A reaction wear protection type nickel-based superalloy and a preparation method thereof

Abstract

This invention discloses a reactive wear-protective nickel-based superalloy and its preparation method, belonging to the field of superalloy preparation technology. The preparation method includes the following steps: S1, preparing the alloy according to the nickel-based superalloy composition, vacuum smelting, and then homogenizing to eliminate harmful phases such as low-melting-point phases, obtaining a nickel-based superalloy ingot; S2, hot-deforming the nickel-based superalloy ingot, annealing, and machining to the target size, obtaining a bulk alloy; S3, locally performing large plastic deformation on the surface of the bulk alloy, electrolytic polishing, and sanding; S4, pre-oxidizing the polished alloy to obtain a reactive wear-protective nickel-based superalloy. This invention forms in-situ phases and microstructures with anti-wear effects during high-temperature friction and wear, thereby significantly enhancing the wear resistance of the bulk material and effectively solving the problems of insufficient wear resistance and wear-strengthening failure in existing reinforced bulk nickel-based superalloys.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy preparation technology, specifically to a reactive wear-protective nickel-based high-temperature alloy and its preparation method. Background Technology

[0002] Nickel-based superalloys possess excellent oxidation and corrosion resistance at high temperatures, as well as superior high-temperature strength and fatigue resistance, making them widely used in the manufacture of hot-end components in aerospace, aviation, marine, chemical, and power industries. However, friction and wear are unavoidable phenomena during their service in these fields, often leading to premature workpiece failure. Furthermore, with the gradual development of high-end equipment manufacturing and cutting-edge industries, the friction and wear problem of nickel-based superalloys is becoming increasingly prominent. Therefore, creating nickel-based superalloys with excellent wear resistance has become an urgent issue to be addressed in many fields.

[0003] Extensive practical work has shown that the main methods for improving the wear resistance of nickel-based superalloys include electroplating, electroless plating, vapor deposition, chemical conversion coatings, and substrate surface modification. However, the surface wear-resistant reinforcing layer introduced by these technologies usually has a clear boundary with the substrate layer, causing the reinforcing layer to easily peel off and fail during actual service. In addition, surface treatment techniques for enhancing the wear resistance of nickel-based superalloys are all implemented on bulk materials, and after treatment, a reinforcing layer of a certain thickness is formed only on the surface of the bulk material. Moreover, the reinforcing layer is usually on the micrometer scale and is prone to losing its reinforcing effect in long-term friction and wear environments.

[0004] The wear resistance of existing bulk nickel-based superalloys is insufficient, which limits their wider application. While surface technology can enhance the wear resistance of bulk materials to some extent, it has problems such as poor adhesion between the reinforcing layer and the base layer, and a thin reinforcing layer. This makes it easy for bulk nickel-based superalloys to lose their reinforcing effect during high-temperature friction and wear. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a reactive wear-protective nickel-based superalloy and its preparation method. During high-temperature friction and wear, a phase and microstructure with anti-wear effect are formed in situ, thereby significantly enhancing the wear resistance of the bulk material. This effectively solves the problems of insufficient wear resistance and wear-strengthening failure in existing reinforced bulk nickel-based superalloys.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing a reactive wear-protective nickel-based superalloy is provided, comprising the following steps:

[0007] S1. Prepare the alloy according to the composition of nickel-based high-temperature alloy, and vacuum smelt until the surface of the ingot is smooth and clean (without surface defects such as cracks, pinholes, and bubbles), and the internal structure of the ingot is uniform and dense (without internal defects such as shrinkage cavities, shrinkage porosity, segregation, and gas pores). Then, homogenize it at 1100-1220 ℃ for 20-50 h to eliminate harmful phases such as low melting point, and obtain nickel-based high-temperature alloy ingot.

[0008] S2. Hot deformation of nickel-based superalloy ingots at 1000-1160 ℃, with a total deformation of 30%-70%, followed by annealing at 900-1100 ℃ for 20-60 min to obtain equiaxed recrystallized grains without deformed grains or substructure grains. Machining to the target size yields a bulk alloy.

