Lightweight high-temperature-resistant alloy powder material suitable for additive manufacturing process and preparation method and application of lightweight high-temperature-resistant alloy powder material

Abstract

The invention belongs to the technical field of additive manufacturing and refractory alloy, and particularly discloses a light high-temperature-resistant alloy powder material suitable for an additive manufacturing process, a preparation method and application. The light high-temperature-resistant alloy powder material comprises elemental element powder of Nb, Ti, Cr, V, W, Mo and Hf, wherein the atomic percent of each metal element is as follows: 30% < = Nb < = 50%, 30% < = Ti < = 50%, 0% < Cr < = 10%, 0% < V < = 10%, 0% < W < = 5%, 0% < Mo < = 5% and 0% < Hf < = 5%; the sum of the atomic percentages is 100%. On the basis of a low-density NbTi alloy, the room-temperature strength of the alloy is improved by introducing Cr and V room-temperature solid solution elements, and the high-temperature strength of the alloy is improved by a small amount of W, Mo and Hf high-temperature solid solution elements. According to the light high-temperature-resistant alloy powder material, the density and the weight of parts are reduced, and the metal parts which are well formed and have excellent room-temperature strength and high-temperature strength at the same time can be obtained by adopting an additive manufacturing process.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing and refractory alloys, and in particular to a lightweight high-temperature resistant alloy powder material for an additive manufacturing process, a preparation method and application thereof in additive manufacturing. Background Art

[0002] In the field of aerospace, high-temperature alloys are important components of engines and propellers. The operating temperature of high-temperature nickel-based alloys does not exceed 1100°C, which will cause damage. Refractory alloys are mainly composed of high-melting-point elements such as Nb, Mo, Ta, W, and Re. They have excellent mechanical properties at high temperatures and have irreplaceable applications in aerospace, thermal load-bearing, nuclear industry and other fields.

[0003] In order to improve the performance of aerospace equipment, lightweighting is a very important consideration. Every 1kg weight reduction of a spacecraft or aircraft can reduce the cost by 50,000 to 500,000 and bring great ecological and economic benefits. However, the density of refractory alloys is generally large. The density of Nb, Mo, Ta, W, Re, Ni and other elements is 8.57g / cm 3 , 10.28g / cm 3 、16.65g / cm 3 、19.25g / cm 3 、8.908g / cm 3 In comparison, niobium alloys have great application potential and are currently widely used in combustion chambers, nozzle extensions, engine nozzles and other components. However, the density of niobium alloys (>8.8g / cm 3 ) is still relatively large compared to titanium alloys and has much room for optimization. It is difficult to meet the weight requirements of new engines, which limits the further promotion and application of niobium alloys.

[0004] It is very important to have both excellent high temperature performance and low alloy density. At present, the existing cast low-density niobium alloys at home and abroad usually introduce Al, V, Cr, Zr, Ti and a small amount of W, Mo, Hf, C elements to reduce the density of the alloy without reducing the high temperature performance of the alloy. The mature systems currently include Nb-Ti-Al, Nb-Ti-Al-Cr, Nb-Ti-Al-Hf, Nb-Ti-Al-Cr-Hf, Nb-Ti-Al-V-Zr, Nb-Ti-Al-VW-Zr, Nb-Ti-Al-W-Mo-Zr, etc. Among them, the density studied by Hu Guolin and others from the Institute of Aerospace Materials and Technology is 6.93g / cm 3 The NbTiAlCrV alloy can meet the use requirements of the engine nozzle extension section, and its tensile strength reaches 231MPa at 1100℃.

[0005] The Chinese patent document with publication number CN112981208A and publication date June 18, 2021, entitled “A Lightweight, Melt-Resistant, High-Temperature Eutectic High-Entropy Alloy and Preparation Method Thereof” discloses a eutectic alloy with a density of 6-7 g / cm 3 Lightweight high temperature resistant eutectic high entropy alloy V a Nb b M (M is Ti, Zr, Ta, Mo, Cr and Al) c Si d , which has excellent strength at room temperature and 1000°C, but due to the large difference in melting points of different elements (such as Al, Ta, Mo), it is difficult to make the original powder material of the predetermined composition and cannot be prepared by the additive manufacturing process, so it cannot meet the process conditions of additive manufacturing. Moreover, without testing the tensile properties, it is difficult to judge the plasticity. It should be noted that in the field of aerospace, there are also strict requirements for the plasticity of alloys.

