy, a multi-component strengthening phase is formed in the α-Al matrix, further refining the grain size. This not only improves the mechanical properties and ductility of the aluminum-cerium alloy at room temperature, but also ensures that the material maintains good tensile strength and excellent elongation even in thermally exposed environments.

[0005] The second objective of this invention is to provide a method for preparing an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy. This method significantly improves the mechanical properties of the alloy by generating TiB2 particles in situ during the smelting process, in conjunction with composition design and selective laser melting additive manufacturing.

[0006] To achieve the above-mentioned technical objectives, the present invention provides an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy, wherein the heat-resistant aluminum rare earth alloy comprises, by mass percentage: Ce 3~10%, Mg 2~5%, Zr 0.1~0.3%, TiB2 1.5~5%, M 2.6~7.3%, impurity elements ≤0.1%, and the balance being Al, wherein M is selected from at least one of Zn, Cu, Si and Sc;

[0007] Alternatively, by mass percentage, the heat-resistant aluminum-rare earth alloy comprises: Ce 5~10%, Mg 4~5%, Zn 3~4%, Zr 0.2~0.3%, TiB 1~1.2%, impurity elements ≤0.1%, and the balance being Al; Al in the heat-resistant aluminum-rare earth alloy 11 The Ce3 eutectic structure is distributed in the α-Al matrix, and the heat-resistant aluminum rare earth alloy has dispersed strengthening phases TiB2 and Al. 13 CeMg6 ternary phase.

[0008] In the alloy system of this invention, by adding Mg to the aluminum-cerium alloy, not only can it enter the α-Al matrix to play a role in solid solution strengthening, but also, when the Mg content is high and the cooling rate is fast, especially under the non-equilibrium solidification conditions of SLM, it can also form Al 13 The CeMg6 ternary phase further enhances strength and participates in high-temperature stabilization. A small amount of Zr can reduce Al... 11 The coarsening rate of the Ce3 phase at high temperatures. Simultaneously, this invention introduces finer and more dispersed TiB2 into the Al-Ce alloy through compositional synergy. This invention utilizes the high melting point and high thermal stability of TiB2, which is less prone to melting failure in the SLM molten pool. It can act as a heterogeneous nucleation core to promote α-Al grain refinement, drive the transformation from columnar to equiaxed crystals, inhibit grain growth, and improve alloy strength. Furthermore, TiB2 can form a relatively good interface relationship with the aluminum matrix, which is beneficial for particle dispersion and strengthening effects, and further inhibits crack / defect formation. In this invention, the amount of TiB2 particles is crucial. If it is below the range specified in this invention, it is difficult to achieve the effect of grain refinement and alloy strength improvement; if the amount is too high, particle agglomeration occurs, leading to decreased density, increased porosity, stress concentration, decreased plasticity, and a poorer grain refinement effect. In addition, by adding at least one of Zn, Cu, Si, and Sc, a second strengthening phase can be further formed in the aluminum-cerium alloy system, thereby synergistically enhancing the Al-Ce alloy. 11 The morphology of the Ce3 eutectic structure distributed in the α-Al matrix and the fine, uniformly distributed TiB2 particles further enhance the high-temperature strength and thermal stability of the alloy, while also giving the alloy excellent elongation.

[0009] Experiments have shown that when using higher concentrations of Ce and Mg, the addition of Zn can preferentially introduce it into the Al system. 11 Ce3, in Al 11 Al2CeZn2 forms within or near Ce3, thereby increasing the hardness and elastic modulus of the AlCe phase itself, while also strengthening the second phase, thus improving tensile strength and elongation at medium and high temperatures. Furthermore, an AlCeMgZn eutectic phase can also form in this system, resulting in good performance even with a TiB2 content of 1-1.2%. However, excessively high Ce content can lead to coarser α-Al grains and easily cause the formation of primary Al... 11 The aggregation of Ce3 phase increases the risk of elemental segregation during solidification.

[0010] As a preferred embodiment, the Al in the as-cast state 11 The Ce3 phase has a width of 0.5~0.7μm. In the printed state, the Al... 11 The Ce3 phase has a width of 200-300 nm, and the particle size of the dispersed reinforcing phase TiB2 in the printed state exhibits a bimodal distribution, with particle sizes ranging from 0.5-1 μm and 50-100 nm, respectively. Under the alloy system of this invention, Al... 11 The Ce3 phase forms a certain width. Meanwhile, the particle size of the dispersed reinforcing phase TiB2 exhibits a bimodal distribution. Through the dispersion of TiB2 within the 50–100 nm range, it can interact with Al... 11 The Ce3 phase produces particle size differences, forming a certain degree of heterogeneous phase reinforcement, thereby enabling the material to maintain good tensile strength and excellent elongation even in thermally exposed environments.

