Surface treatment method and device for a CoNiCrAlY alloy

Abstract

This invention provides a surface treatment method and apparatus for CoNiCrAlY alloys, relating to the field of CoNiCrAlY alloy technology. The surface treatment method includes: performing laser scanning on the surface of the CoNiCrAlY alloy under a predetermined atmosphere to remelt its surface; wherein the predetermined atmosphere is formed by oxygen and a protective gas, wherein the partial pressure of the oxygen in the predetermined atmosphere is 0.001 atm to 0.100 atm, and the partial pressure of the protective gas is 0.900 atm to 0.999 atm. Using the method of this invention, the depletion rate of the β phase inside the CoNiCrAlY alloy can be significantly reduced, which is beneficial to improving the long-term oxidation resistance of the CoNiCrAlY alloy under high-temperature environments.

Description

Technical Field

[0001] This invention relates to the field of CoNiCrAlY alloy technology, and more specifically, to a surface treatment method and apparatus for CoNiCrAlY alloy. Background Technology

[0002] CoNiCrAlY alloy, as a typical MCrAlY (M is Ni, Co or NiCo) type high-temperature oxidation-resistant material, has excellent high-temperature oxidation resistance, corrosion resistance and good thermal matching performance. It is widely used in hot-end components of aero-engines and gas turbines. Its oxidation resistance mainly depends on the continuous supply of Al elements to the surface by the Al-rich β phase in the alloy under high temperature environment, thereby forming a dense Al2O3 oxide film to protect the alloy matrix from further oxidation.

[0003] However, during long-term high-temperature oxidation, the Al2O3 oxide layer exhibits a high grain boundary diffusion rate and a tendency for oxygen to diffuse along grain boundaries into the alloy interior. This leads to the continuous consumption of Al within the CoNiCrAlY alloy, forming a β-phase depletion region, which in turn reduces the structural stability and service life of the CoNiCrAlY alloy. Therefore, reducing the β-phase depletion rate of the CoNiCrAlY alloy under high-temperature oxidation conditions, thereby improving its long-term oxidation resistance, is crucial for enhancing its structural stability and service life. Summary of the Invention

[0004] The problem addressed by this invention is: how to reduce the depletion rate of the β phase in CoNiCrAlY alloys under high-temperature oxidation conditions.

[0005] To address the above problems, this invention provides a surface treatment method for CoNiCrAlY alloy, comprising: The surface of a CoNiCrAlY alloy is laser-scanned under a predetermined atmosphere to remelt the surface; wherein the predetermined atmosphere is formed by oxygen and a protective gas, and the partial pressure of the oxygen in the predetermined atmosphere is 0.001 atm to 0.100 atm, and the partial pressure of the protective gas is 0.900 atm to 0.999 atm.

[0006] Optionally, in the predetermined atmosphere, the partial pressure of the oxygen is 0.001 atm to 0.010 atm, and the partial pressure of the protective gas is 0.990 atm to 0.999 atm.

[0007] Optionally, the protective gas includes one of nitrogen, helium, neon, argon, krypton, xenon, and radon.

[0008] Optionally, the laser power used in the laser scanning is 400W to 600W.

[0009] Optionally, the laser spot diameter used in the laser scanning is 500 μm.

[0010] Optionally, the spacing between adjacent laser scanning trajectories during the laser scanning process is 250 μm.

[0011] Optionally, the laser scanning speed is from 200 mm / min to 600 mm / min.

[0012] Optionally, the surface of the CoNiCrAlY alloy can be laser-scanned using a continuous fiber laser.

[0013] Optionally, the predetermined atmosphere is achieved by adjusting the flow rate ratio of oxygen and protective gas introduced into the surface region of the CoNiCrAlY alloy.

[0014] The present invention also provides an apparatus for implementing the surface treatment method of CoNiCrAlY alloy as described above, comprising a laser system, an atmosphere introduction system, and a control system; the laser system is used to perform laser scanning on the surface of CoNiCrAlY alloy to remelt its surface; the atmosphere introduction system includes a protective gas nozzle and an oxygen nozzle for introducing protective gas and oxygen; the control system is used to adjust the flow rate ratio of the oxygen to the protective gas to ensure that the laser molten pool area on the surface of CoNiCrAlY alloy is in a preset atmosphere.

