Cu-8al aluminum bronze wear-resistant reinforced material and preparation method thereof
Patent Information
- Application Number
- CN202610816423.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-08
- Publication Date
- 2026-08-21
AI Technical Summary
有鉴于此，本发明的目的在于提供一种Cu-8Al铝青铜耐磨强化材料及其制备方法，以解决现有技术中Cu-8Al铝青铜硬度与耐磨性解耦、表面涂层易剥落、粘着磨损严重等问题，实现耐磨性能的显著提升
本发明通过内生纳米Al2O3颗粒弥散强化实现基体强度的均匀提升，具体来说，内生纳米Al2O3颗粒与铜基体呈半共格界面，位错绕过机制有效阻碍塑性变形，基体硬度提升30%～50%，而弹性模量提升幅度控制在15%以内，有效避免了外加强化相引入的弹性模量失配问题。
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Figure CN122609886A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of copper alloy surface strengthening and wear-resistant treatment technology, and relates to a Cu-8Al aluminum bronze wear-resistant strengthening material and its preparation method. Background Technology
[0002] Aluminum bronze alloys are widely used in friction components such as marine propellers, sliding bearings, gears, turbines, and sealing rings due to their high strength, excellent plasticity, and corrosion resistance. Among them, Cu-8Al aluminum bronze alloys with an aluminum content of approximately 8 wt% exhibit significantly increased surface strength when the aluminum content exceeds 7%–8%, but their plasticity and toughness decrease somewhat. During service, they still face the following prominent problems: First, when the Cu-8Al aluminum bronze matrix comes into direct contact with the grinding pair (such as steel), the interfacial affinity is strong, which easily leads to adhesive wear, resulting in material transfer and surface failure.
[0003] Secondly, simply relying on strengthening methods that increase hardness often fails to linearly improve wear resistance. When a ceramic reinforcing phase with a high elastic modulus is introduced, due to the significant elastic modulus mismatch between the reinforcing phase and the copper matrix, the frictional contact stress is highly concentrated at the tip of the reinforcing phase, leading to the initiation and propagation of subsurface fatigue cracks. The wear mechanism changes from plastic furrowing to brittle contact fatigue spalling.
[0004] In addition, in the prior art, directly coating the surface of aluminum bronze with a ceramic coating or a hard chromium plating layer can significantly improve the surface hardness. However, due to the low elastic modulus of the copper substrate (about 110 GPa) and the high elastic modulus of the surface coating (up to 300~400 GPa), severe stress concentration occurs at the interface under load, leading to coating bending fracture and interface peeling.
[0005] Finally, in existing technologies, refining the grain size by adding alloying elements (such as Fe, Ni, Mn, etc.) can improve the strength to a certain extent, but the effect on improving wear resistance is limited; when strengthening by adding external ceramic particles (such as TiC, WC, etc.), if the interface bonding is poor or the particle distribution is uneven, the strengthening effect is unstable and it is easy to introduce the risk of brittle fracture; when preparing coatings by laser cladding, due to the high reflectivity of copper to laser and the lack of mechanical property gradient between the coating and the substrate, cracks and peeling defects are easy to occur.
[0006] Therefore, there is an urgent need to develop a wear-resistant reinforcing material for Cu-8Al aluminum bronze that can effectively suppress adhesive wear and avoid brittle spalling caused by elastic modulus mismatch, as well as a preparation method therefor. Summary of the Invention In view of this, the purpose of this invention is to provide a Cu-8Al aluminum bronze wear-resistant strengthening material and its preparation method, so as to solve the problems of decoupling of hardness and wear resistance, easy peeling of surface coating, and severe adhesive wear in the prior art of Cu-8Al aluminum bronze, and to achieve a significant improvement in wear resistance.
[0007] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, a Cu-8Al aluminum bronze wear-resistant strengthening material is provided, which includes a Cu-8Al aluminum bronze matrix and a composite gradient wear-resistant layer covering the surface of the matrix. The composite gradient wear-resistant layer includes a composition transition layer, a hard strengthening layer and a self-lubricating friction-reducing layer from the inside to the outside. The composition transition layer is metallurgically bonded to the surface of the Cu-8Al aluminum bronze matrix, and the composition in the composition transition layer gradually transitions from the Cu-8Al aluminum bronze matrix to the hard strengthening layer. The compositional transition layer includes several transition sublayers composed of Cu powder and Ni-based alloy powder with different mass fractions. In each transition sublayer, the ratio of Cu powder to Ni-based alloy powder changes continuously along the deposition direction.
