Heterolayered copper-copper zinc alloy with friction anisotropy and method for producing same

Abstract

The application belongs to the field of copper alloy friction, and particularly relates to a heterogeneous layered copper-copper zinc alloy with friction anisotropy and a preparation method thereof. The method comprises the following steps: step (1), mechanical polishing of copper plates and copper zinc alloy plates; step (2), organic oil removal; step (3), alternately stacking the copper and the copper zinc alloy, and diffusion welding to form a copper-copper zinc material blank; step (4), cold rolling of the blank at room temperature with a total deformation of 88% to 98%; and step (5), annealing of the rolled blank in an argon stream at 300 DEG C to 350 DEG C for 3 to 4 hours to obtain the copper-copper zinc alloy. The copper / copper zinc alloy with different layer spacings obtained by the application can be used to study the relationship between the layer spacing and the friction anisotropy by adjusting the layer spacing, thereby providing a criterion for designing a heterogeneous layered alloy with excellent tribological properties.

Description

Technical Field

[0001] This invention belongs to the field of copper alloy friction, specifically relating to a heterogeneous layered copper-copper-zinc alloy with tribotropic properties and its preparation method. Background Technology

[0002] Copper alloys are alloys composed of pure copper as the base material and one or more other elements added. Pure copper is purplish-red and is also known as red copper. Pure copper has a density of 8.96 and a melting point of 1083℃, and possesses excellent electrical and thermal conductivity.

[0003] Ductility and corrosion resistance. Copper and copper alloys are widely used metallic structural materials in the manufacturing industries of engineering machinery, automotive parts, and hydraulics, such as copper-zinc alloys used in bearings / sleeves. However, due to the poor wear resistance of copper alloys, frequent maintenance or replacement of parts is required. As actual working conditions become increasingly harsh, copper alloys are showing their shortcomings. Currently, the application of copper and copper alloys in the field of tribology still faces prominent problems such as high friction, high wear rate, and low strength. With the increasing demands of industrial technical parameters and the harshness of service conditions, it is an inevitable trend for the industry to develop copper and copper alloys with comprehensive properties such as high strength, low friction, and high wear resistance. The idea of ​​improving friction and wear by changing surface morphology has attracted widespread attention. However, heterogeneous surface morphologies are easily filled by wear debris or removed during friction, and their lack of long-term sustainability greatly limits their application. For example, when used as bearing structural materials, the wear resistance of heterogeneous materials decreases rapidly with the increase of wear time. Currently, surface treatment technologies to improve the wear resistance of copper alloys mainly include surface hardening technology, surface coating technology, and surface metallurgy technology. However, existing surface treatment technologies cause significant environmental pollution and resource waste during processing; efficient short-process preparation technologies are still immature, and product quality and performance need to be improved, failing to meet the needs of actual production. Summary of the Invention

[0004] The purpose of this invention is to provide a heterogeneous layered copper-copper-zinc alloy with tribotropic properties and its preparation method.

[0005] The technical solution for achieving the objective of this invention is as follows: a method for preparing a heterogeneous layered copper-copper-zinc alloy with tribotropic anisotropy, comprising the following steps:

[0006] Step (1): Mechanically polish the copper plate and the copper-zinc alloy plate;

[0007] Step (2): Organic degreasing;

[0008] Step (3): Alternately stack and diffuse weld copper and copper-zinc alloy to form a copper-copper-zinc material blank;

[0009] Step (4): Cold rolling the billet at room temperature with a total deformation of 88% to 98%;

[0010] Step (5): Anneal the rolled billet in an argon flow at 300℃~350℃ for 3~4 hours to obtain a copper-copper-zinc alloy.

[0011] Furthermore, the thickness of the copper plate used in step (1) is 1±0.2mm, and the thickness of the copper-zinc alloy plate used is 80% of the thickness of the copper plate.

[0012] The copper plate has a purity greater than 99.9 wt.%, and the copper-zinc alloy has a composition of Cu-32 wt.% Zn.

[0013] Furthermore, the mechanical polishing in step (1) specifically involves:

[0014] Mechanically grind with SiC sandpaper of 1000, 1200, 1500, and 2000 grit in sequence, and then mechanically polish with 3.5μm diamond polishing paste.

