Titanium Carbide Reinforced Nickel-Tungsten Powder, Preparation Method and Application

Abstract

The present invention discloses titanium carbide-reinforced nickel-tungsten powder, a preparation method and applications thereof. Among them, the titanium carbide-reinforced nickel-tungsten powder includes a nickel-tungsten composite matrix and titanium carbide phases dispersed in the nickel-tungsten composite matrix, and the titanium carbide phases are obtained by a displacement reaction between tungsten carbide and titanium. During the displacement reaction, titanium elements combine with carbon elements to form titanium carbide with smaller sizes and a dispersed distribution. The titanium carbide and the nickel-tungsten base material are metallurgically bonded, and finally titanium carbide dispersion-strengthened nickel-tungsten powder is obtained. Using this dispersion-strengthened powder, a titanium carbide dispersion-strengthened nickel-tungsten alloy can be prepared by a laser cladding method. The titanium carbide dispersion-strengthened nickel-tungsten powder provided by the present invention has lower requirements for the particle size of raw materials during preparation, and fewer defects in the nickel-tungsten powder.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and more particularly, to titanium carbide-reinforced nickel-tungsten powder, a preparation method thereof, and an application thereof. Background Art

[0002] Due to characteristics such as high toughness, high hardness, and high wear resistance, cermets are widely used in many fields such as aerospace, petrochemical, and automotive and marine industries. A common cermet is cobalt-tungsten carbide, which has high wear resistance and good economic applicability, and tungsten carbide plays a key role as a wear-resistant phase therein. However, tungsten carbide is prone to oxidation and decomposition above 800 °C, resulting in a significant reduction in the properties of cermet materials such as stability.

[0003] Compared with tungsten carbide, titanium carbide has better high-temperature resistance and oxidation resistance and is used in the preparation of new cermet materials. However, currently, the preparation of cermet powder containing titanium carbide generally adopts a method of directly compounding and granulating metal powder and titanium carbide powder. On the one hand, this method requires that the particle size of the titanium carbide raw material particles is very fine, generally requiring the particle size of titanium carbide to be less than 1 μm. However, titanium carbide itself has high hardness and is not easily broken, resulting in difficult processing of raw materials and high costs. On the other hand, after the metal and titanium carbide powders are compounded and granulated, the internal defects of the powder are high, and it is difficult for the two to form a metallurgical bond, resulting in poor powder properties and affecting the performance of subsequent additive manufacturing alloy preparation.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide titanium carbide-reinforced nickel-tungsten powder, a preparation method thereof, and an application thereof, and to provide a powder with few internal defects.

[0006] The present invention is implemented as follows:

[0007] In a first aspect, the present invention provides a titanium carbide-reinforced nickel-tungsten powder, including a nickel-tungsten composite matrix and a titanium carbide phase dispersedly distributed in the nickel-tungsten composite matrix, and the titanium carbide phase is obtained by a displacement reaction between tungsten carbide and titanium.

[0008] In an optional embodiment, the average size of the titanium carbide phase is less than 1 μm;

[0009] and / or, the mass ratio of nickel to titanium in the nickel-tungsten powder is 1:(0.1 - 0.2);

[0010] and / or, the molar ratio of titanium, carbon, and tungsten in the nickel-tungsten powder is 1:(0.9 - 1.1):(0.9 - 1.1).

[0011] In a second aspect, the present invention provides a method for preparing titanium carbide-reinforced nickel-tungsten powder, including:

[0012] Vacuum melting: Mix a molten solution composed of nickel and titanium elements with tungsten carbide powder to obtain a composite molten solution;

[0013] Atomization: Atomize the composite molten solution to obtain atomized powder;

[0014] Heat treatment: Perform heat treatment on the atomized powder to obtain the nickel-tungsten powder strengthened by titanium carbide.

[0015] In an optional embodiment, the particle size of the tungsten carbide powder is less than 100 μm.

[0016] In an optional embodiment, the composite molten solution is obtained by adding tungsten carbide powder to the molten solution and mixing.

[0017] In an optional embodiment, the particle size of the atomized powder is ≤ 75 μm;

[0018] Preferably, the atomization step includes: using an inert gas to blow and break the composite molten solution into droplets, and cooling the droplets to obtain atomized powder.

[0019] In an optional embodiment, the heat treatment temperature is 1000 °C to 1050 °C, the time is 0.5 h to 1 h, and the vacuum degree is ≤ 100 Pa.

