Additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compound, preparation method of additive manufacturing alloy powder and printed part

Abstract

The embodiment of the invention provides additive manufacturing alloy powder based on a nickel-cobalt-based intermetallic compound, a preparation method of the additive manufacturing alloy powder and a printed piece, the additive manufacturing alloy powder based on the nickel-cobalt-based intermetallic compound comprises metal powder and boron carbide attached to the surface of the metal powder, and the metal powder comprises the following components of 35%-50% of nickel, 10%-30% of boron carbide, 10%-30% of nickel, 10%-30% of cobalt, and the balance of nickel. 10%-30% of cobalt; 2%-15% of iron; 5%-18% of aluminum; 3%-12% of titanium; wherein the boron carbide accounts for 0.1%-1% of the total mass of the metal powder. According to the additive manufacturing alloy powder based on the nickel-cobalt-based intermetallic compound, the preparation method of the additive manufacturing alloy powder based on the nickel-cobalt-based intermetallic compound and the printed piece, the boron carbide particles are added, so that grains are refined, strain caused by thermal stress acts on more grain boundaries, and therefore the local strain level is reduced, and formation of cracks is restrained.

Description

Technical Field

[0001] This application belongs to the field of additive manufacturing technology, and in particular relates to an additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds, its preparation method, and printed parts. Background Technology

[0002] Additive manufacturing, also known as 3D printing, is a bottom-up manufacturing technology that uses computer-aided 3D modeling software to output a model, melts material using an external heat source, and then deposits it layer by layer to directly form parts. It offers advantages such as rapid freeform forming, suitability for processing complex parts, simple processes, short production cycles, and high efficiency. Nickel-cobalt based intermetallic compounds are commonly used intermetallic compounds with excellent high-temperature strength, oxidation resistance, and corrosion resistance, finding wide application in aerospace, shipbuilding, nuclear reactors, and petrochemical equipment.

[0003] Additive manufacturing of nickel-cobalt-based intermetallic compounds has attracted widespread interest from academia and industry due to its unique ability to fabricate complex, high-performance components for high-end industrial systems. However, the intense temperature gradients caused by the rapid heating and cooling processes in additive manufacturing generate high levels of residual stress and metastable chemical and structural states, inevitably leading to severe metallurgical defects in nickel-cobalt-based intermetallic compounds. Among these, cracks pose the greatest threat to the integrity of these materials because they propagate rapidly, resulting in sudden and unpredictable failures.

[0004] Therefore, there is an urgent need to find a technical solution that can effectively suppress cracks in the laser additive manufacturing process of nickel-cobalt based intermetallic compound alloys. Summary of the Invention

[0005] In view of this, embodiments of this application provide an additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds, a method for preparing the same, and printed parts, to solve the technical problem of cracking in existing nickel-cobalt-based intermetallic compounds.

[0006] In a first aspect, embodiments of this application provide an additive manufacturing alloy powder based on a nickel-cobalt-based intermetallic compound, the alloy powder comprising metal powder and boron carbide adhered to the surface of the metal powder, wherein the metal powder has the following components:

[0007] Nickel content: 35%–50%;

[0008] Cobalt 10%–30%;

[0009] Iron 2%–15%;

[0010] Aluminum 5%–18%;

[0011] Titanium 3%–12%;

[0012] The boron carbide comprises 0.1% to 1% of the total mass of the metal powder.

[0013] In some embodiments, the metal powder comprises the following components: 45% nickel, 22.5% cobalt, 12% iron, 11% aluminum, and 9.5% titanium; the boron carbide accounts for 0.25% of the metal powder.

[0014] In some embodiments, the boron carbide particle size is 2 μm to 3 μm.

[0015] In some embodiments, the metal powder further includes at least one of niobium, tantalum, vanadium, chromium, molybdenum, and tungsten.

[0016] Secondly, embodiments of this application provide a method for preparing additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds, comprising:

[0017] It provides 35%–50% nickel, 10%–30% cobalt, 2%–15% iron, 9%–12% aluminum, and 5%–12% titanium as metal raw materials;

[0018] The above-mentioned metal raw materials are mixed and then pre-alloyed to obtain alloy ingots;

[0019] The alloy ingot is made into metal powder;

[0020] Boron carbide, comprising 0.1% to 1% of the mass of the metal powder, is added to the metal powder and mixed to obtain the alloy powder.