[0006] The Chinese patent document with publication number CN115627406A and publication date January 20, 2023, entitled “A Lightweight Refractory Multi-Principal Element Alloy, Preparation Method and Application thereof” discloses a (TiZrNb) 100-x-y Al x O y A lightweight refractory high-entropy alloy was prepared, but it could not meet the process conditions of additive manufacturing and its tensile properties were not tested.

[0007] The Chinese patent document with publication number CN108300926A and publication date July 20, 2018, entitled “A Lightweight Refractory High Entropy Alloy and Preparation Method Thereof” discloses a light refractory high entropy alloy with a density of 6-7 g / cm 3 Ti a Al b Cr c Nb d V e A lightweight refractory high-entropy alloy was prepared, but it could not meet the process conditions of additive manufacturing and its tensile properties were not tested.

[0008] Existing lightweight refractory and refractory high-entropy alloys do not take into account the large difference in melting points of elements. Therefore, the existing systems are difficult to prepare into raw materials for additive manufacturing under the existing powder making process and have poor formability. Up to now, there is still a lack of specialized lightweight high-temperature resistant alloy material systems and powder materials suitable for additive manufacturing processes. Summary of the invention

[0009] The objective of the present invention is to propose a low-density, lightweight, high-temperature resistant alloy powder material that is compatible with additive manufacturing, in order to address the problem that the current refractory high-temperature alloys have high density and complex forming, which seriously limit the further promotion and application of refractory alloys. The alloy has low density and good high-temperature strength.

[0010] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0011] A lightweight high-temperature resistant alloy powder material suitable for an additive manufacturing process, the components of which include single-element powder materials of Nb, Ti, Cr, V, W, Mo, and Hf.

[0012] Furthermore, the atomic percentages of each single substance powder material are: 30%≤Nb≤50%, 30%≤Ti≤50%, 0%<Cr≤10%, 0%<V≤10%, 0%<W≤5%, 0%<Mo≤5%, 0%<Hf≤5%; the sum of the atomic percentages is 100%.

[0013] Furthermore, the particle size of the Nb, Ti, Cr, V, W, Mo, and Hf single-substance powder materials is 5 μm to 250 μm. Additive manufacturing processes are divided into laser powder bed melting process and direct energy deposition process, and the requirements for laser powder particle size are different, which are 5 to 53 μm and 50 to 150 μm respectively (the latter range can be slightly wider). The particle size range of the powder of the present invention is suitable for the requirements of both processes.

[0014] Furthermore, the method for preparing the lightweight high temperature resistant alloy powder material comprises the following steps:

[0015] Step 1: Select the Nb, Ti, Cr, V, W, Mo, Hf single substance powder materials with a purity exceeding 99.9% as raw materials, and perform oxygen reduction and impurity removal treatment on the powders;

[0016] Step 2: Calculate the required mass of each powder according to the atomic ratio of each element in the composition design, and then weigh it using a balance;

[0017] Step 3: Under a protective atmosphere, a planetary ball mill is used to perform a ball milling and mixing process on the composite powder material until the powder materials are evenly mixed;

[0018] Step 4: Use vacuum drying equipment to dry the evenly mixed powder to remove moisture attached to the surface of the powder, thereby obtaining the lightweight, high-temperature resistant alloy powder material suitable for additive manufacturing.

