CN108456797B - A kind of Cu-Ag-Fe-C alloy and its preparation method - Google Patents

Abstract

The invention discloses a Cu-Ag-Fe-C alloy and a preparation method thereof. The Cu-Ag-Fe-C alloy is composed of the following components according to mass percentage: Ag, 0.5-3%; Fe-C pre alloy, 10‑15%, the balance being Cu. Its preparation method comprises: the smelting step of Cu and Ag, the addition step of Fe-C pre-alloy, the rapid solidification step, to obtain the Cu-Ag-Fe-C system in which the Fe-C pre-alloy particles are evenly distributed in the Cu-Ag matrix alloy. The method of the invention can improve the electrical conductivity and tensile strength of the Cu-Fe alloy, and the tensile strength of the obtained cast alloy is 420-500MPa, and the electrical conductivity is 40-55% IACS.

Description

A kind of Cu-Ag-Fe-C alloy and its preparation method

technical field

The invention relates to a method for preparing a copper alloy, more specifically, the invention relates to a Cu-Ag-Fe-C alloy and a method for preparing the same.

Background technique

Copper alloy has good electrical and thermal conductivity, ductility and mechanical properties, and is a key functional material for the development of important industries such as electronic information, electric power, energy, ships and machinery. Compared with high-strength and high-conductivity copper alloys of other systems, the melting point of the alloying element Fe in the Cu-Fe system is relatively low, and it is easier to melt, and the immiscible gap between Fe and Cu is small, and the alloy has better deformability and machinability. It is better, so the research on Cu-Fe alloys has been paid attention to, and it has become one of the important directions for the development of high-strength and high-conductivity copper alloys.

At present, the primary alloys of high-strength and high-conductivity Cu-Fe alloys are mainly prepared by conventional melting and casting methods, and then the primary alloys are subjected to subsequent heat treatment, deformation and other processing to obtain Cu-Fe alloys in the final use state. When the primary alloy is prepared by melting and casting, due to the fast solidification and cooling rate, it is easy to cause a large amount of Fe element to dissolve in the Cu matrix, which seriously reduces the conductivity of the Cu-Fe alloy. Although supersaturated Fe is continuously precipitated during subsequent heat treatment, deformation heat treatment, etc., the diffusion rate of Fe is very slow at low temperature, and it is difficult to completely precipitate Fe in solid solution in Cu, and the solid solution of Fe in Cu is to reduce Cu. -The most important influencing factor of Fe alloy. Therefore, in order to improve the conductivity of Cu-Fe alloy, it is necessary to reduce the solid solution amount of Fe in Cu.

Existing methods often use deformation, heat treatment, strong magnetic field, multi-element alloying, etc., but none of them can solve this problem well. For example: Ag is considered to be the element that has the least effect on the conductivity of Cu alloys, but Cu-Fe-Ag alloys prepared by alloying Cu-Fe alloys with Ag still have more than 2.5% Fe in the as-cast Cu matrix. . Since the diffusion rate of Fe is very slow at low temperature, although other methods can reduce the solid solution amount of Fe in Cu, they cannot reduce the solid solution Fe in Cu to a very low state.

Therefore, there is an urgent need for a method that can more effectively reduce the solid-dissolved Fe in Cu.

Contents of the invention

In order to overcome the defects in the prior art, the object of the present invention is to provide a Cu-Ag-Fe-C alloy and a preparation method thereof.

A Cu-Ag-Fe-C alloy, according to mass percentage, the Cu-Ag-Fe-C alloy is composed of the following components: Ag, 0.5-3%; Fe-C pre-alloyed, 10-15% , the balance being Cu.

In the above-mentioned Cu-Ag-Fe-C alloy, as a preferred embodiment, the C content in the Fe-C pre-alloy is 0.8-1.8wt% (such as: 0.9wt%, 1.0wt%, 1.1wt%) , 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%).