[0015] Compared with related technologies, this invention remelts the surface of CoNiCrAlY alloy using laser scanning in a mixed atmosphere composed of a specific ratio of oxygen and protective gas. This maintains a specific oxygen partial pressure in the molten pool region of the CoNiCrAlY alloy surface. Under this specific oxygen partial pressure and the high temperature (above 1200°C) of the laser molten pool, selective oxidation reactions of Y and Al elements in the CoNiCrAlY alloy are induced, thereby forming an in-situ oxidation reaction of Al2O3 as the continuous phase and Y3Al5O3 as the auxiliary phase on the surface of the CoNiCrAlY alloy. 12 The composite oxide layer, which is a grain boundary strengthening phase, can effectively inhibit the diffusion of O into the CoNiCrAlY alloy and the diffusion of Al out of the CoNiCrAlY alloy, thereby significantly reducing the β phase depletion rate inside the CoNiCrAlY alloy and improving the long-term oxidation resistance of the CoNiCrAlY alloy under high temperature environment. Attached Figure Description

[0016] Figure 1 A schematic diagram of an apparatus for implementing the surface treatment method for CoNiCrAlY alloy of the present invention; Figure 2This is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Example 1 of this invention; Figure 3 The image shown is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Example 1 of this invention after being placed in an oxidizing environment at 1100℃ for 100 hours. Figure 4 The image shown is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Example 4 of this invention after being placed in an oxidizing environment at 1100℃ for 100 hours. Figure 5 The image shown is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Example 5 of this invention after being placed in an oxidizing environment at 1100℃ for 100 hours. Figure 6 The image shown is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Comparative Example 1 of this invention after being placed in an oxidizing environment at 1100℃ for 100 hours. Figure 7 This is a cross-sectional scanning electron microscope image of the CoNiCrAlY alloy sample prepared in Comparative Example 2 of this invention, obtained after being placed in an oxidizing environment at 1100℃ for 100 hours.

[0017] Explanation of reference numerals in the attached figures: 1. Laser generator; 2. Laser beam; 3. Collimating lens; 4. Focusing lens; 5. Protective cover; 6. Oxygen nozzle; 7. Protective gas nozzle; 8. Mass flow meter; 9. Oxygen concentration sensor; 10. CoNiCrAlY alloy sample. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] It should be noted that in this invention, atm represents standard atmospheric pressure.

[0022] This invention provides a surface treatment method for CoNiCrAlY alloy, comprising: The surface of a CoNiCrAlY alloy is laser-scanned under a predetermined atmosphere to remelt the surface; wherein the predetermined atmosphere is formed by oxygen and a protective gas, and the partial pressure of the oxygen in the predetermined atmosphere is 0.001 atm to 0.100 atm, and the partial pressure of the protective gas is 0.900 atm to 0.999 atm.

[0023] In this embodiment of the invention, the surface of a CoNiCrAlY alloy is remelted by laser scanning under a mixed atmosphere composed of a specific ratio of oxygen and a protective gas. This maintains a specific oxygen partial pressure in the molten pool region on the CoNiCrAlY alloy surface. Under this specific oxygen partial pressure and the high temperature (above 1200°C) of the laser molten pool, selective oxidation reactions of Y and Al elements in the CoNiCrAlY alloy are induced, thereby forming an in-situ oxidation reaction of Al2O3 as the continuous phase and Y3Al5O3 as the precursor on the surface of the CoNiCrAlY alloy. 12 The composite oxide layer, which is a grain boundary strengthening phase, can effectively inhibit the diffusion of O into the CoNiCrAlY alloy and the diffusion of Al out of the CoNiCrAlY alloy, thereby significantly reducing the β phase depletion rate inside the CoNiCrAlY alloy and improving the long-term oxidation resistance of the CoNiCrAlY alloy under high temperature environment.

[0024] In some embodiments of the present invention, preferably, the partial pressure of oxygen in the predetermined atmosphere is 0.001 atm to 0.010 atm, and the partial pressure of the protective gas is 0.990 atm to 0.999 atm. Specifically, the predetermined atmosphere can be obtained by adjusting the flow rate ratio of oxygen to protective gas introduced into the surface region of the CoNiCrAlY alloy. Experiments have shown that controlling the oxygen flow rate at 500 sccm to 1500 sccm can effectively suppress the generation of microcracks in the oxide layer on the surface of the CoNiCrAlY alloy caused by high residual stress.

