Oscillating laser directed energy deposition core-shell type heterogeneous CoCrAlY coating, preparation method and application

Abstract

The application discloses an oscillation laser directional energy deposition core-shell type heterogeneous CoCrAlY coating and a method, and the oscillation laser directional energy deposition core-shell type heterogeneous CoCrAlY coating comprises a plurality of cladding layers stacked from bottom to top, each cladding layer is formed by a plurality of alloy tracks stacked in a direction perpendicular to the stacking direction of the cladding layer, and each alloy track is a heterogeneous structure composed of a gamma-Co phase; the heterogeneous structure comprises a beta-CoAl phase and a Laves phase, the Laves phase wraps the beta-CoAl phase to form a core-beta / shell-Laves structure, and the core-beta / shell-Laves structure is dispersedly distributed in the gamma-Co phase; and the Laves phase is CrMoSi4. The core-shell type heterogeneous CoCrAlY coating provided by the application has a core-beta / shell-Laves structure, and the hardness of the core-shell type heterogeneous CoCrAlY coating is 1.5 to 2 times higher than that of a conventional CoCrAlY coating, the oxidation weight gain is reduced by more than 60%, the service temperature can be increased by 100 DEG C, and the service temperature reaches 1100 DEG C.

Description

Technical Field

[0001] This invention relates to the field of surface strengthening technology, and in particular to an oscillating laser-directed energy deposition core-shell heterogeneous CoCrAlY coating, method, and application. Background Technology

[0002] MCrAlY (M = Ni, Co, or NiCo) alloy coatings, due to their excellent resistance to high-temperature oxidation and corrosion, occupy an important position in fields such as the bonding layer of thermal barrier coatings and protective coatings for hot-end components of gas turbine engines. During high-temperature oxidation, the surface of the MCrAlY coating reacts with oxygen to form a thermally grown oxide (TGO) layer. At high temperatures, Al preferentially reacts with oxygen to form α-Al₂O₃, which has an extremely low diffusion coefficient (approximately 10⁻⁶). -17 cm 2 The oxide film (MCrAlY) effectively blocks oxygen diffusion inwards. However, the growth of the oxide film follows a parabolic law (thickness ∝ square root of time), causing Al to continuously migrate from the interior of the coating to the surface. Under prolonged exposure or at high oxidation temperatures, insufficient Al ion supply within the MCrAlY coating can lead to the formation of harmful oxides, such as Ni(Co)Cr2O4. These oxides exhibit high growth stress and rapid growth rates, easily causing cracking and peeling of the TGO layer, thus rendering the coating ineffective.

[0003] In high-temperature protective coating systems, the β-CoAl phase, as the core reservoir phase for Al, plays a crucial role in determining the coating's oxidation resistance through its element migration behavior. However, in practical applications of MCrAlY coatings, the element migration process of the β-CoAl phase is significantly influenced by the complex internal structure of the coating. Studies have shown that the Laves phase intermetallic compounds generated within the MCrAlY coating, with their excellent thermodynamic stability and extremely low atomic diffusion coefficient, can construct an efficient diffusion-barrier layer within the coating system, slowing down the outward diffusion rate of Al and thus protecting and extending the coating's service life. However, during actual preparation, the Laves phase is prone to spatial uneven distribution, hindering its diffusion-barrier effect and weakening the overall protective performance of the coating. Furthermore, the presence of component segregation not only disrupts the uniformity of the coating's microstructure but also significantly increases its brittleness, making it susceptible to cracking under thermal cycling or mechanical stress, ultimately shortening the coating's service life. Therefore, controlling the uniform distribution of the Laves phase and suppressing component segregation have become key research directions for improving the overall performance of MCrAlY coatings. Summary of the Invention

[0004] In view of this, the present invention provides an oscillating laser directional energy deposition core-shell heterogeneous CoCrAlY coating, method and application.

[0005] The first objective of this invention is to provide an oscillating laser-directed energy deposition core-shell heterogeneous CoCrAlY coating.

[0006] The second objective of this invention is to provide a method for oscillating laser directional energy deposition of a core-shell heterogeneous CoCrAlY coating.

[0007] The third objective of this invention is to provide an application method for oscillating laser directional energy deposition of core-shell heterogeneous CoCrAlY coatings.