[0021] In some embodiments, after the pre-alloy is formed into a metal powder, and before adding 0.1% to 1% boron carbide by weight of the metal powder to the metal powder, the following steps are included:

[0022] The metal powder was screened, and metal powder with a particle size range of 15 μm to 53 μm was selected.

[0023] In some embodiments, screening the metal powder includes:

[0024] Fine powder was obtained by multiple sieving using a 270-mesh standard sieve.

[0025] The metal powder was obtained by multiple sieving processes using a 15μm precision sieve.

[0026] In some embodiments, the step of forming the alloy ingot into metal powder includes:

[0027] Devices for atomizing the alloy ingots, such as vacuum atomization devices;

[0028] The process is carried out in an argon atmosphere, maintaining a gas pressure of 4–10 MPa, and using high-speed atomization spraying to produce metal powder.

[0029] Thirdly, embodiments of this application provide a printed part obtained by 3D printing using the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds described in the first aspect or the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds obtained by the preparation method described in the second aspect.

[0030] In some embodiments, the printing method of the printed material includes:

[0031] Model the printed part;

[0032] Set the printing parameters of the 3D printing equipment to the preset values;

[0033] Start the printing equipment to print. After printing, remove the part for wire cutting and surface treatment to finally form the required printed part.

[0034] The additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds, its preparation method, and the printed parts provided in this application effectively suppress cracking in the final printed parts by adding boron carbide. This is because the addition of boron carbide particles refines the grains, causing the strain caused by thermal stress to act on more grain boundaries, thereby reducing the local strain level and suppressing crack formation. After grain refinement, the number of grain boundaries increases, and the length of the liquid channels at the grain boundaries shortens. According to the Hagen-Poiseuille law, due to the flow resistance caused by liquid viscosity, the volume of liquid through the channel increases as the channel length decreases. Therefore, the liquid feeding capacity of the composite material at the grain boundaries becomes stronger, allowing the solidified liquid material to be replenished, thereby reducing cracking. Attached Figure Description

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

[0036] Figure 1 This is a schematic flowchart of the method for preparing additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0037] Figure 2 This is a scanning electron microscope image of an additively manufactured alloy powder based on nickel-cobalt-based intermetallic compounds provided in the comparative example of this application;

[0038] Figure 3This is a scanning electron microscope (SEM) image of an additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in an embodiment of this application.

[0039] Figure 4 This is an energy dispersive spectroscopy (EDS) analysis diagram of nickel in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0040] Figure 5 This is an energy dispersive spectroscopy (EDS) analysis diagram of cobalt in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0041] Figure 6 This is an energy dispersive spectroscopy (EDS) analysis diagram of iron in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0042] Figure 7 This is an energy dispersive spectroscopy (EDS) analysis diagram of aluminum in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0043] Figure 8 This is an energy dispersive spectroscopy (EDS) analysis diagram of titanium in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0044] Figure 9 This is an energy dispersive spectroscopy (EDS) analysis diagram of carbon in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0045] Figure 10 This is an energy dispersive spectroscopy (EDS) analysis diagram of boron in additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds provided in the embodiments of this application;

[0046] Figure 11 This is an optical microscope image of the printed copy provided in the comparative example of this application;

[0047] Figure 12 This is an optical microscope image of the printed document provided in the embodiments of this application;

[0048] Figure 13 This is an electron backscatter diffraction pattern of the printed part provided in the comparative example of this application;

[0049] Figure 14 This is an electron backscatter diffraction pattern of the printed part provided in the embodiments of this application;

[0050] Figure 15 These are electron microscope scans of the printed parts provided in the embodiments of this application at magnifications of 100x, 500x, 1000x, and 2000x.

[0051] Figure 16 This is a stress-strain curve diagram of the printed parts provided in the embodiments and comparative examples of this application. Detailed Implementation

[0052] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the embodiments of this application with unnecessary detail.

[0053] It should also be understood that the term "and / or" as used in the specification of embodiments of this application and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0054] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0055] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0056] Furthermore, in the description of the embodiments and the appended claims of this application, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0057] In the description of embodiments in this application, references to "some embodiments" or "some embodiments" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in some embodiments," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiments, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" refers to two or more.

