A high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy and its preparation method

Abstract

A high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy and its preparation method are disclosed, belonging to the field of high-performance corrosion-resistant copper alloys. In the Cu-based multi-component alloy, the atomic percentages of Cu and Fe are 50.00 at.% and 5 at.%, respectively, while the atomic percentages of the remaining components are: Ni: 32.50~35.00 at.%, Co: 7.50~10.00 at.%, Cr: 7.5~10 at.%, Mo: 1.25~5.00 at.%, and V: 1.25~5.00 at.%. Through precise composition design and reasonable processing technology matching, a multi-level, multi-scale heterogeneous microstructure is constructed, including a Cu-rich FCC1 phase and a Ni-rich FCC2 phase formed by segregation based on the component characteristics, nanoparticle phases precipitated in the Cu-rich FCC1 phase, and amplitude-modulated decomposition microstructure in the Ni-rich FCC2 phase. These microstructure characteristics synergistically enhance the alloy's strength, ductility, corrosion resistance, and antibacterial properties. The series of alloys exhibits good antibacterial properties. The alloys also have a hardness of 224.81~270.85 HV, an ultimate tensile strength of 680~856 MPa, a yield strength of 516~751 MPa, an elongation of 4.9~24.3%, a self-corrosion potential of -0.31V~-0.22V, and a self-corrosion current density of 4.00~13.22 μA / cm². 2 .

Description

Technical Field

[0001] This invention relates to a high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy and its preparation method, belonging to the field of high-performance copper alloy technology. Background Technology

[0002] Copper and its alloys are widely used in marine engineering and related industries due to their excellent comprehensive mechanical properties, resistance to seawater corrosion, and resistance to marine organism adhesion. Applications include propellers, seawater pipelines, pumps, valves, and cooling systems. With the continuous improvement of marine equipment performance, the demand for high-performance marine Cu alloys is becoming increasingly urgent.

[0003] The marine corrosive environment is extremely complex. The corrosion of metals and alloys in the ocean is influenced by multiple factors, primarily material factors and environmental factors. Material factors include alloy composition, microstructure, initial surface condition, and corrosion product films, while environmental factors include temperature, pH, impurity ions, sulfides, and flow rate. Furthermore, marine microbial communities can firmly adhere to metal surfaces, forming a biofilm. The corrosive effect of this biofilm can damage equipment, leading to production losses and increased maintenance costs. Moreover, higher demands are being placed on the mechanical properties of materials. Commonly used materials such as aluminum bronze, tin bronze, silicon brass, and stainless steel are no longer sufficient to meet the performance requirements of high-quality valves. Therefore, the development of high-strength, ductile, corrosion-resistant, and antibacterial Cu alloys is increasingly urgent. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a method for preparing a high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy. Through precise compositional design and reasonable processing technology matching, a modulated decomposition phase strengthening process is introduced to enhance the alloy's strength, ductility, corrosion resistance, and antibacterial properties. It is well known that the FCC structure generally has better deformability than the BCC structure; therefore, the FCC system is more favored in the selection of Cu-based multi-component alloy systems. Cu-Ni-Fe and Cu-Ni-Co alloy systems share a common characteristic: they possess miscibility gaps, enabling modulated decomposition to generate two FCC phases (one Cu-rich FCC1 and one Ni-rich FCC2) with identical structures but different compositions. Compared to precipitation-strengthened alloys, this type of alloy has unique advantages because the precipitated strengthening phase usually differs from the matrix in both structure and composition, while the microstructure formed by modulated decomposition strengthening is uniform, without localized anodic or cathodic (e.g., grain boundary precipitation) deteriorating corrosion resistance. Furthermore, Cu and Fe elements can exert excellent antibacterial effects.

[0005] Based on the above, the Cu-Ni-Co-Fe multi-component alloy system was selected. Considering the need to maximize the alloying effects of Ni, Co, and Fe, the extremely low solid solubility of Co and Fe in Cu, and element economy, Cu was chosen.50 Ni 35 Co 10 Fe5 (at.%) is the composition of the model alloy. Meanwhile, studies have shown that Cr can promote chromium decomposition, improving the strength and hardness of the alloy. Furthermore, the addition of Cr forms a chromium oxide film, which improves the alloy's corrosion resistance and enhances mechanical properties by forming stable precipitates. During Mo alloying, the Mo element dissolved in the matrix induces lattice distortion, thereby hindering dislocation movement and improving the material's strength and ductility to some extent. V can refine grains and improve hardness and strength. Therefore, the effects of different combinations of Cr, Mo, and V on Cu were further considered. 50 Ni 35 Co 10 Optimization of the microstructure and properties of Fe5 (at.%) alloy. It should be noted that, from the perspective of improving the alloy's mechanical properties, Cr, Mo, and V elements were added in place of Ni and Co.