[0008] The first objective of this invention can be achieved by adopting the following technical solution:

[0009] An oscillating laser-directed energy deposition (ODED) core-shell heterogeneous CoCrAlY coating comprises multiple cladding layers stacked sequentially from bottom to top. Each cladding layer is formed by multiple alloy passes stacked sequentially in a direction perpendicular to the stacking direction of the cladding layers. Each alloy pass is a heterogeneous structure composed of a γ-Co phase. The heterogeneous structure includes a β-CoAl phase and a Laves phase. The Laves phase encapsulates the β-CoAl phase to form a core-β / shell-Laves structure, which is dispersed within the γ-Co phase. The Laves phase is CrMoSi4.

[0010] Furthermore, the volume fraction of the γ-Co phase is 60-75%, and the size is 2-4 μm; the volume fraction of the β-CoAl phase is 10-20%, and the size is 0.5-1.2 μm; and the volume fraction of the Laves phase is 4-10%, and the size is 0.5-1.2 μm.

[0011] Furthermore, the Si element captures Cr and Mo to form a Laves phase with low diffusion activity, effectively suppressing the formation of harmful phases such as CoCr2O4 and MoO3.

[0012] Furthermore, during the high-temperature oxidation process, atoms in the β-CoAl phase of the core-β / shell-Laves structure diffuse outward through the Laves phase, requiring them to pass through at least two more phase boundaries. At the same time, internal atoms diffuse outward through the grain boundaries need to bypass the Laves phase, which greatly increases the diffusion path of atoms outward and hinders the outward diffusion of atoms, thereby improving the oxidation resistance of the CoCrAlY coating.

[0013] The second objective of this invention can be achieved by adopting the following technical solution:

[0014] A method for oscillating laser-directed energy deposition of core-shell heterogeneous CoCrAlY coatings, the method comprising:

[0015] S1: Place the CoCrAlY alloy powder into the hopper of the automatic powder feeder; wherein, the chemical composition of the CoCrAlY alloy powder is: Cr 20-25.9 wt.%, Al 6.4-12 wt.%, Y 0.7-1.2 wt.%, CeO 21~3 wt.%, CNTs 0.2wt.%~1.0wt.%, MoSi 28~20 wt.%, with the balance being Co;

[0016] S2: Introduce argon gas into the sealed molding chamber to bring the oxygen concentration inside the chamber to the preset value;

[0017] S3: Turn on the laser after the flow rate of MoSi2-doped MCrAlY alloy powder stabilizes;

[0018] S4: Using a laser to melt alloy powder to form a molten pool, the laser is moved along a preset CAD trajectory, and the molten alloy powder is rapidly solidified and crystallized to form a single-layer alloy coating.

[0019] S5: After a layer is deposited on the substrate, the laser head and powder nozzle return to the designated position and rise along the Z-axis to cover the slice thickness.

[0020] S6: Repeat steps S4 to S5 until the coating preparation is complete.

[0021] Furthermore, the process parameters set in step S4 are as follows: laser power is 1500~2500W, cladding speed is 10~20mm / s, overlap rate is 40%~60%, amplitude is 0~5mm, oscillation frequency is 100~2000Hz, and the preset trajectory is a straight line, a figure-eight shape, or a circle.

[0022] Furthermore, in step S4, under the action of a high-energy laser beam, MoSi2 decomposes into Si and Mo atoms and dissolves into the γ-Co phase, causing the γ-Co phase to transform into the β-CoAl phase with a lower coordination number, which significantly increases the volume fraction of the β-CoAl phase.

[0023] Furthermore, by melting and solidifying the alloy powder, Al diffusion is promoted to form the β-CoAl phase and the Si / Mo-rich Laves phase to form the shell phase, thereby achieving the controllable growth of the core-β / shell-Laves structure.

[0024] Furthermore, the substrate is an iron alloy, a nickel alloy, or a titanium alloy.

[0025] The third objective of this invention can be achieved by adopting the following technical solution:

[0026] An application method for an oscillating laser directional energy deposition core-shell heterogeneous CoCrAlY coating, based on the above-mentioned core-shell heterogeneous CoCrAlY coating or the core-shell heterogeneous CoCrAlY coating prepared by the above-mentioned method, is applied in the fields of aero-engine, gas turbine, and high-temperature components of nuclear reactors.

