CN106756208A - A kind of copper chromium zirconium lanthanum alloy - Google Patents

Abstract

The invention provides a copper-chromium-zirconium-lanthanum alloy, the components of which are 97-99.8% copper, 0.1-2% chromium, 0.05-0.5% zirconium and 0.05-0.25% lanthanum. The vacuum induction melting method is adopted. In the copper-chromium-zirconium-lanthanum alloy in the present invention, part of the rare earth lanthanum reacts with impurities to generate refractory compounds and enters the slag, thereby purifying the matrix, and part of the rare earth lanthanum reacts with copper to form the second phase Cu ₆ La, which has a strengthening effect on the matrix and improves mechanical and electrical properties of the alloy. The steps are simple, the operation is convenient and the practicability is strong.

Description

A copper chromium zirconium lanthanum alloy

technical field

The invention belongs to the technical field of metal materials with high-performance structures, and relates to a copper-chromium-zirconium-lanthanum alloy.

Background technique

At present, Cu-Cr-Zr alloy, as a high-strength and high-conductivity copper alloy, is widely used in the fields of frame materials for large-scale integrated circuits and contact wires for high-speed trains. However, with the high integration of semiconductor devices and the high-speed development of electrified trains, higher requirements are placed on lead frame materials and contact wire materials. Add a certain amount of rare earth La to the alloy, and the rare earth La can react with impurity elements (P, S, O, etc.) to form compounds with low density and enter the slag, thereby purifying the matrix and improving the mechanical and electrical properties of the alloy. . However, if the amount of addition is less controlled, the purification effect of the rare earth La on the matrix is not obvious, and the improvement of the performance of the alloy is not obvious; La will also form a coarse second phase with the Cu matrix, which will degrade the mechanical and electrical properties of the alloy. Therefore, to propose a Cu-Cr-Zr-La alloy with a suitable amount of rare earth La added is one of the problems to be solved urgently.

Contents of the invention

In order to overcome the above disadvantages, the present invention provides a copper-chromium-zirconium-lanthanum alloy. The rare earths La and Ce are the most abundant rare earth elements, their atomic numbers are similar, and their chemical and physical properties are similar, so there is a certain similarity to the properties of copper alloys. Both can be used as additives to improve the properties of copper alloys. While selecting Ce, the present invention proposes to add La to improve the performance of the copper alloy. A part of rare earth La and impurities form refractory compounds and remain in the slag to purify the matrix; a part of rare earth La and Cu form a second phase to precipitate and disperse in the matrix to strengthen the matrix.

In order to achieve the above object, the present invention adopts the following technical solutions:

A copper-chromium-zirconium-lanthanum alloy is composed of the following components in weight percent: 0.1-2% of chromium, 0.05-0.5% of zirconium, 0.05-0.25% of lanthanum, and the balance is copper and unavoidable impurities.

If the addition of lanthanum is less than 0.05%, the purification effect on the matrix is not obvious, and the improvement of alloy performance is not obvious; if the addition of lanthanum is greater than 0.25%, it will not only increase the cost, but also cause waste of rare earths and pollute the environment. At the same time, La will also form a coarse second phase with the Cu matrix, which will reduce the mechanical and electrical properties of the alloy.

Preferably, the copper-chromium-zirconium-lanthanum alloy is composed of the following ingredients in weight percent: chromium 1.0-2%, zirconium 0.25-0.5%, lanthanum 0.15-0.25%, and the balance is copper and unavoidable impurities.

Preferably, the copper-chromium-zirconium-lanthanum alloy is composed of the following components in weight percent: 0.1-1.0% chromium, 0.05-0.15% zirconium, 0.05-0.15% lanthanum, and the balance is copper and unavoidable impurities.

Preferably: the copper-chromium-zirconium-lanthanum alloy is composed of the following components in weight percent: 99.15% copper, 0.5% chromium, 0.2% zirconium, and 0.15% lanthanum.

The present invention also provides a preparation method of copper-chromium-zirconium-lanthanum alloy, comprising:

Under the protection of inert gas, the pretreated red copper, copper-chromium master alloy, copper-zirconium master alloy, and copper-lanthanum master alloy are subjected to vacuum medium-frequency induction melting. After all the alloys are melted, they are kept for 10-30 minutes, vacuum cast and cooled. have to.