A method for preparing a Cu-Ag-Fe-C alloy, comprising:

Cu and Ag smelting step, the solid raw materials Cu and Ag are smelted to obtain liquid Cu-Ag alloy liquid;

The step of adding Fe-C pre-alloy, adding Fe-C pre-alloy powder into the liquid Cu-Ag alloy liquid for stirring treatment, to obtain a uniformly mixed smelting material;

In the rapid solidification step, the melting material is subjected to rapid solidification treatment to obtain a Cu-Ag-Fe-C alloy in which Fe-C pre-alloyed particles are uniformly distributed in a Cu-Ag matrix.

The present invention first smelts copper and Ag into a liquid state, then keeps the smelting temperature slightly higher than the melting point of copper and silver but does not reach the melting point of Fe-C pre-alloy powder, and then adds Fe-C pre-alloy powder at the smelting temperature. alloy powder and stir and mix evenly so that the solid Fe-C pre-alloy powder is evenly dispersed in the liquid copper-silver alloy liquid, and finally cooled rapidly. The present invention utilizes the C and Cu in the Fe-Cu-C ternary system Mutual repulsion, taking advantage of the solid solution of Ag in Cu before Fe, the inhibition of Fe solid solution, taking advantage of the low diffusion rate of Fe in Cu at low temperature, adding Fe to the Cu-Ag alloy liquid in solid form , and then rapidly lower the temperature to control the diffusion of Fe into the Cu matrix, so that Fe is evenly dispersed in the copper-silver alloy matrix, and the amount of Fe dissolved in Cu is reduced; during this process, the Fe-C pre-alloyed powder does not melt , This is also beneficial to reduce the amount of Fe dissolved in the Cu solution and to improve the conductivity of the alloy.

In the above preparation method, as a preferred embodiment, in the Cu and Ag smelting step, the smelting treatment is carried out in a vacuum intermediate frequency induction furnace.

In the above preparation method, as a preferred embodiment, in the smelting step of Cu and Ag, the smelting temperature of the smelting treatment is 1090-1200°C, more preferably 1100-1180°C (such as 1110°C, 1120°C ℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1175℃). Too high melting temperature is not conducive to the connection with the next step.

In the above preparation method, as a preferred embodiment, in the smelting step of Cu and Ag, the vacuum degree during the smelting treatment is below 10Pa (such as 9Pa, 7Pa, 5Pa, 3Pa, 1Pa, 0.5Pa , 0.1Pa, 0.05Pa).

In the above preparation method, as a preferred embodiment, in the step of adding the Fe-C pre-alloy, the temperature during the stirring treatment is 1100-1180°C (such as 1110°C, 1120°C, 1130°C, 1140°C , 1150°C, 1160°C, 1170°C, 1175°C), more preferably, the stirring treatment is carried out at 1100°C. Too high or too low temperature during stirring treatment is not conducive to the uniform dispersion of Fe-C pre-alloyed powder in the copper-silver alloy melt, which will have an adverse effect on the properties of the alloy.

In the above preparation method, as a preferred embodiment, in the step of adding the Fe-C pre-alloy, the stirring process is mechanical stirring or electromagnetic stirring, and the time of the stirring process is 1-5min (such as 1.5min , 2min, 2.5min, 3min, 4min, 4.5min); more preferably, the stirring speed of the mechanical stirring is 240-400rpm (such as 250rpm, 280rpm, 300rpm, 320rpm, 350rpm, 370rpm, 390rpm), the electromagnetic stirring The excitation voltage is 180-220V (such as 185V, 190V, 200V, 210V, 220V). The effect of electromagnetic stirring is better than that of mechanical stirring. Stirring treatment under the electromagnetic stirring parameters of the present invention can make the dispersion of Fe-C pre-alloyed powder more uniform, and can further improve the performance of the alloy.

In the above preparation method, as a preferred embodiment, in the rapid solidification step, the rapid solidification treatment is a water-cooled copper mold casting method or a single-roller stripping method; more preferably, the water-cooled copper mold casting method The cooling rate is 50°C/s～1000°C/s (such as 55°C/s, 100°C/s, 200°C/s, 300°C/s, 400°C/s, 500°C/s, 600°C/s, 700°C/s, 800°C/s, 900°C/s, 950°C/s).

