High-strength wear-resistant alloy powder for additive manufacturing and preparation method of high-strength wear-resistant alloy powder

Abstract

The invention is applicable to the technical field of metal powder material preparation, and provides high-strength wear-resistant alloy powder for additive manufacturing and a preparation method thereof, the high-strength wear-resistant alloy powder for additive manufacturing comprises the following matrix components in percentage by mass: a mixed matrix comprising electrolytic iron and reduced iron powder, a wear-resistant phase strengthening element, a tough phase element and a functional modifier, the surface of the carbon nanotube is modified by a silane coupling agent KH550; through a three-dimensional cooperation strategy of component gradient regulation and control, tissue densification design and nano-enhanced network construction, breakthrough improvement of alloy performance is achieved, a high-hardness-high-toughness gradient structure is formed by a wear-resistant phase and a toughness phase which are precisely proportioned, and chemical bonding of the surface modified carbon nanotubes and a matrix is combined, so that the wear resistance and toughness of the alloy are improved, and the wear resistance and toughness of the alloy are improved. Constructing a three-dimensional enhanced network for inhibiting defect expansion on a micro scale; and crack initiation and expansion are inhibited through a nanometer enhanced network, and a powder material with high reliability and high performance is provided for additive manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of metal powder materials, and particularly relates to a high-strength wear-resistant alloy powder for additive manufacturing and a preparation method thereof. Background Art

[0002] At present, wear-resistant alloy materials (such as high-chromium cast iron, tungsten-molybdenum alloy, etc.) generally improve hardness through a single strengthening phase (such as chromium carbide, tungsten carbide), but there is a problem of significant decrease in toughness; for example, the impact toughness of traditional high-chromium cast iron is usually lower than 5 J / cm², which is difficult to meet the requirements of high-impact load working conditions such as mining machinery and shield cutters; on the other hand, some ductile alloys (such as nickel-based alloys) have fatigue resistance, but the surface hardness is insufficient (HRC≤50), and they are prone to failure under wear conditions; in the prior art, adding hard phases such as tantalum carbide (TaC) and titanium carbonitride (TiCN) can improve wear resistance, but it often leads to uneven dispersion due to weak interfacial bonding with the matrix, resulting in crack initiation; in addition, nano-reinforcing phases (such as carbon nanotubes) are prone to agglomeration in the alloy melt, and lack a chemical bonding mechanism, unable to effectively transfer loads, resulting in the fatigue life of additive manufacturing components being lower than expected; Limitations of Additive Manufacturing Process In the field of additive manufacturing, defects such as pores, unmelted particles and microcracks are easily generated during the melting and solidification process of metal powders; traditional melting processes (such as electric arc furnace melting) have insufficient control of oxygen content (usually ≥0.1%), resulting in oxide inclusions becoming crack sources; during the atomization powder preparation process, large droplets (D50>50μm) and satellite ball structures will reduce the powder fluidity and affect the powder spreading quality; in addition, if the plasma spheroidization process is not combined with gradient cooling, it is easy to form coarse lamellar grains (grain size ≥50μm), significantly reducing the fracture toughness of the material; although the existing patent technology (such as CN2018XXXXXX) uses vacuum induction melting, it does not synergistically optimize the addition rate of deoxidizer and the stirring intensity, resulting in low deoxidation efficiency (oxygen residual content ≥0.12%), and lacking grain refinement means, it is difficult to balance density and mechanical properties; Technical Defects of Interface Modification When carbon nanotubes are used as reinforcements, the prior art mostly relies on physical adsorption or simple mechanical mixing methods, resulting in insufficient interfacial bonding strength with the matrix (interfacial shear strength ≤10 MPa); for example, carbon nanotubes coated with polyethyleneimine (PEI) can improve dispersion, but the interface is prone to oxidation failure during the high-temperature additive manufacturing process, and its high modulus characteristics cannot be exerted; in addition, unmodified carbon nanotubes are prone to agglomeration in the melt, forming stress concentration points and accelerating the propagation of fatigue cracks. Summary of the Invention

[0003] The present invention provides a high-strength wear-resistant alloy powder for additive manufacturing and a preparation method thereof, aiming to solve the problems existing in the existing wear-resistant alloys and additive manufacturing processes, such as single strengthening leading to toughness reduction, weak phase interfaces leading to cracking, nano-agglomeration with carrier differences, many powder defects, poor oxygen control, coarse grains, low deoxidation, weak bonding of nanotubes, and high-temperature failure.