[0015] Furthermore, step (2) organic degreasing specifically involves:

[0016] Step (21): Place the polished sample in acetone and sonicate at 30-40 kHz for 10-15 minutes to remove oil;

[0017] Step (22): After the acetone-degreased sample is placed in alcohol for 10-15 minutes, it is then dried by vacuum drying and stored for later use.

[0018] Furthermore, the specific process parameters for diffusion welding in step (3) are as follows: diffusion welding is carried out at 920±5℃ and 2.5±0.2MPa pressure, with argon protection for 2-2.5 hours.

[0019] Furthermore, the thickness of the blank obtained by welding in step (3) is 20-30 layers.

[0020] Furthermore, in step (5), the deformation amount of each cold rolling pass is 10%.

[0021] A heterogeneous layered copper-copper-zinc alloy with tribotropic anisotropy is prepared by the method described above.

[0022] Furthermore, the grain size of the copper layer is 2–3.5 μm, the grain size of the copper-zinc layer is 1–1.5 μm, and the interlayer spacing is 50 ± 10 μm.

[0023] Compared with the prior art, the significant advantages of this invention are:

[0024] This invention prepares heterogeneous layered copper / copper-zinc alloys with varying interlayer spacings by adjusting the interlayer spacing through rolling. The resulting heterogeneous layered copper / copper-zinc alloys, obtained through diffusion welding and rolling, exhibit significant tribological anisotropy in sliding directions parallel and perpendicular to the interface, with superior tribological performance when sliding perpendicular to the interface. Due to the presence of zinc, the copper-zinc layer grains are more easily refined, thus easily forming an ultrafine-grained copper-zinc layer after rolling and annealing, possessing higher hardness. This layer forms a heterogeneous dual-phase structure with the copper layer, and the strain localization induced by this structure improves the wear resistance of the copper / copper-zinc alloy, making it suitable for complex working conditions in metal components such as bearings. This provides a guideline for designing heterogeneous layered alloys with excellent tribological properties. Attached Figure Description

[0025] Figure 1 The images show the EBSD inverse pole figures of copper / copper-zinc alloys with different interlayer spacings according to the present invention, where a to d represent copper / copper-zinc alloys with interlayer spacings of 200 μm, 100 μm, 50 μm, and 20 μm, respectively. The copper / copper-zinc alloys are identified as consisting of coarse-grained copper layers and ultrafine-grained copper-zinc layers.

[0026] Figure 2 The diagram shows the grain size statistics of copper / copper-zinc alloys with different interlayer spacings according to the present invention, proving that the grain size of the copper layer in the copper / copper-zinc alloy is larger than that of the copper-zinc layer.

[0027] Figure 3 This is a hardness statistical chart of copper / copper-zinc alloys with different interlayer spacings according to the present invention. The hardness of the copper-zinc layer of the copper / copper-zinc alloy is greater than that of the copper layer.

[0028] Figure 4 The graph shows the friction coefficients of copper / copper-zinc alloys with different interlayer spacings according to the present invention, demonstrating that the copper / copper-zinc alloys have significant tribological anisotropy.

[0029] Figure 5 The wear rate statistics of copper / copper-zinc alloys with different interlayer spacings of the present invention are shown in the figure, which further proves that the copper / copper-zinc alloy has significant tribological anisotropy. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] A copper / copper-zinc alloy exhibiting tribological anisotropy is disclosed, along with a simple, low-energy-consumption, and short-cycle preparation method. This invention is achieved by diffusion welding copper and a copper-zinc alloy to form a copper / copper-zinc material billet. The welded billet is then cold-rolled at room temperature. Since the sample thickness can be reduced by approximately 10% with each pass during rolling, the interlayer spacing can be adjusted through cold rolling to obtain copper / copper-zinc materials with different interlayer spacings. Due to the strain localization induced by the heterogeneous two-phase structure, this copper / copper-zinc alloy possesses excellent tribological anisotropy.

[0032] Example 1

[0033] Step (1): Mechanical polishing; The copper (99.9 wt.%) and bronze (Cu-32 wt.%) Zn) alloy was mechanically ground with 1000, 1200, 1500, and 2000 SiC sandpaper, and then mechanically polished with 3.5 μm diamond polishing paste.

[0034] Step (2): Organic degreasing;

[0035] Step (21): Place the polished sample in acetone and ultrasonically clean it (30-40 kHz) for 10 minutes to remove oil;

[0036] Step (22): After removing the oil with acetone, wash the sample in alcohol for 10 minutes, and then dry the sample under vacuum for later use.