Preferably, the pretreatment is: removing oxide scales of copper, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La.

Preferably, the inert gas is argon.

Preferably, the casting temperature is 1200°C to 1300°C.

The invention also provides a copper-chromium-zirconium-lanthanum alloy, the weight percentage of each component is: chromium 0.1-2%, zirconium 0.02-0.5%, lanthanum 0.05-0.25%, and the balance is Cu and unavoidable impurities.

It is prepared from the above-mentioned copper-chromium-zirconium-lanthanum alloy by vacuum induction melting.

The specific steps of the smelting method are as follows:

(1) Raw material red copper wire, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La are proportioned;

(2) Put the prepared raw materials in (1) into a crucible, and use a ZG-10 vacuum medium frequency induction melting furnace for melting, protected by an argon atmosphere;

(3) After the raw materials are completely melted, keep warm for 10-30 minutes;

(4) Vacuum casting is adopted to cast the molten copper into the mold.

The present invention also provides the copper-chromium-zirconium-lanthanum alloy prepared by any one of the above-mentioned methods.

The present invention also provides the application of any one of the above-mentioned copper-chromium-zirconium-lanthanum alloys in the manufacture of frame materials for large-scale integrated circuits or contact wires for high-speed trains.

Beneficial effects of the present invention

(1) When 0.05-0.25% lanthanum is added to the copper-chromium-zirconium alloy, the mechanical and electrical properties of the alloy are improved.

(2) The preparation method of the present invention is simple, practical and easy to popularize.

Description of drawings

Figure 1 is the macrostructure morphology of copper-chromium-zirconium-lanthanum alloys with different La additions: (a) 0.05%; (b) 0.15%; (c) 0.25%; (d) 0.5%;

Figure 2 is the microstructure morphology of copper-chromium-zirconium-lanthanum alloys with different La additions: (a) 0.05%; (b) 0.15%; (c) 0.25%; (d) 0.5%;

Fig. 3 is the point scan diagram of the energy spectrum analysis of the alloy added with 0.5%La;

Figure 4 is a Cu-La alloy phase diagram.

detailed description

The features of the present invention and other relevant features are described in further detail below through the embodiments, so as to facilitate the understanding of those skilled in the art:

Example 1

A copper-chromium-zirconium-lanthanum alloy, the percentage by weight of elements is: copper 99.25%, chromium 0.5%, zirconium 0.2%, lanthanum 0.05%

Smelting method:

(1) Put the raw material red copper wire, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La into the crucible after descaling, preheat the mold to 200°C-250°C, and spray nitrogen Boron release agent;

(2) Adopt ZG-10 vacuum intermediate frequency induction melting furnace for melting. In order to prevent oxidation of copper alloy, the melting and casting process is carried out under the protection of argon atmosphere;

(3) Raise the temperature at a heating rate of 65-85°C/min. After the alloy is completely melted through the observation window, continue to raise the temperature for 2-3 minutes, then slightly reduce the power to 18-20KW to maintain a constant temperature, keep it warm for 10-30 minutes, and then cast it into the mold. The temperature is kept at 1200℃～1300℃;

(4) After the furnace is completely cooled, open the furnace cover and take out the ingot.

Example 2

A copper-chromium-zirconium-lanthanum alloy, the percentage by weight of elements is: copper 99.85%, chromium 0.5%, zirconium 0.2%, lanthanum 0.15%

Smelting method:

(1) Put the raw material red copper wire, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La into the crucible after descaling, preheat the mold to 200°C-250°C, and spray nitrogen Boron release agent;

(2) Adopt ZG-10 vacuum intermediate frequency induction melting furnace for melting. In order to prevent oxidation of copper alloy, the melting and casting process is carried out under the protection of argon atmosphere;

(3) Raise the temperature at a heating rate of 65-85°C/min. After the alloy is completely melted through the observation window, continue to raise the temperature for 2-3 minutes, then slightly reduce the power to 18-20KW to maintain a constant temperature, keep it warm for 10-30 minutes, and then cast it into the mold. The temperature is kept at 1200℃～1300℃;

(4) After the furnace is completely cooled, open the furnace cover and take out the ingot.