[0004] The present invention is realized as follows. A high-strength wear-resistant alloy powder for additive manufacturing includes, by mass percentage: Matrix components: including a mixed matrix of electrolytic iron and reduced iron powder, the purity of electrolytic iron ≥ 99.9%, the D50 of reduced iron powder ≤ 45 μm, and the total addition amount of the two accounts for the balance of the alloy mass; Wear-resistant phase strengthening elements: Chromium: 2.0% - 4.0%; Molybdenum: 0.8% - 2.0%; Vanadium: 0.3% - 1.5%; Tungsten: 1.0% - 3.0%; Toughness phase elements: Nickel 0.3% - 3.0%; Cobalt 0.5% - 2.5%; Deoxidizer: Aluminum: 0.2% - 1%; Functional modifier: Yttrium oxide: 0.05% - 0.3%; Carbon nanotubes: 0.5% - 2.0%, and the surface of the carbon nanotubes is modified by the silane coupling agent KH550.

[0005] The present invention also provides a preparation method for a high-strength wear-resistant alloy powder for additive manufacturing, including the following steps: ① Melting alloying: Put electrolytic iron, reduced iron powder, ferrochromium, ferromolybdenum, ferrovanadium, and ferrotungsten into a vacuum induction melting furnace and heat under argon protection; ② Deoxidation refining: Add aluminum pellets in the later stage of melting, with a stirring rate of 80 - 120 rpm, react for 8 - 15 min, and the oxygen content ≤ 0.08%; ③ Functional modification: Pretreatment of carbon nanotubes: Dissolve with KH550 in ethanol - water at a ratio of 100:1, volume ratio 3:1, and hydrolyze at 50 °C for 1 h; Ultrasonic atomization spraying coating: The spraying amount of the modified liquid is 0.5 - 2.0 wt%, and the temperature shows a gradient increase after the carbon nanotubes are coated; ④ Atomization forming: The superheat of the alloy melt is 150 - 250 °C, and after gas atomization to make powder, magnetic field classification is carried out, and D50 ≤ 45 μm; ⑤ Plasma spheroidization: The spheroidization temperature is 1000 - 1100 °C, the time is 30 - 60 min, and the argon flow rate is 0.5 - 1.0 L / min; ⑥Screening and drying: vacuum drying, 80-120℃, 2-4h, argon protection, oxygen content ≤0.05%.

[0006] Preferably, the two-stage heating program includes: ① Release agent decomposition stage: 1000-1100℃ insulation for 10min; ② Alloy melting stage: step-by-step heating to 1550-1650℃, heating rate 10℃ / min.

[0007] Preferably, the concentration of the alkane coupling agent KH550 ethanol solution is 0.5-2.0wt%, the ultrasonic dispersion power is 200-400W, and the time is 30min.

[0008] Preferably, the particle size D50 of the powder after spheroidization is ≤45 μm.

[0009] Preferably, argon is continuously introduced during the drying process at a flow rate of 0.1-0.3 L / min.

[0010] Preferably, the high temperature sintering gradient of the carbon nanotubes after coating is: Pre-sintering: 300℃ argon protection for 1h; Main sintering: 500℃ under argon protection for 1h, gradient heating rate 5℃ / min.