[0006] The technical solution adopted in this invention is:

[0007] By rationally selecting the types and contents of microalloying components, a series of high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy compositions were designed. In these copper alloy compositions, the atomic percentages of Cu and Fe are 50.00 at.% and 5 at.%, respectively, with the remaining components having atomic percentages of Ni: 32.50~35.00 at.%, and Co: 7.50~10.00 at.%.

[0008] Alternatively, the alloy may contain at least one of Cr, Mo, and V, with the atomic percentages of Cr: 7.5~10 at.%, Mo: 1.25~5.00 at.%, and V: 1.25~5.00 at.%;

[0009] The sum of the atomic percentages of all components in the alloy is 100%.

[0010] The series of alloys synergistically enhances the strength, plasticity, corrosion resistance, and antibacterial properties of the alloys through multi-scale heterogeneous microstructure characteristics. Specific characteristics include Cu-rich FCC1 phase and Ni-rich FCC2 phase formed by segregation based on the characteristics of the components themselves, with a size of 5~20μm; nanoparticle phases precipitated in the Cu-rich FCC1 phase with a size of 10~30nm; and amplitude-modulated decomposition microstructure in the Ni-rich FCC2 phase with a phase width of 20~50nm.

[0011] The alloy has a hardness of 224.81~270.85 HV, an ultimate tensile strength of 680~856 MPa, a yield strength of 516~751 MPa, an elongation of 4.9~24.3%, a self-corrosion potential of -0.31V~-0.22V, and a self-corrosion current density of 4.00-13.22 μA / cm².2 .

[0012] The method for preparing a high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy:

[0013] (1) Non-consumable vacuum arc melting is adopted, and high-purity argon gas is introduced for protection. The prepared raw materials with a purity of 4N or higher are repeatedly melted to obtain alloy ingots with uniform composition.

[0014] (2) The as-cast alloy is cold-rolled, and the thickness and deformation are controlled, with the thickness deformation being 85%;

[0015] (3) Anneal the cold-rolled alloy, with a holding temperature of 800℃-850℃ and a holding time of 50-60 minutes, and air cooling.

[0016] The beneficial effects of this invention are: 1. By rationally configuring the enthalpy interaction between elements, the multi-level and multi-scale heterogeneous microstructure characteristics of Cu-Ni-Co-Fe alloys are studied by adding different combinations of Cr, Mo and V elements; 2. By rationally configuring the heat treatment process, one-step annealing is used to introduce nano-precipitates and modulated decomposition microstructure, thereby achieving a synergistic improvement in the alloy's strength, plasticity, corrosion resistance and antibacterial properties. Attached Figure Description

[0017] Figure 1 It is Cu after annealing. 50.00 Ni 35.00 Co 10 Secondary electron image of Fe5(at.%) alloy obtained by scanning electron microscopy.

[0018] Figure 2 It is Cu after annealing. 50.00 Ni 35.00 Co 10 Fe5(at.%) alloy engineering stress-engineering strain curve.

[0019] Figure 3 It is Cu after annealing. 50.00 Ni 35.00 Co 10 Polarization curve of Fe5(at.%) alloy.

[0020] Figure 4 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Secondary electron image of Fe5Cr5(at.%) alloy obtained by scanning electron microscopy.

[0021] Figure 5 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5Engineering stress-strain curve of Fe5Cr5(at.%) alloy.

[0022] Figure 6 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Polarization curve of Fe5Cr5(at.%) alloy.

[0023] Figure 7 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 2.5( Secondary electron image of the at.%) alloy by scanning electron microscopy.

[0024] Figure 8 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 2.5 (at.%) Alloy engineering stress-engineering strain curve.

[0025] Figure 9 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 2.5 Polarization curves of (at.%) alloys.

[0026] Figure 10 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 V 2.5 Secondary electron image of (at.%) alloy using scanning electron microscopy.

[0027] Figure 11 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 V 2.5 (at.%) Alloy engineering stress-engineering strain curve.

[0028] Figure 12 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 V 2.5 Polarization curves of (at.%) alloys.

[0029] Figure 13 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Mo 2.5 V 2.5 Secondary electron image of (at.%) alloy using scanning electron microscopy.

[0030] Figure 14 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Mo 2.5 V 2.5 (at.%) Alloy engineering stress-engineering strain curve.

