Nb-si-ni-ti based ultrahigh temperature structural material and rapid directional solidification preparation method thereof

Abstract

The application relates to the field of metal materials, in particular to a Nb-Si-Ni-Ti system novel ultrahigh-temperature structural material and a rapid directional solidification preparation method thereof. The preparation method provided by the application is a rapid directional solidification preparation method of the Nb-Si-Ni-Ti system novel ultrahigh-temperature structural material reinforced by Nb4NiSi, the alloy is mainly composed of Nb4NiSi phase and Nb solid solution phase through component design, and the Nb-Si-Ni-Ti system novel ultrahigh-temperature structural material with the microstructure alternately arranged by Nb4NiSi and Nb solid solution is obtained through a temperature field controlled laser direct deposition method. The alloy provides high-temperature strength of the alloy by the Nb4NiSi ternary silicide, the Nb-based solid solution provides room temperature plasticity and toughness of the alloy, and the alloy is arranged in a fine directional microstructure, has excellent room high-temperature mechanical properties, and can be used in application scenes such as aero-engine turbine blades and other application scenes requiring ultrahigh-temperature structural materials.

Description

Technical Field

[0001] This invention relates to the field of metallic materials, and in particular to an Nb-Si-Ni-Ti system ultra-high temperature structural material and its rapid directional solidification preparation method. Background Technology

[0002] The continuous improvement in performance indicators such as thrust-to-weight ratio and efficiency of modern aero engines has placed higher demands on the operating temperature of hot-end components such as turbine blades. Current blade materials—fifth-generation nickel-based single-crystal alloys (5GSX)—have a temperature resistance of no more than 1150℃, reaching only 85% of the alloy's initial melting temperature, close to its limit operating temperature. This cannot meet the design requirements of high thrust-to-weight ratio aero engines, making the development of ultra-high temperature structural materials with higher temperature resistance an urgent priority.

[0003] Currently, the main candidate materials for next-generation ultra-high temperature structural materials include: ceramics and ceramic matrix composites, platinum group metals, C / C composites, and refractory intermetallic compounds. Ceramics and ceramic matrix composites, which can operate at temperatures above 1400℃, are inherently brittle and difficult to process, making them unsuitable for turbine blades and guide vanes in the short term. Refractory alloys based on platinum group metals (such as Ir and Pt) can withstand temperatures above 1700℃, but their high density and high price also make them unsuitable for blade materials. C / C composites have extremely poor oxidation resistance; even with anti-oxidation coating technology, it is difficult to achieve the desired high-temperature oxidation resistance. Furthermore, the processing technology for C / C composites is complex, the preparation cycle is long, and the cost is relatively high. Although their mechanical properties can meet the requirements for operation at temperatures above 1900℃, they are still difficult to apply to key hot-end components such as turbine blades in the short term.

[0004] In comparison, refractory intermetallic compounds possess excellent comprehensive properties such as extremely high melting point, relatively low density, good room temperature processing toughness, good high and low temperature strength, and good oxidation resistance, making them one of the current research hotspots in the field of ultra-high temperature structural materials.

[0005] Nb5Si3 intermetallic compounds are A5B3 type transition metal silicides with the highest melting point at 2620℃ and a density of 7.16 g / cm³. 3 (lower than nickel-based superalloys (9.08 g / cm³)) 3 However, it exhibits strong intrinsic brittleness in the medium and low temperature range (0~800℃) (room temperature fracture toughness is only 1~3 MPa·m). 1 / 2 The extremely low plasticity and toughness of Nb-Si alloys with Nb5Si3 and NbSS as the basic constituent phases result in poor ductility and toughness, which seriously delays their engineering application. Summary of the Invention

[0006] In view of this, the present invention provides an Nb-Si-Ni-Ti system ultra-high temperature structural material and a rapid directional solidification preparation method thereof. The preparation method of the present invention can effectively improve the room temperature mechanical properties of the alloy and overcome the problem of unbalanced mechanical properties in current ultra-high temperature structural materials.

