Method for preparing high-strength and high-conductivity Cu-Cr-Zr alloy

Abstract

The invention relates to a preparation method of a high-strength and high-conductivity Cu-Cr-Zr alloy, which belongs to the technical field of copper alloy preparation, and comprises the following specific steps: smelting pure copper, Cu-Cr and Cu-Zr intermediate alloys in a vacuum induction furnace, and casting to obtain a Cu-Cr-Zr cast ingot; carrying out primary rolling and pre-deformation on the cast ingot, and annealing at 450 DEG C for 1 hour; after annealing, cutting the alloy into a cuboid with the ratio of length to width to height being 4: 1: 2; the cuboid alloy is put into a steel die, the length of a cavity of the steel die is equal to that of the cuboid alloy, the width of the cavity is two times that of the cuboid alloy, and a cuboid with the length, width and height being 4: 2: 1 is pressed on a hydraulic machine through a punch with the cross section size equal to that of the cavity at the speed of 1-5 mm / min; and taking out the pressed cuboid, putting the cuboid into a mold cavity, pressing for 4-6 times according to the same mode, then taking out the cuboid, putting the cuboid into a resistance furnace, and keeping the temperature at 350-450 DEG C for 1-5 hours to obtain the high-strength and high-conductivity Cu-Cr-Zr alloy. In the alloy preparation process, the deformation amount is large, the size and shape are not changed, and the product has high strength, high hardness and high conductivity at the same time and is suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of copper alloy preparation technology, specifically relating to a method for preparing a high-strength, high-conductivity Cu-Cr-Zr alloy. Background Technology

[0002] Copper alloys possess excellent mechanical and physical properties, making them valuable in fields such as electrical appliances, transportation, electronics, aviation, and aerospace. Among them, Cu-Mg, Cu-Fe-P, Cu-Ni-Si, and Cu-Cr-Zr alloys are some of the most widely used conductive alloy systems. Cu-Cr-Zr alloys are low in cost, have high electrical and thermal conductivity, good formability, wear resistance, corrosion resistance, and thermal stability, and are widely used in railway contact wires, integrated circuit lead frames, and resistance welding electrodes. The high conductivity of Cu-Cr-Zr alloys is fundamentally due to the low solid solubility of Cr and Zr elements in copper at room temperature, which makes electrons less prone to scattering during transport in the matrix. However, like other alloy systems, the strength and conductivity of Cu-Cr-Zr alloys are usually mutually restrictive; achieving high conductivity and high strength simultaneously is difficult, limiting the alloy's application range and making it difficult to meet the demands of the ever-evolving high-tech industries. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing high-strength, high-conductivity Cu-Cr-Zr alloys to meet the needs of high-end applications. The preparation method mainly includes the following steps:

[0004] (1) Pure copper, Cu-Cr and Cu-Zr master alloy are melted in a vacuum induction furnace and cast to obtain Cu-Cr-Zr ingots;

[0005] (2) The ingot is pre-deformed by initial rolling and then annealed at 450℃ for 1 hour;

[0006] (3) After annealing, the alloy is cut into cuboids with a length:width:height ratio of 4:1:2;

[0007] (4) Place the above-mentioned rectangular alloy into a steel mold with a cavity length equal to its length and a cavity width twice its width, and press it into a rectangular box with a length:width:height = 4:2:1 using a punch with a cross-sectional dimension equal to that of the cavity on a hydraulic press at a speed of 1-5 mm / min.

[0008] (5) After the above-pressed cuboid is taken out, it is placed into the mold cavity and pressed again 4 to 6 times according to step 4. Then it is taken out and placed in the resistance furnace and kept at 350 to 450°C for 1 to 5 hours to obtain a high-strength and high-conductivity Cu-Cr-Zr alloy.

[0009] Compared with the prior art, the present invention has the following advantages: no other high-cost alloying elements need to be added, the pressing mold structure is simple and easy to design, the equipment requirements are low, the processing steps are easy to operate, the size of the prepared alloy can be adjusted proportionally according to the product needs, the alloy deformation is large and the size and shape remain unchanged during the pressing process, the surface finish is high and the material utilization rate is close to 100%, which is very suitable for large-scale industrial production. The product also has high tensile strength, high yield strength, high hardness and high conductivity. Attached Figure Description

[0010] Figure 1 Metallographic structure of the Cu-1%Cr-0.1%Zr alloy prepared in Example 2 of this invention

[0011] Figure 2 Transmission electron microscopy (TEM) microstructure of the Cu-1%Cr-0.1%Zr alloy prepared in Example 2 of this invention.

[0012] Figure 3 Transmission electron microscopy morphology of nano-precipitated phases in the Cu-1%Cr-0.1%Zr alloy prepared in Example 2 of this invention. Detailed Implementation

[0013] Example 1

[0014] This embodiment provides a method for preparing a high-strength, high-conductivity Cu-1%Cr-0.1%Zr (mass percentage, the same below) alloy, which mainly includes the following steps:

[0015] (1) Pure copper, Cu-10%Cr and Cu-10%Zr master alloy are melted in a vacuum induction furnace and cast to obtain Cu-1%Cr-0.1%Zr ingot;

[0016] (2) The ingot is pre-deformed by initial rolling and then annealed at 450℃ for 1 hour;

[0017] (3) After annealing, the alloy is cut into cuboids with a length:width:height ratio of 4:1:2;

[0018] (4) Place the above-mentioned rectangular alloy into a steel mold with a cavity length equal to its length and a width twice its width, and press it into a rectangular box with a length:width:height = 4:2:1 using a punch with a cross-sectional dimension equal to that of the cavity on a hydraulic press at a speed of 3mm / min.