[0025] In some embodiments of the present invention, the protective gas, exemplarily, includes one of nitrogen, helium, neon, argon, krypton, xenon, and radon.

[0026] In some embodiments of the present invention, the laser power used for laser scanning is 400W to 600W.

[0027] In some embodiments of the present invention, the laser spot diameter used for laser scanning is 500 μm; the spacing between adjacent laser scanning trajectories during the laser scanning process is 250 μm. In some embodiments of the present invention, the laser scanning speed is 200 mm / min to 600 mm / min; experiments have shown that when the laser scanning speed is 200 mm / min to 600 mm / min, the β phase depletion rate inside the CoNiCrAlY alloy can be reduced more significantly.

[0028] In some embodiments of the present invention, the surface of the CoNiCrAlY alloy is laser-scanned using a continuous fiber laser.

[0029] like Figure 1 As shown in the figure, this invention also provides an apparatus for implementing the surface treatment method for CoNiCrAlY alloy as described above, including a laser system, an atmosphere introduction system, and a control system; the laser system includes a laser generator 1, a collimating lens 3, a focusing lens 4, and a protective cover 5, and is used to perform laser scanning on the surface of CoNiCrAlY alloy to remelt its surface; the atmosphere introduction system includes a protective gas nozzle 7, an oxygen nozzle 6, and a mass flow meter 8, and is used to introduce protective gas and oxygen; the control system includes an oxygen concentration sensor 9 and a controller, and the control system adjusts the flow ratio of oxygen to protective gas based on the detection result of the oxygen concentration sensor 9, so that the laser molten pool area on the surface of CoNiCrAlY alloy is in a preset atmosphere.

[0030] In operation, protective gas and oxygen are introduced onto the surface of the CoNiCrAlY alloy through protective gas nozzle 7 and oxygen nozzle 6, respectively. The oxygen partial pressure is detected by oxygen concentration sensor 9. The controller adjusts the flow rate ratio of the protective gas and oxygen based on the sensor's readings to achieve the preset atmosphere. A laser beam 2 emitted by laser generator 1 is applied to the CoNiCrAlY alloy sample 10 via collimating lens 3, protective cover 5, and focusing lens 4. This device monitors the flow rates of the protective gas and oxygen to regulate the oxygen partial pressure, thereby controlling the composition and thickness of the oxide film.

[0031] The present invention will be further described below with reference to specific embodiments.

[0032] Example 1 Under a predetermined atmosphere, the surface of a CoNiCrAlY alloy was laser-scanned to remelt the surface, resulting in a CoNiCrAlY alloy sample. The predetermined atmosphere consisted of oxygen and a protective gas, with nitrogen as the protective gas. The partial pressure of oxygen in the predetermined atmosphere was 0.05 atm, and the partial pressure of the protective gas was 0.950 atm. The laser power used for the laser scanning was 400 W, the laser spot diameter was 500 μm, the spacing between adjacent laser scanning trajectories was 250 μm, and the laser scanning speed was 200 mm / min.

[0033] Example 2 Under a predetermined atmosphere, the surface of a CoNiCrAlY alloy was laser-scanned to remelt the surface, resulting in a CoNiCrAlY alloy sample. The predetermined atmosphere consisted of oxygen and a protective gas, with nitrogen as the protective gas. The partial pressure of oxygen in the predetermined atmosphere was 0.001 atm, and the partial pressure of the protective gas was 0.999 atm. The laser power used for the laser scanning was 400 W, the laser spot diameter was 500 μm, the spacing between adjacent laser scanning trajectories was 250 μm, and the laser scanning speed was 200 mm / min.

[0034] Example 3 Under a predetermined atmosphere, the surface of a CoNiCrAlY alloy was laser-scanned to remelt the surface, resulting in a CoNiCrAlY alloy sample. The predetermined atmosphere consisted of oxygen and a protective gas, with nitrogen as the protective gas. The partial pressure of oxygen in the predetermined atmosphere was 0.100 atm, and the partial pressure of the protective gas was 0.900 atm. The laser power used for the laser scanning was 400 W, the laser spot diameter was 500 μm, the spacing between adjacent laser scanning trajectories was 250 μm, and the laser scanning speed was 200 mm / min.

