Nb-Si-Ni-Ti series novel ultrahigh-temperature structural material and rapid directional solidification preparation method thereof

Abstract

The invention relates to the field of metal materials, in particular to an Nb-Si-Ni-Ti series novel ultrahigh-temperature structural material and a rapid directional solidification preparation method thereof. The preparation method provided by the invention is a rapid directional solidification preparation method of an Nb4NiSi-reinforced Nb-Si-Ni-Ti series novel ultra-high-temperature structural material, the alloy is mainly composed of an Nb4NiSi phase and an Nb solid solution phase through component design, and a laser direct deposition method controlled by a temperature field is adopted to prepare the Nb4NiSi-Ni-Ti series ultra-high-temperature structural material. The microstructure of the Nb-Si-Ni-Ti series novel ultra-high-temperature structural material is formed by alternately and directionally arranging Nb4NiSi and Nb solid solutions. According to the alloy, the high-temperature strength of the alloy is provided by the Nb4NiSi ternary silicide, the room-temperature ductility and toughness of the alloy are provided by the Nb-based solid solution, and the alloy is arranged in a fine directional structure, has relatively excellent room-high-temperature mechanical property and can be applied to application scenes such as aero-engine turbine blades needing ultrahigh-temperature structural materials.

Description

Technical Field

[0001] The present invention relates to the field of metallic materials, and particularly to a novel Nb-Si-Ni-Ti series ultra-high temperature structural material and a rapid directional solidification preparation method thereof. Background Art

[0002] Performance indexes such as the thrust-to-weight ratio and working efficiency of modern aero-engines are continuously increasing, which puts forward higher requirements for the working temperature of hot-end components such as turbine blades. At present, the most advanced blade material - the fifth-generation nickel-based single crystal alloy (5GSX) has a temperature-bearing capacity of no more than 1150 °C, and has reached 85% of the primary melting temperature of the alloy, approaching its limit use temperature, and cannot meet the design requirements of high-thrust-to-weight-ratio aero-engines. It is extremely urgent to develop ultra-high temperature structural materials with higher temperature-bearing capacity.

[0003] At present, the alternative materials for the new generation of ultra-high temperature structural materials mainly include the following categories: ceramics and ceramic matrix composites, platinum group metals, C / C composites, and refractory metal intermetallic compounds. Ceramics and ceramic matrix composites that can be used at temperatures above 1400 °C are difficult to be used for preparing turbine blades and guide vanes in a short time due to their intrinsic brittleness and difficult processing and forming. Refractory alloys based on platinum group metals (such as Ir and Pt) can have a temperature-bearing capacity of more than 1700 °C, but platinum group metals have a large density and a very high price, and are also not very suitable as blade materials. The oxidation resistance of C / C composites is extremely poor, and it is difficult to achieve the use target of high-temperature oxidation resistance even through oxidation-resistant coating technology. In addition, the processing technology of C / C composites is relatively complex, the preparation cycle is long, and the cost is also relatively high. Although its mechanical properties can meet the use requirements at temperatures above 1900 °C, it is still difficult to be applied to key hot-end components such as turbine blade materials in the short term.

[0004] In contrast, refractory metal intermetallic compounds have excellent comprehensive properties such as extremely high melting points, relatively low densities, good room-temperature processing toughness, good high- and low-temperature strengths, and good oxidation resistance, and have become one of the research hotspots in the field of ultra-high temperature structural materials research.

[0005] The Nb5Si3 intermetallic compound is a type A5B3 transition metal silicide with the highest melting point of 2620 °C, and its density (7.16 g / cm 3 ) is lower than that of nickel-based superalloys (9.08 g / cm 3 ), but it shows strong intrinsic brittleness (room-temperature fracture toughness is only 1-3 MPa·m 1 / 2 ) and extremely low plasticity in the medium- and low-temperature range (0-800 °C), making the Nb-Si series alloys with Nb5Si3 and NbSS as the basic constituent phases have poor plasticity and toughness, seriously delaying their engineering application process. Summary of the Invention

[0006] In view of this, the present invention provides a novel Nb-Si-Ni-Ti based ultra-high temperature structural material and a method for rapidly directionally solidifying the same. 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 of current ultra-high temperature structural materials.