[0011] Preferably, in step ①, the vacuum degree of the vacuum induction melting furnace is ≤5Pa, and the melting temperature is controlled in two stages: ① The first stage: keep the temperature at 1400-1450℃ for 20-30min to completely melt chromium, molybdenum, vanadium and tungsten iron; ②The second stage: Gradient temperature rise to 1580-1620℃, keep warm for 15-25min to form a homogeneous melt. Compared with the prior art, the embodiments of the present application have the following beneficial effects: First, the present invention forms a gradient distribution of high-hardness hard points and toughness phases in the matrix by accurately proportioning wear-resistant phase strengthening elements and toughness phase elements, and combines the high-strength interface bonding of surface-modified carbon nanotubes to effectively balance the contradiction between hardness and toughness, so that the alloy has excellent wear resistance and impact resistance when subjected to high-load friction, meeting the service requirements under complex working conditions.

[0012] Second: The present invention adopts vacuum induction melting, aluminum particle deoxidation, plasma spheroidization and other processes, combined with the grain refining effect of trace yttrium oxide, to form a low-oxygen content, high-density microstructure. This structure significantly reduces oxide inclusions and pore defects, improves strength and toughness by refining grains, while reducing the risk of crack propagation, ensuring the stability of the material in extreme environments.

[0013] Thirdly, the surface-modified carbon nanotubes of the present invention form chemical bonds with the matrix through the silane coupling agent KH550. Their high strength and high modulus characteristics cooperate with the alloy matrix to construct a three-dimensional reinforcement network at the microscale. This network not only inhibits the agglomeration of carbon nanotubes but also significantly improves the wear resistance and fatigue resistance of the alloy through the load transfer effect, providing a powder material with both high strength and high reliability for additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the preparation of the metal powder material of the present invention; Figure 2 is a schematic diagram of the key reaction of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] 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 are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0016] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0017] The embodiments of the present invention provide a high-strength and wear-resistant alloy powder for additive manufacturing, as Figure 1-2 shown, including by mass percentage: Matrix components: including a mixed matrix of electrolytic iron and reduced iron powder, the purity of electrolytic iron ≥ 99.9%, the D50 of reduced iron powder ≤ 45 μm, and the total addition amount of the two accounts for the balance of the alloy mass; Wear-resistant phase strengthening elements: Chromium: 2.0% - 4.0%; Molybdenum: 0.8% - 2.0%; Vanadium: 0.3% - 1.5%; Tungsten: 1.0% - 3.0%; Toughness phase elements: Nickel 0.3% - 3.0%; Cobalt 0.5%-2.5%; Deoxidizer: Aluminum: 0.2%-1%; Functional modifiers: Yttrium oxide: 0.05%-0.3%; Carbon nanotubes: 0.5%-2.0%, and the surface of the carbon nanotubes is modified by silane coupling agent KH550.

[0018] It should be noted that, due to the problems of single strengthening leading to toughness reduction, weak cracking at the phase interface, poor nano-agglomeration, many powder defects, poor oxygen control, coarse grains, low deoxidation, weak nanotube bonding and high-temperature failure in existing wear-resistant alloys and additive processes, this scheme has achieved a breakthrough improvement in alloy performance through multi-scale collaborative strengthening design: at the composition design level, through the gradient distribution of wear-resistant phase and toughness phase, combined with the strong interface bonding after modification of carbon nanotubes, a dynamic balance of hardness and toughness is constructed at the microscopic to mesoscopic scale; at the preparation process level, relying on vacuum melting, deoxidation refining, plasma spheroidization and grain refinement technology, a low-oxygen and high-density organizational structure is formed at the macroscopic to nanoscale, which effectively inhibits the propagation of defects and cracks; at the nano-enhancement level, the chemical bonding of modified carbon nanotubes and the matrix forms a three-dimensional reinforcement network, which significantly improves the wear resistance and fatigue resistance of the material; the synergistic effect of the three makes the alloy have high strength, high toughness, excellent wear resistance and impact resistance, and fully meets the stringent requirements of additive manufacturing for high-performance powder materials under complex working conditions.

