A laser-clad nickel-based superalloy wear-resistant gradient coating and its preparation method

Abstract

This invention discloses a laser-clad nickel-based superalloy wear-resistant gradient coating, comprising a transition layer-1, a transition layer-2, and a functional layer from the inside out of the substrate; wherein: transition layer-1 is made of nickel-based superalloy powder; transition layer-2 is made of nickel-based superalloy ceramic particle-reinforced alloy powder; the nickel-based superalloy ceramic particle-reinforced alloy powder used in the functional layer has the following composition by mass percentage: C: 4.0-8.0, Cr: 10.0-17.0, Ni: 30.0-44.0, Mo: 1.6-2.6, Co: 0.1-0.4, Al: 0.06-0.3, Ti: 16.0-32.0, with the balance being Fe. This invention rationally selects and controls the composition and ratio of metal powders in different layers, improving the coating's high-temperature resistance and wear resistance, and extending its service life.

Description

Technical Field

[0001] This invention belongs to the field of material surface technology, specifically relating to a method for preparing a wear-resistant gradient coating for nickel-based high-temperature alloys and laser cladding. Background Technology

[0002] If the working environment of a component involves factors such as high temperature, high-speed flow, and wear, the surface of traditional materials often cannot meet the requirements for long-term stable operation. Nickel-based superalloys, on the other hand, are widely used in aerospace, energy, and chemical industries due to their excellent oxidation resistance, creep resistance, and mechanical properties at high temperatures.

[0003] Coatings for nickel-based superalloys are typically obtained through thermal spraying or laser cladding, but both methods have their drawbacks: First, thermal spraying produces thinner nickel-based superalloy coatings, typically 0.3-0.5 mm thick, with lower adhesion between coatings, making them prone to peeling. Second, laser cladding produces nickel-based superalloys that are prone to cracking, and the coating has poor density. Summary of the Invention

[0004] The problem this invention aims to solve is to provide a laser-clad nickel-based high-temperature alloy wear-resistant gradient coating. By rationally selecting and controlling the composition and ratio of metal powders in different layers, the high-temperature resistance and wear resistance of the coating are improved, extending its service life. Simultaneously, this invention provides a coating preparation method that precisely controls the thickness and quality of the cladding layer through laser cladding technology, resulting in a dense coating with strong adhesion between layers, preventing detachment and further extending the coating's service life.

[0005] This invention discloses a laser-clad wear-resistant gradient coating for nickel-based superalloys, comprising a transition layer-1, a transition layer-2, and a functional layer, arranged from the inside to the outside of the substrate. The transition layer-1 uses nickel-based superalloy powder with the following composition by mass percentage: C: 0.05~0.08%, Cr: 17.0~21.0%, Ni: 50.0~55.0%, Mo: 2.8~3.3%, Co: 0.5-1.0%, Al: 0.3-0.7%, with the balance being Fe. The transition layer-2 uses nickel-based superalloy ceramic particle-reinforced alloy powder with the following composition by mass percentage: C: 1.8~2.5%, Cr: The nickel-based high-temperature alloy ceramic particle-reinforced alloy powder used in the functional layer has the following composition by mass percentage: C: 4.0~8.0%, Cr: 10.0~17.0%, Ni: 30.0~44.0%, Mo: 1.6~2.6%, Co: 0.1-0.4%, Mo: 0.06-0.3%, Ti: 16.0~32.0%, with the balance being Fe.

[0006] Among them, the particle size of the transition layer-1 nickel-based superalloy powder is 100-270 mesh; the particle size of the transition layer-2 nickel-based superalloy ceramic particle reinforced alloy powder is 100-270 mesh; and the particle size of the functional layer nickel-based superalloy ceramic particle reinforced alloy powder is 100-270 mesh.

[0007] The thickness of transition layer-1 is 0.2-2mm, the thickness of transition layer-2 is 0.2-2mm, and the thickness of functional layer is 0.2-2mm.