[0011] As a preferred embodiment, the M in the heat-resistant aluminum rare earth alloy is Zn, Cu, Si, and Sc, comprising, by mass percentage: Ce 5~10%, Mg 3~5%, Zn 2~4%, Cu 1~2%, Si 0.5~1%, Zr 0.2~0.3%, Sc 0.1~0.3%, TiB2 2.5~5%, impurity elements ≤0.1%, and the balance being Al; the heat-resistant aluminum rare earth alloy also contains an Al8CeCu4 strengthening phase, an Al2CeZn2 phase, an AlCeSi2 phase, and an Al3(Sc,Zr) nano-precipitate phase, and the Al3(Sc,Zr) nano-precipitate phase is coherent with the α-Al matrix. In a further preferred alloy system, by adding Cu, a key strengthening phase Al8CeCu4 can be formed with Al and Ce. This phase not only improves the medium- and high-temperature strength and thermal stability of the alloy material, but also helps to form fine eutectic and improve resistance to hot cracking in SLM. Furthermore, the addition of a small amount of Si can form the AlCeSi2 phase, further improving the as-cast strength and hardness, altering the morphology of the Ce-enriched phase, regulating the eutectic structure, and refining the microstructure. Simultaneously added Zr and Sc can further form Al3(Sc,Zr) nanoprecipitates in the system, achieving a coherent relationship with the α-Al matrix. This precipitate and coherent relationship can significantly refine the α-Al grains and regulate the Al... 11 The growth of Ce3 can, on the other hand, provide precipitation strengthening, inhibit recrystallization, and promote high-temperature coarsening. Therefore, in further optimized alloy systems, alloy materials with superior overall performance can be obtained.

[0012] Furthermore, by mass percentage, the heat-resistant aluminum rare earth alloy comprises: Ce 9~10%, Mg 4~5%, Zn 3~4%, Cu 1.5~2%, Si 0.8~1%, Zr 0.2~0.3%, Sc 0.2~0.3%, TiB 24~5%, impurity elements ≤0.1%, and the balance being Al.

[0013] As a preferred embodiment, the heat-resistant aluminum-rare earth alloy has a tensile strength of ≥85MPa and an elongation of ≥45% at a temperature of 350℃; and a tensile strength of ≥49MPa and an elongation of ≥71% at a temperature of 400℃.

[0014] Under a further optimized alloy composition design system, the heat-resistant aluminum-rare earth alloy has a tensile strength of over 109 MPa and an elongation of over 58% at a temperature of 350°C; and a tensile strength of over 53 MPa and an elongation of over 82% at a temperature of 400°C.

[0015] This invention also provides a method for preparing an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy, the method comprising the following steps:

[0016] S1 is prepared by distributing the required raw materials for smelting. After all the raw materials are melted, a refining agent is added for refining and degassing to obtain a melt. The temperature of the melt is adjusted to 700~750℃ and then cast to obtain an alloy ingot. During the smelting process, TiB2 is obtained in situ by adding KFB4 and K2TiF6 to the melt.

[0017] S2 produces heat-resistant aluminum rare earth alloy blocks by atomizing alloy ingots into powder, sieving the resulting alloy powder, and then selectively laser melting additive manufacturing.

[0018] In the preparation method of this invention, TiB2 is generated in situ at a high melt temperature, combined with atomized powdering and selective laser melting (SLM) additive manufacturing. Non-equilibrium rapid solidification conditions are used to suppress the growth and agglomeration of TiB2 particles, resulting in submicron-sized and diffusely distributed TiB2 particles that form a good interface with the aluminum matrix. This effectively refines α-Al grains and promotes the transformation from columnar to equiaxed crystals. This tandem process effectively avoids the localized network structure that occurs with conventional in-situ generated TiB2 particles. Furthermore, it can promote Al production at higher Ce and Mg contents. 11 Ce3 eutectic structure and Al 13 The formation of the CeMg6 ternary phase was facilitated, while the addition of Zr reduced the Al content. 11 The high-temperature coarsening rate of Ce3 and the more uniform distribution of TiB2, while elements such as Zn, Cu, Si, and Sc further introduce second-phase strengthening phases such as Al2CeZn2, synergistically improving medium- and high-temperature strength, thermal stability, and elongation. Furthermore, this invention utilizes selective laser melting additive manufacturing to obtain precipitates and reinforcing phases of various morphologies, which is beneficial for further improving the mechanical properties of the alloy. In practical operation, due to the loss of some boron during the in-situ self-generation process, the addition of KFB4 and K2TiF6 can be approximately 10% over the theoretical amount.

[0019] As a preferred embodiment, the atomization powder preparation conditions are: using an inert gas as the atomization medium, an atomization pressure of 1 MPa to 3 MPa, and an atomization temperature of 1300 to 1500 °C. Further, the inert gas is helium. Under the atomization powder preparation conditions of this invention, uniform powder preparation of hard ceramic particles and soft alloy powder in an alloy system can be achieved.

[0020] As a preferred embodiment, the refining agent comprises a mixture of chloride and fluoride salts, with a dosage of 0.5-1.0% relative to the melt mass. The refining is performed 2-3 times. After refining, surface slag is removed, the mixture is kept at a constant temperature for 10-15 minutes, and Ar gas is introduced into the bottom of the melt for degassing and slag removal for 1-5 minutes.