[0019] The present invention also provides an application of the above-mentioned lightweight high temperature resistant alloy powder material in additive manufacturing, and the application method thereof comprises the following steps:

[0020] Step 1: Select a metal substrate that is compatible with the additive manufacturing equipment, polish the surface of the substrate, and use dust-free paper to remove the oil and dust on the surface;

[0021] Step 2: If a powder feeding additive manufacturing device is used, the sieved composite powder needs to be filled into the feeding device, and used in conjunction with an industrial robot device, an air supply device, a preheating device, etc. to complete part preparation; if a powder bed powder spreading additive manufacturing device is used, the sieved composite powder needs to be filled into the powder spreading cylinder device, and used in conjunction with a forming cylinder device and a scraper mechanical device to complete the spreading of the composite powder during the preparation process;

[0022] Step 3: Build a 3D model of the part in the appropriate software, convert it into a heat source movement path file, and import it into the equipment control system;

[0023] Step 4: The heat source moves along a predetermined trajectory and cooperates with a powder feeding system to complete the layer-by-layer manufacturing of the lightweight high-temperature resistant alloy;

[0024] Step 5: After completing the predetermined task, use the wire cutting process to complete the sampling of parts;

[0025] Step 6: Clean, grind and polish the surface of the parts as required to obtain a lightweight, high-temperature resistant alloy.

[0026] Furthermore, in step 4 of the application method, if a powder feeding additive manufacturing device is used, the parameter conditions for layer-by-layer manufacturing are controlled as follows: laser power 1200-1800W, overlap spacing 2-3μm, layer thickness 1-2μm, and scanning speed 2-10mm / s.

[0027] Furthermore, in step 4 of the application method, if a powder bed additive manufacturing device is used, the parameter conditions for layer-by-layer manufacturing are controlled as follows: laser power 150-300W, overlap spacing 30-70μm, layer thickness 20-30μm, and scanning speed 800-1500mm / s.

[0028] Furthermore, the density of the lightweight high-temperature resistant alloy obtained by the application method is 6.0-7.0 g / cm 3 The room temperature tensile strength is 900-1100 MPa, and the tensile strength at 1000°C is 180-250 MPa.

[0029] Furthermore, the phase structure of the lightweight high-temperature resistant alloy prepared by the application method at room temperature is a composite structure of a body-centered cubic crystal structure + a small amount of hexagonal crystal structure.

[0030] The present invention has the following beneficial effects:

[0031] 1. Combining the application requirements of lightweight and high-temperature resistant niobium alloys with the process characteristics of additive manufacturing, a high-temperature resistant alloy powder material and preparation process method suitable for the process characteristics of additive manufacturing are provided, which broadens the forming process of lightweight and high-temperature resistant niobium alloys.

[0032] 2. A large amount of Ti element is introduced through the composition design optimization method to improve the oxidation resistance of the niobium alloy while reducing the density; an appropriate amount of solid solution strengthening elements V and Cr are introduced to improve the room temperature strength; a small amount of high temperature solid solution strengthening elements W, Mo and Hf are introduced to maintain the high high temperature strength of the alloy; and the combination of elements such as Nb, Ti, Cr, V, W, Mo and Hf makes the alloy suitable for additive manufacturing process.

[0033] 3. The additive manufacturing process not only improves the utilization rate of refractory alloy materials and reduces alloy costs, but also enables the manufacture of lightweight, high-temperature resistant alloy complex components. The preparation method of alloy powder materials is simple, the cost is lower, and it is easier to achieve industrial production than pre-alloyed powders. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 : Microscopic morphology of the lightweight high-temperature resistant alloy powder material prepared by mechanical alloying process in Example 1.

[0035] Figure 2 : Actual pictures of the tensile test piece and test sample of the lightweight high-temperature resistant alloy prepared by the additive manufacturing process of Example 1.

[0036] Figure 3 : XRD pattern of the tensile test piece prepared according to the method of Example 1.