[0019] Specifically, in this embodiment, the high-strength wear-resistant alloy powder manufactured by the additive manufacturing of this scheme is composed of a mixed matrix of high-purity electrolytic iron and fine-grained reduced iron powder, which work together as an alloy skeleton to provide basic mechanical support and good fluidity required for additive manufacturing; wear-resistant phase strengthening elements are added in a precise ratio to form hard points such as high-hardness carbides and intermetallic compounds in the alloy, and these hard points are evenly distributed in the matrix, which significantly improves the hardness and wear resistance of the alloy, so that it can still maintain surface integrity when subjected to high-load friction; In order to balance the brittleness risk brought by high hardness, tough phase elements are introduced. These elements form tough phases in the alloy through solid solution strengthening and second phase strengthening mechanisms, effectively hindering crack propagation, improving the impact resistance and toughness of the alloy, and ensuring its structural stability under complex stress environments; During the smelting process, an appropriate amount of deoxidizer aluminum is added to utilize its strong deoxidizing ability to remove oxygen in the alloy melt, purify the melt, reduce oxide inclusions, and improve the purity and mechanical properties of the alloy; trace yttrium oxide is used as a grain refiner to significantly refine the alloy grains by pinning grain boundaries and inhibiting grain growth, thereby enhancing strength and toughness; while the carbon nanotubes with a surface modified by silane coupling agent KH550 further enhance the mechanical properties of the alloy, especially wear resistance and fatigue resistance, by virtue of their high strength, high modulus characteristics and good interfacial bonding with the matrix.

[0020] The present invention also provides a method for preparing a high-strength and wear-resistant alloy powder for additive manufacturing, as Figure 1 shown, which includes the following steps: ① Melting alloying: Put electrolytic iron, reduced iron powder, ferrochromium, ferromolybdenum, ferrovanadium, and ferrotungsten into a vacuum induction melting furnace and heat under argon protection; ② Deoxidation refining: Add aluminum pellets in the later stage of melting, stir at a rate of 80 - 120 rpm for 8 - 15 min, and the oxygen content ≤ 0.08%; ③ Functional modification: Pretreatment of carbon nanotubes: Dissolve them with KH550 in ethanol - water at a ratio of 100:1, with a volume ratio of 3:1, and hydrolyze at 50 °C for 1 h; Ultrasonic atomization spraying coating: The spraying amount of the modified liquid is 0.5 - 2.0 wt%, and the temperature shows a gradient increase after the carbon nanotubes are coated; ④ Atomization forming: The superheat of the alloy melt is 150 - 250 °C, and after gas atomization powder making, magnetic field classification is carried out, and D50 ≤ 45 μm; ⑤ Plasma spheroidization: The spheroidization temperature is 1000 - 1100 °C, the time is 30 - 60 min, and the argon flow rate is 0.5 - 1.0 L / min; ⑥ Screening and drying: Vacuum drying at 80 - 120 °C for 2 - 4 h under argon protection, and the oxygen content ≤ 0.05%.

[0021] In this embodiment, electrolytic iron and fine - particle - sized reduced iron powder are used as the matrix, and are put into a vacuum induction melting furnace in proportion with strengthening alloys such as ferrochromium, ferromolybdenum, ferrovanadium, and ferrotungsten, and heated to melting under argon protection; through high - temperature melting and electromagnetic stirring in this process, the atoms of each element are fully diffused to form a uniform alloy melt, laying a foundation for subsequent performance regulation; In the later stage of melting, by adding aluminum pellets as a deoxidizer and reacting for 8 - 15 minutes at a stirring rate of 80 - 120 rpm, the oxygen content of the melt is reduced to ≤ 0.08%; the Al 2 O 3 inclusions generated by the deoxidation reaction are removed by flotation, significantly improving the purity of the alloy, reducing the crack sources in subsequent processing, and optimizing the mechanical properties; Carbon nanotube pretreatment: Carbon nanotubes and silane coupling agent KH550 are dissolved in an ethanol-water mixture at a mass ratio of 100:1 and hydrolyzed at 50 °C for 1 hour; the silanol groups generated by the hydrolysis of KH550 react with the hydroxyl groups on the surface of the carbon nanotubes to form covalent bond grafting, endowing it with surface activity; Ultrasonic atomization spraying coating: The modified liquid is evenly coated on the carbon nanotubes with a spraying amount of 0.5-2.0 wt%, and the organic-inorganic composite coating is cured by gradient heating; this process enhances the interfacial bonding force between the carbon nanotubes and the matrix, prevents agglomeration, and ensures its uniform dispersion in the alloy; The alloy melt after deoxidation and refining is atomized into powder by gas atomization technology at a superheat temperature of 150-250 °C. High-pressure inert gas is used to break the melt into droplets, and then the particle size of the powder is controlled to D50≤45 μm by magnetic field classification technology; this step realizes the refinement and spheroidization of the powder, improves its fluidity and spreading property, and meets the strict requirements of additive manufacturing for powder properties; The atomized powder is spheroidized in a plasma flame at 1000-1100 °C for 30-60 minutes, and the argon flow rate is 0.5-1.0 L / min; the high temperature of the plasma melts the surface of the powder, and smooth spherical particles are formed under the action of surface tension. At the same time, internal pores are eliminated, and the packing density and density are increased; The spheroidized powder is dried at a low temperature of 80-120 °C for 2-4 hours in a vacuum environment, and is protected by argon throughout the process to ensure that the oxygen content ≤0.05%; this step completely removes moisture and residual gases, prevents oxidation or performance deterioration of the material during storage or use, and ensures the long-term stability of the powder.