[0021] As a preferred embodiment, in S1, the smelting process is specifically as follows: first, pure aluminum is heated to 810~900℃, and after the pure aluminum raw material is completely melted, the temperature is lowered to 750~800℃. Then, Al-Ce master alloy, Al-Zr master alloy, and Al-M master alloy are added in sequence, and after melting, they are stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. The temperature is further lowered to 680~720℃, and Al-Mg master alloy is pressed into the melt and waited for 3~5 minutes to prevent Mg oxidation and burn-off. After complete melting, it is stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. Then, the temperature is raised to 760~800℃, and KFB4 and K2TiF6 with a mass ratio of 1:(1~2) are added to the melt. The mixture is stirred for 2~3 minutes until completely melted, the surface dross is removed, and the temperature is held for 10~15 minutes. M is selected from at least one of Zn, Cu, Si, and Sc.

[0022] Alternatively, as a preferred embodiment, the smelting process is as follows: first, pure aluminum is heated to 810~900℃, and after the pure aluminum raw material is completely melted, the temperature is lowered to 750~800℃. Then, Al-Ce master alloy, Al-Zn master alloy, and Al-Zr master alloy are added in sequence, and after melting, they are stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. The temperature is then lowered to 680~720℃, and Al-Mg master alloy is pressed into the melt and waited for 3~5 minutes to prevent Mg oxidation and burn-off. After complete melting, it is stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. Then, the temperature is raised to 760~800℃, and KFB4 and K2TiF6 with a mass ratio of 1:(1~2) are added to the melt. The mixture is stirred for 2~3 minutes until completely melted, the surface dross is removed, and the temperature is held for 10~15 minutes.

[0023] As a preferred embodiment, the casting conditions are: temperature of 700~750℃ and time of 10~15min.

[0024] As a preferred embodiment, the alloy powder is sieved to control the particle size to ≤0.075mm, and the average particle size to ≤0.03mm.

[0025] As a preferred embodiment, the process parameters for selective laser melting additive manufacturing are: scanning power of 300-400W, scanning speed of 800-1200mm / s, scanning spacing of 0.12-0.15mm, and average thickness of 0.02-0.03mm. In this invention, the average thickness of the sample during selective laser melting additive manufacturing cannot be too large, otherwise it will lead to a decrease in the uniformity of the printed sample, thereby affecting the product performance. Furthermore, if the scanning power of selective laser melting is too low, it is easy to cause poor fusion and porosity, while if the scanning power is too high, it will cause Al... 11 Ce3 phase growth and low-melting-point element burn-off, while too low a scanning speed will cause overheating and coarsening of the eutectic phase, while too high a speed will lead to incomplete fusion.

[0026] Further preferably, the scanning power is 300~350W, and the scanning speed is 1000~1100mm / s. Under these further preferred parameters, submicron TiB2 dispersion and Al can be obtained. 11 Ce3 and Al 13 The microstructure exhibits uniform precipitation of the CeMg6 eutectic network.

[0027] Further preferably, the present invention provides a method for preparing an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy, specifically including the following steps:

[0028] (1) Batching: Weigh high-purity aluminum raw materials, Al-Ce master alloy, Al-Zn master alloy, Al-Cu master alloy, Al-Si master alloy, Al-Zr master alloy, Al-Sc master alloy and Al-Mg master alloy according to the design composition, clean them and preheat them (among which, Al-Mg master alloy does not need to be preheated).

[0029] (2) Melting: Continue heating the preheated high-purity aluminum raw material to 810~900℃. After the pure aluminum raw material is completely melted, cool down to 750~800℃, and then add Al-Ce master alloy, Al-Zn master alloy, Al-Cu master alloy, Al-Si master alloy, Al-Zr master alloy, and Al-Sc master alloy in sequence. After melting, stir for 2~3 minutes, remove the surface dross, and hold for 10~15 minutes. Continue to cool down to 680~720℃, press the Al-Mg master alloy into the melt and wait for 3~5 minutes to prevent Mg oxidation and burn-off. After completely melting, stir for 2~3 minutes, remove the surface dross, and hold for 10~15 minutes. Then raise the temperature to 760~800℃, and add KFB4 and K2TiF6 in a mass ratio of 1:(1~2) into the melt. Stir for 2~3 minutes to allow the mixed salt to fully react with the melt and generate heat in situ until completely melted. Stir for 1~2 minutes, remove the surface scum, and keep warm for 10~15 minutes.

[0030] (3) Refining: Reduce the temperature to 720~750℃, refine with refining agent 2~3 times, remove surface slag, keep warm for 10~15min, and pass Ar gas to the bottom of the melt for 1~5min to remove gas.

[0031] (4) Casting: Reduce the temperature to 700~750℃, keep it warm for 10~15 minutes, pour it into the mold, and air cool it to obtain the alloy ingot.

[0032] (5) Powdering: The precast alloy ingot is prepared into Al-Ce / TiB2 alloy powder (particle size ≤ 0.15 mm) by atomization powdering.