[0027] The present invention has the following advantages over the prior art:

[0028] (1) The oscillating laser directed energy deposition core-shell heterogeneous CoCrAlY coating provided by the present invention has a core-shell structure (core-β / shell-Laves) in which the Laves phase encapsulates the β-CoAl phase. Due to its unique "core-shell" structure, the alloy coating has excellent high-temperature stability, high-temperature oxidation resistance, fatigue resistance and high-temperature wear resistance. Compared with conventional CoCrAlY coatings, the oxidation weight gain is significantly reduced, and it has broad application prospects in high-temperature components such as aero-engines, gas turbine blades and nuclear reactors.

[0029] (2) The method provided by this invention introduces MoSi2 into the CoCrAlY coating, uses an oscillating laser to melt and decompose the high-melting-point MoSi2, and promotes the full diffusion of Mo and Si elements, thus solving the problem of element segregation. In addition, by controlling the peak and valley energy parameters of the laser (controlling process parameters), the high cooling rate of the laser during the melting and solidification of the alloy powder promotes the diffusion of Al to form the β-CoAl core phase and the Si / Mo rich Laves phase to form the shell phase, thereby achieving the controllable growth of the core-β / shell-Laves structure. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 CoCrAlY- of Embodiment 1 of the present invention x A schematic diagram of the microstructure of the MoSi2 alloy coating.

[0032] Figure 2 The CoCrAlY- of Examples 2-4 of this invention x A schematic diagram of the oxidation process of the MoSi2 alloy coating.

[0033] Figure 3 The CoCrAlY- of Examples 2-4 of this inventionx Surface morphology of MoSi2 alloy coating after oxidation at 1100℃ for 100h.

[0034] Figure 4 The CoCrAlY- of Examples 2-4 of this invention x Cross-sectional morphology of MoSi2 alloy coating after oxidation at 1100℃ for 100h.

[0035] Among them, there are 1-γ-Co phase, 2-phase boundary, 3-core-β / shell-Laves structure, 4-Al2O3, 5-β-CoAl phase, and 6-Laves phase. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described are merely used to explain this application and are not intended to limit this application.

[0037] In the description of the embodiments of the present invention, the technical terms "upper", "lower", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship between the components. They are only for the convenience of describing the embodiments of the present invention 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 the present invention.

[0038] Example 1:

[0039] This embodiment provides an oscillating laser-directed energy deposition (ODED) core-shell heterogeneous CoCrAlY coating, comprising multiple cladding layers stacked sequentially from bottom to top. Each cladding layer is formed by multiple alloy layers stacked sequentially in a horizontal direction. Each alloy layer is a heterogeneous structure composed of a γ-Co phase, including a β-CoAl phase and a Laves phase. The Laves phase encapsulates the β-CoAl phase to form a core-β / shell-Laves structure, which is dispersed within the γ-Co phase. The Laves phase is CrMoSi4. The core-shell heterogeneous CoCrAlY coating (CoCrAlY- x The microstructure of the MoSi2 alloy coating can be found in [reference]. Figure 1 .

[0040] Specifically, the volume fraction of the γ-Co phase is 60-75%, and the size is 2-4 μm; the volume fraction of the β-CoAl phase is 10-20%, and the size is 0.5-1.2 μm; and the volume fraction of the Laves phase is 4-10%, and the size is 0.5-1.2 μm.

[0041] During the high-temperature oxidation process, the Cr element enriched inside the Laves phase exhibits low diffusion activity, which can effectively inhibit the formation of the harmful spinel phase CoCr2O4.

[0042] During high-temperature oxidation, atoms in the β-CoAl phase of the core-β / shell-Laves structure diffuse outward through the Laves phase, requiring them to pass through at least two more phase boundaries. At the same time, internal atoms diffusing outward through grain boundaries need to bypass the Laves phase, which greatly increases the diffusion path of atoms and hinders their outward diffusion, thereby improving the oxidation resistance of the CoCrAlY coating.