[0058] It should be noted that the English words appearing below correspond to the Chinese meanings as follows:

[0059] Ni - Nickel; Co - Cobalt; Fe - Iron; Al - Aluminum; Ti - Titanium; B4C - Boron Carbide; Nb - Niobium; Ta - Tantalum; V - Vanadium; Cr - Chromium; Mo - Molybdenum; W - Tungsten.

[0060] The first aspect of this application provides an additive manufacturing alloy powder based on a nickel-cobalt-based intermetallic compound. The alloy powder includes metal powder and boron carbide attached to the surface of the metal powder. The metal powder includes the following components: 35%–50% nickel, 10%–40% cobalt, 2%–15% iron, 5%–18% aluminum, and 3%–12% titanium; wherein boron carbide accounts for 0.1%–1% of the total mass of the metal powder.

[0061] Hot cracking, primarily solidification cracking and liquefaction cracking, is easily generated when high-strength nickel-based alloys (especially those with high Al and Ti content) are subjected to fusion welding, laser cladding, electron beam welding, or additive manufacturing. To address the issue of cracking in nickel-cobalt-based intermetallic compounds during additive manufacturing, which affects product performance, this application proposes adding boron carbide to suppress cracking and improve performance.

[0062] Specifically, the method for improving additive manufacturing performance of nickel-cobalt-based intermetallic compound-based additive manufacturing alloy powder by adding boron carbide, as provided in this application embodiment, has the following mechanism: boron carbide particles can act as nuclei for heterogeneous formation during the solidification process of the molten pool. This promotes the formation of more crystal nuclei, resulting in significant grain refinement. Fine equiaxed grains have more grain boundaries than coarse columnar grains. When the liquid phase is separated and isolated by grain boundaries in the later stage of solidification, the fine grain structure can provide more and more tortuous grain boundary channels, which is beneficial to the flow and feeding of residual liquid phase, reducing the concentration of solidification shrinkage stress caused by insufficient liquid phase, thereby reducing the susceptibility to solidification cracking. At the same time, fine grains themselves have higher strength and are more resistant to cracking.

[0063] In applications, boron forms a low-melting-point boride eutectic phase with nickel in the alloy at the grain boundaries. These low-melting-point eutectic phases remain liquid after the main alloy solidifies (at even lower temperatures). They wet the grain boundaries and fill the tiny voids and crack initiation points caused by solidification shrinkage at the grain boundaries through capillary action, acting as a "healing" or "bridging" agent, effectively releasing solidification shrinkage stress and preventing crack propagation. This is the most classic and important mechanism by which boron reduces hot cracking. Boron atoms segregate to the grain boundaries, which can alter the chemical composition and structure of the grain boundaries. Boron may combine with harmful impurity elements at the grain boundaries (such as S, P, O, etc., which severely weaken the grain boundaries and promote hot cracking) to form high-melting-point compounds or change their distribution, reducing their harmful effects at the grain boundaries.

[0064] In a preferred embodiment, the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds comprises the following components: 45% nickel, 22.5% cobalt, 12% iron, 11% aluminum, and 9.5% titanium, with boron carbide accounting for 0.25% of the metal powder. Controlling the total amount of aluminum and titanium at 20.5% strikes a perfect balance between ultra-high strength and machinability. Referring to the IN718 alloy, the γ' phase volume fraction is approximately 19%, while this formulation, through the combination of 11% aluminum and 9.5% titanium, combined with 0.3% boron carbide for grain boundary control, is expected to achieve a γ' phase content of over 65%, avoiding welding cracking issues. The iron content of 12% is also carefully considered, utilizing inexpensive iron to reduce costs while ensuring it does not exceed the solid solution limit of the nickel matrix, thus avoiding the formation of a brittle σ phase. The addition of 0.25% boron carbide allows boron atoms to primarily function as grain boundary modifiers (forming nickel-boron eutectic healed cracks), while the introduced carbon combines with titanium to form titanium-carbon dispersed strengthening particles. This "one-dose-two-effect" design is more economical and efficient than adding boron or carbon alone.

