CN106756207A - A kind of short process making method of high-strength highly-conductive deformation Cu Cr Ag in-situ composites - Google Patents

Abstract

A short-process preparation method of high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material, the steps of which are as follows: (1) Melting and casting Cu-Cr-Ag ternary alloy ingots by adopting medium-frequency induction melting combined with graphite mold casting; (2) Put the ingot into the regional melting-directional solidification furnace for directional solidification treatment, so that the Cr dendrites form oriented micro-nano-scale fibers along the axial direction; The cold-drawing deformation further refines the micro-nano-scale fibers formed in the directional solidification process into nano-scale fibers; (4) The final aging heat treatment is used to comprehensively control the strength, electrical conductivity and elongation of the material. The present invention forms continuous oriented micro-nano-scale fibers through the control of the as-cast structure, combined with cold drawing deformation, alloying and final aging heat treatment, shortens the preparation process, reduces the amount of cold deformation strain, and significantly increases the size of the final material. And make the final material obtain stable and good comprehensive performance in use, which can broaden the application scope of the deformed Cu-based in-situ composite material in the high-tech field.

Description

A short-process preparation method of high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material

technical field

The invention belongs to the technical field of preparation of non-ferrous metal materials, in particular to a short-flow preparation method of large-size, high-strength, high-conductivity deformation Cu-Cr-Ag in-situ composite material.

Background technique

The development of modern science and technology has put forward higher and higher requirements for the performance of conductive materials. In many applications such as high-intensity magnetic field coils, large-scale integrated circuit lead frames and high-speed electrified railway contact wires, not only conductive materials are required to have high Electrical conductivity also requires the material to have high tensile strength and elongation. At present, the deformation in-situ composite method is the most ideal method to prepare high-strength and high-conductivity Cu-based materials. It forms the second phase in-situ in the as-cast alloy through melting and casting technology, and the second phase in the alloy is formed along the processing direction through large plastic deformation. Oriented fibers, in which the fiber phase is the main bearer of the load, and the Cu matrix mainly acts as a conductive channel. Most of the existing studies on deformation in situ composite methods focus on alloys such as Cu-Nb, Cu-Ag, Cu-Fe and Cu-Cr. Nb and Ag are noble metals, which limit the industrial production and commercial application of corresponding materials. Fe The high-temperature solid solubility in the Cu matrix is high, and the low-temperature diffusion rate is slow, while the Fe atoms solid-dissolved in the Cu matrix seriously damage the electrical conductivity of the material. Deformed Cu-Cr based in-situ composites have attracted extensive attention from scientific and technological workers because of the small liquid miscibility gap between the second phase Cr and Cu, low cost, and good strengthening effect.

The main preparation processes of deformed Cu-Cr in-situ composite materials are usually: medium frequency induction melting, casting, long-term preliminary heat treatment or solution treatment, hot rolling, large plastic cold deformation interspersed with intermediate heat treatment, final heat treatment, etc. Among them, the preparatory heat treatment is to eliminate or reduce the non-equilibrium solidification structure effect caused by the uneven composition during the casting process, and reduce the deformation resistance; the hot rolling is to eliminate or reduce the microscopic defects of the as-cast structure, break the second phase dendrite, and make It transforms into a fine granular or rod-like structure; the large plastic cold deformation is to make the broken second-phase dendrites distributed randomly in the as-cast structure gradually transform into fibers aligned along the processing direction; the appropriate intermediate heat treatment is In order to eliminate or reduce the residual stress caused by large plastic cold deformation to facilitate further cold deformation; the final heat treatment is to promote the precipitation of solid solution Cr atoms and improve the electrical conductivity of the material. The fiber phase of this preparation method is obtained by crushing and refining the Cr dendrites of the second phase through large plastic deformation. The fiber continuity is poor, and it is difficult to ensure the stability of the comprehensive performance of the material in various applications. In addition, in order to obtain high strength, the large plastic cold deformation strain of this type of material often reaches 10 or even higher. The above-mentioned analysis of the existing deformation Cu-Cr system in-situ composite material preparation method shows that the method is complicated in process, long in process, large in thermal and cold deformation strain, the cross-sectional size of the final material is small, and the fiber continuity is poor. The comprehensive performance is unstable. Therefore, it is very necessary to develop a new large-size, high-strength, high-conductivity deformation Cu-Cr system in-situ composite material and its preparation method, simplify the preparation process of the material, shorten the preparation process of the material, obtain a material with a large cross-sectional size, and strengthen the fiber The continuity of the material improves the comprehensive performance of the material.

Contents of the invention

Aiming at the deficiencies in existing deformable Cu-Cr in-situ composite materials and preparation technologies, the present invention provides a short-process preparation method for high-strength and high-conductivity deformable Cu-Cr-Ag in-situ composite materials, which enables directional solidification and cold-drawn deformation phase Combined, the cold deformation strain is greatly reduced, the process flow is shortened, the cross-sectional size of the final material is significantly increased, continuous reinforcing phase fibers are formed, and the comprehensive performance of the material is improved.