[0033] (6) Printing and molding: Al-Ce / TiB2 alloy powder is passed through a 200-mesh sieve (particle size ≤ 0.075 mm), and then additively manufactured into a block material by selective laser melting process.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy provided by the present invention uses α-Al as the matrix, and Al 11 The Ce3 eutectic structure is uniformly distributed in the α-Al matrix in elliptical, short rod-shaped, and granular forms, without a distinct continuous coarsening network. This fine, uniform Al... 11 The Ce3 distribution endows the alloy with excellent high-temperature structural stability, heat resistance, and good plasticity. Simultaneously, this invention, by adding TiB2 particles and Mg, Zr, Zn, Cu, Si, and Sc to the aluminum-cerium alloy, forms a multi-component strengthening phase within the α-Al matrix. Specifically, Mg primarily strengthens through solid solution and synergistically interacts with the Ce phase to form Al... 13 The CeMg6 ternary phase; while Zn and Cu elements are mainly enriched in the Ce phase to form key reinforcing phases containing Zn and Cu respectively, thereby enhancing the reinforcing effect of the second phase; Sc and Zr elements refine Al 11 The Ce3 phase inhibits coarsening and forms thermally stable Al3(Sc,Zr) nanoprecipitates. TiB2 particles serve as heterogeneous nucleation sites and particle reinforcement phases. This invention utilizes the high melting point and high thermal stability of TiB2, which is not easily melted and fails in the SLM molten pool. It can act as a heterogeneous nucleation core to promote α-Al grain refinement, drive the transformation of columnar crystals to equiaxed crystals, and inhibit grain growth, thereby improving the strength of the alloy. At the same time, TiB2 can form a relatively good interfacial relationship with the aluminum matrix, which is conducive to the dispersion distribution of particles and the exertion of the strengthening effect, and further inhibits the formation of cracks / defects. As a result, the aluminum alloy material of this invention maintains good mechanical properties and ductility at room temperature, while also maintaining good tensile strength and excellent elongation in thermal exposure environments.

[0036] (2) Without aging and homogenization treatment, the alloy material of the present invention exhibits a tensile strength of ≥85 MPa and an elongation of ≥45% at a temperature of 350°C; and a tensile strength of ≥49 MPa and an elongation of ≥71% at a temperature of 400°C. Under further optimized conditions, the tensile strength is ≥109 MPa and the elongation is ≥58% at a temperature of 350°C; and the tensile strength is ≥53 MPa and the elongation is ≥82% at a temperature of 400°C. Attached Figure Description

[0037] Figure 1 The image shows the particle morphology of the Al-Ce / TiB2 alloy powder in Example 1.

[0038] Figure 2 The microstructure of as-cast Al-3Ce-2Mg-3Zn-0.2Zr / 1.0TiB2 in Comparative Example 10 is shown.

[0039] Figure 3 The images shown are transmission electron microscope (TEM) image (a) and scanning electron microscope (SEM) image (b) of the phase distribution of the printed Al-Ce / TiB2 in Example 2.

[0040] Figure 4 The image shows the morphology of the TiB2 phase in the as-cast Al-Ce / TiB2 in Example 5.

[0041] Figure 5 The morphology of the TiB2 phase in the as-cast Al-Ce / TiB2 in Comparative Example 16 is shown. Detailed Implementation

[0042] The present invention will be further described below with reference to specific accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, substitutions, or replacements made without departing from the spirit and principle of the invention are included within the scope of protection of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the scope of protection of the invention.

[0043] Unless otherwise specified, all reagents, instruments, and equipment used in this invention are those commonly used by those skilled in the art. The raw materials used in this invention are all industrial pure aluminum, as well as Al-Ce master alloys, Al-Mg master alloys, Al-Zn master alloys, Al-Zr master alloys, and Al-Sc master alloys.

[0044] According to an embodiment of the present invention, the scanning power of the process parameters for selective laser melting additive manufacturing includes 300W, 350W, or 400W.

[0045] According to an embodiment of the present invention, the scanning speed of the process parameters for selective laser melting additive manufacturing includes 800 mm / s, 1000 mm / s, or 1200 mm / s.

[0046] The refining agents used in the embodiments and comparative examples of this invention are composed of the following components: 11.0 wt% NaF, 29.5 wt% NaCl, 46.5 wt% Na2CO3, 3.0 wt% CaF2, and 10.0 wt% Na3AlF6.

[0047] Example 1

[0048] A method for preparing an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy includes the following steps:

[0049] S1 Ingredients: Weigh out the high-purity aluminum raw material, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy and Al-Zn master alloy according to the composition Al-5Ce-5Mg-3Zn-0.3Zr / 1.0TiB2 respectively, clean them and preheat them to 500℃ (Al-Mg master alloy does not need to be preheated).