[0037] Step (3): Copper and copper-zinc alloy were diffusion welded into a copper / copper-zinc material blank; 1mm thick copper alloy and 0.8mm thick bronze alloy were alternately stacked and diffusion welded at 920℃ and 2.5MPa pressure, with argon protection for 2 hours. The initial thickness of the blank obtained after welding was 36mm, with a total of 20 layers.

[0038] Step (4): The above-mentioned blank is cold rolled at room temperature; each pass during rolling can reduce the sample thickness by about 10%, and after 21 rolling passes, a blank with a layer spacing of 200 μm is obtained.

[0039] Step (5): Place the rolled sample into a tube furnace and anneal it in an argon flow at 350°C for 3 hours to obtain a copper / copper-zinc alloy.

[0040] Example 2

[0041] Step (1): Mechanical polishing; The copper (99.9 wt.%) and bronze (Cu-32 wt.%) Zn) alloy was mechanically ground with 1000, 1200, 1500, and 2000 SiC sandpaper, and then mechanically polished with 3.5 μm diamond polishing paste.

[0042] Step (2): Organic degreasing;

[0043] Step (21): Place the polished sample in acetone and ultrasonically clean it (30-40 kHz) for 10 minutes to remove oil;

[0044] Step (22): After removing the oil with acetone, wash the sample in alcohol for 10 minutes, and then dry the sample under vacuum for later use.

[0045] Step (3): Copper and copper-zinc alloy were diffusion welded into a copper / copper-zinc material blank; 1mm thick copper alloy and 0.8mm thick bronze alloy were alternately stacked and diffusion welded at 920℃ and 2.5MPa pressure, with argon protection for 2 hours. The initial thickness of the blank obtained after welding was 36mm, with a total of 20 layers.

[0046] Step (4): The above-mentioned blank is cold rolled at room temperature; each pass during rolling can reduce the sample thickness by about 10%, and after 28 rolling passes, a blank with a layer spacing of 100 μm is obtained.

[0047] Step (5): Place the rolled sample into a tube furnace and anneal it in an argon flow at 350°C for 3 hours to obtain a copper / copper-zinc alloy.

[0048] Example 3

[0049] Step (1): Mechanical polishing; The copper (99.9 wt.%) and bronze (Cu-32 wt.%) Zn) alloy was mechanically ground with 1000, 1200, 1500, and 2000 grit Sic sandpaper, and then mechanically polished with 3.5 μm diamond polishing paste.

[0050] Step (2): Organic degreasing;

[0051] Step (21): Place the polished sample in acetone and ultrasonically clean it (30-40 kHz) for 10 minutes to remove oil;

[0052] Step (22): After removing the oil with acetone, wash the sample in alcohol for 10 minutes, and then dry the sample under vacuum for later use.

[0053] Step (3): Copper and copper-zinc alloy were diffusion welded into a copper / copper-zinc material blank; 1mm thick copper alloy and 0.8mm thick bronze alloy were alternately stacked and diffusion welded at 920℃ and 2.5MPa pressure, with argon protection for 2 hours. The initial thickness of the blank obtained after welding was 36mm, with a total of 20 layers.

[0054] Step (4): The above-mentioned blank is cold rolled at room temperature; each pass during rolling can reduce the sample thickness by about 10%, and after 35 rolling passes, a blank with a layer spacing of 50 μm is obtained.

[0055] Step (5): Place the rolled sample into a tube furnace and anneal it in an argon flow at 350°C for 3 hours to obtain a copper / copper-zinc alloy.

[0056] Example 4

[0057] Step (1): Mechanical polishing; The copper (99.9 wt.%) and bronze (Cu-32 wt.%) Zn) alloy was mechanically ground with 1000, 1200, 1500, and 2000 SiC sandpaper, and then mechanically polished with 3.5 μm diamond polishing paste.

[0058] Step (2): Organic degreasing;

[0059] Step (21): Place the polished sample in acetone and ultrasonically clean it (30-40 kHz) for 10 minutes to remove oil;

[0060] Step (22): After removing the oil with acetone, wash the sample in alcohol for 10 minutes, and then dry the sample under vacuum for later use.