[0022] In a further preferred embodiment of the present invention, as Figure 1 shown, the two-stage heating program includes: ① Demoulding agent decomposition stage: Keep warm at 1000-1100 °C for 10 min; ② Alloy melting stage: Gradually heat up to 1550-1650 °C at a heating rate of 10 °C / min.

[0023] In this embodiment, in the initial heating stage, the system temperature is stably controlled within a narrow range of 1000-1100 °C and maintained for 10 minutes; this temperature range is designed according to the thermal decomposition characteristics of the demoulding agent, and its molecular chain is broken by high temperature to release volatile gases; the heat preservation process ensures the complete decomposition of the demoulding agent, avoids the formation of pores or inclusions by residues in subsequent processing, and prevents oxidation or volatilization of the alloy raw materials due to too high temperature; this stage provides a clean and impurity-free reaction environment for alloy melting; After the release agent is decomposed, the temperature is increased stepwise at a stable rate of 10 °C / min to 1550 - 1650 °C; this heating rate avoids local overheating of the alloy raw materials or melt splashing by slowly increasing the heat input, while promoting uniform diffusion and chemical reactions between elements; within the target temperature range, the alloy completely melts and forms a uniform liquid melt, ensuring the consistency of material properties in subsequent processing; the stepwise heating design also takes into account the control of equipment thermal stress to prevent structural damage caused by rapid heating.

[0024] In a further preferred embodiment of the present invention, as Figure 1 shown, the concentration of the alkane coupling agent KH550 ethanol solution is 0.5 - 2.0 wt%, the ultrasonic dispersion power is 200 - 400 W, and the time is 30 min.

[0025] In this embodiment, KH550 is dissolved in ethanol at a mass concentration of 0.5 - 2.0 wt% to form a solution with low viscosity and high dispersibility; this concentration range ensures its sufficient dissolution while maintaining sufficient hydrolysis activity in subsequent processing by balancing the solubility and reactivity of KH550; a high concentration can increase the number of KH550 molecules per unit volume, but dispersion processes need to be combined to avoid agglomeration; a low concentration reduces the processing cost, but the reaction time needs to be extended to ensure the grafting effect; The prepared KH550 ethanol solution is placed in an ultrasonic device and ultrasonically dispersed at a power of 200 - 400 W for 30 minutes; the ultrasonic action generates micron-sized bubbles in the solution through the cavitation effect, and the energy released by the bubble rupture destroys the van der Waals forces between KH550 molecules, while promoting its molecular-level mixing with the ethanol solvent; a high power can accelerate molecular movement, but overheating leading to ethanol volatilization needs to be avoided; a low power extends the processing time to compensate for the energy input; this process ensures that KH550 exists stably in the solution in the form of single molecules or oligomers, providing active sites for subsequent reactions.