[0037] Figure 4 : Tensile stress-strain curves of the test specimens prepared according to the method of Example 1 at room temperature and 1000 degrees Celsius. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] A light-weight high-temperature resistant alloy powder material includes single-substance powder materials of Nb, Ti, Cr, V, W, Mo, and Hf, wherein the atomic percentages of the single-substance powder materials are respectively: Nb 45.7%, Ti 36.83%, Cr 4.84%, V 9.89%, W0.98%, Mo 0.75%, and Hf 1.01%. The particle size of the single-substance powder materials of Nb, Ti, Cr, V, W, Mo, and Hf is 5-53 μm. The light-weight high-temperature resistant alloy powder material is prepared according to the following steps:

[0041] Step 1: Select the Nb, Ti, Cr, V, W, Mo, Hf single substance powder materials with a purity exceeding 99.9% as raw materials, and perform oxygen reduction and impurity removal treatment on the powders;

[0042] Step 2: Calculate the required mass of each powder according to the atomic ratio of each element in the composition design, and then weigh it using a balance;

[0043] Step 3: Under a protective atmosphere, a planetary ball mill is used to perform a ball milling and mixing process on the composite powder material until the powder materials are evenly mixed;

[0044] Step 4: Use vacuum drying equipment to dry the evenly mixed powder to remove moisture attached to the surface of the powder, thereby obtaining the lightweight, high-temperature resistant alloy powder material suitable for additive manufacturing.

[0045] The method for preparing a lightweight high temperature resistant alloy by using the above-mentioned lightweight high temperature resistant alloy powder material as raw material and adopting an additive manufacturing process is as follows:

[0046] Step 1: Select a (pure niobium) substrate that is compatible with the additive manufacturing equipment, polish the surface of the substrate, and use dust-free paper to remove oil and dust on the surface;

[0047] Step 2: Use a powder bed powder spreading additive manufacturing device (Trumpf 1000) to fill the sieved composite powder into the powder spreading cylinder device, and cooperate with the forming cylinder device and the scraper mechanical device to complete the spreading of the composite powder during the preparation process;

[0048] Step 3: Build a 3D model of the part in the appropriate (Materialise Magics) software, convert it into a heat source movement path file, and import it into the equipment control system;

[0049] Step 4: The heat source moves along a predetermined trajectory and cooperates with the powder feeding system to complete the layer-by-layer manufacturing of the lightweight high-temperature resistant alloy; the parameters used are laser power 200W, overlap spacing 60μm, layer thickness 30μm, and scanning speed 1000mm / s;

[0050] Step 5: After completing the predetermined task, use the wire cutting process to complete the sampling of parts;

[0051] Step 6: Clean, grind and polish the surface of the parts as required to obtain a lightweight, high-temperature resistant alloy.

[0052] Characterization performance test:

[0053] (1) Figure 1 This is a microscopic morphology of the additive manufacturing powder raw material prepared by the mechanical alloying process in Example 1. It can be seen that the sphericity is good, so that the powder has good fluidity in the additive manufacturing process, avoiding affecting the product quality.

[0054] (2) Figure 2Two molded parts (tensile test pieces and test specimens) of different shapes obtained in step 4 according to the additive manufacturing method of Example 1 are shown. It can be seen that the surfaces are smooth and bright, and the moldability is good.

[0055] (3) After grinding the test sample in (2), XRD test and alloy density determination were performed. The XRD test results are as follows: Figure 3 As shown, the structure is composed of body-centered cubic phase + a small amount of hexagonal crystal phase. The alloy density is measured to be 6.957g / cm 3 , meeting lightweight requirements.

[0056] (4) The tensile test piece in (2) was cut transversely into 1 mm thick test samples, and the engineering stress-strain curve test was performed on the samples. The results are as follows: Figure 4 As shown in the figure, the room temperature tensile strength is 1040MPa, the plastic strain is 0.97%, the tensile strength at 1000℃ is 216.02MPa, and the plastic strain is 9.64%. It can be concluded that the alloy system has good mechanical properties at room temperature and excellent tensile mechanical properties at 1000℃.

[0057] Comparative Example 1

[0058] This comparative example is basically the same as Example 1, except that the additive manufacturing process is different, specifically, the scanning speed exceeds the forming parameter window range (800-1500 mm / s). The results show that when the scanning speed is too small, the surface forming quality of the sample is poor; when the scanning speed is too large, a large number of unfused defects appear.