[0008] This invention discloses a method for preparing a wear-resistant gradient coating on a nickel-based superalloy by laser cladding, the specific steps of which are as follows:

[0009] Step 1: Prepare alloy powders for the transition layer and functional layer;

[0010] Step 2, matrix preparation;

[0011] Step 3, Laser Cladding Transition Layer-1: A high-power semiconductor laser is used to laser clad the transition layer-1 on the surface of the metal substrate. Powder is fed by pneumatic or gravity feeding methods, and the powder thickness is 0.5-2.5mm.

[0012] Step 4: Remove the surface oxide scale by turning until a smooth and bright surface is visible;

[0013] Step 5, Laser cladding transition layer-2: The transition layer-2 is laser clad onto the surface of the transition layer-1 using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, and the powder thickness is 0.5-2.5 mm.

[0014] Step 6: Grind with a grinding wheel to remove the surface oxide scale, resulting in a smooth and bright surface;

[0015] Step 7, Laser Cladding Functional Layer: The functional layer is laser clad onto the surface of the transition layer-2 using a high-power semiconductor laser. Powder is fed using pneumatic or gravity feeding methods, with a powder thickness of 0.5-2.5 mm.

[0016] Step 2 specifically involves removing oil and oxide scale from the substrate surface by turning followed by oxyacetylene torching or shot peening.

[0017] In step 3, the laser process parameters are: laser wavelength 1064nm, power 1000-4000W, spot size 5mm diameter circular spot, scanning speed 500-700mm / min, and overlap rate 50%-70%.

[0018] In step 5, the laser process parameters are: laser wavelength 1064nm, power 1000-4000W, spot size 5mm diameter circular spot, scanning speed 360-600mm / min, and overlap rate 50%-70%.

[0019] In step 7, the laser process parameters are as follows: laser wavelength 1064nm, power 1000-4000W, spot size 5mm diameter circular spot, scanning speed 360-600mm / min, and overlap rate 50%-70%.

[0020] In step 5, the alloy powder of the transition layer-2 is mixed evenly using a mechanical powder mixer before cladding, and the mixing time is 2-3 hours; in step 7, the alloy powder of the functional layer is mixed evenly using a mechanical powder mixer before cladding, and the mixing time is 2-3 hours.

[0021] In step 1, after the three alloy powders are prepared, they are placed in a drying oven for 2 hours at a set temperature of 150°C to remove water vapor from the powders.

[0022] The advantages of the coating of this invention are: 1. It fully considers the temperature gradient and thermal stress distribution between the coating surface and the substrate. The coating consists of three layers: transition layer-1, transition layer-2, and functional layer. This reduces the stress concentration at the interface between the coating and the substrate, making it less prone to cracking, improving the bonding strength of the coating, effectively reducing the risk of coating peeling caused by thermal stress, and extending the service life of the substrate parts; 2. Based on the high-temperature alloy steel substrate and the requirements of the working conditions, the composition of the two transition layers and one functional layer is carefully designed: (i) Al and Ti in the functional layer can form a γ' phase (Ni3(Al, (i)Ni, as the matrix element of the γ' phase, works together with elements such as aluminum and titanium to promote the uniform precipitation and stability of the γ' phase, enhancing the strength and creep resistance of the alloy at high temperatures; (ii)Cr is present in all three layers: 1. Cr forms a stable chromium oxide layer (such as Cr2O3) in the alloy. The oxide layer can protect the alloy matrix in high-temperature and corrosive environments, preventing further expansion of oxidation and corrosion; 2. Cr forms a solid solution in the alloy, increasing the strength and hardness of the material through the solid solution strengthening mechanism; 3. Cr promotes the precipitation of the γ' phase (Ni3(Al, The uniform distribution and stability of Ti improve the high-temperature mechanical properties of the alloy; (III) Mo is present in all three layers: 1. Mo works with other elements (such as Al and Ti) to form a solid solution strengthening phase, which improves the bonding strength between coatings; 2. Mo introduces lattice distortion, increasing the difficulty of dislocation movement and improving the strength of the alloy; especially in high-temperature environments, the addition of Mo significantly improves the creep resistance of the alloy; 3. Mo works with elements such as Cr to enhance the stability of the oxide film on the alloy surface and improve the corrosion resistance of the alloy in high-temperature oxidizing environments; (IV) Co is present in all three layers: 1. Co forms a solid solution in the nickel matrix, which improves the strength of the alloy by increasing the difficulty of dislocation slip; 2. The solid solution strengthening effect of Co is particularly important for improving the high-temperature performance of the alloy, and the addition of cobalt can improve the toughness of the alloy, especially in high-temperature environments; 3. The presence of Co helps to improve the plasticity and fracture resistance of the alloy at high temperatures. (v) The transition layer-2 contains C and W, and the functional layer contains C and Ti: W, Ti and C elements combine to form WC or TiC hard phase, which has very high hardness and wear resistance. Therefore, it can significantly improve the hardness of the coating and enable it to resist wear and surface damage.