In the above preparation method, as a preferred embodiment, the solid raw materials Cu and Ag are electrolytic copper and Ag with a purity of 99.9 wt% or more; or the solid raw materials Cu and Ag are Cu-Ag pre-alloyed powders. Cu-Ag pre-alloyed powder is a commercially available product, and of course it can also be prepared according to a conventional method. It can be prepared by a vacuum atomization furnace, and the raw materials electrolytic copper and elemental aluminum in the required ratio are smelted and atomized into powder particles. The addition of too little Ag will not reduce the solid solution content of Fe in the matrix. Too much Ag addition will not only increase the cost, but more importantly, it will lead to coarsening of the iron phase and reduce the service temperature of the alloy.

In the above preparation method, as a preferred embodiment, the particle size of the Fe-C pre-alloyed powder is 60-220nm (such as 70nm, 80nm, 100nm, 120nm, 150nm, 180nm, 190nm, 210nm or the above-mentioned specific point value any size range formed). The Fe-C pre-alloyed powder is a commercially available product, and of course it can also be prepared according to a conventional method. It can be prepared by a vacuum atomization furnace, and the raw material pure iron and carburant of the required ratio are smelted and atomized into powder particles. Then prepare Fe-C pre-alloyed powder with required particle size by high-energy ball milling. The particle size of the Fe-C pre-alloyed powder used in the present invention is 60-220nm. If the particle size is too large, the strengthening effect will be poor. If the particle size is too small, Fe will be easily dissolved in Cu, the conductivity will be poor, and agglomeration will easily occur.

In the above preparation method, as a preferred embodiment, based on the total mass of the Fe-C pre-alloy powder and the solid raw materials Cu and Ag, the amount of the Fe-C pre-alloy powder is 10wt%～ 15wt% (such as 11%, 12%, 13%, 14%), the amount of the solid raw material Cu is 82wt% ~ 89.5wt% (such as 86%, 87%, 88%, 89%), the solid raw material The amount of Ag used is 0.5wt%-3wt% (such as 0.6wt%, 0.8wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2.3wt%, 2.8wt%).

In the above preparation method, as a preferred embodiment, in the Fe-C pre-alloyed powder, the C content is 0.8-1.8wt% (such as: 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%).

In the alloy of the present invention, if the C content is too low, more Fe will be dissolved into Cu, which is detrimental to the conductivity of the alloy. If the C content is too high, graphite or Fe3C may be formed.

In the above preparation method, as a preferred embodiment, the preparation method also includes an alloy post-treatment step, and the Cu-Ag-Fe-C alloy obtained in the rapid solidification step is post-treated to obtain Cu-Ag- Fe-C alloy finished products. More preferably, the post-treatment is one or more of heat treatment, deformation treatment, and magnetic field treatment; the post-treatment is conventional treatment.

Compared with the prior art, the present invention has the following beneficial effects:

In order to more effectively reduce the solid solution Fe content in the Cu-Fe alloy matrix, this patent proposes to use the mutual repulsion of C and Cu in the Fe-Cu-C ternary system to add Fe-C to Cu; Ag is solid-dissolved in Cu earlier than Fe, and it inhibits the solid-solution of Fe. At the same time, taking advantage of the low diffusion rate of Fe in Cu at low temperature, Fe is added into Cu liquid in the form of Fe-C in solid form, and then rapidly cooled to control The diffusion of Fe into the Cu matrix greatly reduces the amount of solid solution of Fe in the Cu-Ag matrix. The method of the invention can improve the electrical conductivity and tensile strength of the Cu-Fe alloy, and the tensile strength of the obtained cast alloy is 420-500MPa, and the electrical conductivity is 40-55% IACS.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only for the present invention and are not intended to limit the scope of the present invention. It should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

The alloy prepared in this embodiment is Cu-2.0wt%Ag-15wt% (Fe-C) alloy, that is: in this alloy, the content of Fe-C is 15wt%, the content of Cu is 83wt%, and the content of Ag is 2wt%, wherein, the mass percentage of C in the Fe-C alloy powder is 1wt%. The specific preparation method is as follows:

Melt 99.9wt% electrolytic high-purity Cu and elemental Ag in a vacuum intermediate frequency induction furnace. The melting temperature is controlled at 1100±5°C and the vacuum degree is 10Pa. -120nm Fe-C alloy powder is added to the copper-silver alloy liquid, and mechanically stirred at a stirring speed of 300rpm under the condition of 1100±5°C for 3 minutes, so that the solid Fe-C powder alloy is evenly distributed in the copper-silver alloy liquid, and then It is poured into a water-cooled copper mold for rapid cooling at a cooling rate of 100°C/s, and the obtained Cu-2.0wt%Ag-15wt% (Fe-C) alloy is obtained after pouring.