[0065] In other embodiments, nickel can also be any value within the range of 35% to 50% of the total metal powder mass, such as 35%, 40%, 43%, 43.5%, 44%, 44.5%, 45%, 46%, 47%, and 50%. Nickel, as a matrix element, constitutes the austenitic matrix (face-centered cubic structure) of the alloy, providing the entire alloy powder with excellent high-temperature strength, toughness, ductility, oxidation resistance, and corrosion resistance. Nickel is the core element for forming and stabilizing the γ matrix. Nickel reacts with aluminum and titanium to form the main reinforcing phase γ'-Ni3(Al,Ti). Cobalt can also be any value within the range of 10% to 30% of the total metal powder mass, such as 10%, 12%, 15%, 16%, 18%, 19%, 20%, 21%, 22.5%, 23%, 24%, 25%, 28%, and 30%. Cobalt atoms dissolve in the nickel matrix, causing lattice distortion and increasing the matrix's strength (especially high-temperature strength) and hardness. Cobalt can raise the dissolution temperature of the γ' strengthening phase into the matrix, thereby improving the alloy's high-temperature stability (resistance to over-aging) and upper service temperature limit. It also helps form a finer dislocation structure during high-temperature deformation, improving high-temperature creep strength. Iron can be any value within the range of 2% to 15% by mass of the metal powder, such as 2%, 4%, 5%, 8%, 11%, 11.2%, 11.4%, 11.5%, 11.7%, 11.8%, 12%, 13%, 14%, and 15%. Iron is a relatively inexpensive element, partially replacing expensive Ni and Co, reducing alloy costs. Iron atoms dissolve in the matrix, providing a certain degree of solid solution strengthening. Aluminum can also be any value within the range of 5% to 18% by mass, such as 5%, 6%, 7%, 8%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 13%, 14%, 15%, 16%, 17%, and 18%. Al is the most critical element for forming the γ'-Ni3Al strengthening phase. A high Al content means that the alloy aims to form a high volume fraction of the γ' phase, which is the primary strengthening mechanism, giving the alloy extremely high strength and hardness. Aluminum preferentially oxidizes at high temperatures, forming a dense, well-adhesive Al2O3 protective film, which is key to the alloy's excellent high-temperature oxidation resistance. Titanium can also be any value within the range of 3% to 12% by mass of the metal powder, such as 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 9.5%, 10%, 11%, and 12%. Titanium can replace some Al atoms in γ'-Ni3Al to form the γ'-Ni3(Al,Ti) phase. It also participates in strengthening. The addition of Ti can further increase the volume fraction and strength of the γ' phase (because Ti has a lower solid solubility in Ni than Al, and is more inclined to form γ'). Ti readily combines with C and N to form hard particles such as TiC and TiN, providing additional dispersion strengthening (a secondary role) and potentially refining the grain size.Al and Ti together determine the quantity, size, distribution, and stability of the γ' phase.

[0066] In some embodiments, boron carbide can also be any value within the range of 0.1% to 1% of the metal powder's mass percentage, such as 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. Excessive boron leads to the formation of a large number of continuous, brittle boride networks distributed at the grain boundaries, severely deteriorating toughness and plasticity, increasing the risk of cold cracking, and potentially promoting the precipitation of harmful phases. The addition of B4C also introduces carbon, and excessive carbon may also form coarse carbides, which are detrimental to performance. Adding a small amount of boron carbide (B4C) is mainly to introduce boron, promote grain refinement, reduce solidification shrinkage stress concentration, form low-melting-point boron eutectic at grain boundaries, and purify and strengthen the grain boundaries.

[0067] In some embodiments, the boron carbide particle size is 2 μm to 3 μm. The size of boron carbide is close to the dendrite arm spacing in a typical molten pool, effectively serving as a heterogeneous nucleation site; it is smaller than the critical agglomeration size, avoiding agglomeration due to van der Waals forces; and it is larger than the diffusion distance of boron atoms, ensuring continuous release of boron. Small-sized boron carbide (<2 μm) may completely dissolve and lose its nucleation function, while large-sized particles (>3 μm) can lead to stress concentration caused by unmelted particles. 2-3 μm retains some unmelted nuclei while allowing surface dissolution to provide a boron source.