[0023] The laser cladding method of this invention: During the cladding process in steps 3, 5, and 7, appropriate process parameters are determined, and the laser energy is controlled by adjusting the melting rate, ensuring the density and bonding strength of the coating; a uniform high-temperature alloy transition layer is formed on the surface of the metal substrate in step 3; a uniform nickel-based ceramic particle reinforced surface coating is obtained on the surface of the transition layer-1 alloy in step 5, that is, a uniform wear-resistant transition layer with gradient changes is obtained; a uniform nickel-based ceramic particle reinforced surface coating is obtained on the surface of the transition layer-2 alloy in step 7, that is, a uniform high-temperature wear-resistant functional layer with gradient changes is obtained.

[0024] In summary, the gradient coating of this invention: 1. Significantly improves the wear resistance of the substrate material, effectively reducing wear and surface damage under high-speed flow or high-load operating conditions; 2. Possesses excellent high-temperature resistance, enhancing the stability of the material in high-temperature environments; 3. Has plasticity and fracture resistance, preventing cracking; 4. Has good mechanical strength and enhanced fatigue life; 5. The wear resistance and high-temperature resistance of the gradient coating exhibit a gradient improvement, and the coating has good density and strong adhesion between layers, making it less prone to peeling off, thus extending its service life. Therefore, the gradient coating of this invention has been widely used under high-temperature, high-pressure, and high-speed operating conditions, greatly extending the service life of substrate parts coated with the gradient coating. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the gradient coating structure of the present invention. Detailed Implementation

[0026] To better understand the present invention, the following detailed description is provided in conjunction with embodiments.

[0027] from Figure 1As can be seen, the present invention discloses a laser-clad nickel-based superalloy wear-resistant gradient coating, which includes a transition layer-1, a transition layer-2, and a functional layer from the inside to the outside of the substrate; wherein: the nickel-based superalloy powder selected for the transition layer-1 has the following composition by mass percentage: C: 0.05~0.08%, Cr: 17.0~21.0%, Ni: 50.0~55.0%, Mo: 2.8~3.3%, Co: 0.5-1.0%, Al: 0.3-0.7%, with the balance being Fe; the nickel-based superalloy ceramic particle-reinforced alloy powder selected for the transition layer-2 has the following composition by mass percentage: C: 1.8~2.5%, C The composition by mass percentage of the nickel-based high-temperature alloy ceramic particle-reinforced alloy powder used in the functional layer is as follows: C: 4.0~8.0%, Cr: 10.0~17.0%, Ni: 30.0~44.0%, Mo: 30.0~44.0%, Mo: 1.6~2.6%, Co: 0.1-0.4%, Al: 0.06-0.3%, Ti: 16.0~32.0%, with the balance being Fe. Example 1