[0043] Example 2:

[0044] This embodiment provides a method for directional energy deposition of a core-shell heterogeneous CoCrAlY coating using an oscillating laser. The specific implementation steps are as follows:

[0045] S1: Using 316L stainless steel plate as the substrate, the surface of the substrate is ground and polished, and ultrasonically cleaned in acetone solution; the uniformly mixed MoSi2-doped CoCrAlY pre-alloyed powder is placed in the hopper of an automatic powder feeder, wherein the chemical composition of the CoCrAlY pre-alloyed powder is: Cr 25.9 wt.%, Al 6.41 wt.%, Y 0.68 wt.%, with the balance being Co, and MoSi2 accounting for 15 wt.% of the total mass.

[0046] S2: Introduce argon gas into the sealed molding chamber to make the oxygen concentration inside the chamber 0.05%.

[0047] S3: Draw a CAD 3D model using software, import the model into the processing software, slice the CAD 3D model into layers according to the thickness of the single layer to be deposited, and set the deposition parameters, including deposition power, deposition rate, overlap ratio, laser beam oscillation parameters, etc.

[0048] The laser power is 1800W, the deposition rate (v) is 8mm / s, the overlap rate is 50%, the amplitude (A) is 3mm, the oscillation frequency (ω) is 100Hz, and the laser beam trajectory is circular (the motion function is x=x0+vt-Acosωt, y=y0+Asinωt).

[0049] S4: Start feeding powder, and turn on the laser after the powder flow rate stabilizes;

[0050] S5: Using a laser to melt alloy powder to form a molten pool, the laser is moved along a preset CAD trajectory, and the molten alloy powder is rapidly solidified and crystallized to form a single-pass alloy.

[0051] S6: After one layer is deposited, the laser head and powder nozzle return to the designated position according to the CAD 3D model and rise along the Z-axis to cover the slice thickness.

[0052] S7: The equipment automatically repeats steps S5 to S6 based on the CAD model until the work is completed.

[0053] Using the above process parameters, the CoCrAlY-15MoSi2 coating prepared in this embodiment achieves a density of 98.7% and a Vickers hardness of 640 HV. 0.5 This represents a 3-fold increase; a schematic diagram of oxidation at 1100℃ can be referenced. Figure 2 Surface morphology can be referenced Figure 3 (a) The cross-sectional morphology can be referenced. Figure 4 (a) Measurements revealed that the oxide layer thickness was 0.7 μm, and the weight gain per unit area from oxidation was only 0.2 mg / cm². 2 Compared to the CoCrAlY coating, the oxidation weight gain was reduced by 87%.

[0054] Example 3:

[0055] This embodiment provides a method for directional energy deposition of a core-shell heterogeneous CoCrAlY coating using an oscillating laser. The specific implementation steps are as follows:

[0056] S1: Using Inconel 718 alloy as the substrate, the surface of the substrate is ground and polished, and then ultrasonically cleaned in acetone solution; the uniformly mixed MoSi2-doped CoCrAlY pre-alloy powder is placed in the hopper of an automatic powder feeder, wherein the chemical composition of the CoCrAlY pre-alloy powder is: Cr 25.9 wt.%, Al 6.41 wt.%, Y 0.68 wt.%, with the balance being Co, and MoSi2 accounting for 10 wt.% of the total mass.

[0057] S2: Introduce argon gas into the sealed molding chamber to make the oxygen concentration inside the chamber 0.05%.

[0058] S3: Draw a CAD 3D model using software and import the model into the processing software. Slice the CAD 3D model into layers according to the thickness of the single layer to be deposited, and set the deposition parameters, including deposition power, deposition rate, overlap rate, laser beam oscillation parameters, etc.

[0059] The laser power is 1500W, the deposition rate (v) is 16mm / s, the overlap rate is 50%, the amplitude (A) is 2mm, the oscillation frequency (ω) is 200Hz, and the laser beam trajectory is a figure-eight shape (the motion functions are x=x0+vt-Asin2ωt, y=y0+Asinωt).

[0060] S4: Start feeding powder, and turn on the laser after the powder flow rate stabilizes;

[0061] S5: Using a laser to melt alloy powder to form a molten pool, the laser is moved along a preset CAD trajectory, and the molten alloy powder is rapidly solidified and crystallized to form a single-pass alloy.