[0007] This invention provides a rapid directional solidification preparation method for Nb-Si-Ni-Ti system ultra-high temperature structural materials, comprising the following steps:

[0008] A) Establish a three-dimensional CAD model of the shape of the alloy to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system.

[0009] B) The alloy powder raw material of Nb-Si-Ni-Ti ultra-high temperature structural material is loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as the powder carrier gas and the protective gas.

[0010] The alloy powder raw material comprises, by atomic percentage:

[0011] Ni: 4–12 at.%;

[0012] Si: 10–18 at.%;

[0013] Ti: 0~30 at.%;

[0014] Zr: 0~15 at.%;

[0015] Al: 0–10 at.%;

[0016] Cr: 0~10 at.%;

[0017] Hf: 0~10 at.%%;

[0018] Nb: Balance;

[0019] The atomic ratio of Ni to Si is 0.1 to 1.

[0020] C) Deposited alloys:

[0021] c1: Heat the intended forming position on the forming substrate. When the target temperature is reached, start the laser direct deposition equipment so that the laser and powder are output coaxially and move according to the scanning path set in step A). ​​Under the action of the laser, the powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer is obtained.

[0022] c2: Reduce the shaped substrate by one deposition layer thickness, repeat step c1, and obtain the next deposition layer;

[0023] c3: Repeat step c2 until the alloy preparation is complete;

[0024] There is no order restriction between steps A) and B).

[0025] Preferably, in step A), the layer thickness of the layer slicing process is 0.2~0.5mm.

[0026] Preferably, in step B), the alloy powder raw material of the Nb-Si-Ni-Ti ultra-high temperature structural material includes at least one of Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, Nb-12Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, and Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder.

[0027] Preferably, in step B), the particle size of the alloy powder raw material of the Nb-Si-Ni-Ti ultra-high temperature structural material is 45~150μm.

[0028] Preferably, in step B), the flow rate of the powder carrier gas is 5~20 L / min; the feeding rate of the alloy powder raw material is 5~20 g / min; and the flow rate of the protective gas is 5~20 L / min.

[0029] Preferably, in step B), the protective gas is argon.

[0030] Preferably, in step c1, the formed substrate is a titanium alloy or an Nb-based alloy.

[0031] Preferably, in step c1, the target temperature is 500~1200℃.

[0032] Preferably, in step c1, the laser power is 500~1500 W; the laser scanning speed is 300~1000 mm / min.

[0033] The present invention also provides an Nb-Si-Ni-Ti ultra-high temperature structural material prepared by the preparation method described in the above technical solution.

[0034] The method provided by this invention is a rapid directional solidification preparation method for Nb4NiSi-reinforced Nb-Si-Ni-Ti ultra-high temperature structural materials. Through compositional design, the alloy is mainly composed of two phases: Nb4NiSi and Nb solid solution. A temperature-controlled laser direct deposition method is used to obtain an Nb-Si-Ni-Ti ultra-high temperature structural material with an alternating directional arrangement of Nb4NiSi and Nb solid solution microstructure. This alloy utilizes Nb4NiSi ternary silicides to provide high-temperature strength and Nb-based solid solution to provide room-temperature plasticity and toughness, exhibiting a fine directional microstructure and excellent room-temperature mechanical properties. It can be used in applications requiring ultra-high temperature structural materials, such as turbine blades for aero-engines. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0036] Figure 1 The image shows the microstructure of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1.

[0037] Figure 2 The room temperature stress-strain curve of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1 is shown.

[0038] Figure 3 The image shows the microstructure of the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 2. Detailed Implementation

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0040] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0041] The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0042] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0043] In this article, when referring to units of data ranges, if the unit is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 4~12 at.% means that the units of the left endpoint "4" and the right endpoint "12" are both at.%.

[0044] A rapid directional solidification preparation method for Nb-Si-Ni-Ti system ultra-high temperature structural materials includes the following steps:

[0045] A) Establish a three-dimensional CAD model of the shape of the alloy to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system.