[0031] Figure 15 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Mo 2.5 V 2.5 Polarization curves of (at.%) alloys.

[0032] Figure 16 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Secondary electron image of Fe5V5 (at.%) alloy obtained by scanning electron microscopy.

[0033] Figure 17 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 The stress-strain curve of Fe5V5 (at.%) alloy.

[0034] Figure 18 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Polarization curve of Fe5V5 (at.%) alloy.

[0035] Figure 19 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 1.25 V 1.25 Secondary electron image of (at.%) alloy using scanning electron microscopy.

[0036] Figure 20 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5Fe5Cr 2.5 Mo 1.25 V 1.25 (at.%) Alloy engineering stress-engineering strain curve.

[0037] Figure 21 It is Cu after annealing. 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 1.25 V 1.25 Polarization curves of (at.%) alloys.

[0038] Figure 22 The results are from an antibacterial test conducted 24 hours after the series of annealed alloys (using Escherichia coli as the bacterial strain). Detailed Implementation

[0039] The specific embodiments of the present invention are described in detail below with reference to the technical solutions.

[0040] Example 1: Cu 50.00 Ni 35.00 Co 10 Fe5(at.%) alloy

[0041] Step 1: Alloy preparation and microstructure characterization

[0042] Composition of Cu 50.00 Ni 35.00 Co 10 The Fe5 (at.%) alloy, converted to weight percentage, was prepared using Cu, Ni, Co, and Fe raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0043] Step 2: Characterization of alloy structure and properties

[0044] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 1 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 2 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 3 As shown. The alloy has a hardness of 224.8 HV, an ultimate tensile strength of 680 MPa, a yield strength of 516 MPa, an elongation of 24.3%, a self-corrosion potential of -0.22 V, and a self-corrosion current density of 9.33 μA / cm.2 .

[0045] Example 2: Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr5(at.%) alloy

[0046] Composition of Cu 50.00 Ni 32.50 Co 7.5 The Fe5Cr5 (at.%) alloy, converted to weight percentage, was prepared using Cu, Ni, Co, Fe, and Cr raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0047] Step 2: Characterization of alloy structure and properties

[0048] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 4 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 5 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 6 As shown. The alloy has a hardness of 252.8 HV, an ultimate tensile strength of 747 MPa, a yield strength of 641 MPa, an elongation of 18.4%, a self-corrosion potential of -0.24 V, and a self-corrosion current density of 4 μA / cm. 2 .

[0049] Example 3: Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 2.5 (at.%) alloy

[0050] Composition of Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 2.5(at.%) alloy composition converted to weight percentage: The alloy was prepared using Cu, Ni, Co, Fe, Cr, and Mo raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0051] Step 2: Characterization of alloy structure and properties

[0052] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 7 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 8 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 9 As shown. The alloy has a hardness of 270.9 HV, an ultimate tensile strength of 829 MPa, a yield strength of 696 MPa, an elongation of 12.2%, a self-corrosion potential of -0.28 V, and a self-corrosion current density of 11.04 μA / cm². 2 .

[0053] Example 4: Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 V 2.5 (at.%) alloy

[0054] Composition of Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 V 2.5 (at.%) alloy composition converted to weight percentage: The alloy was prepared using Cu, Ni, Co, Fe, Cr, and V raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0055] Step 2: Characterization of alloy structure and properties

[0056] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 10 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 11As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 12 As shown. The alloy has a hardness of 256.8 HV, an ultimate tensile strength of 815 MPa, a yield strength of 716 MPa, an elongation of 11.1%, a self-corrosion potential of -0.26 V, and a self-corrosion current density of 6.47 μA / cm. 2 .

[0057] Example 5: Cu 50.00 Ni 32.50 Co 7.5 Fe5Mo 2.5 V 2.5 (at.%) alloy

[0058] The composition is: Cu 50.00 Ni 32.50 Co 7.5 Fe5Mo 2.5 V 2.5 (at.%) alloy composition was converted to weight percentage using Cu, Ni, Co, Fe, and Cr raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0059] Step 2: Characterization of alloy structure and properties

[0060] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 13 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 14 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 15 As shown. The alloy has a hardness of 260.1 HV, an ultimate tensile strength of 800 MPa, a yield strength of 703 MPa, an elongation of 8.3%, a self-corrosion potential of -0.29 V, and a self-corrosion current density of 13.22 μA / cm². 2 .