[0009] S3. Local large plastic deformation is performed on the surface of the bulk alloy to obtain a gradient structure layer with a thickness greater than 500 μm. The size of the gradient structure decreases from the surface to the inside. The microstructure of the gradient structure mainly includes large and small angle grain boundaries, dislocations, and twins. Then, the surface roughness of the bulk alloy is electropolished to less than 0.1 μm, and sandpaper is used to polish it to a roughness of 0.8 μm ≤ Ra ≤ 1.8 μm.

[0010] S4. The polished alloy is pre-oxidized at 500-800 ℃ for 10-30 min to form Cr2O3 and Ni(Fe,Cr)2O4 oxides on the surface, thus obtaining a reactive wear-protected nickel-based high-temperature alloy.

[0011] Further, in step S1, the nickel-based superalloy comprises the following components by mass percentage: Cr: 17-23%, Mo: 8.5-10.5%, Fe: 3-6%, Nb: 3-4.5%, W: 1.5-4%, Co: 0.5-1.5%, Al: 0.2-0.5%, Ti: 0.1-0.5%, Mn: 0.3-0.7%, Si: 0.3-0.6%, P: 0.01-0.015%, S: 0.01-0.015%, C: 0.1-0.3%, Ni: balance.

[0012] Furthermore, in step S1, the ingot gas content is O2≤86 ppm, N2≤86 ppm, and the inclusions are controlled below level 2 (GB / T10561-2023 "Standard Rating Chart Microscopic Examination Method for Determination of Non-metallic Inclusion Content in Steel").

[0013] Furthermore, in step S1, vacuum induction melting is performed at a temperature of 1350-1400 ℃ for 5-10 min.

[0014] Furthermore, the vacuum degree of vacuum induction melting is ≤0.1 Pa.

[0015] Furthermore, in step S2, the material is machined to 100×40×5 mm. 3 Square.

[0016] Furthermore, in step S3, large local plastic deformation of the block alloy surface is carried out by mechanical rolling.

[0017] Furthermore, in step S3, electropolishing is performed in a mixture of perchloric acid and alcohol at a volume ratio of 1:9.

[0018] The present invention also provides a reactive wear-protected nickel-based superalloy prepared by the above-mentioned method.

[0019] Furthermore, the surface of nickel-based superalloys has oxides and subsurface layers.

[0020] The present invention has the following beneficial effects:

[0021] 1. The nickel-based superalloy prepared by the method of the present invention can form wear-resistant surface oxides and special internal microstructures in situ during high-temperature friction and wear, that is, reactive wear-protective nickel-based superalloy. The reasons are as follows: 1) The nickel-based superalloy with this smelting ratio has excellent tensile strength and elongation, and can generate a large number of twins during large plastic deformation, which helps to enhance the wear resistance of the sample; 2) By performing local plastic deformation on the alloy surface, a gradient microstructure is formed on its surface. The gradient microstructure can accommodate a larger strain without strain localization during friction and wear, thereby enhancing the wear resistance of the alloy; furthermore, during friction, the alloy surface is also subjected to a strain gradient, which causes the original gradient structure to re-form a gradient structure in situ on the surface after one layer is worn away; 3) By controlling the surface roughness to be between 0.8 μm≤Ra≤1.8 μm, this range helps to form Cr2O3 and Ni(Fe,Cr)2O4 oxides. These oxides can undergo structural deformation from ordered to disordered after being subjected to shear force during friction and wear, ultimately leading to improved wear resistance.

[0022] 2. The reactive wear-resistant bulk nickel-based superalloy of the present invention exhibits excellent wear resistance. During high-temperature friction and wear, Cr₂O₃ and Ni(Fe,Cr)₂O₄ oxides with sufficiently excellent wear resistance are generated near the surface of the wear track, while a gradient microstructure and numerous twins with excellent wear resistance are generated on the subsurface of the wear track. The near-surface oxides and the special microstructure of the subsurface layer form a composite protective layer. This alloy continuously forms a wear-resistant composite structure in situ during friction and wear, thus constituting a reactive wear-resistant nickel-based superalloy.