[0046] B) The alloy powder raw material of Nb-Si-Ni-Ti ultra-high temperature structural material is loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as the powder carrier gas and the protective gas.

[0047] The alloy powder raw material comprises, by atomic percentage:

[0048] Ni: 4–12 at.%;

[0049] Si: 10–18 at.%;

[0050] Ti: 0~30 at.%;

[0051] Zr: 0~15 at.%;

[0052] Al: 0–10 at.%;

[0053] Cr: 0~10 at.%;

[0054] Hf: 0~10 at.%%;

[0055] Nb: Balance;

[0056] The atomic ratio of Ni to Si is 0.1 to 1.

[0057] C) Deposited alloys:

[0058] c1: Heat the intended forming position on the forming substrate. When the target temperature is reached, start the laser direct deposition equipment so that the laser and powder are output coaxially and move according to the scanning path set in step A). ​​Under the action of the laser, the powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer is obtained.

[0059] c2: Reduce the shaped substrate by one deposition layer thickness, repeat step c1, and obtain the next deposition layer;

[0060] c3: Repeat step c2 until the alloy preparation is complete;

[0061] There is no order restriction between steps A) and B).

[0062] [Regarding step A]:

[0063] A) Establish a three-dimensional CAD model of the alloy shape to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system.

[0064] In this invention, a three-dimensional CAD model is first established based on the shape of the alloy to be prepared (i.e., the target alloy part, such as a turbine blade), and then it is sliced ​​in layers along the height direction. The layer thickness (i.e., the thickness of each slice) is preferably controlled to be 0.2~0.5 mm, specifically 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. This invention performs scan path filling on each slice, and then imports the slice information and scan path information into a laser direct deposition system.

[0065] [Regarding step B]:

[0066] B) The alloy powder raw material of Nb-Si-Ni-Ti ultra-high temperature structural material is loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as the powder carrier gas and the protective gas.

[0067] In this invention, the alloy powder raw material of the Nb-Si-Ni-Ti ultra-high temperature structural material, by atomic percentage, comprises:

[0068] Ni: 4–12 at.%;

[0069] Si: 10–18 at.%;

[0070] Ti: 0~30 at.%;

[0071] Zr: 0~15 at.%;

[0072] Al: 0–10 at.%;

[0073] Cr: 0~10 at.%;

[0074] Hf: 0~10 at.%%;

[0075] Nb: Balance;

[0076] The atomic ratio of Ni to Si is 0.1 to 1.

[0077] In the aforementioned alloy powder, the Ni content can specifically be 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, and 12 at.%. The Si content can specifically be 10 at.%, 11 at.%, 12 at.%, 13 at.%, 14 at.%, 15 at.%, 16 at.%, 17 at.%, and 18 at.%. Specifically, the Ti content can be 0 at.%, 1 at.%, 2 at.%, 3at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, 12 at.%, 13at.%, 14 at.%, 15 at.%, 16 at.%, 17 at.%, 18 at.%, 19 at.%, 20 at.%, 21 at.%, 22 at.%, 23 at.%, 24 at.%, 25 at.%, 26 at.%, 27 at.%, 28 at.%, 29 at.%, 30 at.%. Specifically, the Zr content can be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10at.%, 11 at.%, 12 at.%, 13 at.%, 14 at.%, 15 at.%. The Al content can be specifically 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, and 10 at.%. The Cr content can be specifically 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, and 10 at.%. The Hf content can be specifically 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, and 10 at.%. Nb is the balance, i.e., to make up to 100%. The atomic ratio of Ni / Si is 0.1~1, specifically 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0.In this invention, the alloy powder raw materials for the Nb-Si-Ni-Ti ultra-high temperature structural materials include, but are not limited to, at least one of Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, Nb-12Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, and Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder. In this invention, the alloy powder raw materials for the Nb-Si-Ni-Ti ultra-high temperature structural materials can be prepared by conventional methods known in the art, such as vacuum argon atomization, electrode induction gas atomization, or plasma rotating electrode method.