[0050] S2 Melting: The preheated high-purity aluminum raw material is further heated to 830℃ to melt. After complete melting, the temperature is lowered to 800℃, and then Al-Ce master alloy, Al-Zr master alloy, and Al-Zn master alloy are added sequentially. After melting, the mixture is stirred for 2 minutes, surface dross is removed, and the temperature is held for 15 minutes. The temperature is then further lowered to 700℃, and the Al-Mg master alloy is pressed into the melt and held for 5 minutes to prevent Mg oxidation and burn-off. After complete melting, the mixture is stirred for 2 minutes, surface dross is removed, and the temperature is held for 10 minutes. Subsequently, the temperature is raised to 780℃, and KFB4 and K2TiF6 are added in a 1:2 mass ratio and uniformly mixed into the melt. The mixture is stirred for 2 minutes to allow the mixed salts to fully react with the melt through in-situ self-generation. After complete melting, surface dross is removed, and the temperature is held for 10 minutes.

[0051] S3 Refining: Raise the temperature to 750℃, hold for 10 minutes, refine the melt three times with 10g of refining agent, and purge the bottom of the melt with argon gas for 2 minutes to remove gas and slag.

[0052] S4 casting: The melt temperature is reduced to 740℃ and held for 10 minutes before being poured into a steel mold. The mold is then air-cooled and demolded to obtain an alloy ingot.

[0053] S5 Powder Preparation: The alloy ingot is atomized to produce powder. The atomization pressure is 2MPa and the atomization temperature is 1400℃ to obtain Al-Ce / TiB2 alloy powder.

[0054] S6 Printing: Al-Ce / TiB2 alloy powder was passed through a 200-mesh sieve (particle size ≤ 0.075 mm), and then Al-5Ce-5Mg-3Zn-0.3Zr / 1.0TiB2 alloy was prepared by SLM additive manufacturing process with laser power of 350W, scanning speed of 1000mm / s, scanning spacing of 0.15mm, and average thickness of 0.03mm. The mechanical property test results are shown in Table 1.

[0055] Example 2

[0056] The only difference between this embodiment and Example 1 is that the alloy composition is changed to Al-3Ce-2Mg-3Zn-0.2Zr / 1.5TiB2, and the laser power is changed to 300W. All other steps and conditions remain the same, resulting in an Al-3Ce-2Mg-3Zn-0.2Zr / 1.5TiB2 alloy. The mechanical property test results are shown in Table 1.

[0057] Example 3

[0058] The only difference between this embodiment and Example 1 is that the alloy composition was changed to Al-5Ce-3Mg-2Cu-0.5Si-0.1Zr-0.1Sc / 2.5TiB2, and the scanning rate was changed to 1200 mm / s. All other steps and conditions remained the same, resulting in the Al-5Ce-3Mg-2Cu-0.5Si-0.1Zr-0.1Sc / 2.5TiB2 alloy. The mechanical property test results are shown in Table 1.

[0059] Example 4

[0060] The only difference between this embodiment and Example 1 is that the alloy composition is changed to Al-10Ce-3Mg-2Zn-2Cu-0.5Si-0.3Zr-0.3Sc / 2.5TiB2. All other steps and conditions remain the same, resulting in the Al-10Ce-3Mg-2Zn-2Cu-0.5Si-0.3Zr-0.3Sc / 2.5TiB2 alloy. The mechanical property test results are shown in Table 1.

[0061] Example 5

[0062] The only difference between this embodiment and Example 1 is that the alloy composition is changed to Al-10Ce-5Mg-4Zn-2Cu-1.0Si-0.3Zr-0.3Sc / 5.0TiB2, the laser power is changed to 400W, and the scanning rate is changed to 1200mm / s. All other steps and conditions remain the same, resulting in the Al-10Ce-5Mg-4Zn-2Cu-1.0Si-0.3Zr-0.3Sc / 5.0TiB2 alloy. Its mechanical property test results are shown in Table 1.

[0063] Comparative Example 1

[0064] A typical A354 aluminum-silicon heat-resistant alloy is used. Its composition is Al-8Si-2Cu-0.5Mg-0.1Mn-0.1Ti, and the raw materials are added in the form of pure aluminum, Al-Si master alloy, Al-Cu master alloy, Al-Mg master alloy, Al-Mn master alloy and Al-Ti master alloy. The alloy was melted at 800℃ (Al-Mg master alloy was melted at 700℃). After the alloy was completely melted, it was stirred for 2 minutes, the surface slag was removed, and it was held at the temperature for 10 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was passed through the bottom of the melt to remove gas and slag for 2 minutes. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The ingot alloy was homogenized at 525℃ for 12 hours and then aged at 165℃ for 5 hours to obtain the Al-8Si-2Cu-0.5Mg-0.1Mn-0.1Ti alloy. The mechanical property test results are shown in Table 1.

[0065] Comparative Example 2

[0066] A typical cast aluminum-cerium heat-resistant alloy with the composition Al-8Ce-3Mg-0.5Mn-0.2Zr-0.1Sc was used. Raw materials were added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, Al-Mn master alloy, and Al-Sc master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 10 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The cast alloy was then subjected to peak aging treatment at 350℃ for 5 hours to obtain the Al-8Ce-3Mg-0.5Mn-0.2Zr-0.1Sc alloy. The mechanical property test results are shown in Table 1.