[0020] In a third aspect, the present invention provides a method for preparing a nickel-tungsten alloy strengthened by titanium carbide, including: using laser cladding to spray the nickel-tungsten powder strengthened by titanium carbide described in the foregoing embodiment to obtain the nickel-tungsten alloy strengthened by titanium carbide.

[0021] In an optional embodiment, the cladding laser power is 1 kW to 2 kW;

[0022] and / or, the cladding speed is 1 mm / s to 5 mm / s;

[0023] and / or, the powder feeding rate is 60 g / min to 120 g / min.

[0024] In a fourth aspect, the present invention provides a nickel-tungsten alloy strengthened by titanium carbide, which is prepared by the method described in the foregoing embodiment.

[0025] The present invention has the following beneficial effects:

[0026] In the present invention, titanium carbide dispersed in nickel-tungsten powder is obtained by a displacement reaction between tungsten carbide and titanium. During the displacement reaction, titanium elements combine with carbon elements to form titanium carbide with smaller size and dispersed distribution. The titanium carbide and nickel-tungsten substrate are metallurgically bonded, and finally titanium carbide dispersion-strengthened nickel-tungsten powder is obtained. Using this dispersion-strengthened powder, titanium carbide dispersion-strengthened nickel-tungsten alloy can be prepared by laser cladding method. The requirements for the particle size of raw materials are relatively low when preparing the titanium carbide dispersion-strengthened nickel-tungsten powder provided by the present invention, and there are fewer defects in the nickel-tungsten powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a flowchart of the preparation method of the nickel-tungsten powder strengthened by titanium carbide of the present invention;

[0029] Figure 2 It is a microstructural diagram of the titanium carbide dispersion-strengthened nickel-tungsten powder prepared in Example 1;

[0030] Figure 3 It is a microstructural diagram of the titanium carbide dispersion-strengthened nickel-tungsten alloy prepared in Example 1;

[0031] Figure 4 It is a microstructural diagram of the titanium carbide dispersion-strengthened nickel-tungsten powder prepared in Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0033] An embodiment of the present invention provides a titanium carbide-strengthened nickel-tungsten powder, which includes a nickel-tungsten composite matrix and a titanium carbide phase dispersed in the nickel-tungsten composite matrix, and the titanium carbide phase is obtained by a displacement reaction between tungsten carbide and titanium.

[0034] In the embodiments of the present invention, titanium carbide dispersed in nickel-tungsten powder is obtained by a displacement reaction between tungsten carbide and titanium. During the displacement reaction, titanium elements combine with carbon elements to form titanium carbide with smaller size and dispersed distribution. The titanium carbide and the nickel-tungsten substrate are metallurgically bonded, and finally titanium carbide dispersion-strengthened nickel-tungsten powder is obtained. Using this dispersion-strengthened powder, titanium carbide dispersion-strengthened nickel-tungsten alloy can be prepared by laser cladding method. When preparing the titanium carbide dispersion-strengthened nickel-tungsten powder provided by the present invention, the requirement for the particle size of raw materials is relatively low, and there are fewer defects in the nickel-tungsten powder.

[0035] In an alternative embodiment, the average size of the titanium carbide phase is less than 1 μm.

[0036] In an alternative embodiment, the mass ratio of nickel to titanium in the nickel-tungsten powder is 1:(0.1 - 0.2). If the titanium content is too low, the content of titanium carbide formed by heat treatment will be too low, and the wear resistance of the alloy is poor; if the titanium content is too high, the nickel-tungsten powder after heat treatment is more brittle and has poor toughness. A mass ratio of nickel to titanium of 1:(0.1 - 0.2) can balance toughness and wear resistance.

[0037] In an alternative embodiment, the molar ratio of titanium, carbon and tungsten in the nickel-tungsten powder is 1:(0.9 - 1.1):(0.9 - 1.1). At this time, titanium can react with tungsten carbide by stoichiometric ratio to obtain titanium carbide, so that the nickel-tungsten powder has a lower content of tungsten carbide and titanium. If the proportion of titanium is too small, tungsten carbide phase will remain in the nickel-tungsten powder; if the proportion of titanium is too large, too much titanium element will remain in the nickel-tungsten powder, generating nickel-titanium intermetallic compounds and reducing the toughness of the matrix.