The performance test of the as-cast alloy product prepared by the method of this embodiment shows that its tensile strength is 465 MPa, and its electrical conductivity is 50% IACS.

Example 2-4

Examples 2-4 are the same as Example 1 except that the mass percentage of C in the Fe-C alloy powder is different from Example 1. See Table 1 for the mass percentage of C in the Fe—C alloy powders of Examples 2-4 and the properties of the obtained alloys.

Process parameter and performance result of table 1 embodiment 2-4

Embodiment 5-6 and comparative example 1

Embodiment 5-6 and comparative example 1 are different from embodiment 1 except that melting temperature and temperature during stirring (melting temperature is equal to temperature during stirring) are different from embodiment 1, and other process parameters are the same as embodiment 1. See Table 2 for the melting temperatures of Examples 5-6 and Comparative Example 1 and the properties of the obtained alloys.

Table 2 embodiment 5-6 and the process parameter and performance result of comparative example 1

Embodiment 7-8 and comparative example 2

Examples 7-8 and Comparative Example 2 are the same as Example 1 except that the particle size of the Fe-C pre-alloyed powder is different from Example 1. See Table 3 for the particle size of the Fe-C pre-alloyed powders of Examples 7-8 and Comparative Example 2 and the properties of the obtained alloys.

Table 3 embodiment 7-8 and the process parameter and performance result of comparative example 2

Embodiment 9-10 and comparative example 3

Examples 9-10 and Comparative Example 3 are the same as Example 1 except that the content of Ag in the alloy is different from Example 1. See Table 4 for the contents of Ag elemental substance in the alloys of Examples 9-10 and Comparative Example 3 and the properties of the obtained alloys.

Table 4 embodiment 9-10 and the process parameter and performance result of comparative example 3

Examples 11-14

Embodiment 11-14 is different from embodiment 1 except stirring mode and parameter, and other process parameters are the same as embodiment 1. See Table 5 for the stirring parameters of Examples 11-14 and the properties of the obtained alloys.

Process parameter and performance result of table 5 embodiment 11-14

Comparative example 4

The alloy prepared in this comparative example is a Cu-15wt% Fe alloy (that is, the content of Fe in the alloy is 15wt%, and the content of Cu is 85wt%; that is, the consumption of electrolytic copper in the raw material is 85wt of the total mass of electrolytic copper and Fe powder %, the consumption of Fe powder is 15wt% of electrolytic copper and Fe powder gross mass), and concrete preparation method is as follows:

Melt 99.9wt% electrolytic high-purity Cu and Fe in a vacuum intermediate frequency induction furnace. The melting temperature is controlled at about 1600°C and the vacuum degree is 10Pa. After the melting is completed, it is poured into a water-cooled copper mold for rapid cooling. 100°C/s, Cu-15wt% Fe alloy obtained after pouring.

Performance tests were carried out on the cast alloy product prepared by the comparative method, and its tensile strength was 310 MPa, and its electrical conductivity was 15% IACS.

Comparative example 5

The alloy prepared in this comparative example is a Cu-15wt% (Fe-C) alloy (that is, the content of Fe-C in the alloy is 15wt%, the content of Cu is 85wt%, and the content of C in Fe-C is 1wt%. Methods as below:

Melting 99.9wt% electrolytic high-purity Cu and Fe-C powder in a vacuum intermediate frequency induction furnace, the melting temperature is controlled at about 1600°C, and the vacuum degree is 10Pa. After the melting is completed, it is poured into a water-cooled copper mold for rapid cooling. The cooling rate is 100°C/s, and the Cu-15wt% (Fe-C) alloy obtained after casting.