The concrete steps of the technical solution adopted in the present invention are as follows:

1. Melting and casting Cu-Cr-Ag ternary alloy ingots by medium frequency induction melting combined with graphite mold casting;

2. Put the ingot into the regional melting-directional solidification furnace for directional solidification, so that the Cr dendrites form oriented micro-nano-scale fibers along the axial direction;

3. Perform multi-pass cold drawing deformation on the material treated by directional solidification, so that the micro-nano-scale fibers formed during the directional solidification process are refined into nano-scale fibers;

4. The final aging heat treatment is used to comprehensively control the strength, electrical conductivity and elongation of the material.

The Cu-Cr-Ag ternary alloy described in the above step 1 has the following composition (by mass percentage): chromium is 6-30; silver is 0.008-0.200; copper is the balance.

The directional solidification treatment described in the above step 2 is specifically: put the Cu-Cr-Ag alloy ingot into the _{Al2O3 two} -way ceramic tube with a purity of 99.99% and the inner layer is coated with a high-temperature resistant inert coating, and the The ceramic tube is loaded into the regional smelting-directional solidification furnace, and smelted in a high-purity argon atmosphere of 300-400Pa through a high-frequency induction power supply. After melting, the alloy melt together with the ceramic tube is under the action of the base and the pulling mechanism. It moves downward at a speed of 50-300 μm/s and is simultaneously cooled by the gallium-indium alloy liquid to form a directionally solidified ingot.

The multi-pass cold drawing deformation described in the above step 3 is specifically: carried out at room temperature, and the total cold deformation strain is less than or equal to 6.

The final aging heat treatment described in the above step 4 is specifically: keeping the temperature at 200-650° C. for 0.5-8 hours, and then cooling to room temperature with the furnace.

The advantages of the present invention are: (1) adding a small amount of Ag to the Cu-Cr binary alloy reduces the solid solubility of Cr in the Cu matrix and improves the electrical conductivity of the material; (2) adopts directional solidification treatment to obtain continuous orientation The arranged micro-nano-scale fibers reduce the cold deformation strain and increase the cross-sectional size of the final material; (3) Combining directional solidification treatment with cold deformation does not require preparatory heat treatment and multiple intermediate heat treatments, which simplifies the process flow; ( 4) The final aging heat treatment is adopted to adjust the strength, electrical conductivity and elongation of the material according to the actual needs, so that the final material has stable and good comprehensive performance.

detailed description

Example 1

(1) Weigh 6% of pure chromium, 0.008% of pure silver and the rest of pure copper according to the mass percentage, put them into an intermediate frequency induction furnace for melting and cast them into ingots with graphite molds;

(2) Put the ingot into an Al ₂ O ₃ two-way ceramic tube with a purity of 99.99% and an inner layer coated with a high-temperature resistant inert coating, put the ceramic tube into a zone melting-directional solidification furnace, and pass a high-frequency induction power supply Melting is carried out in a high-purity argon atmosphere of 300Pa. After melting, the alloy melt moves down with the ceramic tube at a speed of 50 μm/s under the action of the base and the drawing mechanism and is simultaneously cooled by the gallium-indium alloy liquid to form Directional solidification ingot;

(3) The directionally solidified ingot is subjected to multi-pass cold drawing deformation at room temperature, and the total cold deformation strain is 6;

(4) The cold-drawn deformed material was kept at 200°C for 8 hours, and then cooled to room temperature with the furnace to obtain a high-strength and high-conductivity deformable Cu-Cr-Ag in-situ composite material.

The tensile strength of the deformed Cu-Cr-Ag in-situ composite material prepared in this example is 916 MPa, the electrical conductivity is 82.1%IACS, and the elongation is 4.1%.

Example 2

(1) Weigh 15% of pure chromium, 0.06% of pure silver and the rest of pure copper according to the mass percentage, put them into an intermediate frequency induction furnace for melting and cast them into ingots with graphite molds;

(2) Put the ingot into an Al ₂ O ₃ two-way ceramic tube with a purity of 99.99% and an inner layer coated with a high-temperature resistant inert coating, put the ceramic tube into a zone melting-directional solidification furnace, and pass a high-frequency induction power supply Melting is carried out in a high-purity argon atmosphere of 350Pa. After melting, the alloy melt moves down with the ceramic tube at a speed of 100 μm/s under the action of the base and the drawing mechanism and is simultaneously cooled by the gallium-indium alloy liquid to form Directional solidification ingot;

(3) The directionally solidified ingot is subjected to multi-pass cold drawing deformation at room temperature, and the total cold deformation strain is 5.5;

(4) The cold-drawn and deformed material was kept at 400°C for 2 hours, and then cooled to room temperature with the furnace to obtain a high-strength and high-conductivity deformable Cu-Cr-Ag in-situ composite material.