[0062] S6: After one layer is deposited, the laser head and powder nozzle return to the designated position according to the CAD 3D model and rise along the Z-axis to cover the slice thickness.

[0063] S7: The equipment automatically repeats steps S5 to S6 based on the CAD model until the work is completed.

[0064] Using the above process parameters, the prepared CoCrAlY-10MoSi2 coating achieves a density of 99.4% and a Vickers hardness of 520 HV. 0.5 This represents a 2.5-fold increase. A schematic diagram of the oxidation process at 1100℃ can be found here. Figure 2 Surface morphology can be referenced Figure 3 (b) The cross-sectional morphology can be referenced. Figure 4 (b) Measurements revealed that the oxide layer thickness was 1.1 μm, and the weight gain per unit area from oxidation was only 0.36 mg / cm². 2 Compared to the CoCrAlY coating, the oxidation weight gain was reduced by 80%.

[0065] Example 4:

[0066] This embodiment provides a method for directional energy deposition of a core-shell heterogeneous CoCrAlY coating using an oscillating laser. The specific implementation steps are as follows:

[0067] S1: Using TC4 board as the substrate, the surface of the substrate is ground and polished, and then ultrasonically cleaned in acetone solution; the uniformly mixed MoSi2-doped CoCrAlY pre-alloyed powder is placed in the hopper of an automatic powder feeder, wherein the chemical composition of the CoCrAlY pre-alloyed powder is: Cr 25.9 wt.%, Al 6.41 wt.%, Y 0.68 wt.%, with the balance being Co; MoSi2 accounts for 5 wt.% of the total mass.

[0068] S2: Introduce argon gas into the sealed molding chamber to make the oxygen concentration inside the chamber 0.05%.

[0069] S3: Draw a CAD 3D model using software and import the model into the processing software. Slice the CAD 3D model into layers according to the thickness of the single layer to be deposited, and set the deposition parameters, including deposition power, deposition rate, overlap rate, laser beam oscillation parameters, etc.

[0070] The laser power is 2000W, the deposition rate (v) is 13mm / s, the overlap rate is 60%, the amplitude (A) is 3mm, the oscillation frequency (ω) is 50Hz, and the laser beam trajectory is linear (the motion function is x=x0+vt, y=y0+Asinωt).

[0071] S4: Start feeding powder. After the powder flow rate stabilizes, turn on the laser. S5: Use the laser to melt the alloy powder to form a molten pool. Move the laser along the CAD preset trajectory. The molten alloy powder will quickly solidify and crystallize to form a single-pass alloy.

[0072] S6: After one layer is deposited, the laser head and powder nozzle return to the designated position according to the CAD 3D model and rise along the Z-axis to cover the slice thickness.

[0073] S7: The equipment automatically repeats steps S5 to S6 based on the CAD model until the work is completed.

[0074] Using the above process parameters, the prepared CoCrAlY-15MoSi2 coating achieves a density of 99.6% and a Vickers hardness of 307 HV. 0.5 This represents a 1.5-fold increase. A schematic diagram of the oxidation process at 1100℃ can be found here. Figure 2 Surface morphology can be referenced Figure 3 As shown in (c), the cross-sectional morphology can be referenced. Figure 4 (c) Measurements revealed that the oxide layer thickness was 1.6 μm, and the weight gain per unit area from oxidation was only 1.5 mg / cm³. 2 Compared to the CoCrAlY coating, the oxidation weight gain was reduced by 60%.

[0075] The method for oscillating laser-directed energy deposition (OL-DED) of core-shell heterogeneous CoCrAlY coatings provided in Examples 2-4 precisely controls the laser motion and parameters to decompose MoSi2 and promote element diffusion. By utilizing the periodic changes in laser energy, Al diffuses to form the β-CoAl phase during the melting and solidification process of the molten pool, while the Si and Mo-rich Laves phase preferentially precipitates during the energy trough phase. By synergistically controlling the parameters, the controllable growth of the "core-β / shell-Laves" structure is achieved, resulting in a "core-β / shell-Laves" heterostructure MCrAlY coating with high oxidation resistance.

[0076] For process parameters not given in embodiments 2 to 4 above, conventional techniques can be used for setting.