[0026] In a further preferred embodiment of the present invention, as Figure 1 shown, the particle size D50 of the powder after spheroidization is ≤45 μm.

[0027] In this embodiment, the particle size distribution of the powder after spheroidization is controlled to ≤45 μm through magnetic field classification or screening technology. Magnetic field classification separates particles based on their different movements in a magnetic field, and screening ensures product consistency by physically restricting large particles from passing through the aperture.

[0028] In a further preferred embodiment of the present invention, as Figure 1 shown, argon is continuously introduced during the drying process, and the flow rate is 0.1 - 0.3 L / min.

[0029] In this embodiment, during the drying stage, argon gas with a flow rate of 0.1 - 0.3 L / min is continuously introduced to form an inert gas layer covering the powder surface. As a chemically inert gas, argon does not react with the powder, effectively isolating oxygen and moisture in the air, inhibiting oxidation and moisture absorption reactions at the source, and ensuring the chemical stability of the powder. The argon gas continuously flows at a low flow rate, breaking the gas stratification phenomenon in the drying chamber and preventing local enrichment of oxygen or moisture. Through molecular diffusion, the dynamically flowing argon gas accelerates the desorption of adsorbed moisture on the powder surface and carries volatile substances out of the system, improving the drying efficiency and uniformity.

[0030] In a further preferred embodiment of the present invention, as Figure 1 shown, the high-temperature sintering gradient after carbon nanotube coating is as follows: Pre-sintering: Argon protection at 300°C for 1 h. Main sintering: Argon protection at 500°C for 1 h, with a gradient heating rate of 5°C / min.

[0031] In this embodiment, the gradient treatment process of the carbon nanotube-coated material during high-temperature sintering follows the following coherent working principle: First, a pre-sintering stage is carried out, continuously heating at 300°C for 1 hour with argon as a protective atmosphere to promote the initial densification of the material structure through low-temperature pretreatment while avoiding oxidation reactions. Subsequently, it enters the main sintering stage, raising the temperature to 500°C at a gradient heating rate of 5°C / min and maintaining the argon protection environment to continue sintering for 1 hour. In this stage, through precise temperature control, uniform growth of grains inside the material and strengthening of interface bonding are achieved, ultimately obtaining a composite structure with gradient properties.

[0032] In a further preferred embodiment of the present invention, as Figure 1 shown, in step ①, the vacuum degree of the vacuum induction melting furnace ≤ 5 Pa, and the melting temperature is controlled in two stages: ① The first stage: Keep the temperature at 1400 - 1450°C for 20 - 30 min to completely melt chromium, molybdenum, vanadium, and ferrotungsten. ② The second stage: Gradually raise the temperature to 1580 - 1620°C and keep it for 15 - 25 min to form a homogeneous melt.

[0033] In this embodiment, the vacuum degree in the furnace is controlled to an extremely low level of ≤5 Pa to completely eliminate air interference and prevent oxidation of alloy elements. Subsequently, precise melting is achieved through two-stage temperature control: in the first stage, it is maintained at a temperature range of 1400 - 1450 °C for 20 - 30 minutes to ensure that high-melting-point alloy elements such as chromium, molybdenum, vanadium, and ferrotungsten are completely melted and form a preliminary liquid mixture; in the second stage, the temperature is raised to the refining range of 1580 - 1620 °C in a gradient heating manner and kept warm for 15 - 25 minutes. Through the action of high-temperature diffusion, the full diffusion and homogenization of each element are promoted, and finally a melt with homogeneous composition and dense structure is formed, providing a high-quality raw material basis for subsequent casting or forming processes.

[0034] It should be noted that for the foregoing embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps may be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0035] In several embodiments provided by the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the above division of units can have other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the shown or discussed coupling or communication connection between each other can be through some interfaces, and the indirect coupling or communication connection between devices or units can be in the form of telecommunications or other forms.