[0067] Comparative Example 3

[0068] A typical cast aluminum-cerium heat-resistant alloy is used, with the composition Al-8Ce-3Mg-0.5Mn-0.2Zr-0.1Sc / 0.5TiB2. Raw materials are added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, Al-Mn master alloy, and Al-Sc master alloy. All alloys are melted at 800℃ (Al-Mg master alloy melts at 700℃), and the temperature is raised to 780℃ at the end of the melting process. KFB4 and K2TiF6 are added to the melt in a 1:2 mass ratio and stirred for 2 minutes to allow the mixed salts to fully react with the melt through in-situ autogenous combustion until complete melting. Surface slag is removed, and the mixture is held at this temperature for 10 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was then refined twice with 15g of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The ingot alloy was then subjected to peak aging treatment at 350℃ for 5 hours to obtain the Al-8Ce-3Mg-0.5Mn-0.2Zr-0.1Sc / 0.5TiB2 alloy. The mechanical property test results are shown in Table 1.

[0069] Comparative Example 4

[0070] A typical cast aluminum-copper heat-resistant alloy with the composition Al-5Cu-0.1Ce was used, with raw materials added in the form of pure aluminum, Al-Cu master alloy, and Al-Ce master alloy. The alloy was melted at 800℃. After complete melting, it was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The cast alloy was homogenized at 535℃ for 24 hours and then aged at 170℃ for 12 hours. The mechanical property test results are shown in Table 1.

[0071] Comparative Example 5

[0072] A typical SLM (Surface Mount Technology) additive manufacturing process was used to produce an Al-15Ce-3Mg heat-resistant alloy. The raw materials were pure aluminum, Al-Ce master alloy, and Al-Mg master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was introduced to the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The alloy was then atomized into powder (particle size ≤0.075mm) and prepared using an SLM additive manufacturing process with a laser power of 350W, a scanning rate of 1000mm / s, a scanning interval of 0.15mm, and an average thickness of 0.03mm. The mechanical property test results are shown in Table 1.

[0073] Comparative Example 6

[0074] A typical SLM (Surface Mount Technology) additive manufacturing process was used to produce an Al-15Ce-3Mg heat-resistant alloy. The raw materials were pure aluminum, Al-Ce master alloy, and Al-Mg master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was introduced to the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The alloy was then atomized into powder (particle size ≤ 0.075mm) and prepared using an SLM additive manufacturing process with a laser power of 400W, a scanning rate of 1000mm / s, a scanning interval of 0.15mm, and an average thickness of 0.03mm. The mechanical property test results are shown in Table 1.

[0075] Comparative Example 7

[0076] A typical SLM (Surface Mount Technology) additive manufacturing process was used to produce an Al-15Ce-3Mg heat-resistant alloy. The raw materials were pure aluminum, an Al-Ce master alloy, and an Al-Mg master alloy. All alloys were melted at 800℃ (the Al-Mg master alloy melted at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was introduced to the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 740℃ and held for 10 minutes before being poured into a steel mold. The alloy was then atomized into powder (particle size ≤ 0.075mm) and prepared using an SLM additive manufacturing process with a laser power of 350W, a scanning rate of 900mm / s, a scanning interval of 0.15mm, and an average thickness of 0.03mm. The mechanical property test results are shown in Table 1.

[0077] Comparative Example 8

[0078] A typical SLM (Surface Mount Technology) additive manufacturing process was used to produce an Al-15Ce-3Mg heat-resistant alloy. The raw materials were pure aluminum, Al-Ce master alloy, and Al-Mg master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the mixture was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 15g of refining agent. Argon gas was introduced to the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 750℃ and held for 10 minutes before being poured into a steel mold. The alloy was then atomized into powder (particle size ≤0.075mm) and prepared using an SLM additive manufacturing process with a laser power of 350W, a scanning rate of 1000mm / s, a scanning interval of 0.15mm, and an average thickness of 0.05mm. The mechanical property test results are shown in Table 1.

[0079] Comparative Example 9

[0080] A typical cast aluminum-cerium heat-resistant alloy with the composition Al-3Ce-2Mg-3Zn-0.2Zr was used. Raw materials were added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, and Al-Zn master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with 10g of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 750℃ and held for 10 minutes before being poured into a steel mold. The cast alloy was then subjected to a peak aging treatment at 350℃ for 5 hours. The mechanical property test results are shown in Table 1.

[0081] Comparative Example 10

[0082] A typical cast aluminum-cerium heat-resistant alloy is used, with the composition Al-3Ce-2Mg-3Zn-0.2Zr / 1.0TiB2. Raw materials are added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, and Al-Zn master alloy. All alloys are melted at 800℃ (Al-Mg master alloy melts at 700℃), and the temperature is raised to 780℃ at the end of the melting process. KFB4 and K2TiF6 are added to the melt in a 1:2 mass ratio and stirred for 2 minutes to allow the mixed salts to fully react with the melt through in-situ autogenous combustion until complete melting. Surface slag is removed, and the mixture is held at this temperature for 10 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was then refined twice with (10g) of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 750℃ and held for 10 minutes before being poured into a steel mold. The ingot alloy was then subjected to a peak aging treatment at 350℃ for 5 hours. The mechanical property test results are shown in Table 1.