[0008] Furthermore, the compositional transition layer includes a first transition sublayer and a second transition sublayer. The mass ratio of the powder in the first transition sublayer is: 70%–85% Cu powder and 15%–30% Ni-based alloy powder. The mass ratio of the powder in the second transition sublayer is: 30%–50% Cu powder and 50%–70% Ni-based alloy powder. In the first transition sublayer, the specific range in which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 85% to 70%, and the mass fraction of Ni-based alloy powder continuously increases from 15% to 30%. In the second transition sublayer, the specific range in which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 50% to 30%, and the mass fraction of Ni-based alloy powder continuously increases from 50% to 70%.
[0009] Furthermore, the first transition layer contains 70%–85% Cu powder, which includes 2%–5% Al powder by mass, and 15%–30% Ni-based alloy powder, which is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni. The second transition layer contains 30%–50% Cu powder, which includes 1%–3% Al powder by mass, and 50%–70% Ni-based alloy powder, which is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni.
[0010] Furthermore, the thickness of the component transition layer is 100–300 μm, and the elastic modulus varies continuously along the thickness direction, ranging from 120 to 180 GPa.
[0011] Furthermore, the Cu-8Al aluminum bronze matrix contains uniformly dispersed endogenous nano-Al2O3 particles; the mass fraction of the endogenous nano-Al2O3 particles is 0.5% to 3.0% of the total mass of the matrix, and the particle size ranges from 5 to 50 nm; the Cu-8Al aluminum bronze melt used to prepare the Cu-8Al aluminum bronze matrix contains 0.05% to 0.15% Zr element by mass, which is used to suppress the formation of coarse Al2O3 films at grain boundaries.
[0012] Furthermore, the hardened layer is synthesized in situ by laser cladding of Ni-based alloy powder and ceramic reinforcing phase powder. The thickness of the hardened layer is 300-600 μm, and the microhardness is 450-650 HV. The laser cladding powder of the hardened layer contains the following components by mass percentage: 75%-90% Ni-based alloy powder and 10%-25% ceramic reinforcing phase powder. The ceramic reinforcing phase powder is selected from one or a combination of TiB2 powder, WC powder and Cr3C2 powder.
[0013] Furthermore, the self-lubricating friction-reducing layer is formed by laser cladding of Cu-Ni-Sn alloy powder and solid lubricating phase powder, and the thickness of the self-lubricating friction-reducing layer is 80-150 μm. The laser cladding powder of the self-lubricating friction-reducing layer contains the following components by mass percentage: 70%-85% Cu-Ni-Sn alloy powder and 15%-30% solid lubricating phase powder; the solid lubricating phase powder is selected from one or a combination of several of MoS2 powder, WS2 powder and graphite powder, and the solid lubricating phase powder is chemically coated with nickel before laser cladding, and the coating layer thickness is 1-3 μm.
[0014] Furthermore, the surface of the composite gradient wear-resistant layer is treated with high-current pulsed electron beam irradiation to form a dense nanocrystalline surface layer with a thickness of 2-8 μm on the surface of the self-lubricating friction-reducing layer. The surface microhardness is 550-700 HV and the surface roughness Ra≤0.4 μm.
[0015] On the other hand, a method for preparing Cu-8Al aluminum bronze wear-resistant strengthening material is also provided, the method comprising: S1. The Cu-8Al aluminum bronze melt is subjected to internal oxidation treatment under a controlled oxygen partial pressure atmosphere to oxidize the Al element in the matrix in situ to generate Al2O3 particles, thereby obtaining a Cu-8Al aluminum bronze matrix with internal nano Al2O3 particle dispersion reinforcement. S2. The substrate surface obtained in step S1 is subjected to mechanical grinding, ultrasonic cleaning and preheating treatment in sequence. S3. A laser cladding and synchronous powder feeding process is adopted to deposit a composition transition layer layer by layer on the preheated substrate surface. By controlling the ratio of Cu powder to Ni-based alloy powder in the powder feeder to continuously change along the deposition direction, the gradient transition of composition is achieved. S4. On the surface of the component transition layer obtained in step S3, a hard reinforcement layer powder is deposited using a laser cladding and simultaneous powder feeding process. S5. On the surface of the hardened layer obtained in step S4, a self-lubricating friction-reducing layer powder is deposited using a laser cladding and simultaneous powder feeding process. S6. The surface of the self-lubricating friction-reducing layer obtained in step S5 is irradiated with a high-current pulsed electron beam to cause the surface layer to remelt and resolidify, forming a dense nanocrystalline surface layer.