[0007] The present invention provides a method for rapidly directionally solidifying a novel Nb-Si-Ni-Ti based ultra-high temperature structural material, comprising the following steps:

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

[0009] B) Load the alloy powder raw material of the novel Nb-Si-Ni-Ti based ultra-high temperature structural material into the powder feeder of the laser direct deposition system, and use a protective gas as the powder-carrying gas and protective gas;

[0010] In atomic percentage, the alloy powder raw material comprises:

[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: the balance;

[0019] Wherein, the atomic ratio of Ni / Si elements is 0.1-1;

[0020] C) Deposit the alloy:

[0021] c1: Heat the position to be formed on the forming substrate. When the heating reaches the target temperature, start the laser direct deposition equipment to output the laser and powder coaxially, 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, and as the powder and laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposited layer is obtained;

[0022] c2: Lower the formed substrate by a deposition layer thickness, and repeat step c1 to obtain the next deposition layer;

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

[0024] Among them, there is no order restriction between step A) and step B).

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

[0026] Preferably, in step B), the alloy powder raw materials of the Nb - Si - Ni - Ti series of novel ultra - high temperature structural materials include 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 materials of the Nb - Si - Ni - Ti series of novel ultra - high temperature structural materials is 45 - 150 μm.

[0028] Preferably, in step B), the gas flow of the powder - carrying gas is 5 - 20 L / min; the powder feeding rate of the alloy powder raw materials is 5 - 20 g / min; 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 °C.

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

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

[0034] The preparation method provided by the present invention is a rapid directional solidification preparation method for a new type of ultra-high temperature structural material of the Nb-Si-Ni-Ti system strengthened by Nb4NiSi. Through composition design, the alloy mainly consists of two phases, namely the Nb4NiSi phase and the Nb solid solution phase. And through the laser direct deposition method controlled by the temperature field, a new type of ultra-high temperature structural material of the Nb-Si-Ni-Ti system with a microstructure of alternately oriented Nb4NiSi and Nb solid solution is obtained. The high temperature strength of the alloy is provided by the Nb4NiSi ternary silicide, and the room temperature plasticity and toughness of the alloy are provided by the Nb-based solid solution. Moreover, it has a fine oriented structure arrangement and has excellent mechanical properties at room temperature and high temperature. It can be used in application scenarios such as aero-engine turbine blades that require ultra-high temperature structural materials. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0036] Figure 1 It is the microstructure diagram of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1;

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

[0038] Figure 3 It is the microstructure diagram of the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 2. Detailed Embodiments

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0040] In this article, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

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

[0042] In this article, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when the range refers to integers, it includes every integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

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

[0044] A method for rapidly directionally solidifying a new type of Nb-Si-Ni-Ti ultra-high temperature structural material includes the following steps:

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

[0046] B) Load the alloy powder raw materials of the new type of Nb-Si-Ni-Ti ultra-high temperature structural material into the powder feeder of the laser direct deposition system, and use a protective gas as the powder-carrying gas and protective gas;

[0047] In atomic percentages, the alloy powder raw materials include:

[0048] Ni: 4~12at.%;

[0049] Si: 10~18at.%;

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

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

[0052] Al: 0~10at.%;

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

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

[0055] Nb: the balance;

[0056] Among them, the atomic ratio of Ni / Si elements is 0.1~1;

[0057] C) Deposit the alloy:

[0058] c1: Heat the position to be formed on the formed substrate. When it is heated to the target temperature, start the laser direct deposition equipment, output the laser and powder coaxially, move according to the scanning path set in step A). Under the action of the laser, the powder melts on the formed 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 deposited layer is obtained.

[0059] c2: Lower the formed substrate by the thickness of a deposited layer, and repeat step c1 to obtain the next deposited layer.

[0060] c3: Repeat step c2 until the alloy preparation is completed.

[0061] Among them, there is no order restriction between step A) and step B).