[0028] Step 1: Based on the metal substrate and operating conditions, prepare the alloy powders for the transition layer and functional layer: The nickel-based high-temperature alloy powder used for transition layer-1 has the following composition and mass percentage: C: 0.06%, Cr: 20.0%, Ni: 55.0%, Mo: 3.0%, Co: 0.6%, Al: 0.4%, with the balance being Fe. Mix the powders; the alloy powder particle size is 100-270 mesh. The nickel-based ceramic-reinforced alloy powder used for transition layer-2 has the following composition and mass percentage: C: 2.0%, Cr: 16.0%, Ni: 43.0%, Mo: 2.4%, Co: 0.0%. The alloy powder was mixed with the following components: 0.3% Al, 0.25% W, 18.7% Ti, and the balance Fe. The particle size of the alloy powder was 100-270 mesh. The nickel-based ceramic reinforced alloy powder used for the functional layer had the following composition and mass percentage: C: 5.0%, Cr: 16.0%, Ni: 43.0%, Mo: 2.4%, Co: 0.3%, Al: 0.2%, Ti: 17.0%, and the balance Fe. The alloy powder had a particle size of 100-270 mesh. The three powders were placed in a drying oven for 2 hours at a temperature of 150°C to remove water vapor from the powders.

[0029] Step 2, substrate preparation: Remove oil and oxide scale from the substrate surface by turning followed by oxyacetylene torching or shot peening.

[0030] Step 3, Laser Cladding Transition Layer-1: Laser cladding is performed on the surface of the metal substrate using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, with a powder thickness of 1.7 mm. The laser process parameters are: laser wavelength 1064 nm, power 3000 W, spot size 5 mm diameter circular spot, scanning speed 600 mm / min, and overlap rate 50%. As the semiconductor laser moves, a uniform high-temperature alloy transition layer is formed on the bottom layer. The thickness of transition layer-1 is 1.5 mm.

[0031] Step 4: Remove the oxide scale from the transition layer-1 surface by turning to obtain a smooth and bright surface;

[0032] Step 5, Laser Cladding Transition Layer-2: Laser cladding is performed on the surface of transition layer-1 using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, with a powder thickness of 1.7 mm. The laser process parameters are: laser wavelength 1064 nm, power 2500 W, spot size 5 mm diameter circular spot, scanning speed 480 mm / min, and overlap rate 50%. As the semiconductor laser moves, a uniform nickel-based ceramic particle-reinforced surface coating is obtained on the alloy surface of transition layer-1, resulting in a uniform, gradient-varying wear-resistant transition layer. The thickness of transition layer-2 is 1.5 mm.

[0033] Step 6: Grind with a grinding wheel to remove the surface oxide scale, resulting in a smooth and bright surface;

[0034] Step 7, Laser Cladding Functional Layer: Laser cladding is performed on the surface of transition layer-2 using a high-power semiconductor laser. Powder is fed using pneumatic or gravity methods, with a powder thickness of 1.7 mm. The laser process parameters are: laser wavelength 1064 nm, power 2500 W, spot size 5 mm diameter circular spot, scanning speed 480 mm / min, and overlap rate 50%. As the semiconductor laser moves, a uniform nickel-based ceramic particle-reinforced surface coating is obtained on the alloy surface of transition layer-2, resulting in a uniform, gradient-varying high-temperature wear-resistant functional layer with a thickness of 1.5 mm. Example 2

[0035] Step 1: Based on the metal substrate and operating conditions, prepare the alloy powders for the transition layer and functional layer: The nickel-based high-temperature alloy powder used for transition layer-1 has the following composition and mass percentage: C: 0.07%, Cr: 18.0%, Ni: 52.0%, Mo: 3.2%, Co: 0.8%, Al: 0.6%, with the balance being Fe, and is mixed; the alloy powder particle size is 100-270 mesh; The nickel-based ceramic-reinforced alloy powder used for transition layer-2 has the following composition and mass percentage: C: 2.4%, Cr: 12.0%, Ni: 33.0%, Mo: 1.8%, Co: 0. The alloy powder was mixed with the following components: 36% Al, 0.25% W, 37.5% Fe, and the balance was 100-270 mesh. The nickel-based ceramic reinforced alloy powder used for the functional layer had the following composition and mass percentage: C: 7.0%, Cr: 12.0%, Ni: 33.0%, Mo: 1.8%, Co: 0.36%, Al: 0.25%, Ti: 30.0%, and the balance was Fe. The alloy powder had the following particle size: 100-270 mesh. The three powders were placed in a drying oven for 2 hours at a temperature of 150℃ to remove water vapor from the powders.