[0016] Furthermore, each step of the method specifically includes: In step S1, the processing temperature is 850–950℃, the processing time is 2–8 hours, and the particle size of Al2O3 particles is 5–50 nm; before the internal oxidation treatment, 0.05%–0.15% Zr element by mass fraction is added to the Cu-8Al aluminum bronze melt; the controlled oxygen partial pressure range is 10. - ¹ 5 ~10 - ¹ 8 MPa; In step S2, the preheating temperature is 150–250°C; In step S3, the ratio of Cu powder to Ni-based alloy powder changes continuously along the deposition direction as follows: during the powder feeding process of the first transition sublayer, the mass ratio of Cu powder to Ni-based alloy powder changes linearly from 85:15 to 70:30; during the powder feeding process of the second transition sublayer, the mass ratio changes linearly from 50:50 to 30:70. In step S4, the laser power is 1.5–2.5 kW, the scanning speed is 5–15 mm / s, and the overlap rate is 40%–60%. In step S5, the laser power is 1.0–2.0 kW, the scanning speed is 10–20 mm / s, and the overlap rate is 30%–50%. The solid lubricating phase powder is pretreated with chemical nickel plating before laser cladding. The plating solution composition is: nickel sulfate 25–35 g / L, sodium hypophosphite 20–30 g / L, sodium citrate 10–20 g / L, sodium acetate 10–15 g / L, the pH value of the plating solution is 4.5–5.5, the plating temperature is 75–85 °C, and the plating time is 15–30 min. In step S6, the irradiation parameters are: accelerating voltage 20–30 kV, pulse number 5–20, energy density 2–6 J / cm², pulse width 1–5 μs, and vacuum degree ≤5 × 10⁻⁶. - ³Pa.
[0017] The beneficial effects of this invention are as follows: This invention achieves uniform improvement of matrix strength through dispersion reinforcement of endogenous nano-Al2O3 particles. Specifically, the endogenous nano-Al2O3 particles form a semi-coherent interface with the copper matrix, and the dislocation bypass mechanism effectively hinders plastic deformation, increasing the matrix hardness by 30% to 50%, while the increase in elastic modulus is controlled within 15%, effectively avoiding the problem of elastic modulus mismatch introduced by external strengthening phase.
[0018] This invention eliminates interfacial stress concentration by designing an elastic modulus gradient in the composition transition layer. Specifically, the elastic modulus of the composition transition layer changes continuously along the thickness direction (120-180 GPa), avoiding the "hard shell effect" between the hard reinforcement layer and the copper substrate. This allows the frictional contact stress to be effectively dissipated within the gradient layer, significantly reducing the risk of interfacial peeling and fatigue crack initiation.
[0019] This invention employs a dual-layer functional structure—a hardened reinforcing layer and a self-lubricating friction-reducing layer—to synergistically suppress adhesive wear. The hardened reinforcing layer provides high hardness support and anti-ploughing capability, while the self-lubricating friction-reducing layer continuously releases a solid lubricating phase during friction, forming a transfer film that effectively reduces the coefficient of friction and suppresses adhesive wear. The solid lubricating phase powder, after being chemically coated with nickel, effectively inhibits the oxidative decomposition and flotation of the lubricating phase during laser cladding.
[0020] This invention further enhances the surface hardness and smoothness through high-current pulsed electron beam surface densification treatment. Electron beam irradiation causes the surface of the self-lubricating friction-reducing layer to remelt and resolidify, forming a dense nanocrystalline surface layer, which further improves the hardness while significantly reducing the surface roughness, thus facilitating the formation of a stable friction transfer film.
[0021] Tests showed that the wear rate of the Cu-8Al aluminum bronze wear-resistant reinforced material prepared by this invention was reduced by 65% to 85% compared with the untreated Cu-8Al aluminum bronze substrate, the coefficient of friction was reduced by 30% to 50%, and the bonding strength between the surface coating and the substrate was ≥250MPa.