[0062] [Regarding step A]:

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

[0064] In the present invention, first establish a three-dimensional CAD model according to the shape of the alloy to be prepared (i.e., the target alloy part, such as components like turbine blades, etc.), and perform layer-by-layer slicing on it in the height direction. Among them, the slicing thickness of the layer-by-layer slicing (i.e., the thickness of each layer of slice) is preferably controlled to be 0.2 - 0.5 mm, specifically it can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm. The present invention fills the scanning path for each layer of slice, and then imports the slice information and scanning path information into the laser direct deposition system.

[0065] [Regarding step B]:

[0066] B) Load the alloy powder raw material of the Nb - Si - Ni - Ti series of new ultra-high temperature structural materials into the powder feeder of the laser direct deposition system, and use a protective gas as the powder-carrying gas and protective gas.

[0067] In the present invention, in atomic percentage, the alloy powder raw material of the Nb - Si - Ni - Ti series of new ultra-high temperature structural materials includes:

[0068] Ni: 4 - 12 at.%;

[0069] Si: 10 - 18 at.%;

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

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

[0072] Al: 0 to 10 at.%;

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

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

[0075] Nb: the balance;

[0076] Among them, the atomic ratio of Ni / Si elements is 0.1 to 1.

[0077] In the above alloy powder, the Ni content can specifically be 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, 12 at.%. The Si content can specifically be 10 at.%, 11 at.%, 12 at.%, 13 at.%, 14 at.%, 15 at.%, 16 at.%, 17 at.%, 18 at.%. The Ti content can specifically be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, 12 at.%, 13 at.%, 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.%. The Zr content can specifically be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, 12 at.%, 13 at.%, 14 at.%, 15 at.%. The Al content can specifically be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%. The Cr content can specifically be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%. The Hf content can specifically be 0 at.%, 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%. Nb is the balance, that is, to make up 100%. Among them, the atomic ratio of Ni / Si elements is 0.1 - 1, and can specifically be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. In the present invention, the alloy powder raw materials of the novel Nb-Si-Ni-Ti series ultra-high temperature structural material 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 the present invention, the alloy powder raw materials of the novel Nb-Si-Ni-Ti based ultra-high temperature structural material can be prepared by conventional preparation methods known in the art, such as vacuum argon atomization method, electrode induction gas atomization method or plasma rotating electrode method.

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

[0079] In the present invention, the alloy powder raw materials of the novel Nb-Si-Ni-Ti based ultra-high temperature structural material are loaded into the powder feeder of the laser direct deposition system, and a protective gas is used as the powder-carrying gas and the shielding gas. Among them, the protective gas is preferably argon. The argon is preferably high-purity argon, and the purity is preferably ≥99%. In the present invention, the gas flow rate of the powder-carrying gas is preferably 5 - 20 L / min, specifically, it can be 5 L / min, 8 L / min, 10 L / min, 15 L / min, 20 L / min. In the present invention, the powder feeding rate of the alloy powder raw materials is preferably 5 - 20 g / min, specifically, it can be 5 g / min, 8 g / min, 10 g / min, 15 g / min, 20 g / min. In the present invention, the gas flow rate of the shielding gas is preferably 5 - 20 L / min, specifically, it can be 5 L / min, 8 L / min, 10 L / min, 15 L / min, 20 L / min.

[0080] [Regarding step C]:

[0081] C) Depositing the alloy: In the present invention, a laser direct deposition device is used, with a titanium alloy or Nb-based alloy as the forming substrate. During the forming process, an electromagnetic induction heating method is adopted to keep the laser direct deposition forming area at a high temperature state for laser direct deposition. Specifically, refer to the following steps c1 - c3.

[0082] c1: Heat the position to be formed on the forming substrate. When it is heated to the target temperature, start the laser direct deposition device to make the laser and the powder output coaxially, 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, and as the powder and the laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposited layer is obtained.

[0083] In the present invention, the forming substrate is preferably a titanium alloy or an Nb-based alloy. Among them, the Nb-based alloy is preferably an Nb-Si alloy.

[0084] In the present invention, the position to be formed on the formed substrate is heated to make the laser direct deposition forming area in a high-temperature state. In the present invention, the heating method is preferably electromagnetic induction heating, that is, heating is carried out by using a battery induction heating coil. When it is heated to a suitable temperature, i.e., the target temperature, the laser direct deposition equipment is then started. Among them, the target temperature is preferably 500-1200 °C, specifically, it can be 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C, 1100 °C, 1200 °C.