[0061] Example 6: Cu 50.00 Ni 32.50 Co 7.5 Fe5V5 (at.%) alloy

[0062] Composition of Cu 50.00 Ni 32.50 Co 7.5The Fe5V5 (at.%) alloy, converted to weight percentage, was prepared using Cu, Ni, Co, Fe, and V raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0063] Step 2: Characterization of alloy structure and properties

[0064] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 16 As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 17 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 18 As shown. The alloy has a hardness of 262.7 HV, an ultimate tensile strength of 857 MPa, a yield strength of 751 MPa, an elongation of 4.9%, a self-corrosion potential of -0.31 V, and a self-corrosion current density of 9.73 μA / cm². 2 .

[0065] Example 7: Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 1.25 V 1.25 (at.%) alloy

[0066] Composition of Cu 50.00 Ni 32.50 Co 7.5 Fe5Cr 2.5 Mo 1.25 V 1.25 (at.%) alloy composition converted to weight percentage: The alloy was prepared using Cu, Ni, Co, Fe, Cr, Mo, and V raw materials with a purity of 4N. A non-consumable vacuum arc melting furnace was used, with high-purity Ar gas provided for protection. The prepared alloy raw materials were repeatedly melted five times to obtain a homogeneous alloy ingot. The cast alloy was cold-rolled, with controlled thickness and deformation, achieving a thickness deformation of 85%. The cold-rolled alloy underwent annealing treatment, holding at 800℃ for 60 minutes, followed by air cooling.

[0067] Step 2: Characterization of alloy structure and properties

[0068] Its secondary electron image was observed using a scanning electron microscope, as shown below. Figure 19As shown, the alloy exhibits a two-phase microstructure. The tensile properties of the alloy were tested using a universal tensile testing machine, and its engineering stress-strain curve is shown below. Figure 20 As shown. The corrosion resistance of the alloy was tested using an electrochemical workstation, and its polarization curve is shown in the figure. Figure 21 As shown. The alloy has a hardness of 258.5 HV, an ultimate tensile strength of 804 MPa, a yield strength of 678 MPa, an elongation of 17.2%, a self-corrosion potential of -0.22 V, and a self-corrosion current density of 6.63 μA / cm. 2 .

[0069]

[0070] Example 8

[0071] The general steps of the antibacterial experiment are as follows: first, the material and bacteria are co-incubated for 24 h, and then the bacteria are spread onto a 6 cm bacterial solid culture dish and incubated at 37 degrees Celsius for 12 h; the images are then taken by agarose gel electrophoresis.

[0072]

[0073] Figure 22 The results of the antibacterial test (using Escherichia coli as the bacterial strain) on the alloy 24 hours after the series of annealing treatments are shown in the table above.

Claims

1. A high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy, characterized in that: The alloy composition contains Cu and Fe with atomic percentages of 50.00 at.% and 5 at.%, respectively, and Ni and Co with atomic percentages of 32.50~35.00 at.% and 7.50~10.00 at.%, respectively. Alternatively, the alloy may contain at least one of Cr, Mo, and V, with the atomic percentages of Cr: 7.5~10 at.%, Mo: 1.25~5.00 at.%, and V: 1.25~5.00 at.%; The sum of the atomic percentages of all components in the alloy is 100%; The metallographic features of the alloy include Cu-rich FCC1 phase and Ni-rich FCC2 phase formed by segregation based on the characteristics of the components themselves, with a size of 5~20μm; nanoparticle phases precipitated in the Cu-rich FCC1 phase with a size of 10~30nm; and amplitude-modulated decomposition structure in the Ni-rich FCC2 phase with a phase width of 20~50nm.

2. The high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy according to claim 1, characterized in that: The alloy has a hardness of 224.81~270.85 HV, an ultimate tensile strength of 680~856 MPa, a yield strength of 516~751 MPa, an elongation of 4.9~24.3%, a self-corrosion potential of -0.31V~-0.22V, and a self-corrosion current density of 4.00-13.22 μA / cm². 2 .

3. The method for preparing a high-strength, ductile, corrosion-resistant, and antibacterial Cu-based multi-component alloy according to claim 1 or 2, characterized in that, Includes the following steps: (1) Non-consumable vacuum arc melting is adopted, and high-purity argon gas is introduced for protection. The prepared raw materials with a purity of 4N or higher are repeatedly melted to obtain alloy ingots with uniform composition. (2) The as-cast alloy is cold-rolled, and the thickness and deformation are controlled, with the thickness deformation being 85%; (3) Anneal the cold-rolled alloy at a holding temperature of 800℃-850℃ for 50-60 minutes, and then air cool it.

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