[0038] The embodiments of the present invention also provide a preparation method of titanium carbide-strengthened nickel-tungsten powder, as Figure 1 shown, including:

[0039] Vacuum melting, mixing a melt composed of nickel element and titanium element with tungsten carbide powder to obtain a composite melt;

[0040] Atomization, atomizing the composite melt to obtain atomized powder;

[0041] Heat treatment, performing heat treatment on the atomized powder to obtain the titanium carbide-strengthened nickel-tungsten powder.

[0042] In the prior art, in order to obtain titanium carbide dispersion-strengthened nickel-tungsten powder and alloy, nickel-tungsten metal particles and titanium carbide particles are usually compounded and granulated, and then subjected to high-temperature sintering. However, the size of titanium carbide particles in the powder obtained by this conventional process is limited by the size of the raw materials used and is often relatively large, and the pores in the powder cannot be completely discharged. The existing titanium carbide composite nickel-tungsten powder and cladding alloy generally have problems such as many defects and weak dispersion degree of titanium carbide.

[0043] In the embodiment of the present invention, driven by the thermodynamic free energy, the large tungsten carbide particles decompose, and tungsten elements enter the nickel matrix to form a new nickel-tungsten matrix; titanium elements combine with carbon elements to form titanium carbide with small size and dispersed distribution. The titanium carbide and the nickel-tungsten base material are metallurgically bonded, and finally titanium carbide dispersion-strengthened nickel-tungsten powder is obtained.

[0044] In an alternative embodiment, the particle size of the tungsten carbide powder is less than 100 μm. If the particle size of the raw tungsten carbide powder is greater than 100 microns, during the heat treatment process, limited by the element diffusion rate, the distribution of tungsten carbide particles is prone to be uneven or the reaction is insufficient, which is not conducive to improving the performance of the nickel-tungsten powder.

[0045] In an alternative embodiment, the composite melt is obtained by adding tungsten carbide powder to the melt. In order to improve the uniformity of the composite melt, in the present invention, when vacuum melting, the nickel block and the titanium block are first melted into a liquid state, and then tungsten carbide powder is added thereto. If the tungsten carbide is first placed in the melting furnace, due to the large weight of the tungsten carbide itself, the tungsten carbide cannot enter the nickel-titanium melt above it, and thus a uniform composite melt cannot be obtained; if the nickel block, the titanium block and the tungsten carbide powder are simultaneously placed in the melting furnace, since the particle size of the tungsten carbide powder is significantly smaller than that of other bulk materials, the tungsten carbide powder will flow to the bottom of the melting furnace, and thus a uniform composite melt cannot be formed either.

[0046] In an alternative embodiment, the particle size of the atomized powder ≤ 75 μm is beneficial to obtaining a relatively dense alloy by subsequent laser cladding. If the particle size of the atomized powder is greater than 75 μm, the large particle powder is prone to insufficient melting during laser cladding, resulting in a decrease in the density of the alloy and affecting the bonding force of the alloy, etc.

[0047] In an alternative embodiment, the atomization step includes: using an inert gas to blow and break the composite melt into droplets, and cooling the droplets to obtain atomized powder.

[0048] In an alternative embodiment, the heat treatment temperature is 1000 °C to 1050 °C, the time is 0.5 h to 1 h, and the vacuum degree ≤ 100 Pa.

[0049] The embodiment of the present invention utilizes the principle that titanium and tungsten carbide can undergo a displacement reaction at 1000 - 1050 °C to convert tungsten carbide into titanium carbide. If the vacuum heat treatment temperature is lower than 1000 °C and the holding time is less than 0.5 hours, it is not conducive to the decomposition of tungsten carbide, and the chemical reaction between titanium and tungsten carbide is insufficient; if the heat treatment temperature is higher than 1050 °C and the holding time is higher than 1 hour, the powder particles are prone to adhesion, reducing the fluidity of the prepared nickel-tungsten powder. If the vacuum degree is greater than 100 Pa, the oxygen content in the environmental atmosphere of the powder is relatively higher, and oxidation is likely to occur on the powder surface, affecting the oxygen content of the powder, and the clad alloy is prone to internal oxidation or cracking.

[0050] An embodiment of the present invention further provides a method for preparing a titanium carbide-reinforced nickel-tungsten alloy, comprising: using laser cladding to spray the titanium carbide-reinforced nickel-tungsten powder described in the aforementioned embodiment to obtain the titanium carbide-reinforced nickel-tungsten alloy.

[0051] In an optional embodiment, the cladding laser power is 1 kW to 2 kW; if the laser power is too low, the alloy is not dense; if the laser power is too high, it is easy to cause excessive chemical elements in the cladding substrate to enter the alloy coating, causing hybridization of the alloy elements.