[0035] Example 4 The difference from Example 1 is that the laser scanning speed is 400 mm / min.

[0036] Example 5 The difference from Example 1 is that the laser scanning speed is 600 mm / min.

[0037] Comparative Example 1 The CoNiCrAlY alloy was heat-treated under a nitrogen protective atmosphere to obtain a CoNiCrAlY alloy sample; the heat treatment temperature was 1100℃ and the time was 2h.

[0038] Comparative Example 2 The difference from Example 1 is that the laser scanning speed is 800 mm / min.

[0039] Effect Example The cross-section of the CoNiCrAlY alloy sample prepared in Example 1 was characterized by scanning electron microscopy. The results are shown in the figure. Figure 2 The CoNiCrAlY alloy samples prepared in Examples 1, 4, 5, Comparative Example 1, and Comparative Example 2 were placed in an oxidation environment at 1100℃ for 100 h. The cross-sections of the resulting samples were then analyzed by scanning electron microscopy. The results are shown in [Figure 1]. Figures 3 to 7 ,from Figures 3 to 7 It can be seen that the CoNiCrAlY alloy samples prepared in Examples 1, 4, and 5, after being placed in an oxidizing environment at 1100℃ for 100 hours, did not exhibit a β-phase depletion region, while the samples obtained in Comparative Examples 1 and 2 all showed obvious β-phase depletion regions. Therefore, the β-phase depletion rate of the CoNiCrAlY alloy samples prepared in Examples 1, 4, and 5 is relatively low. Figure 6 and Figure 7 It can be seen that, compared with Comparative Example 1, the β-phase depletion region of the sample obtained in Comparative Example 2 is smaller, indicating that the β-phase depletion rate of the CoNiCrAlY alloy sample prepared in Comparative Example 2 is relatively small.

[0040] It should be noted that, Figures 3 to 7 In this context, "β phase" represents the β phase. Figure 6 and Figure 7 The term "β depletion zone" refers to the β phase depletion zone.

[0041] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A surface treatment method for CoNiCrAlY alloy, characterized in that, include: The surface of a CoNiCrAlY alloy is laser-scanned under a predetermined atmosphere to remelt the surface; wherein the predetermined atmosphere is formed by oxygen and a protective gas, and the partial pressure of the oxygen in the predetermined atmosphere is 0.001 atm to 0.100 atm, and the partial pressure of the protective gas is 0.900 atm to 0.999 atm.

2. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, In the predetermined atmosphere, the partial pressure of oxygen is 0.001 atm to 0.010 atm, and the partial pressure of the protective gas is 0.990 atm to 0.999 atm.

3. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The protective gas includes one of nitrogen, helium, neon, argon, krypton, xenon, and radon.

4. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The laser scanning uses a laser power of 400W to 600W.

5. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The laser scanning uses a laser spot diameter of 500 μm.

6. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The distance between adjacent laser scanning trajectories during the laser scanning process is 250 μm.

7. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The laser scanning speed is from 200 mm / min to 600 mm / min.

8. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The surface of the CoNiCrAlY alloy was laser-scanned using a continuous fiber laser.

9. The surface treatment method for CoNiCrAlY alloy according to claim 1, characterized in that, The predetermined atmosphere is achieved by adjusting the flow rate ratio of oxygen and protective gas introduced into the surface region of the CoNiCrAlY alloy.

10. An apparatus for performing the surface treatment method for CoNiCrAlY alloy as described in any one of claims 1 to 9, characterized in that, The system includes a laser system, an atmosphere introduction system, and a control system. The laser system is used to perform laser scanning on the surface of the CoNiCrAlY alloy to remelt its surface. The atmosphere introduction system includes a protective gas nozzle and an oxygen nozzle for introducing protective gas and oxygen. The control system is used to adjust the flow ratio of the oxygen to the protective gas so that the laser molten pool area on the CoNiCrAlY alloy surface is in a preset atmosphere.

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