[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1This is a schematic diagram of the cross-sectional structure of the Cu-8Al aluminum bronze wear-resistant strengthening material according to an embodiment of the present invention; Figure 2 This is a graph showing the variation of the elastic modulus of the composite gradient wear-resistant layer along the thickness direction in an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the dispersion distribution of endogenous nano-Al2O3 particles in an aluminum bronze matrix according to an embodiment of the present invention. Figure 3 (a) is a schematic diagram of the tissue at low magnification. Figure 3 (b) is a high-magnification partial magnification schematic diagram; Figure 4 This is a schematic diagram illustrating the microstructure changes on the surface of the self-lubricating and friction-reducing layer before and after high-current pulsed electron beam irradiation, according to an embodiment of the present invention. Figure 4 (a) is the image before irradiation. Figure 4 (b) is the image after irradiation. Detailed Implementation
[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0025] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0026] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0027] Please see Figures 1-4This invention relates to a Cu-8Al aluminum bronze wear-resistant reinforcing material and its preparation method.
[0028] Example 1 This embodiment first provides a Cu-8Al aluminum bronze wear-resistant strengthening material, such as... Figure 1 As shown, it includes a Cu-8Al aluminum bronze substrate and a composite gradient wear-resistant layer covering the surface of the substrate. The composite gradient wear-resistant layer includes, from the inside out, a composition transition layer, a hard reinforcement layer and a self-lubricating friction-reducing layer. The composition transition layer is metallurgically bonded to the surface of the Cu-8Al aluminum bronze substrate, and the composition in the composition transition layer gradually transitions from the Cu-8Al aluminum bronze substrate to the hard reinforcement layer. The compositional transition layer includes several transition sublayers composed of Cu powder and Ni-based alloy powder with different mass fractions. In each transition sublayer, the ratio of Cu powder to Ni-based alloy powder changes continuously along the deposition direction.
[0029] Specifically, the thickness of the composition transition layer is 100–300 μm, and the elastic modulus exhibits a continuous gradient change along the thickness direction, ranging from 120 to 180 GPa. The curve showing the change in elastic modulus along the thickness direction of the entire composite gradient wear-resistant layer is shown below. Figure 2 As shown.
[0030] In this embodiment, the compositional transition layer includes a first transition sublayer and a second transition sublayer. The mass ratio of the powder in the first transition sublayer is: 70%–85% Cu powder and 15%–30% Ni-based alloy powder; the mass ratio of the powder in the second transition sublayer is: 30%–50% Cu powder and 50%–70% Ni-based alloy powder. In the first transition sublayer, the specific range within which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 85% to 70%, and the mass fraction of Ni-based alloy powder continuously increases from 15% to 30%. In the second transition sublayer, the specific range within which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 50% to 30%, and the mass fraction of Ni-based alloy powder continuously increases from 50% to 70%.
[0031] In this embodiment, the 70%–85% Cu powder in the first transition layer also includes 2%–5% Al powder by mass of the Cu powder, and the 15%–30% Ni-based alloy powder is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni; the 30%–50% Cu powder in the second transition layer also includes 1%–3% Al powder by mass of the Cu powder, and the 50%–70% Ni-based alloy powder is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni.
[0032] In this embodiment, endogenous nano-Al2O3 particles are uniformly dispersed in the Cu-8Al aluminum bronze matrix. A schematic diagram of the dispersion distribution of endogenous nano-Al2O3 particles in the aluminum bronze matrix is shown below. Figure 3 As shown, where, Figure 3 (a) is a schematic diagram of the tissue at low magnification. Figure 3 (b) is a high-magnification partial magnification schematic diagram; the mass fraction of endogenous nano-Al2O3 particles is 0.5% to 3.0% of the total mass of the matrix, and the particle size ranges from 5 to 50 nm; the Cu-8Al aluminum bronze melt used to prepare the Cu-8Al aluminum bronze matrix contains 0.05% to 0.15% Zr element by mass, which is used to suppress the formation of coarse Al2O3 film at grain boundaries.
[0033] In this embodiment, the hard reinforcing layer is synthesized in situ by laser cladding of Ni-based alloy powder and ceramic reinforcing phase powder. The thickness of the hard reinforcing layer is 300-600 μm, and the microhardness is 450-650 HV. The laser cladding powder of the hard reinforcing layer contains the following components by mass percentage: 75%-90% Ni-based alloy powder and 10%-25% ceramic reinforcing phase powder. The ceramic reinforcing phase powder is selected from one or a combination of TiB2 powder, WC powder, and Cr3C2 powder.