[0052] In an optional embodiment, the cladding speed is 1 mm / s to 5 mm / s; if the cladding speed is too low, too much laser heat will be transferred to the substrate, causing hybridization of alloy elements in the coating; if the cladding speed is too high, some cladding areas are prone to leaking.

[0053] In an optional embodiment, the powder feeding rate is 60 g / min to 120 g / min. If the powder feeding rate is too low, serious oxidation of the powder is likely to occur; if the powder feeding rate is too high, part of the powder is likely to be insufficiently melted, forming powder accumulation in the alloy, resulting in an increase in porosity defects in the coating.

[0054] An embodiment of the present invention further provides a titanium carbide reinforced nickel-tungsten alloy, which is prepared by the method described in the aforementioned embodiment.

[0055] The titanium carbide-reinforced nickel-tungsten alloy in the embodiment of the present invention has high density and the titanium carbide is dispersedly distributed.

[0056] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0057] Example 1

[0058] This embodiment provides a method for preparing a titanium carbide dispersion strengthened nickel-tungsten alloy, comprising the following steps:

[0059] Step 1: Put 1kg of nickel block and 0.1kg of titanium block into a vacuum melting furnace for melting, then add 0.4kg of tungsten carbide powder with a particle size of less than 100μm into the melt, mix evenly to obtain a composite melt, atomize the composite melt and sieve the atomized powder to obtain an atomized powder with a particle size of less than 75μm.

[0060] Step 2: Put the atomized powder into a vacuum heat treatment furnace, the heat treatment temperature is 1000°C, the heat treatment holding time is 0.5 hours, the vacuum pressure is 100Pa, and titanium carbide dispersion strengthened nickel tungsten powder is obtained after heat treatment.

[0061] Step 3: Laser cladding of the titanium carbide dispersion-strengthened nickel-tungsten powder obtained in Step 2, with a cladding laser power of 1 kW, a cladding speed of 5 mm / s, and a powder feeding rate of 60 g / min, to obtain a titanium carbide dispersion-strengthened nickel-tungsten alloy.

[0062] Example 2

[0063] This example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 1, the mass of the titanium block added is 0.2 kg, and the mass of the tungsten carbide powder is 0.8 kg.

[0064] Example 3

[0065] This example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 2, the heat treatment temperature is 1050 °C, and the heat treatment holding time is 1 hour.

[0066] Example 4

[0067] This example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 3, the cladding laser power is 2 kW, the cladding speed is 1 mm / s, and the powder feeding rate is 120 g / min.

[0068] Comparative Example 1

[0069] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 1, the particle size of the tungsten carbide added is 120 μm.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 1, the mass of the titanium block added is 0.3 kg, and the mass of the tungsten carbide powder is 1.2 kg.

[0072] Comparative Example 3

[0073] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 2, the heat treatment temperature is 1080 °C.

[0074] Comparative Example 4

[0075] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 3, the laser cladding power is 2.5 kW.

[0076] Comparative Example 5

[0077] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 1, the mass of the titanium block added is 0.1 kg, and the mass of the tungsten carbide powder is 0.6 kg.

[0078] Comparative Example 6

[0079] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 2, the heat treatment temperature is 950 °C.

[0080] Comparative Example 7

[0081] This comparative example provides a method for preparing a titanium carbide dispersion-strengthened nickel-tungsten alloy, which is only different from Example 1 in that: in Step 3, the laser cladding power is 0.5 kW.

[0082] Test Example

[0083] Detect the powder microstructure or cladding alloy microstructure prepared in each example and comparative example, and focus on observing the titanium carbide particles and matrix densification in the powder or alloy. The detection method is electron microscope image analysis (JY / T 010-1996). At the same time, the sphericity of the powder (reference standard: YS / T 1491-2021 Determination method for the sphericity of nickel-based superalloy powder - Scanning electron microscopy method) and the bonding strength between the alloy and the substrate (HB5476-1991 Test method for the bonding strength of thermal spray coatings) are detected. The detection results are shown in Table 1. Among them, the powder microstructure after heat treatment in Example 1 and the internal microstructure of the prepared alloy are as shown in Figure 2 and Figure 3 , and the alloy microstructure of Comparative Example 1 is shown in Figure 4 .