[0036] Step 2, substrate preparation: Remove oil and oxide scale from the substrate surface by turning followed by oxyacetylene torching or shot peening.

[0037] Step 3, Laser Cladding Transition Layer-1: Laser cladding is performed on the surface of the metal substrate using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, with a powder thickness of 0.55 mm. The laser process parameters are: laser wavelength 1064 nm, power 1000 W, spot size 5 mm diameter circular spot, scanning speed 660 mm / min, and overlap rate 60%. As the semiconductor laser moves, a uniform high-temperature alloy transition layer is formed at the bottom layer. The thickness of transition layer-1 is 0.2 mm.

[0038] Step 4: Remove the oxide scale from the transition layer-1 surface by turning to obtain a smooth and bright surface;

[0039] Step 5, Laser Cladding Transition Layer-2: Laser cladding is performed on the surface of transition layer-1 using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, with a powder thickness of 1.2 mm. The laser process parameters are: laser wavelength 1064 nm, power 2000 W, spot size 5 mm diameter circular spot, scanning speed 540 mm / min, and overlap rate 60%. As the semiconductor laser moves, a uniform nickel-based ceramic particle-reinforced surface coating is obtained on the alloy surface of transition layer-1, resulting in a uniform, gradient-varying wear-resistant transition layer. The thickness of transition layer-2 is 1 mm.

[0040] Step 6: Grind with a grinding wheel to remove the surface oxide scale, resulting in a smooth and bright surface;

[0041] Step 7, Laser Cladding Functional Layer: Laser cladding is performed on the surface of transition layer-2 using a high-power semiconductor laser. Powder is fed using pneumatic or gravity methods, with a powder thickness of 1.7 mm. The laser process parameters are: laser wavelength 1064 nm, power 2500 W, spot size 5 mm diameter circular spot, scanning speed 480 mm / min, and overlap rate 60%. As the semiconductor laser moves, a uniform nickel-based ceramic particle-reinforced surface coating is obtained on the alloy surface of transition layer-2, resulting in a uniform, gradient-varying high-temperature wear-resistant functional layer with a thickness of 1.5 mm.

[0042] In summary, the advantages of the coating of this invention are: 1. The coating consists of three layers from the substrate outwards: transition layer 1, transition layer 2, and functional layer. The composition and ratio of the metal powder in each layer are rationally selected and controlled. Considering temperature gradients and thermal stress distribution, the risk of coating peeling caused by thermal stress is effectively reduced through gradient structure control, while simultaneously enhancing the bonding strength between the coating and the substrate. This results in a greater gradient change in the wear resistance and high-temperature resistance of the three layers. Therefore, the coating can significantly improve the wear resistance, high-temperature resistance, and mechanical strength of the substrate material, effectively reducing wear under high-speed flow or high-load working conditions. First, by reducing surface damage, the stability and lifespan of the material are enhanced in high-temperature environments, leading to its widespread application under high-temperature, high-pressure, and high-speed operating conditions. Second, by precisely determining the process parameters of laser cladding, the density of the coating is ensured, avoiding cladding defects, improving the bonding strength, achieving tight bonding between multiple cladding layers, and ensuring a thicker cladding layer. This results in a composite cladding layer with excellent surface properties, enhancing the stability of the material in high-temperature environments, thereby extending the service life of the coating, significantly reducing maintenance cycles and costs, and having a positive impact on the stability and reliability of equipment operation.