[0034] In this embodiment, the self-lubricating friction-reducing layer is formed by laser cladding of Cu-Ni-Sn alloy powder and solid lubricating phase powder, and the thickness of the self-lubricating friction-reducing layer is 80-150 μm. The laser cladding powder of the self-lubricating friction-reducing layer contains the following components by mass percentage: 70%-85% Cu-Ni-Sn alloy powder and 15%-30% solid lubricating phase powder; the solid lubricating phase powder is selected from one or a combination of several of MoS2 powder, WS2 powder and graphite powder, and the solid lubricating phase powder is chemically coated with nickel before laser cladding, and the coating layer thickness is 1-3 μm.
[0035] Preferably, the surface of the composite gradient wear-resistant layer is treated with high-current pulsed electron beam irradiation. A schematic diagram of the microstructure changes on the surface of the self-lubricating friction-reducing layer before and after high-current pulsed electron beam irradiation is shown below. Figure 4 As shown, a dense nanocrystalline surface layer with a thickness of 2–8 μm is formed on the surface of the self-lubricating friction-reducing layer. The surface microhardness is 550–700 HV, and the surface roughness Ra ≤ 0.4 μm. Figure 4 (a) is the image before irradiation. Figure 4 (b) is the image after irradiation.
[0036] Example 2 This embodiment provides a method for preparing the Cu-8Al aluminum bronze wear-resistant reinforcing material in Example 1, which includes: S1. Preparation of an endogenous nano-Al2O3 particle dispersion-reinforced aluminum bronze matrix: A Cu-8Al aluminum bronze alloy ingot with an aluminum content of 8 wt% was melted in a medium-frequency induction furnace, and then 0.10% Zr was added and stirred thoroughly. The melt was cast into ingots and then placed in a controlled atmosphere heat treatment furnace for internal oxidation treatment. The treatment atmosphere was a mixture of N2 and trace amounts of O2, with the oxygen partial pressure controlled at 5 × 10⁻⁶. - ¹ 7 The treatment was carried out at a pressure of MPa, a temperature of 900℃, and a holding time of 4 hours. After treatment, the material was air-cooled to room temperature, resulting in an aluminum bronze matrix with endogenous Al2O3 particles of 10–40 nm in diameter uniformly dispersed within the matrix. The mass fraction of Al2O3 particles was approximately 1.5%. Testing showed that the microhardness of the matrix was 195 HV, an increase of approximately 39% compared to untreated Cu-8Al aluminum bronze (approximately 140 HV), and the elastic modulus was 125 GPa, an increase of approximately 5%.
[0037] S2. Surface pretreatment of the substrate: Cut the substrate obtained in step S1 into 100mm×50mm×20mm test blocks, and polish the surface with 200#, 400# and 600# sandpaper in sequence to remove the oxide layer; place it in anhydrous ethanol for ultrasonic cleaning for 15min, and blow dry; place it in a heat treatment furnace for preheating to 200℃ and keep it at that temperature for 30min.
[0038] S3. Preparation of the transition layer: A laser cladding process with simultaneous powder feeding was employed. The first transition layer powder ratio was 80wt% Cu powder + 20wt% Ni60A powder; the second transition layer powder ratio was 40wt% Cu powder + 60wt% Ni60A powder. Laser cladding parameters: laser power 1.8kW, scanning speed 10mm / s, powder feeding rate 10g / min, overlap rate 50%, argon protection flow rate 15L / min. The first transition layer was deposited to a thickness of approximately 100μm, and then the ratio of the two powder streams in the powder feeder was gradually adjusted to continuously deposit the second transition layer until the total transition layer thickness was approximately 200μm. The chemical composition of the Ni60A powder was: Ni balance, Cr 16%, B 3.5%, Si 4%, C 0.8%, Fe ≤ 5%.
[0039] S4. Preparation of the hardened reinforcing layer: The powder composition was 85wt% Ni60A powder + 15wt% TiB2 ceramic powder. The TiB2 powder particle size was 5–20 μm. Laser cladding parameters: laser power 2.0 kW, scanning speed 8 mm / s, powder feed rate 12 g / min, overlap rate 50%, argon protection flow rate 15 L / min. The deposition thickness was approximately 450 μm. The microhardness of the hardened reinforcing layer was tested to be 520 HV, and the elastic modulus was 205 GPa.