[0077] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A oscillatory laser directed energy deposition core-shell type heterostructured CoCrAlY coating, characterized in that, The device comprises multiple cladding layers stacked sequentially from bottom to top. Each cladding layer is formed by multiple alloy layers stacked sequentially in a direction perpendicular to the stacking direction of the cladding layers. Each alloy layer is a heterogeneous structure composed of a γ-Co phase. The heterogeneous structure includes a β-CoAl phase and a Laves phase. The Laves phase encapsulates the β-CoAl phase to form a core-β / shell-Laves structure, which is dispersed in the γ-Co phase. The Laves phase is CrMoSi4. The volume fraction of the γ-Co phase is 60-75%, and the size is 2-4 μm. The volume fraction of the β-CoAl phase is 10-20%, and the size is 0.5-1.2 μm. The volume fraction of the Laves phase is 4-10%, and the size is 0.5-1.2 μm.

2. The oscillating laser directed energy deposition core-shell hetero CoCrAlY coating of claim 1, wherein, The low-diffusion-activity Laves phase is formed by Si capturing Cr and Mo, and can effectively suppress the formation of harmful phases such as CoCr2O4 and MoO3.

3. The oscillating laser directed energy deposition core-shell type hetero- CoCrAlY coating according to any one of claims 1-2, characterized in that, During the high-temperature oxidation process, atoms in the β-CoAl phase of the core-β / shell-Laves structure diffuse outward through the Laves phase, requiring them to pass through at least two more phase boundaries. At the same time, internal atoms diffuse outward through the grain boundaries need to bypass the Laves phase, which greatly increases the diffusion path of atoms and hinders their outward diffusion, thereby improving the oxidation resistance of the CoCrAlY coating.

4. A method for oscillating laser-directed energy deposition of core-shell heterogeneous CoCrAlY coatings, characterized in that, The method includes: S1: Place the CoCrAlY alloy powder into the hopper of the automatic powder feeder; wherein, the chemical composition of the CoCrAlY alloy powder is: Cr 20-25.9wt.%, Al 6.4-12wt.%, Y 0.7-1.2wt.%, CeO 21~3wt.%, CNTs 0.2wt.%~1.0wt.%, MoSi 28~20wt.%, with the balance being Co; S2: Introduce argon gas into the sealed molding chamber to bring the oxygen concentration inside the chamber to the preset value; S3: Turn on the laser after the flow rate of MoSi2-doped MCrAlY alloy powder stabilizes; S4: Using a laser to melt alloy powder to form a molten pool, the laser is moved along a preset CAD trajectory, and the molten alloy powder is rapidly solidified and crystallized to form a single-layer alloy coating. S5: After a layer is deposited on the substrate, the laser head and powder nozzle return to the designated position and rise along the Z-axis to cover the slice thickness. S6: Repeat steps S4 to S5 until the coating preparation is complete.

5. The method of claim 4, wherein, The process parameters set in step S4 are: laser power of 1500~2500W, cladding speed of 10~20mm / s, overlap rate of 40%~60%, amplitude of 0~5mm, oscillation frequency of 100~2000Hz, and preset trajectory of straight line, figure-eight or circle.

6. The method of claim 4, wherein, In step S4, under the action of a high-energy laser beam, MoSi2 decomposes into Si and Mo atoms and dissolves into the γ-Co phase, causing the γ-Co phase to transform into the β-CoAl phase with a lower coordination number, which significantly increases the volume fraction of the β-CoAl phase.

7. The method of claim 4, wherein, By melting and solidifying the alloy powder, Al diffuses to form the β-CoAl phase and the Si / Mo-rich Laves phase forms the shell phase, thereby achieving the controllable growth of the core-β / shell-Laves structure.

8. The method according to any one of claims 4 to 7, characterized in that, The substrate is an iron alloy, nickel alloy, or titanium alloy.

9. A method of using an oscillating laser directed energy deposition core-shell hetero CoCrAlY coating, characterized in that, Applications of core-shell heterogeneous CoCrAlY coatings according to any one of claims 1 to 3 or core-shell heterogeneous CoCrAlY coatings prepared by the method according to any one of claims 4 to 8 in the fields of aero-engine, gas turbine, and high-temperature components of nuclear reactors.

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