The tensile strength of the deformed Cu-Cr-Ag in-situ composite material prepared in this example is 1237MPa, the electrical conductivity is 81.2%IACS, and the elongation is 3.9%.

Example 3

(1) Weigh 20% of pure chromium, 0.12% of pure silver and the rest of pure copper according to the mass percentage, put them into an intermediate frequency induction furnace for melting and cast them into ingots with graphite molds;

(2) Put the ingot into an Al ₂ O ₃ two-way ceramic tube with a purity of 99.99% and an inner layer coated with a high-temperature resistant inert coating, put the ceramic tube into a zone melting-directional solidification furnace, and pass a high-frequency induction power supply Melting is carried out in a high-purity argon atmosphere of 350Pa. After melting, the alloy melt moves down with the ceramic tube at a speed of 200μm/s under the action of the base and the drawing mechanism and is cooled by the gallium-indium alloy liquid at the same time, forming Directional solidification ingot;

(3) The directionally solidified ingot is subjected to multi-pass cold drawing deformation at room temperature, and the total cold deformation strain is 5.5;

(4) The cold-drawn deformed material was kept at 550°C for 1 hour, and then cooled to room temperature with the furnace to obtain a high-strength and high-conductivity deformable Cu-Cr-Ag in-situ composite material.

The tensile strength of the deformed Cu-Cr-Ag in-situ composite material prepared in this example is 1369MPa, the electrical conductivity is 80.4%IACS, and the elongation is 3.7%.

Example 4

(1) Weigh 30% of pure chromium, 0.2% of pure silver and the rest of pure copper according to the mass percentage, put them into an intermediate frequency induction furnace for melting and cast them into ingots with graphite molds;

(2) Put the ingot into an Al ₂ O ₃ two-way ceramic tube with a purity of 99.99% and an inner layer coated with a high-temperature resistant inert coating, put the ceramic tube into a zone melting-directional solidification furnace, and pass a high-frequency induction power supply Melting is carried out in a high-purity argon atmosphere of 400Pa. After melting, the alloy melt moves down with the ceramic tube at a speed of 300μm/s under the action of the base and the drawing mechanism and is simultaneously cooled by the gallium-indium alloy liquid to form Directional solidification ingot;

(3) The directionally solidified ingot is subjected to multi-pass cold drawing deformation at room temperature, and the total cold deformation strain is 5;

(4) The cold-drawn and deformed material was kept at 650°C for 0.5 hours, and then cooled to room temperature with the furnace to obtain a high-strength and high-conductivity deformable Cu-Cr-Ag in-situ composite material.

The tensile strength of the deformed Cu-Cr-Ag in-situ composite material prepared in this example is 1461 MPa, the electrical conductivity is 78.9%IACS, and the elongation is 3.4%.

Claims (5)

1. A short process preparation method of high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material, characterized in that it comprises the following steps: (1) Melting and casting Cu-Cr-Ag ternary alloy ingots by medium frequency induction melting combined with graphite mold casting; (2) Put the ingot into the zone smelting-directional solidification furnace for directional solidification treatment, so that Cr dendrites form oriented micro-nano-scale fibers along the axial direction; (3) Perform multi-pass cold drawing deformation on the material treated by directional solidification, so that the micro-nano-scale fibers formed during the directional solidification process are further refined into nano-scale fibers; (4) The final aging heat treatment is used to comprehensively control the strength, electrical conductivity and elongation of the material. 2. The short-process preparation method of a high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material according to claim 1, characterized in that in step (1), the formula composition of Cu-Cr-Ag ternary alloy The composition is as follows (by mass percentage): 6-30% chromium; 0.008-0.200% silver; and copper as the balance. 3. The short-process preparation method of a high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material according to claim 1, characterized in that in step (2), the material is subjected to directional solidification treatment, specifically: The Cu-Cr-Ag alloy ingot is put into the Al ₂ O ₃ two-way ceramic tube with a purity of 99.99% and the inner layer is coated with a high-temperature resistant inert coating. The induction power supply is smelted in a high-purity argon atmosphere of 300-400Pa. After melting, the alloy melt moves down with the ceramic tube at a speed of 50-300μm/s under the action of the base and the pulling mechanism and is simultaneously absorbed by the gallium. The indium alloy liquid is cooled to form a directionally solidified ingot. 4. The short-process preparation method of a high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material according to claim 1, characterized in that in step (3), the multi-pass cold drawing deformation is carried out at room temperature, The total cold deformation strain is less than or equal to 6. 5. The short-process preparation method of a high-strength and high-conductivity deformation Cu-Cr-Ag in-situ composite material according to claim 1, characterized in that in step (4), the final aging heat treatment is carried out at 200-650°C, Keep warm for 0.5-8 hours, then cool to room temperature with the furnace.