[0040] S5. Preparation of Self-Lubricating Friction-Reducing Layer: First, the solid lubricating phase powder is pretreated with electroless nickel plating. 10g of MoS2 powder (particle size 3-10μm) is placed in the plating solution for electroless nickel plating. The plating solution composition is: nickel sulfate 30g / L, sodium hypophosphite 25g / L, sodium citrate 15g / L, sodium acetate 12g / L, pH 5.0, plating temperature 80℃, and plating time 20min. After plating, the powder is cleaned and dried to obtain nickel-coated MoS2 powder with a coating thickness of approximately 2μm. The laser cladding powder ratio is 80wt% Cu-10Ni-5Sn alloy powder + 20wt% nickel-coated MoS2 powder. Laser cladding parameters are: laser power 1.5kW, scanning speed 12mm / s, powder feed rate 8g / min, and overlap rate 40%. The deposition thickness is approximately 120μm.
[0041] S6. Surface densification treatment: Place the specimen obtained in step S5 in the vacuum chamber of a high-current pulsed electron beam device, with a vacuum degree of 3×10⁻⁶. - ³Pa. Irradiation parameters: accelerating voltage 25kV, pulse number 10, energy density 4J / cm², pulse width 2μs. After treatment, a dense nanocrystalline surface layer with a thickness of approximately 5μm was formed on the specimen surface.
[0042] Performance testing: An MM-200 wear testing machine was used. The wear material was a GCr15 steel ring (hardness 60HRC). The load was 100N, the sliding speed was 0.5m / s, and the wear test was conducted for 60 minutes under dry friction conditions. The wear rate of the material prepared in Example 1 was measured to be 0.48×10⁻⁶. -4 The friction coefficient is 0.32, and the wear rate is lower than that of the untreated Cu-8Al aluminum bronze substrate (wear rate approximately 3.2 × 10⁻⁶ mm³ / (N·m)). -4 The coating thickness (mm³ / (N·m)) decreased by approximately 85%. The coating bond strength was determined using the scratch test, with a critical load Lc2 ≥ 80 N and a corresponding bond strength ≥ 250 MPa.
[0043] Example 3 The difference from Example 2 is that the oxygen partial pressure in the internal oxidation treatment in step S1 is 1×10⁻⁶. - ¹ 6 The treatment was carried out at a pressure of MPa, a temperature of 920℃, and a holding time of 6 hours. The Zr element addition was 0.08 wt%, and the final Al2O3 particle mass fraction was approximately 2.2%. In step S4, the ceramic reinforcing phase powder was WC powder (15 wt%). In step S5, the solid lubricating phase powder was WS2 powder (20 wt%). In step S6, the number of irradiation pulses was 15. The remaining steps were the same as in Example 1.
[0044] The wear rate of the material prepared in this embodiment was tested to be 0.55 × 10⁻⁶. -4 The surface area is mm³ / (N·m), the friction coefficient is 0.35, and the wear rate is reduced by about 83% compared with the untreated substrate.
[0045] Example 4 The difference from Example 2 is as follows: In step S1, the Zr element addition amount is 0.12wt%, the internal oxidation temperature is 880℃, the holding time is 3 hours, and the Al2O3 particle mass fraction is approximately 1.0%; in step S4, the ceramic reinforcing phase powder is a TiB2+Cr3C2 mixed powder (10wt%+5wt%); in step S5, the solid lubricating phase powder is a MoS2+graphite mixed powder (15wt%+10wt%); and in step S6, the irradiation energy density is 5J / cm², and the number of pulses is 8. The remaining steps are the same as in Example 1.
[0046] The wear rate of the material prepared in this embodiment was tested to be 0.62 × 10⁻⁶. -4 The surface area is mm³ / (N·m), the friction coefficient is 0.30, and the wear rate is reduced by about 81% compared with the untreated substrate.
[0047] Comparative Example 1 This embodiment compares a material with only internal matrix reinforcement and no surface coating with the material prepared in Example 2. In Example 2, an internally reinforced Cu-8Al aluminum bronze matrix with dispersed Al2O3 nanoparticles was prepared according to step S1, but no surface coating was applied. Under the same wear test conditions, its wear rate was measured to be 1.85 × 10⁻⁶. -4 mm³ / (N·m), which is about 42% lower than that of the untreated matrix.