Performance tests were carried out on the cast alloy product prepared by the comparative method, and its tensile strength was 315 MPa, and its electrical conductivity was 17% IACS.

Comparative example 6

The alloy prepared in this comparative example is Cu-2.0wt%Ag-15wt% (Fe-C) alloy (that is, the content of Fe-C in the alloy is 15wt%, the content of Cu is 83wt%, and the content of Ag is 2wt%. The C content in Fe-C is 1wt%, and the specific preparation method is as follows:

Melting 99.9wt% electrolytic high-purity Cu, silver element and Fe-C powder in a vacuum intermediate frequency induction furnace. The melting temperature is controlled at about 1600°C and the vacuum degree is 10Pa. After the melting is completed, it is poured into a water-cooled copper mold. Rapid cooling, the cooling rate is 100°C/s, and the Cu-2.0wt%Ag-15wt% (Fe-C) alloy obtained after casting.

Performance tests were carried out on the cast alloy product prepared by the comparative method, and its tensile strength was 318 MPa, and its electrical conductivity was 24% IACS.

Claims (12)

1. a preparation method of Cu-Ag-Fe-C alloy, is characterized in that, comprises: Cu and Ag smelting step, the solid raw materials Cu and Ag are smelted to obtain liquid Cu-Ag alloy liquid; the smelting temperature of the smelting treatment is 1090-1200°C; The step of adding Fe-C pre-alloy, adding Fe-C pre-alloy powder into the liquid Cu-Ag alloy liquid for stirring treatment to obtain a uniformly mixed smelting material; the temperature during the stirring treatment is 1100-1180°C; Rapid solidification step, subjecting the molten material to rapid solidification treatment to obtain a Cu-Ag-Fe-C alloy in which Fe-C pre-alloyed particles are evenly distributed in the Cu-Ag matrix; According to mass percentage, the Cu-Ag-Fe-C alloy is composed of the following components: Ag, 0.5-3%; Fe-C pre-alloyed, 10-15%, the balance is Cu; The particle size of the Fe-C pre-alloyed powder is 60-220nm. 2. The preparation method according to claim 1, characterized in that, in the smelting step of Cu and Ag, the smelting treatment is carried out in a vacuum intermediate frequency induction furnace. 3. The preparation method according to claim 1, characterized in that, in the smelting step of Cu and Ag, the smelting temperature of the smelting treatment is 1100-1180°C. 4. The preparation method according to claim 1, characterized in that, the degree of vacuum during the smelting treatment is below 10 Pa. 5. The preparation method according to claim 1, characterized in that, in the step of adding the Fe-C pre-alloy, the stirring treatment is carried out under the condition of 1100°C. 6. The preparation method according to claim 1, characterized in that, in the step of adding the Fe-C pre-alloy, the stirring treatment is mechanical stirring or electromagnetic stirring, and the stirring treatment time is 1-5 minutes. 7. The preparation method according to claim 6, characterized in that, the stirring speed of the mechanical stirring is 240-400rpm, and the excitation voltage of the electromagnetic stirring is 180-220V. 8. The preparation method according to claim 1, characterized in that, in the rapid solidification step, the rapid solidification treatment is a water-cooled copper mold casting method or a single-roller stripping method. 9. The preparation method according to claim 8, characterized in that, the cooling rate of the water-cooled copper mold casting method is 50°C/s-1000°C/s. 10. preparation method according to claim 1 is characterized in that, with the total mass of described Fe-C pre-alloy powder and described solid raw material Cu and Ag as benchmark, the consumption of described Fe-C pre-alloy powder is 10wt%-15wt%, the amount of Ag is 0.5wt%-3wt%, and the amount of Cu is 82wt%-89.5wt%. 11. The preparation method according to claim 1, characterized in that, the solid raw materials Cu and Ag are electrolytic copper and Ag simple substances with a purity of more than 99.9 wt%. 12. The preparation method according to any one of claims 1-11, characterized in that, in the Fe-C pre-alloyed powder, the C content is 0.8-1.8 wt%.