[0019] (5) After the above-pressed cuboid is taken out, it is placed into the mold cavity and pressed 4 more times according to step 4. Then it is taken out and placed in the resistance furnace and kept at 350℃ for 3 hours to obtain a high-strength, high-conductivity Cu-1%Cr-0.1%Zr alloy.

[0020] The alloy was tested for performance, and the results were: tensile strength 649 MPa, yield strength 626 MPa, Vickers hardness 180.2, and electrical conductivity 79.6% IACS.

[0021] Example 2

[0022] The method for preparing a high-strength, high-conductivity Cu-1%Cr-0.1%Zr alloy in this embodiment mainly includes the following steps:

[0023] (1) Pure copper, Cu-10%Cr and Cu-10%Zr master alloy are melted in a vacuum induction furnace and cast to obtain Cu-1%Cr-0.1%Zr ingot;

[0024] (2) The ingot is pre-deformed by initial rolling and then annealed at 450℃ for 1 hour;

[0025] (3) After annealing, the alloy is cut into cuboids with a length:width:height ratio of 4:1:2;

[0026] (4) Place the above-mentioned rectangular alloy into a steel mold with a cavity length equal to its length and a width twice its width, and press it into a rectangular box with a length:width:height = 4:2:1 using a punch with a cross-sectional dimension equal to that of the cavity on a hydraulic press at a speed of 3mm / min.

[0027] (5) After the above-pressed cuboid is taken out, it is placed into the mold cavity and pressed 4 more times according to step 4. Then it is taken out and placed in the resistance furnace and kept at 400℃ for 1.5h to obtain a high-strength and high-conductivity Cu-1%Cr-0.1%Zr alloy.

[0028] The alloy was tested for performance and found to have a tensile strength of 641 MPa, a yield strength of 616 MPa, a Vickers hardness of 178.1, and an electrical conductivity of 79.2% IACS.

[0029] Microstructure analysis of the alloy was performed. Figure 1 It is its metallographic appearance, Figure 2 The structure observed by transmission electron microscopy shows that the grains and the second phase are very fine, with a large number of ultrafine grains and second phase particles with a size of less than 1 μm, which makes the strengthening effect significant. Figure 3 The images show the transmission electron microscopy morphology of the large number of Cr-rich nano-reinforcing phases precipitated after aging. The vast majority of these phases are less than 10 nm in size. The precipitation of these Cr-rich nano-phases not only plays a role in dispersion reinforcement, but also reduces the solid solution of Cr in the matrix, which greatly reduces its electron scattering effect and thus significantly improves the conductivity.

[0030] Example 3

[0031] The method for preparing a high-strength, high-conductivity Cu-1%Cr-0.1%Zr alloy in this embodiment mainly includes the following steps:

[0032] (1) Pure copper, Cu-10%Cr and Cu-10%Zr master alloy are melted in a vacuum induction furnace and cast to obtain Cu-1%Cr-0.1%Zr ingot;

[0033] (2) The ingot is pre-deformed by initial rolling and then annealed at 450℃ for 1 hour;

[0034] (3) After annealing, the alloy is cut into cuboids with a length:width:height ratio of 4:1:2;

[0035] (4) Place the above-mentioned rectangular alloy into a steel mold with a cavity length equal to its length and a width twice its width, and press it into a rectangular box with a length:width:height = 4:2:1 using a punch with a cross-sectional dimension equal to that of the cavity on a hydraulic press at a speed of 3mm / min.

[0036] (5) After taking out the above-pressed cuboid, put it into the mold cavity and press it 5 more times according to step 4. Then take it out and put it into the resistance furnace and keep it at 450℃ for 1 hour to obtain a high-strength, high-conductivity Cu-1%Cr-0.1%Zr alloy.

[0037] The alloy was tested for performance and found to have a tensile strength of 652 MPa, a yield strength of 623 MPa, a Vickers hardness of 178.9, and an electrical conductivity of 80.3% IACS.

[0038] For ease of comparison, the alloy properties after initial rolling and annealing in the above embodiments were tested, and the tensile strength was 473 MPa, the yield strength was 426 MPa, the Vickers hardness was 143.7, and the electrical conductivity was 81.6% IACS.

[0039] It is evident that the method employed in this invention significantly improves strength and hardness while essentially maintaining the conductivity of the annealed alloy.

Claims

1. A method for preparing a high-strength, high-conductivity Cu-Cr-Zr alloy, the specific steps are as follows: (1) pure copper, Cu-Cr, Cu-Zr intermediate alloy are melted in a vacuum induction furnace and cast to obtain Cu-Cr-Zr ingots; (2) the ingots are pre-deformed by initial rolling and annealed at 450℃ for 1h; (3) after annealing, the alloy is cut into a cuboid with length:width:height = 4:1:2; (4) the above cuboid alloy is placed in a steel mold with a cavity length equal to its length and a cavity width twice its width, and pressed into a cuboid with a length:width:height = 4:2:1 at a speed of 1-5mm / min using a punch with a cross-sectional size equal to the cavity on a hydraulic press; (5) the above-pressed cuboid is taken out and placed in the mold cavity and pressed again 4-6 times according to step 4, and then taken out and placed in a resistance furnace and kept at 350-450℃ for 1-5h to obtain a high-strength, high-conductivity Cu-Cr-Zr alloy; The Cu-Cr-Zr alloy is a Cu-1%Cr-0.1%Zr alloy.

Images