[0023] 3. During preparation, the resulting open-rolled and annealed alloy exhibits a uniformly distributed microstructure, a tensile strength of 880 MPa, an elongation of 33%, and a microhardness of 310 HV. 0.2 Furthermore, the obtained nickel-based superalloy exhibits a gradient structure in the subsurface layer of the wear track during high-temperature friction and wear, and contains a large number of deformed twins. As is well known, twins have a significant effect on the strength, stability, and wear resistance of alloys. During high-temperature friction and wear, a large amount of Cr2O3 and Ni(Fe,Cr)2O4 oxides can be formed on the wear track surface; these oxides can significantly reduce friction and wear.

[0024] 4. The nickel-based superalloy of the present invention has a friction coefficient of 0.12 and a wear rate of 6.3 × 10⁻⁶ at 700 °C. -4 mm 3 / (N·m); the coefficient of friction at 800℃ is 0.08, and the wear rate is 4.1×10. -4 mm 3 / (N·m); Compared with existing nickel-based superalloys, it has better wear resistance.

[0025] 5. The nickel-based superalloy of this invention exhibits a strong reactive wear protection effect during high-temperature friction and wear processes. It can continuously generate oxides and renew the special microstructure of the subsurface layer, significantly enhancing its wear resistance. Compared with existing methods that enhance the wear resistance of nickel-based superalloys through surface treatment, the bulk alloy of this invention can enhance its wear resistance itself and has self-repairing capabilities, i.e., a reactive wear protection effect. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the microstructure of the nickel-based superalloy of the present invention;

[0027] Figure 2 This is a schematic diagram of the gradient microstructure on the surface of the nickel-based superalloy of the present invention;

[0028] Figure 3 The figures show a comparison between the nickel-based superalloy of the present invention and the conventional Inconel 625 alloy; (a) shows the Raman peak of the wear surface of the conventional Inconel 625 alloy, and (b) shows the Raman peak of the wear surface of the nickel-based superalloy obtained in Example 1. Detailed Implementation

[0029] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] Example 1

[0031] A reactive wear-protective nickel-based superalloy is prepared by the following steps:

[0032] S1. Prepare the alloy according to the composition of nickel-based superalloy, and vacuum smelt (vacuum induction melting at 1380 ℃ for 8 min, vacuum degree of 0.1 Pa) until the surface of the ingot is smooth and clean (no surface defects such as cracks, pinholes, and bubbles), the internal structure of the ingot is uniform and dense (no internal defects such as shrinkage cavities, shrinkage porosity, segregation, and gas pores), the gas content of the ingot is O2≤86 ppm, N2≤86 ppm, and the inclusions are controlled below level 2 (GB / T10561-2023 "Standard Rating Chart Microscopic Inspection Method for Determination of Non-metallic Inclusion Content in Steel"). Then, homogenize it at 1140 ℃ for 48 h to eliminate harmful phases such as low melting point, and obtain nickel-based superalloy ingot.

[0033] The nickel-based superalloy comprises the following components by weight percentage: Cr: 23%, Mo: 9.5%, Fe: 4.5%, Nb: 4.5%, W: 2%, Co: 1.5%, Al: 0.3%, Ti: 0.2%, Mn: 0.6%, Si: 0.4%, P: 0.01%, S: 0.01%, C: 0.2%, Ni: balance;

[0034] S2. The nickel-based superalloy ingot was hot-deformed at 1125 °C, with a total deformation of 43.5%. It was then annealed at 1100 °C for 30 min to obtain an equiaxed recrystallized grain structure without deformed grains or substructured grains. Its tensile strength and elongation were 885.4 MPa and 33.6%, respectively, and its microhardness was 318.9 HV. 0.2 Machining to 100×40×5 mm 3 Cube, obtain block alloy;

[0035] S3. The bulk alloy block is mechanically rolled on the surface of the plate to obtain a gradient structure layer with a thickness greater than 650 μm. The size of the gradient structure decreases from the surface to the inside. The microstructure of the gradient structure mainly includes large and small angle grain boundaries, dislocations, and twins. Then, it is electrolyzed (perchloric acid and alcohol volume ratio 1:9) and polished until the surface roughness Ra=0.067 μm, and then sanded with 120-1500 mesh water sandpaper until the roughness Ra=1.12 μm.