[0083] Comparative Example 11

[0084] A typical cast aluminum-cerium heat-resistant alloy with the composition Al-5Ce-3Mg-2Cu-0.1Zr-0.1Sc was used. Raw materials were added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, Al-Cu master alloy, Al-Zr master alloy, and Al-Sc master alloy. All alloys were melted at 800℃ (Al-Mg master alloy at 700℃). After complete melting, the alloy was stirred for 2 minutes, surface slag was removed, and the temperature was held for 15 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was refined twice with (10g) of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 750℃ and held for 10 minutes before being poured into a steel mold. The cast alloy was then subjected to a peak aging treatment at 350℃ for 5 hours. The mechanical property test results are shown in Table 1.

[0085] Comparative Example 12

[0086] A typical cast aluminum-cerium heat-resistant alloy is used, with the composition Al-8Ce-3Mg-2Cu-0.2Sc-0.1Zr / 3TiB2. Raw materials are added in the form of pure aluminum, Al-Ce master alloy, Al-Zr master alloy, Al-Mg master alloy, Al-Cu master alloy, Al-Zr master alloy, and Al-Sc master alloy. All alloys are melted at 800℃ (Al-Mg master alloy melts at 700℃), and the temperature is raised to 780℃ at the end of the melting process. KFB4 and K2TiF6 are added to the melt in a 1:2 mass ratio and stirred for 2 minutes to allow the mixed salts to fully react with the melt through in-situ autogenous combustion until complete melting. Surface slag is removed, and the mixture is held at this temperature for 10 minutes. The temperature was then raised to 750℃ and held for 10 minutes. The melt was then refined twice with (10g) of refining agent. Argon gas was passed through the bottom of the melt for 2 minutes to remove gas and slag. Finally, the melt temperature was lowered to 750℃ and held for 10 minutes before being poured into a steel mold. The ingot alloy was then subjected to a peak aging treatment at 350℃ for 5 hours. The mechanical property test results are shown in Table 1.

[0087] Comparative Example 13

[0088] The only difference between this comparative example and Example 5 is that the alloy composition was changed to Al-2Ce-1Mg-2Cu-0.1Zr / 1.0TiB2, the laser power was changed to 300W, and the scanning rate was changed to 800mm / s. All other steps and conditions were the same, resulting in an Al-2Ce-1Mg-2Cu-0.1Zr / 1.0TiB2 alloy. The mechanical property test results are shown in Table 1.

[0089] Comparative Example 14

[0090] The only difference between this comparative example and Example 5 is that the amount of TiB2 is changed to 6%, while the other steps and conditions are the same. The Al-10Ce-5Mg-4Zn-2Cu-1.0Si-0.3Zr-0.3Sc / 6TiB2 alloy was obtained, and its mechanical property test results are shown in Table 1.

[0091] Comparative Example 15

[0092] The only difference between this comparative example and Example 5 is that Zn, Cu, Si, and Sc are not added. All other steps and conditions are the same, resulting in an Al-10Ce-5Mg-0.3Zr / 5.0TiB2 alloy. The mechanical property test results are shown in Table 1.

[0093] Comparative Example 16

[0094] The only difference between this comparative example and Example 5 is that the Al-TiB2 master alloy was directly added at 780°C in a non-in-situ self-generated manner during the melting process. All other steps and conditions were the same, resulting in an Al-10Ce-5Mg-4Zn-2Cu-1.0Si-0.3Zr-0.3Sc / 5.0TiB2 alloy.

[0095] Table 1 Mechanical properties of alloys prepared in the examples and comparative examples

[0096] ;

[0097] Figure 3 This is the phase distribution diagram of Al-Ce / TiB2 in the printed state in Embodiment 2 of the present invention. Figure 3 As can be seen in (a) of the present invention, Al in the alloy system prepared by the present invention 11 The Ce3 eutectic structure is distributed in the α-Al matrix, and also contains dispersed reinforcing phases TiB2 and Al. 13 CeMg6 ternary phase, and Al 11 The Ce3 phase has a width of 200 nm to 300 nm, while the dispersed strengthening phase TiB2 has a particle size of 50 to 100 nm. From... Figure 3 In the scanning electron microscope image (b), TiB2 shows a bimodal distribution with a coarser particle size distribution ranging from 0.5 to 1 μm.

[0098] Figure 4 and Figure 5 The figures show the morphology of the TiB2 phase in the as-cast Al-Ce / TiB2 of Example 5 and Comparative Example 16 of this invention. As can be seen from the figures, the Al-TiB2 particles added in situ are finer and more dispersed than those added in non-situ. This morphology is more conducive to improving the mechanical properties of the alloy system of this invention.