[0084] Table 1

[0085]

[0086]

[0087] As can be seen from Table 1, compared with the comparative examples, in the solution of the embodiment of the present invention, the obtained powder and alloy both have a microstructure of titanium carbide dispersion-strengthened nickel tungsten. The titanium carbide and the nickel tungsten substrate are metallurgically bonded, and there are no pore defects in the coating alloy. Further, it can be seen from Example 1 and Comparative Example 1 that when using tungsten carbide powder raw materials with larger sizes, it is easy to cause incomplete decomposition of tungsten carbide in the cladding alloy, and there are defects in the powder and alloy structures, with low powder sphericity, low alloy density and strength; it can be seen from Example 1 and Comparative Example 2 that if the contents of the added titanium and tungsten carbide raw materials are too high, it is easy to cause an increase in the brittleness of the cladding alloy, resulting in cracking of the metal matrix, and there are defects in the powder and alloy structures, with low powder sphericity, low alloy density and strength; it can be seen from Example 1 and Comparative Example 3 that if the heat treatment temperature is too high, it is easy to cause the powders to adhere to each other, resulting in the loss of good fluidity of the powders and the inability to perform cladding normally, and there are defects in the powder and alloy structures, with low powder sphericity, low alloy density and strength; it can be seen from Example 1 and Comparative Example 4 that if the laser power is too high, it is easy to cause obvious internal oxidation phenomenon and substrate element hybridization phenomenon in the metal matrix, and there are defects in the powder and alloy structures, with low powder sphericity, low alloy density and strength; it can be seen from Example 1 and Comparative Example 5 that if the added titanium and tungsten carbide are too little and the titanium carbide content is less, the alloy strength is low; it can be seen from Example 1 and Comparative Example 6 that if the heat treatment temperature is too low, tungsten carbide cannot be completely converted into titanium carbide, and there are defects in the powder and alloy structures, with low powder sphericity, low alloy density and strength; it can be seen from Example 1 and Comparative Example 7 that if the laser cladding power is too low, there are defects in the alloy structure and the alloy density and strength are low.

[0088] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A titanium carbide strengthened nickel-tungsten powder, characterized in that, It includes a nickel-tungsten composite matrix and titanium carbide phases dispersedly distributed in the nickel-tungsten composite matrix, and the titanium carbide phases are obtained by a displacement reaction between tungsten carbide and titanium; the average size of the titanium carbide phases is less than 1 μm; In the titanium carbide-reinforced nickel-tungsten powder, the mass ratio of nickel to titanium is 1:(0.1 - 0.2); In the titanium carbide-reinforced nickel-tungsten powder, the molar ratio of titanium, carbon and tungsten is 1:(0.9 - 1.1):(0.9 - 1.1); The preparation method of the titanium carbide-reinforced nickel-tungsten powder includes: Vacuum melting, mixing a melt composed of nickel element and titanium element with tungsten carbide powder to obtain a composite melt; Atomization, atomizing the composite melt to obtain atomized powder; Heat treatment, performing heat treatment on the atomized powder to obtain the titanium carbide-reinforced nickel-tungsten powder; The particle size of the tungsten carbide powder is less than 100 μm, the heat treatment temperature is 1000 °C - 1050 °C, the time is 0.5 h - 1 h, and the vacuum degree is ≤ 100 Pa.

2. The titanium carbide-reinforced nickel-tungsten powder according to claim 1, wherein The composite melt is obtained by adding tungsten carbide powder to the melt composed of nickel element and titanium element and mixing them.

3. The titanium carbide-reinforced nickel-tungsten powder according to claim 1, wherein The particle size of the atomized powder is ≤ 75 μm.

4. The titanium carbide-reinforced nickel-tungsten powder according to claim 1, wherein The atomization step includes: using an inert gas to blow and break the composite melt into droplets, and cooling the droplets to obtain atomized powder.

5. A preparation method of titanium carbide strengthened nickel-tungsten alloy, characterized in that, It includes: Spraying the titanium carbide-reinforced nickel-tungsten powder according to any one of claims 1 - 4 by laser cladding to obtain the titanium carbide-reinforced nickel-tungsten alloy.

6. The preparation method of the titanium carbide-reinforced nickel-tungsten alloy according to claim 5, characterized in that, The cladding laser power is 1 kW - 2 kW; and / or, the cladding speed is 1 mm / s - 5 mm / s; and / or, the powder feeding rate is 60 g / min - 120 g / min.

7. A titanium carbide strengthened nickel-tungsten alloy, characterized in that, It is prepared by the method according to claim 5 or 6.

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