[0068] In some embodiments, the metal powder further includes at least one of niobium, tantalum, vanadium, chromium, molybdenum, and tungsten. Further, Nb accounts for 0-10%, Ta 0-10%, V 0-10%, Cr 0-20%, Mo 0-5%, and W 0-5%. In specific embodiments, Nb accounts for any value within the range of 0-10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. It replaces Ti / Al in γ'-Ni3(Al,Ti,Nb), improving the thermal stability of the γ' phase and generating fine MC-type NbC (pinned grain boundaries). Ta accounts for any value within the range of 0-10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. Ta has extremely high solubility in the γ' phase, significantly improving high-temperature strength / creep resistance; it forms a composite oxide film of Ta2O5 and Al2O3. V comprises any value within the range of 0% to 10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. V atoms distort the crystal lattice, increasing strength while simultaneously lowering the liquidus temperature, refining the solidification structure, and reducing anisotropy; the formation of VC inhibits Cr... 23C6 is a brittle phase. Cr comprises any value within the range of 0-20%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, and 20%. It forms a dense Cr2O3 film (better than Al2O3 at <800℃), moderately improving room temperature strength. Mo comprises any value within the range of 0-5%, such as 1%, 2%, 3%, 4%, and 5%. It has large differences in atomic radius, severely distorting the crystal lattice to improve strength / creep resistance; it also inhibits grain boundary segregation. W comprises any value within the range of 0-5%, such as 1%, 2%, 3%, 4%, and 5%. Its effect is comparable to Mo but it is more resistant to oxidation (lower atomic diffusion rate); it stabilizes carbides; the formation of W2C delays carbide coarsening; it increases γ / γ' mismatch, enhancing the coherent strengthening effect.

[0069] This application also provides a method for preparing additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds, such as... Figure 1 As shown, it includes:

[0070] S10 provides 43%–47% nickel, 15%–24% cobalt, 11%–13% iron, 9%–12% aluminum, and 5%–12% titanium as metal raw materials;

[0071] S20. After mixing the above metal raw materials, a pre-alloying treatment is carried out to obtain an alloy ingot;

[0072] S30. The alloy ingot is made into metal powder;

[0073] S40. Add 0.1% to 0.5% (by weight of the metal powder) of boron carbide to the metal powder and mix to obtain alloy powder. This method, through the separation of highly reactive elements and the precise introduction of composite strengthening phases, provides a mass production-scale solution for the additive manufacturing of high-crack-susceptibility superalloys.

[0074] In step S10, the content ranges of the above-mentioned metal components have already been discussed in detail in the first aspect and will not be repeated here. It should be noted that ultrasonic cleaning instruments are used to clean various metal raw materials to remove impurities, which facilitates the subsequent formation of alloy powder.

[0075] In step S20, the above metal raw materials are mixed and then pre-alloyed to obtain an alloy ingot. This includes melting the metal raw materials from step S10 in an induction furnace to form the alloy ingot. In a specific embodiment, melting is carried out at 1550°C to completely dissolve the high-melting-point intermetallic compounds; then, electromagnetic stirring is used to eliminate gravity segregation; finally, argon refining is used to reduce the oxygen content to ≤80ppm to prevent Al / Ti oxidation and burn-off.

[0076] In step S30, the alloy ingot is made into metal powder, including:

[0077] S31. Add the alloy ingot to the vacuum atomization equipment;

[0078] S32. The process is carried out in an argon atmosphere, maintaining a gas pressure of 4–10 MPa, and using high-speed gas atomization spraying to produce powder. In one specific embodiment, electrode-induction gas atomization is preferred, using a tightly coupled nozzle, with an atomization pressure of 4–6 MPa, a superheat ΔT ≥ 250°C to avoid generating excessive satellite spheres, and a condensation rate of 10. 5 -10 6 K / s, thereby suppressing the in-situ precipitation of the γ' phase.

[0079] After step S30 and before step S40, the metal powder is further screened to select metal powder with a particle size range of 15 μm to 53 μm. The following considerations are taken into account when selecting metal powder within this particle size range:

[0080] First, 15μm is the lower limit for avoiding powder bridging (van der Waals forces dominate when the particle size is less than 15μm), while 53μm corresponds to a process window of 30-60μm single-layer powder thickness (the powder layer thickness needs to be greater than 1.5 times the maximum particle size of the powder). Data shows that powders larger than 53μm are prone to trajectory streaks under the action of a powder spreading tool. Second, there is the special nature of the melt pool dynamics. The melting time difference between 15-53μm powders under a 200W laser is only 0.2ms, which ensures the stability of the melt pool. However, in a user case, the use of 80μm powder resulted in a surge in incomplete fusion defects due to melting delay. Third, the coverage of 1-2μm B4C particles on the surface of 15μm metal powder is about 8.2%, which drops to 2.1% for 53μm powder—which exactly matches the theoretical coverage rate corresponding to an addition of 0.1-0.5%. Particle size that is too small will lead to excessive B4C coverage and cause brittleness. Fourthly, there are economic factors. In atomized powders, the 15-53μm particle size typically accounts for 65%, and screening can improve raw material utilization. Increasing the proportion of this particle size range from 50% to 80% can reduce the cost per kilogram of powder by 34%. It should be noted that fine powders below 15μm are easily oxidized during recycling (due to their large specific surface area), while coarse powders above 53μm can lead to poor interlayer bonding. Screening is essentially a quality control method.

[0081] In some embodiments, screening metal powder includes:

[0082] Fine powder was obtained by multiple sieving using a 270-mesh standard sieve.

[0083] Metal powder is obtained by multiple sieving processes using a 15μm precision sieve. Specifically, the sieving is performed three times to ensure thorough separation. A 270-mesh sieve (approximately 53μm) serves as the first stage of screening and is highly efficient, while the 15μm precision sieve is used in conjunction to accurately control the lower limit. The key lies in the "multiple sieving" operation—it's not simply passing the powder through a sieve once, but rather achieving high-precision classification through cyclic sieving. In application, an airflow-assisted sieving design can also be used, which effectively solves the problem of fine powder clogging the mesh.

[0084] In step S40, boron carbide is mixed with metal powder, and 1-2 μm B4C is embedded in the pits on the surface of the matrix powder to form a "pinning effect". In situ reaction, Ti + B4C → TiB2 + TiC forms a nano-reinforcing phase.

[0085] It is important to note that the B4C powder needs to be very uniformly dispersed in the metal powder to ensure consistent performance and avoid localized boron enrichment. In applications, mechanical alloying can be used to uniformly disperse the boron carbide powder in the metal powder particles, i.e., directly mixing the boron carbide and metal powder and then processing them in a high-energy ball mill. In other embodiments, dispersion can also be achieved using three-dimensional motion mixing combined with surface activation, specifically including premixing (metal powder + 0.1% zinc stearate, 20 min), gradient addition (B4C added in three batches, 10 min apart); three-dimensional rotation (revolution 30 rpm + rotation 10 rpm, 120 min); and nitrogen purging (to remove adsorbed oxygen). Furthermore, fluidized bed vapor deposition, solvent dispersion combined with spray drying can also be used for dispersion. In one specific embodiment, boron carbide and metal powder are added to a mixer, maintained at a speed of 60 rpm, and mixed for 12 h to obtain a uniformly dispersed alloy powder.

[0086] This application also provides a printed part, which is obtained by 3D printing using the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds as described in the first aspect or the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds prepared by the preparation method described in the second aspect.

[0087] The printed parts provided in this application embodiment have improved performance by adding boron carbide to suppress cracking during additive manufacturing.

[0088] In some embodiments, the printing method for the printed material includes:

[0089] Model the printed part;

[0090] Set the printing parameters of the 3D printing equipment to the preset values;

[0091] The printing equipment is started for printing. After printing, the part is removed for wire cutting and surface treatment, ultimately forming the desired printed part. This process ensures that the printed part meets the required specifications and has excellent overall performance, effectively reducing the occurrence of cracks.

[0092] In one specific embodiment, the printing method includes:

[0093] Model the components that need to be printed, slice them using slicing software, and import the sliced ​​files into the SLM device;

[0094] Set the substrate preheating temperature: 100-200℃; Set the part scanning parameters: laser power 225-250mA, scanning rate 1200-1500mm / s, scanning spacing 0.09mm, printing layer thickness 0.04mm; Set the part scanning strategy.

[0095] 10 kg of alloy powder was loaded into the hopper of the SLM (Selective Laser Melting) equipment. The substrate was leveled, and argon gas was filled into the forming chamber until the oxygen content was less than 0.01%.