[0036] The units described as separate components above may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still, without conflict and without creative efforts, combine, add or delete the features in the embodiments of the present invention according to the circumstances or make other adjustments, so as to obtain different technical solutions that essentially do not deviate from the concept of the present invention, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A high-strength wear-resistant alloy powder for additive manufacturing, characterized in that: Included by mass percentage: Matrix composition: A mixed matrix of electrolytic iron and reduced iron powder, with the purity of electrolytic iron ≥ 99.9% and the D50 of reduced iron powder ≤ 45μm, and the total amount of the two added accounts for the remainder of the alloy mass; Wear-resistant phase strengthening elements: Chromium: 2.0%-4.0%; Molybdenum: 0.8%-2.0%; Vanadium: 0.3%-1.5%; Tungsten: 1.0%-3.0%; Ductile phase elements: Nickel 0.3%-3.0%; Cobalt 0.5%-2.5%; Deoxidizer: Aluminum: 0.2%-1%; Functional modifiers: Yttrium oxide: 0.05%-0.3%; Carbon nanotubes: 0.5%-2.0%, and the surface of the carbon nanotubes is modified by silane coupling agent KH550.

2. A method for preparing high-strength wear-resistant alloy powder for additive manufacturing, characterized in that: The following steps are involved: ① Melting and alloying: put the electrolytic iron, reduced iron powder, ferrochrome, ferromolybdenum, ferrovanadium and ferrotungsten into a vacuum induction melting furnace and heat under argon protection; ② Deoxidation refining: Add aluminum particles in the later stage of smelting, stir at 80-120rpm, react for 8-15min, oxygen content ≤0.08%; ③ Functional modification: Pretreatment of carbon nanotubes: Dissolved in ethanol-water with KH550 at a ratio of 100:1, volume ratio 3:1, hydrolyzed at 50°C for 1 h; Ultrasonic atomization spray coating: The spray amount of the modified liquid is 0.5-2.0wt%, and the temperature rises gradually after the carbon nanotubes are coated; ④ Atomization molding: alloy melt superheat 150-250℃, gas atomization powder making and magnetic field classification, D50≤45μm; ⑤ Plasma spheroidization: spheroidization temperature 1000-1100℃, time 30-60min, argon flow rate 0.5-1.0L / min; ⑥Screening and drying: vacuum drying, 80-120℃, 2-4h, argon protection, oxygen content ≤0.05%.

3. The method for preparing a high-strength wear-resistant alloy powder for additive manufacturing according to claim 2, characterized in that: The two-stage heating program includes: ① Release agent decomposition stage: 1000-1100℃ insulation for 10min; ② Alloy melting stage: step-by-step heating to 1550-1650℃, heating rate 10℃ / min.

4. The method for preparing high-strength wear-resistant alloy powder for additive manufacturing according to claim 3, characterized in that: The concentration of the alkane coupling agent KH550 ethanol solution is 0.5-2.0wt%, the ultrasonic dispersion power is 200-400W, and the time is 30min.

5. The method for preparing high-strength wear-resistant alloy powder for additive manufacturing according to claim 2, characterized in that: The particle size of the powder after spheroidization is D50≤45μm.

6. A method for preparing a high-strength wear-resistant alloy powder for additive manufacturing according to claim 2 The method is characterized in that During the drying process, argon gas was continuously introduced at a flow rate of 0.1-0.3 L / min.

7. The method for preparing high-strength wear-resistant alloy powder for additive manufacturing according to claim 2, characterized in that: The high temperature sintering gradient after carbon nanotube coating is: Pre-sintering: 300℃ argon protection for 1h; Main sintering: 500℃ under argon protection for 1h, gradient heating rate 5℃ / min.

8. The method for preparing high-strength wear-resistant alloy powder for additive manufacturing according to claim 2, characterized in that: In step ①, the vacuum degree of the vacuum induction melting furnace is ≤5Pa, and the melting temperature is controlled in two stages: ① The first stage: keep the temperature at 1400-1450℃ for 20-30min to completely melt chromium, molybdenum, vanadium and tungsten iron; ②The second stage: Gradient temperature rise to 1580-1620℃, keep warm for 15-25min to form a homogeneous melt.

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