[0061] Step (3): Copper and copper-zinc alloy were diffusion welded into a copper / copper-zinc material blank; 1mm thick copper alloy and 0.8mm thick bronze alloy were alternately stacked and diffusion welded at 920℃ and 2.5MPa pressure, with argon protection for 2 hours. The initial thickness of the blank obtained after welding was 36mm, with a total of 20 layers.

[0062] Step (4): The above-mentioned blank is cold rolled at room temperature; each pass during rolling can reduce the sample thickness by about 10%, and after 43 rolling passes, a blank with a layer spacing of 20 μm is obtained.

[0063] Step (5): Place the rolled sample into a tube furnace and anneal it in an argon flow at 350°C for 3 hours to obtain a copper / copper-zinc alloy.

[0064] The products obtained in Examples 1-4 were characterized by EBSD. Figure 1 (a) to (d) are the inverse pole diagrams of Examples 1-4, respectively. Figure 2 for Figure 1 A statistical diagram of grain size distribution. (From...) Figure 1 and Figure 2 It is known that the copper / copper-zinc alloy consists of a coarse-grained copper layer and an ultra-fine-grained copper-zinc layer, wherein the grain size of the copper layer is 2–3.5 μm, and the grain size of the copper-zinc layer is approximately 1–1.5 μm. Hardness characterization was performed on the products obtained in Examples 1-4. Figure 3 This is a hardness statistical chart for Examples 1-4. (From...) Figure 3It is known that the hardness of the copper-zinc layer is 100–150 HV, while the hardness of the copper layer is 50–100 HV. The hardness of the copper-zinc layer is higher than that of the copper layer. The copper-zinc layer is the hard phase, and the copper layer is the soft phase. The copper / copper-zinc alloy has a two-phase structure combining hard and soft phases. Friction and wear tests were conducted on the products obtained in Examples 1-4 in directions parallel and perpendicular to the interface. Figure 4 and Figure 5 This is a statistical chart showing the friction coefficient and wear rate for Examples 1-4. (Source: [Insert chart here]) Figure 4 It can be seen that when the friction direction is perpendicular to the interface, the tribological anisotropy of Examples 1-4 is more pronounced, and the friction coefficient is lowest when the interlayer spacing is 50 μm. Figure 5 It can be seen that when the friction direction is perpendicular to the interface, the wear rate of the copper / copper-zinc alloy is significantly lower than that when sliding parallel to the interface, exhibiting better friction performance.

Claims

1. A method for preparing a heterogeneous layered copper-copper-zinc alloy with tribotropic properties, characterized in that, Includes the following steps: Step (1): Mechanically polish the copper plate and the copper-zinc alloy plate; Step (2): Organic degreasing; Step (3): Alternately stack and diffuse weld copper and copper-zinc alloy to form a copper-copper-zinc material blank; Step (4): Cold rolling the billet at room temperature with a total deformation of 88%~98%; Step (5): Anneal the rolled billet in an argon flow at 300℃~350℃ for 3~4 hours to obtain a copper-copper-zinc alloy; The copper plate used in step (1) has a thickness of 1 ± 0.2 mm, and the copper-zinc alloy plate used has a thickness of 80% of the copper plate thickness; The copper plate has a purity greater than 99.9 wt.%, and the copper-zinc alloy composition is Cu-32 wt.% Zn; The mechanical polishing in step (1) specifically involves: Mechanically polish with 1000, 1200, 1500, and 2000 grit SiC sandpaper in sequence, and then mechanically polish with 3.5μm diamond polishing paste. The specific process parameters for diffusion welding in step (3) are as follows: diffusion welding is carried out at 920±5℃ and 2.5±0.2MPa pressure, with argon protection for 2-2.5 hours; The thickness of the blank obtained by welding in step (3) is 20-30 layers; In step (5), the deformation amount per cold rolling pass is 10%; The grain size of the copper layer is 2~3.5μm, the grain size of the copper-zinc layer is 1~1.5μm, and the interlayer spacing is 50±10μm.

2. The method according to claim 1, characterized in that, Step (2) Organic degreasing specifically involves: Step (21): Place the polished sample in acetone and sonicate at 30-40 kHz for 10-15 minutes to remove oil; Step (22): After the acetone-degreased sample is placed in alcohol for 10-15 minutes, it is then dried by vacuum drying and stored for later use.

3. A heterogeneous layered copper-copper-zinc alloy with tribotropic properties, characterized in that, Prepared using the method described in any one of claims 1-2.

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