[0096] The printing equipment is started. The SLM equipment stacks materials in a cycle, with the worktable descending by one layer thickness, the doctor blade spreading powder, the substrate preheating, the parts scanning, and the selected area scanning, until the desired printed part is formed.

[0097] After printing, the parts are removed for wire cutting and surface treatment to finally form the desired printed parts.

[0098] Example

[0099] Example 1

[0100] This application provides an additive manufacturing alloy powder based on a nickel-cobalt-based intermetallic compound and a method for preparing the same, wherein the preparation method includes:

[0101] We provide 4.5 kg of nickel, 2.25 kg of cobalt, 1.2 kg of iron, 1.1 kg of aluminum, and 0.95 kg of titanium as metal raw materials, and use an ultrasonic cleaning instrument to clean the various metal raw materials.

[0102] The above metal raw materials are mixed and pre-alloyed to obtain alloy ingots; specifically, this includes melting them in an induction furnace to obtain qualified alloy ingots.

[0103] The alloy ingot is made into metal powder; the alloy ingot is injected into a vacuum atomization device and the metal powder is produced by high-speed spraying through air atomization; a standard vibrating powder sieve is used to sieve the fine powder three times using a 270-mesh standard sieve, and then the coarse powder is obtained by sieving the fine powder three times using a 15-micron precision sieve.

[0104] Add 30g of boron carbide to the metal powder, mix to obtain alloy powder, and obtain the sample.

[0105] Comparative Example

[0106] Comparative Example 1

[0107] Comparative Example 1 is basically the same as Example 1, except that boron carbide was not added.

[0108] Application examples

[0109] The alloy powder obtained in Example 1 was used for additive manufacturing to obtain printed parts. Specifically, this included:

[0110] Model the components that need to be printed, slice them using slicing software, and import the sliced ​​files into the SLM device;

[0111] Set the substrate preheating temperature: 200℃; Set the part scanning parameters: laser power 250mA, scanning rate 1500mm / s, scanning spacing 0.09mm, printing layer thickness 0.04mm; Set the part scanning strategy.

[0112] 10 kg of alloy powder was loaded into the SLM equipment hopper, the substrate was leveled, and argon gas was filled into the forming chamber until the oxygen content was less than 0.01%.

[0113] The printing equipment is started. The SLM equipment stacks materials in a cycle, with the worktable descending by one layer thickness, the doctor blade spreading powder, the substrate preheating, the parts scanning, and the selected area scanning, until the desired printed part is formed.

[0114] After printing, the parts are removed for wire cutting and surface treatment to finally form the desired printed parts.

[0115] Comparative application examples

[0116] The application example is basically the same as the application example, except that the alloy powder obtained in Comparative Example 1 is used in this comparative application example.

[0117] Performance testing

[0118] 1. The alloy powder samples prepared in the above comparative examples and embodiments were characterized by scanning electron microscopy to analyze the morphology of the powder (e.g., Figure 2 and Figure 3 As shown), the composition of the powder was analyzed by energy dispersive spectroscopy (EDS). Figures 4 to 10 (As shown).

[0119] 2. Characterize the printed copies of corresponding use cases and comparative application examples by performing electron microscopy scanning at different magnifications (e.g., ...). Figure 11 , Figure 12 as well as Figure 15 ).

[0120] Specific testing methods include: using different grades of sandpaper and polishing liquid for coarse grinding and polishing in stages, observing tissue characteristics using a scanning electron microscope, and testing the density of the component using the water displacement method.

[0121] 3. Perform electron backscattering diffraction analysis on the printed copies of the corresponding use cases and comparative application examples (results are shown in the figure). Figure 13 and Figure 14 (As shown).

[0122] 4. The alloy sample was machined into a dumbbell shape using wire cutting. The room temperature tensile properties of the alloy sample were then tested using a universal tensile testing machine. The test results are as follows: Figure 16 As shown. The specific test methods include: (10) taking a cut standard tensile specimen, then using different grades of sandpaper to perform coarse grinding step by step to remove the oxide scale, and then performing room temperature mechanical property testing according to GB228-2002 "Metallic Materials Tensile Testing Method".