[0078] In this invention, the particle size of the alloy powder raw material for the Nb-Si-Ni-Ti ultra-high temperature structural material is preferably 45~150μm.

[0079] In this invention, the alloy powder raw material of the aforementioned Nb-Si-Ni-Ti ultra-high temperature structural material is loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as both the powder carrier gas and the protective gas. The protective gas is preferably argon. The argon is preferably high-purity argon, with a purity preferably ≥99%. The flow rate of the powder carrier gas is preferably 5~20 L / min, specifically 5 L / min, 8 L / min, 10 L / min, 15 L / min, or 20 L / min. The powder feeding rate of the alloy powder raw material is preferably 5~20 g / min, specifically 5 g / min, 8 g / min, 10 g / min, 15 g / min, or 20 g / min. The flow rate of the protective gas is preferably 5~20 L / min, specifically 5 L / min, 8 L / min, 10 L / min, 15 L / min, or 20 L / min.

[0080] [Regarding step C]:

[0081] C) Deposited Alloy: This invention employs a laser direct deposition equipment, using titanium alloy or Nb-based alloy as the forming substrate. During the forming process, electromagnetic induction heating is used to keep the laser direct deposition forming area at a high temperature for laser direct deposition. See steps c1 to c3 for details.

[0082] c1: The intended forming position on the forming substrate is heated. When the target temperature is reached, the laser direct deposition equipment is started, so that the laser and powder are output coaxially and move according to the scanning path set in step A). ​​Under the action of the laser, the powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer is obtained.

[0083] In this invention, the formed substrate is preferably a titanium alloy or an Nb-based alloy. The Nb-based alloy is preferably an Nb-Si alloy.

[0084] In this invention, the area to be formed on the substrate is heated to bring the laser direct deposition area to a high temperature. The heating method is preferably electromagnetic induction heating, i.e., heating using a battery-powered induction heating coil. Once the target temperature is reached, the laser direct deposition equipment is activated. The target temperature is preferably 500~1200℃, specifically 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, or 1200℃.

[0085] In this invention, after heating to the target temperature, the laser direct deposition equipment is activated, so that the laser and powder are output coaxially. The laser focus is at the forming substrate and moves according to the scanning path set in step A). ​​Under the action of the laser, the powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer is obtained. The laser power is preferably 500~1500 W, specifically 500W, 600W, 700W, 800W, 900W, 1000W, 1100W, 1200W, 1300W, 1400W, or 1500W. The preferred laser scanning speed is 300~1000 mm / min, specifically 300 mm / min, 400 mm / min, 500 mm / min, 600 mm / min, 700 mm / min, 800 mm / min, 900 mm / min, 1000 mm / min, 1100 mm / min, 1200 mm / min, 1300 mm / min, 1400 mm / min, and 1500 mm / min.

[0086] c2: Reduce the thickness of the formed substrate by one deposition layer, and repeat step c1 to obtain the next deposition layer.

[0087] In this invention, after obtaining the first deposition layer at the end of step c1, the forming substrate is lowered by one deposition layer thickness, keeping the position of the induction heating coil and the deposition layer unchanged, that is, keeping the position of the induction heating coil and the liquid metal relatively fixed, and step c1 is repeated to obtain the next deposition layer.

[0088] c3: Repeat step c2 until the alloy preparation is complete.

[0089] In this invention, after step c2 is completed, step c2 is repeated, that is, the deposition continues layer by layer until the alloy preparation is completed.

[0090] The present invention also provides an Nb-Si-Ni-Ti ultra-high temperature structural material prepared by the preparation method described in the above technical solution.

[0091] The preparation method provided by this invention is a rapid directional solidification preparation method for Nb4NiSi-reinforced Nb-Si-Ni-Ti ultra-high temperature structural materials. Through composition design, the alloy is mainly composed of two phases: Nb4NiSi phase and Nb solid solution phase. By using a temperature field-controlled laser direct deposition method, an Nb-Si-Ni-Ti ultra-high temperature structural material with an alternating directional arrangement of Nb4NiSi and Nb solid solution is obtained.