[0036] S4. The polished alloy is pre-oxidized at 600 ℃ for 30 min to form Cr2O3 and Ni(Fe,Cr)2O4 oxides on the surface, thus obtaining a reactive wear-protected nickel-based high-temperature alloy.

[0037] The microstructure of the nickel-based superalloy of the present invention is as follows: Figure 1 As shown, the gradient microstructure on the surface of the nickel-based superalloy is as follows: Figure 2 As shown.

[0038] Depend on Figure 1 It is known that the grain structure of the nickel-based superalloy of the present invention is equiaxed recrystallized grains, without deformed grains and substructure grains.

[0039] Depend on Figure 2 It can be seen that the gradient structure on the surface of nickel-based superalloys decreases in size from the surface to the interior. The microstructure of the gradient structure mainly includes large and small angle grain boundaries, dislocations, and twins.

[0040] The obtained reactive wear-protected nickel-based superalloy was subjected to wear resistance testing at 700 °C (load 15 N, sliding speed 1 m / s) on a ball-and-disc high-temperature dry sliding friction and wear test. The friction coefficient of the reactive wear-protected nickel-based superalloy was found to be 0.12, and the wear rate was 6.3 × 10⁻⁶. -4 mm 3 / (N·m). This nickel-based superalloy exhibits better wear resistance compared to existing nickel-based superalloys. Raman spectroscopy was used to analyze the oxide peaks of Inconel 625 alloy (Inconel 625 alloy is generally considered to be a nickel-based superalloy with good wear resistance) and the alloy of this invention, such as... Figure 3 As shown. By Figure 3 It is known that the wear surface of the nickel-based superalloy of the present invention has strong Cr2O3 and Ni(Fe,Cr)2O4 oxide peaks (a large number of studies have shown that Cr2O3 and Ni(Fe,Cr)2O4 oxides can effectively reduce the wear rate and enhance the wear resistance of the alloy).

[0041] Example 2

[0042] A reactive wear-protective nickel-based superalloy is prepared by the following steps:

[0043] S1. Prepare the alloy according to the composition of nickel-based superalloy, and vacuum smelt (vacuum induction melting at 1380 ℃ for 8 min, vacuum degree of 0.1 Pa) until the surface of the ingot is smooth and clean (no surface defects such as cracks, pinholes, and bubbles), the internal structure of the ingot is uniform and dense (no internal defects such as shrinkage cavities, shrinkage porosity, segregation, and gas pores), the gas content of the ingot is O2≤86 ppm, N2≤86 ppm, and the inclusions are controlled below level 2 (GB / T10561-2023 "Standard Rating Chart Microscopic Inspection Method for Determination of Non-metallic Inclusion Content in Steel"). Then, homogenize it at 1120 ℃ for 48 h to eliminate harmful phases such as low melting point, and obtain nickel-based superalloy ingot.

[0044] The nickel-based superalloy comprises the following components by weight percentage: Cr: 19%, Mo: 10.5%, Fe: 5%, Nb: 4.5%, W: 3.2%, Co: 1.1%, Al: 0.2%, Ti: 0.3%, Mn: 0.6%, Si: 0.5%, P: 0.012%, S: 0.011%, C: 0.2%, Ni: balance;

[0045] S2. The nickel-based superalloy ingot was hot-deformed at 1000 °C with a total deformation of 50%, and then annealed at 1100 °C for 30 min to obtain equiaxed recrystallized grains without deformed grains or substructure grains. Its tensile strength and elongation were 897.4 MPa and 33.1%, respectively, and its microhardness was 321.4 HV. 0.2 Machining to 100×40×5 mm 3 Cube, obtain block alloy;

[0046] S3. The bulk alloy block is mechanically rolled on the surface of the plate to obtain a gradient structure layer with a thickness greater than 650 μm. The size of the gradient structure decreases from the surface to the inside. The microstructure of the gradient structure mainly includes large and small angle grain boundaries, dislocations, and twins. Then, it is electrolyzed (perchloric acid and alcohol volume ratio 1:9) and polished until the surface roughness Ra=0.07 μm. Then, it is sanded with 120-1500 mesh water sandpaper until the roughness Ra=1.72 μm.