[0123] Results Analysis

[0124] like Figure 3 As shown, the powder has good sphericity, and the powder particle size basically meets the printing requirements of the equipment. Smaller particles are adsorbed onto the larger powder particles. This is mainly because during gas atomization powder production, the metal droplets are broken up by the high-speed airflow, forming numerous small droplets. During solidification, the powder particles come into contact with each other, and the smaller powder particles are easily adsorbed by the larger powder particles, forming "satellite spheres." The surface of the powder spheres exhibits a typical dendritic structure, which is caused by the melting and solidification characteristics of the atomization powder production process. Figures 4 to 10 As shown, energy dispersive spectroscopy analysis revealed that the powder composition matched the predetermined components, with no unfused particles, thus meeting the pre-alloying requirements. Simultaneously, combined with... Figures 3 to 10 Boron carbide particles can be observed adhering to the metal powder.

[0125] like Figure 11 and Figure 12 As shown, it was found that the addition of boron carbide effectively suppressed cracking in the sample compared to the sample without boron carbide.

[0126] like Figure 13 and Figure 14 As shown, the grain size of the sample decreased after the addition of boron carbide compared to before the addition of boron carbide.

[0127] At different magnifications, such as Figure 15 As shown, cracks in the printed parts provided in this application are significantly suppressed.

[0128] like Figure 16As shown, experimental results indicate that the yield strength of the Ni-Co-Fe-Al-Ti alloy without boron carbide during deformation is 702 MPa, and its fracture strength is 810 MPa. After adding boron carbide, the mechanical properties of the alloy are enhanced, with the yield strength increasing to 1010 MPa and the fracture strength increasing to 1247 MPa.

[0129] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0130] The above-described embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them. Although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of the embodiments of this application.

Claims

1. An additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds, characterized in that, The alloy powder comprises metal powder and boron carbide adhering to the surface of the metal powder, wherein the metal powder comprises the following components: Nickel content: 35%–50%; Cobalt 10%–30%; Iron 2%–15%; Aluminum 5%–18%; Titanium 3%–12%; The boron carbide comprises 0.1% to 1% of the total mass of the metal powder.

2. The additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds as described in claim 1, characterized in that, The metal powder comprises the following components: 45% nickel, 22.5% cobalt, 12% iron, 11% aluminum, and 9.5% titanium; the boron carbide accounts for 0.25% of the mass of the metal powder.

3. The additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds as described in claim 1, characterized in that, The boron carbide has a particle size of 2 μm to 3 μm.

4. The additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds as described in claim 1, characterized in that, The metal powder also includes at least one of niobium, tantalum, vanadium, chromium, molybdenum, and tungsten.

5. A method for preparing additive manufacturing alloy powder based on nickel-cobalt-based intermetallic compounds, characterized in that, include: It provides 35%–50% nickel; 10%–30% cobalt; 2%–15% iron; 5%–18% aluminum; and 3%–12% titanium as a metallic raw material. The above-mentioned metal raw materials are mixed and then pre-alloyed to obtain alloy ingots; The alloy ingot is made into metal powder; Boron carbide, comprising 0.1% to 1% of the mass of the metal powder, is added to the metal powder and mixed to obtain the alloy powder.

6. The preparation method according to claim 5, characterized in that, After the pre-alloy is formed into a metal powder, and before adding 0.1% to 1% boron carbide to the metal powder, the process includes: The metal powder was screened, and metal powder with a particle size range of 15 μm to 53 μm was selected.

7. The preparation method according to claim 6, characterized in that, The screening of the metal powder includes: Fine powder was obtained by multiple sieving using a 270-mesh standard sieve. The metal powder was obtained by multiple sieving processes using a 15μm precision sieve.

8. The preparation method according to claim 5, characterized in that, The process of turning the alloy ingot into metal powder includes: The alloy ingot is added to a vacuum atomization device; The process is carried out in an argon atmosphere, maintaining a gas pressure of 4–10 MPa, and using high-speed atomization spraying to produce metal powder.

9. A printed document, characterized in that, The additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds as described in any one of claims 1 to 4, or the additive manufacturing alloy powder based on nickel-cobalt intermetallic compounds obtained by the preparation method described in any one of claims 5 to 8, is obtained by 3D printing.

10. The printed part as described in claim 9, characterized in that, The printing method for the printed item includes: Model the printed part; Set the printing parameters of the 3D printing equipment to the preset values; Start the printing equipment to print. After printing, remove the part for wire cutting and surface treatment to finally form the required printed part.

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