[0048] Comparative Example 2 This embodiment compares the material with the one without a component transition layer and the one with the hard reinforcement layer prepared by direct laser cladding with the material prepared in Example 2. After preparing the substrate according to step S1 of Example 2, step S3 is skipped, and the hard reinforcement layer is directly deposited on the substrate surface according to the parameters of step S4, followed by steps S5 and S6. Under the same wear test conditions, multiple spalling pits appeared on the surface in the early stage of wear, the bonding strength between the coating and the substrate was only about 120 MPa, and the wear rate was 1.15 × 10⁻⁶. -4 mm³ / (N·m).
[0049] The above embodiments demonstrate that the present invention significantly improves the wear resistance of Cu-8Al aluminum bronze through the synergistic modification of endogenous nano-Al2O3 dispersion reinforcement and surface gradient coating. In particular, the gradient design of the composition transition layer effectively eliminates interfacial stress concentration and avoids coating peeling; the synergistic function of the self-lubricating friction-reducing layer and the hard reinforcement layer effectively suppresses adhesive wear; and the high-current pulsed electron beam surface densification treatment further improves the surface performance and surface quality.
[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A Cu-8Al aluminum bronze wear-resistant reinforcing material, characterized in that: It includes a Cu-8Al aluminum bronze substrate and a composite gradient wear-resistant layer covering the surface of the substrate. The composite gradient wear-resistant layer includes a composition transition layer, a hard reinforcement layer and a self-lubricating friction-reducing layer from the inside to the outside. The composition transition layer is metallurgically bonded to the surface of the Cu-8Al aluminum bronze substrate, and the composition in the composition transition layer gradually transitions from the Cu-8Al aluminum bronze substrate to the hard reinforcement layer. The compositional transition layer includes several transition sublayers composed of Cu powder and Ni-based alloy powder with different mass fractions. In each transition sublayer, the ratio of Cu powder to Ni-based alloy powder changes continuously along the deposition direction.
2. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The compositional transition layer includes a first transition sublayer and a second transition sublayer. The mass ratio of the powder in the first transition sublayer is: 70%–85% Cu powder and 15%–30% Ni-based alloy powder. The mass ratio of the powder in the second transition sublayer is: 30%–50% Cu powder and 50%–70% Ni-based alloy powder. In the first transition sublayer, the specific range in which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 85% to 70%, and the mass fraction of Ni-based alloy powder continuously increases from 15% to 30%. In the second transition sublayer, the specific range in which the ratio of Cu powder to Ni-based alloy powder continuously changes along the deposition direction is: the mass fraction of Cu powder continuously decreases from 50% to 30%, and the mass fraction of Ni-based alloy powder continuously increases from 50% to 70%.
3. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 2, characterized in that: The first transition layer, consisting of 70%–85% Cu powder, also includes 2%–5% Al powder by mass, and 15%–30% Ni-based alloy powder, which is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni. The second transition layer, consisting of 30%–50% Cu powder, also includes 1%–3% Al powder by mass, and 50%–70% Ni-based alloy powder, which is a Ni-Cr-B-Si self-fluxing alloy powder with the following mass composition: Cr 16%–20%, B 3.0%–4.5%, Si 3.5%–5.0%, C 0.6%–1.0%, and the balance Ni.
4. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The thickness of the component transition layer is 100–300 μm, and the elastic modulus varies continuously along the thickness direction, ranging from 120 to 180 GPa.
5. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The Cu-8Al aluminum bronze matrix contains uniformly dispersed endogenous nano-Al2O3 particles; the mass fraction of the endogenous nano-Al2O3 particles is 0.5% to 3.0% of the total mass of the matrix, and the particle size ranges from 5 to 50 nm; the Cu-8Al aluminum bronze melt used to prepare the Cu-8Al aluminum bronze matrix contains 0.05% to 0.15% Zr element by mass, which is used to inhibit the formation of coarse Al2O3 film at grain boundaries.
6. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The hardened layer is synthesized in situ by laser cladding of Ni-based alloy powder and ceramic reinforcing phase powder. The thickness of the hardened layer is 300-600 μm and the microhardness is 450-650 HV. The laser cladding powder of the hardened layer contains the following components by mass percentage: 75%-90% Ni-based alloy powder and 10%-25% ceramic reinforcing phase powder. The ceramic reinforcing phase powder is selected from one or a combination of TiB2 powder, WC powder and Cr3C2 powder.
7. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The self-lubricating friction-reducing layer is formed by laser cladding of Cu-Ni-Sn alloy powder and solid lubricating phase powder. The thickness of the self-lubricating friction-reducing layer is 80-150 μm. The laser cladding powder of the self-lubricating friction-reducing layer contains the following components by mass percentage: 70%-85% Cu-Ni-Sn alloy powder and 15%-30% solid lubricating phase powder. The solid lubricating phase powder is selected from one or more of MoS2 powder, WS2 powder and graphite powder, and the solid lubricating phase powder is chemically coated with nickel before laser cladding. The coating layer thickness is 1-3 μm.
8. The Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 1, characterized in that: The surface of the composite gradient wear-resistant layer is treated with high-current pulsed electron beam irradiation to form a dense nanocrystalline surface layer with a thickness of 2-8 μm on the surface of the self-lubricating friction-reducing layer. The surface microhardness is 550-700 HV and the surface roughness Ra≤0.4 μm.
9. A method for preparing a Cu-8Al aluminum bronze wear-resistant reinforcing material as described in any one of claims 1-8, characterized in that: The method includes: S1. The Cu-8Al aluminum bronze melt is subjected to internal oxidation treatment under a controlled oxygen partial pressure atmosphere to oxidize the Al element in the matrix in situ to generate Al2O3 particles, thereby obtaining a Cu-8Al aluminum bronze matrix with internal nano Al2O3 particle dispersion reinforcement. S2. The substrate surface obtained in step S1 is subjected to mechanical grinding, ultrasonic cleaning and preheating treatment in sequence. S3. A laser cladding and synchronous powder feeding process is adopted to deposit a composition transition layer layer by layer on the preheated substrate surface. By controlling the ratio of Cu powder to Ni-based alloy powder in the powder feeder to continuously change along the deposition direction, the gradient transition of composition is achieved. S4. On the surface of the component transition layer obtained in step S3, a hard reinforcement layer powder is deposited using a laser cladding and simultaneous powder feeding process. S5. On the surface of the hardened layer obtained in step S4, a self-lubricating friction-reducing layer powder is deposited using a laser cladding and simultaneous powder feeding process. S6. The surface of the self-lubricating friction-reducing layer obtained in step S5 is irradiated with a high-current pulsed electron beam to cause the surface layer to remelt and resolidify, forming a dense nanocrystalline surface layer.
10. The method for preparing a Cu-8Al aluminum bronze wear-resistant reinforcing material according to claim 9, characterized in that: Each step of the method specifically includes: In step S1, the processing temperature is 850–950℃, the processing time is 2–8 hours, and the particle size of Al2O3 particles is 5–50 nm; before the internal oxidation treatment, 0.05%–0.15% Zr element by mass fraction is added to the Cu-8Al aluminum bronze melt; the controlled oxygen partial pressure range is 10. - ¹ 5 ~10 - ¹ 8 MPa; In step S2, the preheating temperature is 150–250°C; In step S3, the ratio of Cu powder to Ni-based alloy powder changes continuously along the deposition direction as follows: during the powder feeding process of the first transition sublayer, the mass ratio of Cu powder to Ni-based alloy powder changes linearly from 85:15 to 70:30; during the powder feeding process of the second transition sublayer, the mass ratio changes linearly from 50:50 to 30:
70. In step S4, the laser power is 1.5–2.5 kW, the scanning speed is 5–15 mm / s, and the overlap rate is 40%–60%. In step S5, the laser power is 1.0–2.0 kW, the scanning speed is 10–20 mm / s, and the overlap rate is 30%–50%. The solid lubricating phase powder is pretreated with chemical nickel plating before laser cladding. The plating solution composition is: nickel sulfate 25–35 g / L, sodium hypophosphite 20–30 g / L, sodium citrate 10–20 g / L, sodium acetate 10–15 g / L, the pH value of the plating solution is 4.5–5.5, the plating temperature is 75–85 °C, and the plating time is 15–30 min. In step S6, the irradiation parameters are: accelerating voltage 20–30 kV, pulse number 5–20, energy density 2–6 J / cm², pulse width 1–5 μs, and vacuum degree ≤5 × 10⁻⁶. - ³Pa.