[0047] S4. The polished alloy is pre-oxidized at 600 ℃ for 30 min to form Cr2O3 and Ni(Fe,Cr)2O4 oxides on the surface, thus obtaining a reactive wear-protected nickel-based high-temperature alloy.

[0048] The obtained nickel-based superalloy was subjected to wear resistance testing at 800 °C (load 15 N, sliding speed 1 m / s) on a ball-and-disc high-temperature dry sliding friction and wear test. The friction coefficient of the reactive wear-protective nickel-based superalloy was found to be 0.08, and the wear rate was 4.1 × 10⁻⁶. -4 mm 3 / (N·m). This nickel-based superalloy has better wear resistance compared to existing nickel-based superalloys.

[0049] In summary, the excellent wear resistance of the nickel-based superalloy of the present invention is due to the continuous formation of a large number of Cr2O3 and Ni(Fe,Cr)2O4 oxides on its wear surface and the continuous induction of gradient structure in the subsurface layer of the wear, wherein the gradient structure contains a large number of deformed twins.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a reactive wear-protective nickel-based superalloy, characterized in that, Includes the following steps: S1. Prepare the alloy according to the composition of nickel-based high-temperature alloy, vacuum smelt until the surface of the ingot is smooth and clean, and the internal structure of the ingot is uniform and dense, and then homogenize it at 1100-1220 ℃ for 20-50 h to obtain nickel-based high-temperature alloy ingot. S2. Hot deformation of nickel-based high-temperature alloy ingots at 1000-1160 ℃, with a total deformation of 30%-70%, followed by annealing at 900-1100 ℃ for 20-60 min, and machining to the target size to obtain bulk alloy. S3. Local large plastic deformation is performed on the surface of the bulk alloy to obtain a gradient structure layer with a thickness greater than 500 μm. The size of the gradient structure decreases from the surface to the inside. Then, the surface roughness of the bulk alloy is electropolished until it is less than 0.1 μm, and sandpaper is used to polish it until the roughness is 0.8 μm≤Ra≤1.8 μm. S4. The polished alloy is pre-oxidized at 500-800 ℃ for 10-30 min to form Cr2O3 and Ni(Fe,Cr)2O4 oxides on the surface, thus obtaining a reactive wear-protected nickel-based high-temperature alloy.

2. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S1, the nickel-based superalloy comprises the following components by mass percentage: Cr: 17-23%, Mo: 8.5-10.5%, Fe: 3-6%, Nb: 3-4.5%, W: 1.5-4%, Co: 0.5-1.5%, Al: 0.2-0.5%, Ti: 0.1-0.5%, Mn: 0.3-0.7%, Si: 0.3-0.6%, P: 0.01-0.015%, S: 0.01-0.015%, C: 0.1-0.3%, Ni: balance.

3. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S1, the ingot gas content is O2≤86 ppm, N2≤86 ppm, and inclusions are controlled to level 2 or below.

4. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S1, vacuum induction melting is carried out at a temperature of 1350-1400 ℃ for 5-10 min.

5. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S2, the material is machined to 100×40×5 mm. 3 Square.

6. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S3, large local plastic deformation of the block alloy surface is carried out by mechanical rolling.

7. The method for preparing the reactive wear-protective nickel-based superalloy as described in claim 1, characterized in that, In step S3, electropolishing is performed in a mixture of perchloric acid and alcohol at a volume ratio of 1:

9.

8. The reactive wear-protected nickel-based superalloy prepared by the method of any one of claims 1-7.

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