[0059] This specific implementation is only an explanation of the present invention, not a limitation of the present invention. Any changes made by those skilled in the art after reading the specification of the present invention will be protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A lightweight high temperature resistant alloy powder material suitable for additive manufacturing process, characterized in that: The components include single substance powder materials of Nb, Ti, Cr, V, W, Mo and Hf.

2. The lightweight high temperature resistant alloy powder material suitable for additive manufacturing process according to claim 1, characterized in that: The atomic percentages of the single substance powder materials are: 30%≤Nb≤50%, 30%≤Ti≤50%, 0%<Cr≤10%, 0%<V≤10%, 0%<W≤5%, 0%<Mo≤5%, 0%<Hf≤5%; the sum of the atomic percentages is 100%.

3. The lightweight high temperature resistant alloy powder material suitable for additive manufacturing process according to claim 1, characterized in that: The particle size of the Nb, Ti, Cr, V, W, Mo and Hf single substance powder materials is between 5 μm and 250 μm.

4. The lightweight high temperature resistant alloy powder material suitable for additive manufacturing process according to claim 1, characterized in that: The preparation method is as follows: Step 1: Select the Nb, Ti, Cr, V, W, Mo, Hf single substance powder materials with a purity exceeding 99.9% as raw materials, and perform oxygen reduction and impurity removal treatment on the powders; Step 2: Calculate the required mass of each powder according to the atomic ratio of each element in the composition design, and then weigh it using a balance; Step 3: Under a protective atmosphere, a planetary ball mill is used to perform a ball milling and mixing process on the composite powder material until the powder materials are evenly mixed; Step 4: Use vacuum drying equipment to dry the evenly mixed powder to remove moisture attached to the surface of the powder, thereby obtaining the lightweight, high-temperature resistant alloy powder material suitable for additive manufacturing.

5. The use of the lightweight high temperature resistant alloy powder material according to any one of claims 1 to 4 in additive manufacturing, characterized in that: The application method is as follows: Step 1: Select a metal substrate that is compatible with the additive manufacturing equipment, polish the surface of the substrate, and use dust-free paper to remove the oil and dust on the surface; Step 2: If a powder feeding additive manufacturing device is used, the sieved composite powder needs to be filled into the feeding device, and the parts are prepared in cooperation with the industrial robot device, the air supply device, and the preheating device; if a powder bed powder spreading additive manufacturing device is used, the sieved composite powder needs to be filled into the powder spreading cylinder device, and the composite powder is spread in cooperation with the forming cylinder device and the scraper mechanical device during the preparation process; Step 3: Build a 3D model of the part in the appropriate software, convert it into a heat source movement path file, and import it into the equipment control system; Step 4: The heat source moves along a predetermined trajectory and cooperates with a powder feeding system to complete the layer-by-layer manufacturing of the lightweight high-temperature resistant alloy; Step 5: After completing the predetermined task, use the wire cutting process to complete the sampling of parts; Step 6: Clean, grind and polish the surface of the parts as required to obtain a lightweight, high-temperature resistant alloy.

6. The use according to claim 5, characterized in that: In step 4 of the application method, if a powder feeding additive manufacturing device is used, the parameter conditions for layer-by-layer manufacturing are controlled as follows: laser power 1200-1800 W, overlap spacing 2-3 μm, layer thickness 1-2 μm, and scanning speed 2-10 mm / s.

7. The use according to claim 5, characterized in that: In step 4 of the application method, if a powder bed additive manufacturing device is used, the parameter conditions for layer-by-layer manufacturing are controlled as follows: laser power 150-300 W, overlap spacing 30-70 μm, layer thickness 20-30 μm, and scanning speed 800-1500 mm / s.

8. The use according to claim 5, characterized in that: The density of the lightweight high-temperature resistant alloy prepared by the application method is 6.0-7.0 g / cm 3 The room temperature tensile strength is 900-1100 MPa, and the tensile strength at 1000°C is 180-250 MPa.

9. The use according to claim 5, characterized in that: The phase structure of the lightweight high-temperature resistant alloy prepared by the application method at room temperature is a composite structure of body-centered cubic crystal structure + a small amount of hexagonal crystal structure.

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