[0085] In the present invention, after heating to the above target temperature, the laser direct deposition equipment is started to make the laser and the powder output coaxially, the laser focus is at the forming base surface, and it moves along the scanning path set in step A). Under the action of the laser, the powder melts on the formed substrate to form a molten pool, and as the powder and the laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposited layer is obtained. Among them, the laser power is preferably 500-1500 W, specifically, it can be 500 W, 600 W, 700 W, 800 W, 900 W, 1000 W, 1100 W, 1200 W, 1300 W, 1400 W, 1500 W. The scanning speed of the laser is preferably 300-1000 mm / min, specifically, it can be 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, 1500 mm / min.

[0086] c2: Lower the formed substrate by a deposited layer thickness, and repeat step c1 to obtain the next deposited layer.

[0087] In the present invention, after the first deposited layer is obtained at the end of step c1, the formed substrate is lowered by a deposited layer thickness, and the position of the induction heating coil is kept unchanged with respect to the deposited layer, that is, the position of the induction heating coil is kept relatively fixed with respect to the liquid metal, and step c1 is repeated to obtain the next deposited layer.

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

[0089] In the present invention, after the end of step c2, step c2 is continuously repeated, that is, continuous layer-by-layer deposition is carried out until the alloy preparation is completed.

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

[0091] The preparation method provided by the present invention is a rapid directional solidification preparation method for a new type of ultra-high temperature structural material of the Nb4NiSi-reinforced Nb-Si-Ni-Ti system. Through composition design, the alloy mainly consists of two phases, namely the Nb4NiSi phase and the Nb solid solution phase. And through the laser direct deposition method controlled by the temperature field, a new type of ultra-high temperature structural material of the Nb-Si-Ni-Ti system with a microstructure of alternately oriented Nb4NiSi and Nb solid solution is obtained.

[0092] Specifically, in the composition design, by adding a certain content of Ni element to the Nb-Si-Ti alloy system, the present invention can promote the formation of the Nb4NiSi ternary silicide in the alloy, and form an in-situ composite structure with the Nb-based solid solution. Compared with the Nb5Si3 binary silicide, the compressive strength of the Nb4NiSi ternary silicide at 1200 °C is as high as 2480 MPa; the density is only 5.05 g / cm3, about 70% of that of Nb5Si3; the room temperature fracture toughness reaches 6.1 MPa·m 1 / 2 , more than twice that of Nb5Si3, and its toughness level has reached that of the as-cast binary Nb-16Si alloy itself. It can be seen that the Nb4NiSi ternary silicide has the basic conditions for high-temperature applications, and its room temperature plasticity and toughness and density have obvious advantages compared with the Nb5Si3 binary silicide. In addition, there is a eutectic reaction between Nb4NiSi and Nb, which has the basic conditions for forming an in-situ composite material. At the same time, Nb4NiSi also has a large composition change range and a high solid solubility with alloying elements such as Ti, Hf, and Mo, which provides a large selection space and possibility for designing and optimizing the material composition and microstructure and further improving the plasticity and toughness.

[0093] Based on the high-temperature application potential of the Nb4NiSi ternary silicide and the obvious room temperature ductility and plasticity advantages compared with the Nb5Si3 binary silicide, the present invention provides a composition design for a new type of Nb-Ni-Si-Ti system ultra-high temperature alloy with Nb4NiSi + Nb-based solid solution as the basic constituent phases, and obtains an ultra-high temperature structural material with alternately oriented Nb4NiSi ternary silicide and Nb-based solid solution through the temperature field controlled laser melting deposition directional solidification method. This alloy provides the high-temperature strength of the alloy by the Nb4NiSi ternary silicide, and the room temperature plasticity and toughness of the alloy by the Nb-based solid solution, and is arranged in a fine directional structure, having excellent room and high temperature mechanical properties, and overcoming the major engineering application bottleneck problem of the unbalanced mechanical properties of current ultra-high temperature structural materials.