[0092] Specifically, in the composition design, this invention, by adding a certain amount of Ni to the Nb-Si-Ti alloy system, can promote the formation of Nb4NiSi ternary silicide in the alloy, and form an in-situ multiphase structure with the Nb-based solid solution. Compared with Nb5Si3 binary silicide, Nb4NiSi ternary silicide has a compressive strength of up to 2480 MPa at 1200℃; its density is only 5.05 g / cm3, about 70% of that of Nb5Si3; and its room temperature fracture toughness reaches 6.1 MPa·m. 1 / 2 Its toughness is more than twice that of Nb5Si3, already reaching the toughness level of as-cast binary Nb-16Si alloys. This demonstrates that Nb4NiSi ternary silicides possess the basic requirements for high-temperature applications, and its room-temperature toughness and density are significantly superior to Nb5Si3 binary silicides. Furthermore, Nb4NiSi exhibits a eutectic reaction with Nb, providing the basic conditions for forming in-situ composite materials. Simultaneously, Nb4NiSi has a wide range of compositional variations and high solid solubility with alloying elements such as Ti, Hf, and Mo. This provides ample room for design and optimization of material composition and microstructure, further improving toughness and plasticity.

[0093] Based on the high-temperature application potential of Nb4NiSi ternary silicides and their significant room-temperature toughness and plasticity advantages compared to Nb5Si3 binary silicides, this invention provides a novel Nb-Ni-Si-Ti ultra-high temperature alloy composition design with Nb4NiSi + Nb-based solid solution as the basic constituent phase. Furthermore, it utilizes a temperature-controlled laser melting deposition directional solidification method to obtain an ultra-high temperature structural material with alternating directional arrangements of Nb4NiSi ternary silicides and Nb-based solid solutions. This alloy utilizes Nb4NiSi ternary silicides to provide high-temperature strength and Nb-based solid solutions to provide room-temperature plasticity and toughness, exhibiting a fine directional microstructure and superior room-temperature mechanical properties. This overcomes the major engineering application bottleneck problem of unbalanced mechanical properties in current ultra-high temperature structural materials.

[0094] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0095] Example 1

[0096] A) Establish a three-dimensional CAD model of the alloy shape to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system.

[0097] B) Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder with a particle size of 45~150 μm is loaded into the powder feeder of the laser direct deposition system. High-purity argon is used as the powder feed gas flow, and the powder carrier gas flow rate is set to 8 L / min. The powder feeding rate of the mixed powder is 8 g / min. Argon is used as the protective gas, and the protective gas flow rate is 20 L / min.

[0098] C) Deposited alloys:

[0099] c1: Using an induction heating device, the intended forming position on the titanium alloy forming substrate is heated to 1000℃. The laser direct deposition equipment is started, with the laser and powder output coaxially. The laser focus is on the forming substrate surface and moves according to the scanning path set in step A). ​​Under the action of the laser, the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer with a thickness of about 0.5mm is obtained.

[0100] c2: Lower the forming substrate by 0.5mm, keep the position of the induction heating coil and the liquid metal relatively fixed, and repeat step c1 to obtain the next deposition layer.

[0101] c3: Repeat step c2 until the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy is prepared.

[0102] Product Testing :

[0103] (1) Microscopic tissue characterization

[0104] Figure 1 The image shows the microstructure of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1, in which the gray Nb4NiSi phase and NbSS phase are arranged in an alternating coupled pattern.

[0105] (2) Mechanical property testing

[0106] Figure 2 The image shows the room temperature stress-strain curve of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1. This alloy exhibits excellent ductility and toughness with a room temperature tensile elongation of 3.8%.

[0107] Example 2

[0108] A) Establish a three-dimensional CAD model of the alloy shape to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system.