Example 3

A copper-chromium-zirconium-lanthanum alloy, the percentage by weight of elements is: copper 99.95%, chromium 0.5%, zirconium 0.2%, lanthanum 0.25%

Smelting method:

(1) Put the raw material red copper wire, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La into the crucible after descaling, preheat the mold to 200°C-250°C, and spray nitrogen Boron release agent;

(2) Adopt ZG-10 vacuum intermediate frequency induction melting furnace for melting. In order to prevent oxidation of copper alloy, the melting and casting process is carried out under the protection of argon atmosphere;

(3) Raise the temperature at a heating rate of 65-85°C/min. After the alloy is completely melted through the observation window, continue to raise the temperature for 2-3 minutes, then slightly reduce the power to 18-20KW to maintain a constant temperature, keep it warm for 10-30 minutes, and then cast it into the mold. The temperature is kept at 1200℃～1300℃;

(4) After the furnace is completely cooled, open the furnace cover and take out the ingot.

Example 4

A copper-chromium-zirconium-lanthanum alloy, the percentage by weight of elements is: copper 98.8%, chromium 0.5%, zirconium 0.2%, lanthanum 0.5%

Smelting method:

(1) Put the raw material red copper wire, Cu-10wt.%Cr, Cu-10wt.%Zr, Cu-20wt.%La into the crucible after descaling, preheat the mold to 200°C-250°C, and spray nitrogen Boron release agent;

(2) Adopt ZG-10 vacuum intermediate frequency induction melting furnace for melting. In order to prevent oxidation of copper alloy, the melting and casting process is carried out under the protection of argon atmosphere;

(3) Raise the temperature at a heating rate of 65-85°C/min. After the alloy is completely melted through the observation window, continue to raise the temperature for 2-3 minutes, then slightly reduce the power to 18-20KW to maintain a constant temperature, keep it warm for 10-30 minutes, and then cast it into the mold. The temperature is kept at 1200℃～1300℃;

(4) After the furnace is completely cooled, open the furnace cover and take out the ingot.

The specific analysis is as follows:

(1) Effect of rare earth La on alloy structure

The copper alloy ingots with different La content were sampled, ground, polished and corroded for microstructure observation. The macrostructure is shown in Figure 1; the microstructure shown in the optical microscope is shown in Figure 2. It can be seen from Figure 1 that the grain size tends to decrease with the increase of La addition. It can be seen from Figure 2 that there is a close relationship between the distribution of La and the amount of addition. When the amount of addition is 0.05%, there is only a very small amount of La precipitated phases in the dendrite gap. Elements such as P, S, and O react preferentially to form refractory compounds that enter the slag, thereby purifying the matrix. When 0.15-0.25% La is added, the La-containing precipitates on the matrix increase, and the dendrite morphology changes; the primary and secondary crystal axes become shorter and thicker, because La dissolves into the matrix, making Cr , Cu _x Zr, Cu ₆ La and other dispersed second phases increase, hindering the growth of dendrites, and Cu ₆ La can also provide nucleation centers for grain nucleation, making the grain size smaller. When 0.5% La is added, there are a large amount of Cu ₆ La second phases in the dendrite gap, the dendrite morphology changes significantly, the secondary crystal axis becomes longer and thicker, and the proportion increases significantly. The Cu ₆ La second phase is precipitated in the dendrite gap and grain boundary, in the form of spheres and rods (Fig. 2(d)).

(2) Existence form of rare earth La in the alloy

The EDS test was carried out on different Cu _x La second phase precipitation points of the 0.5% La sample, and the results are shown in Figure 3 and Table 1. According to the Cu-La alloy phase diagram (as shown in Figure 4), the intermediate phases formed by the two are CuLa, Cu ₂ La, Cu ₅ La and Cu ₆ La, and the highest atomic ratio of the two is 6:1, and the table 1, the atomic ratio of Cu to La is the closest to 6:1, so it is speculated that the intermetallic compound formed by Cu and La is Cu ₆ La.