Claims

1. A heat-resistant aluminum-rare earth alloy reinforced with in-situ self-generated particles, characterized in that: The heat-resistant aluminum rare earth alloy comprises, by mass percentage: Ce 3~10%, Mg 2~5%, Zr 0.1~0.3%, TiB2 1.5~5%, M 2.6~7.3%, impurity elements ≤0.1%, and the balance being Al, wherein M is selected from at least one of Zn, Cu, Si and Sc; or; The heat-resistant aluminum rare earth alloy comprises, by mass percentage: Ce 5~10%, Mg 4~5%, Zn 3~4%, Zr 0.2~0.3%, TiB2 1~1.2%, impurity elements ≤0.1%, and the balance being Al; Al in heat-resistant aluminum rare earth alloy 11 The Ce3 eutectic structure is distributed in the α-Al matrix, and the heat-resistant aluminum rare earth alloy has dispersed strengthening phases TiB2 and Al. 13 CeMg6 ternary phase.

2. The in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 1, characterized in that: The heat-resistant aluminum rare earth alloy contains M as Zn, Cu, Si, and Sc, comprising, by mass percentage: Ce 5~10%, Mg 3~5%, Zn 2~4%, Cu 1~2%, Si 0.5~1%, Zr 0.2~0.3%, Sc 0.1~0.3%, TiB 22.5~5%, impurity elements ≤0.1%, and the balance being Al; The heat-resistant aluminum rare earth alloy also contains Al8CeCu4 strengthening phase, Al2CeZn2 phase, AlCeSi2 phase and Al3(Sc,Zr) nano-precipitated phase, and the Al3(Sc,Zr) nano-precipitated phase is coherent with the α-Al matrix.

3. The in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 1 or 2, characterized in that: At a temperature of 350℃, the tensile strength of the heat-resistant aluminum rare earth alloy is above 85MPa and the elongation is above 45%; at a temperature of 400℃, the tensile strength of the heat-resistant aluminum rare earth alloy is above 49MPa and the elongation is above 71%.

4. A method for preparing an in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy as described in any one of claims 1 to 3, characterized in that: Includes the following steps: S1 is prepared by distributing the required raw materials for smelting. After all the raw materials are melted, a refining agent is added for refining and degassing to obtain a melt. The temperature of the melt is adjusted to 700~750℃ and then cast to obtain an alloy ingot. During the smelting process, TiB2 is obtained in situ by adding KFB4 and K2TiF6 to the melt. S2 produces heat-resistant aluminum rare earth alloy blocks by atomizing alloy ingots into powder, sieving the resulting alloy powder, and then selectively laser melting additive manufacturing.

5. The method for preparing the in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 4, characterized in that: In S1, the smelting process is as follows: First, pure aluminum is heated to 810~900℃. After the pure aluminum raw material is completely melted, the temperature is lowered to 750~800℃. Then, Al-Ce master alloy, Al-Zr master alloy, and Al-M master alloy are added in sequence. After melting, the mixture is stirred for 2~3 minutes, surface dross is removed, and the temperature is held for 10~15 minutes. The temperature is then lowered to 680~720℃. Al-Mg master alloy is pressed into the melt and waited for 3~5 minutes to prevent Mg oxidation and burn-off. After complete melting, the mixture is stirred for 2~3 minutes, surface dross is removed, and the temperature is held for 10~15 minutes. Then, the temperature is raised to 760~800℃. KFB4 and K2TiF6 with a mass ratio of 1:(1~2) are added to the melt. The mixture is stirred for 2~3 minutes until completely melted. Surface dross is removed, and the temperature is held for 10~15 minutes. M is selected from at least one of Zn, Cu, Si, and Sc. or; The smelting process is as follows: First, pure aluminum is heated to 810~900℃. After the pure aluminum raw material is completely melted, the temperature is lowered to 750~800℃. Then, Al-Ce master alloy, Al-Zn master alloy, and Al-Zr master alloy are added in sequence. After melting, the mixture is stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. The temperature is then lowered to 680~720℃. Al-Mg master alloy is pressed into the melt and waited for 3~5 minutes to prevent Mg oxidation and burn-off. After complete melting, the mixture is stirred for 2~3 minutes, the surface dross is removed, and the temperature is held for 10~15 minutes. Then, the temperature is raised to 760~800℃. KFB4 and K2TiF6 with a mass ratio of 1:(1~2) are added to the melt. The mixture is stirred for 2~3 minutes until completely melted. The surface dross is removed, and the temperature is held for 10~15 minutes.

6. The method for preparing the in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 5, characterized in that: The refining agent includes a mixture of chloride and fluoride salts, with a dosage of 0.5-1.0% relative to the melt mass. The refining is performed 2-3 times. After refining, the surface slag is removed, the mixture is kept at a constant temperature for 10-15 minutes, and Ar gas is introduced into the bottom of the melt for degassing and slag removal for 1-5 minutes.

7. The method for preparing the in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 6, characterized in that: The casting conditions are: temperature 700~750℃, time 10~15min.

8. The method for preparing the in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 7, characterized in that: The alloy powder is sieved to control the particle size to ≤0.075mm, and the average particle size to ≤0.03mm.

9. The method for preparing the in-situ self-generated particle-reinforced heat-resistant aluminum rare earth alloy according to claim 8, characterized in that: The process parameters for selective laser melting additive manufacturing are: scanning power of 300~400W, scanning speed of 800~1200mm / s, scanning spacing of 0.12~0.15mm, and average thickness of 0.02~0.03mm.

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