[0109] B) Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder with a particle size of 45~150 μm is loaded into the powder feeder of the laser direct deposition system. High-purity argon is used as the powder feed gas flow, and the powder carrier gas flow rate is set to 20 L / min. The powder feeding rate of the mixed powder is 10 g / min. Argon is used as the protective gas, and the protective gas flow rate is 20 L / min.

[0110] C) Deposited alloys:

[0111] c1: An induction heating device is used to heat the intended forming position on the titanium alloy forming substrate to 1200℃. The laser direct deposition equipment is started, with the laser and powder output coaxially. The laser focus is on the forming substrate surface and moves according to the scanning path set in step A). ​​Under the action of the laser, the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer with a thickness of about 0.3 mm is obtained.

[0112] c2: Lower the substrate by 0.3 mm, keeping the induction heating coil and liquid metal in a relatively fixed position, and repeat step c1 to obtain the next deposition layer.

[0113] c3: Repeat step c2 until the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy is prepared.

[0114] Product Testing :

[0115] Figure 3The image shows the microstructure of the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 2. It also exhibits an alternating microstructure of Nb4NiSi and NbSS, which is beneficial for improving its room temperature fracture toughness and room temperature elongation.

[0116] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A rapid directional solidification preparation method for Nb-Si-Ni-Ti system ultra-high temperature structural materials, characterized in that, Includes the following steps: A) Establish a three-dimensional CAD model of the shape of the alloy to be prepared, perform layered slicing in the height direction, fill the scanning path of each slice, and then import the slice information and scanning path information into the laser direct deposition system. B) The alloy powder raw material of Nb-Si-Ni-Ti ultra-high temperature structural material is loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as the powder carrier gas and the protective gas. The alloy powder raw material comprises, by atomic percentage: Ni: 4-12 at.%; Si: 10–18 at.%; Ti: 0~30 at.%; Zr: 0~15 at.%; Al: 0–10 at.%; Cr: 0~10 at.%; Hf: 0~10 at.%%; Nb: Balance; The atomic ratio of Ni to Si is 0.1 to 1. C) Deposited alloys: c1: Heat the intended forming position on the forming substrate. When the target temperature is reached, start the laser direct deposition equipment so that the laser and powder are output coaxially and move according to the scanning path set in step A). ​​Under the action of the laser, the powder melts on the forming substrate to form a molten pool. As the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposition layer is obtained. c2: Reduce the shaped substrate by one deposition layer thickness, repeat step c1, and obtain the next deposition layer; c3: Repeat step c2 until the alloy preparation is complete; There is no order restriction between steps A) and B). In step B), the flow rate of the powder carrier gas is 5~20 L / min; the feeding rate of the alloy powder raw material is 5~20 g / min; and the flow rate of the protective gas is 5~20 L / min. In step c1, the target temperature is 500~1200℃; In step c1, the laser power is 500~1500 W; the laser scanning speed is 300~1000 mm / min; The resulting alloy is an ultra-high temperature structural material of Nb-Si-Ni-Ti system, mainly composed of two phases: Nb4NiSi phase and Nb solid solution phase, with the microstructure consisting of alternating oriented Nb4NiSi and Nb solid solution phases.

2. The preparation method according to claim 1, characterized in that, In step A), the layer thickness of the layered slicing process is 0.2~0.5mm.

3. The preparation method according to claim 1, characterized in that, In step B), the alloy powder raw material of the Nb-Si-Ni-Ti ultra-high temperature structural material includes at least one of Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, Nb-12Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder, and Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder.

4. The preparation method according to claim 1, characterized in that, In step B), the particle size of the alloy powder raw material of the Nb-Si-Ni-Ti ultra-high temperature structural material is 45~150μm.

5. The preparation method according to claim 1, characterized in that, In step B), the protective gas is argon.

6. The preparation method according to claim 1, characterized in that, In step c1, the formed substrate is a titanium alloy or an Nb-based alloy.

7. A Nb-Si-Ni-Ti ultra-high temperature structural material prepared by any one of claims 1 to 6.

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