Table 1 EDS test of different points of alloy containing La0.5%

(3) Effect of rare earth La on the mechanical and electrical properties of the alloy

Table 2 shows the changes in tensile strength, elongation and electrical conductivity of Cu-Cr-Zr-La alloys with the addition of La. It can be seen that with the increase of La addition, the strength of the alloy first increases and then decreases. When the addition of La is 0.15%, the strength of the alloy reaches the maximum value of 222MPa. When 0.05% La is added, the rare earth element La mainly reacts with impurities and enters the slag to purify the matrix and improve the mechanical properties of the alloy; however, due to the small amount added, the improvement of mechanical properties cannot be optimized. When 0.15% La is added, the strength of the alloy is the highest, and the decrease in elongation is not obvious. This is because the purification effect of the rare earth La on the collective is relatively sufficient, and the properties of the alloy are greatly improved. When the amount of La added reaches 0.25% or 0.5%, the tensile strength and elongation of the alloy show a downward trend. This is because the amount of La added is too much, which not only plays a role in purifying the matrix, but also because the excess La and Cu Coarse Cu ₆ La second phases are formed, and part of the coarse second phases are segregated at grain boundaries and dendrite gaps, and the mechanical properties of the alloy decrease.

Comparing the conductivity of copper alloys with different La additions, it can be seen that when the addition of rare earth La is less than 0.15%, the conductivity of the alloy increases slowly; when the addition of rare earth La is greater than 0.15%, the conductivity of the alloy rapidly increases. Decrease, the electrical conductivity of the alloy decreases rapidly. This is caused by the combined effect of the purifying effect of rare earth on the alloy matrix and the lattice distortion introduced by La entering the matrix. When the added La content is below 0.15%, the rare earth La reacts with impurities to form refractory compounds and enters the slag, thereby purifying the matrix, reducing the amount of impurities in the alloy, reducing the lattice distortion caused by lattice distortion, and the amount of electron scattering effect of lattice distortion Enhanced, the electrical conductivity of the alloy increases. When the La content is above 0.15%, La dissolves into the copper alloy matrix and forms Cu ₆ La precipitates with Cu, causing large lattice distortion, which enhances the scattering of electrons and decreases the electrical conductivity; In addition, the introduction of La can refine the grains to a certain extent, increase the density of grain boundaries, enhance the scattering effect of grain boundaries on electrons, and reduce the electrical conductivity of the alloy. At the same time, when the addition of La continues to increase, the number and size of the Cu ₆ La second phase increase, resulting in an increase in the degree of lattice distortion, and these factors will also reduce the electrical conductivity of the alloy.

Table 2 shows the changes in strength, elongation and electrical conductivity of copper alloys with different La additions

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it is still The technical solutions described in the foregoing embodiments may be modified, or part of them may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. A copper-chromium-zirconium-lanthanum alloy, characterized in that it consists of the following components in percentage by weight: 0.1-2% chromium, 0.05-0.5% zirconium, 0.05-0.25% lanthanum, and the balance is copper and unavoidable impurities. 2. The copper-chromium-zirconium-lanthanum alloy as claimed in claim 1, characterized in that it consists of the following components in percentage by weight: chromium 1.0-2%, zirconium 0.25-0.5%, lanthanum 0.15-0.25%, and the balance is copper and unavoidable impurities. 3. The copper-chromium-zirconium-lanthanum alloy as claimed in claim 1, characterized in that it consists of the following components in percentage by weight: chromium 0.1-1.0%, zirconium 0.05-0.15%, lanthanum 0.05-0.15%, and the balance is copper and unavoidable impurities. 4. The copper-chromium-zirconium-lanthanum alloy according to claim 1, characterized in that it consists of the following components in weight percent: 99.15% copper, 0.5% chromium, 0.2% zirconium, and 0.15% lanthanum. 5. A preparation method of copper-chromium-zirconium-lanthanum alloy, characterized in that, comprising: Under the protection of inert gas, the pretreated red copper, copper-chromium master alloy, copper-zirconium master alloy, and copper-lanthanum master alloy are subjected to vacuum medium-frequency induction melting. After all the alloys are melted, they are kept for 10-30 minutes, vacuum cast and cooled. have to. 6 . The method according to claim 5 , wherein the pretreatment is: removing oxide scales of copper, copper-chromium master alloy, copper-zirconium master alloy, and copper-lanthanum master alloy. 7 . 7. The method of claim 5, wherein the inert gas is argon. 8. The method according to claim 5, characterized in that the casting temperature is 1200°C-1300°C. 9. The copper-chromium-zirconium-lanthanum alloy prepared by the method described in any one of claims 5-8. 10. Application of the copper-chromium-zirconium-lanthanum alloy described in any one of claims 1-4 or 9 in the manufacture of frame materials for large-scale integrated circuits or contact wires for high-speed trains.