[0094] To further understand the present invention, the preferred implementation schemes of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0095] Example 1

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

[0097] B) Load the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder with a particle size of 45 - 150 μm into the powder feeder of the laser direct deposition system. Use high-purity argon as the powder feeding gas flow, set the powder-carrying gas flow to: 8 L / min, and the powder feeding rate of the mixed powder to 8 g / min. Use argon as the shielding gas, and the shielding gas flow rate to: 20 L / min.

[0098] C) Deposit the alloy:

[0099] c1: Use an induction heating device to heat the position to be formed on the titanium alloy forming substrate to 1000 °C. Start the laser direct deposition equipment to output the laser and powder coaxially. The laser focus is at the forming base surface and moves along 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 sliced layer, a deposited layer with a thickness of about 0.5 mm is obtained.

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

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

[0102] Product Testing :

[0103] (1) Microstructure characterization

[0104] Figure 1 It is the microstructure diagram 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 alternately and coupled.

[0105] (2) Mechanical property testing

[0106] Figure 2The stress-strain curve at room temperature of the Nb-16Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy obtained in Example 1. The tensile elongation of this alloy at room temperature reaches 3.8%, showing excellent plastic toughness.

[0107] Example 2

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

[0109] B) Load the Nb-18Si-8Ni-12Ti-10Zr-3Al-3Cr-3Hf alloy powder with a particle size of 45 - 150 μm into the powder feeder of the laser direct deposition system. Use high-purity argon as the powder feeding gas flow, set the powder-carrying gas flow to 20 L / min, the powder feeding rate of the mixed powder to 10 g / min, and use argon as the shielding gas with a shielding gas flow of 20 L / min.

[0110] C) Deposit the alloy:

[0111] c1: Use an induction heating device to heat the position to be formed on the titanium alloy forming substrate to 1200 °C. Start the laser direct deposition equipment to output the laser and powder coaxially. The laser focus is at the forming base surface and moves along 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 sliced layer, a deposited layer with a thickness of about 0.3 mm is obtained.

[0112] c2: Lower the forming substrate by 0.3 mm, keep the position of the induction heating coil relative to the liquid metal fixed, and repeat step c1 to obtain the next deposited layer.

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

[0114] Product Testing :

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

[0116] In this article, specific examples are used to illustrate the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables 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 for those of ordinary skill in the art in the technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention 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 the literal expression of the claims, or if they include equivalent structural elements that have no substantial difference from the literal expression of 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 a novel Nb-Si-Ni-Ti based ultra-high temperature structural material, characterized in that, It includes the following steps: A) Establish a three-dimensional CAD model of the shape of the alloy to be prepared, perform layer slicing on it in the height direction, fill the scanning path for each layer slice, and then import the slice information and scanning path information into the laser direct deposition system; B) Load the alloy powder raw material of the new Nb-Si-Ni-Ti ultra-high temperature structural material into the powder feeder of the laser direct deposition system, and use a protective gas as the powder-carrying gas and protective gas; In atomic percentage, the alloy powder raw material includes: 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: the balance; wherein, the atomic ratio of Ni / Si elements is 0.1 - 1; C) Deposit the alloy: c1: Heat the position to be formed on the forming substrate. When it is heated to the target temperature, start the laser direct deposition equipment, make the laser and the powder output coaxially, 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, and as the powder and the laser move away, the molten pool solidifies. After the laser scans the entire slice layer, a deposited layer is obtained; c2: Lower the forming substrate by the thickness of a deposited layer, and repeat step c1 to obtain the next deposited layer; c3: Repeat step c2 until the alloy preparation is completed; wherein, there is no order limit for step A) and step B).

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

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

5. The preparation method according to claim 1, characterized in that, In step B), the gas flow of the powder-carrying gas is 5 - 20 L / min; the powder feeding rate of the alloy powder raw material is 5 - 20 g / min; the flow rate of the protective gas is 5 - 20 L / min.

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

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

8. The preparation method according to claim 1, wherein In step c1, the target temperature is 500 - 1200 °C.

9. The preparation method according to claim 1, characterized in that, In step c1, the laser power is 500 - 1500 W; the scanning speed of the laser is 300 - 1000 mm / min.

10. A new Nb-Si-Ni-Ti ultra-high temperature structural material prepared by the preparation method according to any one of claims 1 - 9.

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