Claims

1. A laser-clad nickel-based superalloy wear-resistant gradient coating, characterized in that: It comprises a transition layer-1, a transition layer-2, and a functional layer, arranged from the inside out of the matrix. The transition layer-1 uses nickel-based superalloy powder with the following composition by mass percentage: C: 0.05-0.08%, Cr: 17.0-21.0%, Ni: 50.0-55.0%, Mo: 2.8-3.3%, Co: 0.5-1.0%, Al: 0.3-0.7%, with the balance being Fe. The transition layer-2 uses nickel-based superalloy ceramic particle-reinforced alloy powder with the following composition by mass percentage: C: 1.8-2.5%, Cr: 10.0-17.0%. Ni: 30.0-44.0%, Mo: 1.6-2.6%, Co: 0.1-0.4%, Al: 0.06-0.3%, W: 18.0-38.0%, balance Fe; The nickel-based high-temperature alloy ceramic particle reinforced alloy powder used in the functional layer has the following composition by mass percentage: C: 4.0-8.0%, Cr: 10.0-17.0%, Ni: 30.0-44.0%, Mo: 1.6-2.6%, Co: 0.1-0.4%, Al: 0.06-0.3%, Ti: 16.0-32.0%, balance Fe.

2. The gradient coating according to claim 1, characterized in that: The particle size of the transition layer-1 nickel-based superalloy powder is 100-270 mesh; the particle size of the transition layer-2 nickel-based superalloy ceramic particle reinforced alloy powder is 100-270 mesh; and the particle size of the functional layer nickel-based superalloy ceramic particle reinforced alloy powder is 100-270 mesh.

3. The gradient coating according to claim 1, characterized in that: The thickness of transition layer-1 is 0.2-2mm, the thickness of transition layer-2 is 0.2-2mm, and the thickness of functional layer is 0.2-2mm.

4. The method for preparing a laser-clad nickel-based superalloy wear-resistant gradient coating according to claim 1, comprising the following specific steps: Step 1: Prepare alloy powders for the transition layer and functional layer; Step 2, matrix preparation; Step 3, Laser Cladding Transition Layer-1: A high-power semiconductor laser is used to laser clad the transition layer-1 on the surface of the metal substrate. Powder is fed by pneumatic or gravity feeding methods, and the powder thickness is 0.5-2.5mm. Step 4: Remove the surface oxide scale by turning; Step 5, Laser cladding transition layer-2: The transition layer-2 is laser clad onto the surface of the transition layer-1 using a high-power semiconductor laser. Powder is fed by pneumatic or gravity feeding methods, and the powder thickness is 0.5-2.5 mm. Step 6: Grind with a grinding wheel to remove the surface oxide scale; Step 7, Laser Cladding Functional Layer: The functional layer is laser clad onto the surface of the transition layer-2 using a high-power semiconductor laser. Powder is fed using pneumatic or gravity feeding methods, with a powder thickness of 0.5-2.5 mm.

5. The preparation method according to claim 4, characterized in that: Step 2 specifically involves removing oil and oxide scale from the substrate surface by turning followed by oxyacetylene torching or shot peening.

6. The preparation method according to claim 4, characterized in that: In step 3, the laser process parameters are: laser wavelength 1064nm, power 1000-4000W, spot size 5mm diameter circular spot, scanning speed 500-700mm / min, and overlap rate 50%-70%.

7. The preparation method according to claim 4, characterized in that: in step 5: the laser process parameters are: laser wavelength 1064nm, power 1000-4000W, spot size is a circular spot with a diameter of 5mm, scanning speed is 360-600mm / min, and overlap rate is 50%-70%.

8. The preparation method according to claim 4, characterized in that: In step 7: the laser process parameters are: laser wavelength 1064nm, power 1000-4000W, spot size 5mm diameter circular spot, scanning speed 360-600mm / min, and overlap rate 50%-70%.

9. The preparation method according to claim 4, characterized in that: In step 5: the alloy powder of transition layer-2 is mixed evenly using a mechanical powder mixer before cladding, and the mixing time is 2-3 hours; in step 7: the alloy powder of functional layer is mixed evenly using a mechanical powder mixer before cladding, and the mixing time is 2-3 hours.

10. The preparation method according to claim 4, characterized in that: in step 1: after the three alloy powders are prepared, they are placed in a drying oven for 2 hours at a set temperature of 150°C to remove water vapor from the powders.

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