CN113564408B - High-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y and a preparation method thereof. The preparation method includes the following steps: Step (1): placing pure copper, chromium raw materials, zirconium raw materials and yttrium raw materials in a In the medium-frequency induction melting furnace, smelting is carried out in an atmospheric environment, and after smelting, a rare earth copper-chromium-zirconium alloy ingot is obtained; step (2): solid solution treatment is performed on the rare-earth copper-chromium-zirconium alloy ingot to obtain a rare-earth copper-chromium-zirconium alloy billet; step (3) alternately rolling and aging the rare earth copper-chromium-zirconium alloy billet to prepare a high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y. The high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y is prepared by the above method. The rare earth copper alloy prepared by the method has excellent performance, the tensile strength exceeds 700MPa, and the relative electrical conductivity is higher than 80% IACS, which can meet the performance requirements of the industry for high-strength and high-conductivity copper alloys and meet the requirements of high-performance cutting-edge technology; It is also conducive to the industrialized large-scale production of high-strength and high-conductivity copper-chromium-zirconium alloys.

Description

A kind of high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y and preparation method thereof

technical field

The invention relates to the technical field of rare earth copper alloys. Specifically, it is a high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y and a preparation method thereof.

Background technique

Copper and copper alloys are widely used in large-scale integrated circuit lead frames and high-speed rail contact wires because of their good electrical and thermal conductivity, high strength and good plasticity. With the rapid development of my country's electronics industry and high-speed railways, higher requirements have been placed on the performance of copper alloys. In engineering, it has been hoped that isotropy, tensile strength of more than 600MPa, and relative conductivity of more than 80% ICSA can be obtained. Copper alloys that can meet large-scale production. Japan has already developed a method of producing copper-chromium-zirconium alloys using non-vacuum production technology, and has successfully developed several high-strength and high-conductivity copper-chromium-zirconium series lead frame materials, and has formed an industrial scale. At present, among the copper-chromium-zirconium alloys produced by non-vacuum production technology in Japan, the representative ones are OMCL-1 and NK120. Among them, the tensile strength and electrical conductivity of OMCL-1 alloy are 592MPa and 82.7%IACS respectively; NK120 alloy The tensile strength and electrical conductivity are 580MPa and 80% IACS, respectively. However, there is still a big gap between the production, application and actual service performance of domestic copper-chromium-zirconium alloys and international high-strength and high-conductivity copper-chromium-zirconium series copper alloys.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is to provide a high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y and a preparation method thereof, so as to solve the problem that high strength and high conductivity of common copper-chromium-zirconium alloys are difficult to coexist, Provided are a high-strength and high-conductivity copper alloy that can meet the requirements of high-performance cutting-edge technology, and a method that is conducive to industrialized large-scale production of high-strength and high-conductivity copper-chromium-zirconium alloys.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

A preparation method of high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, comprising the following steps:

Step (1): placing pure copper, chromium raw material, zirconium raw material and yttrium raw material in an intermediate frequency induction melting furnace, smelting in an atmospheric environment, and obtaining a rare earth copper-chromium-zirconium alloy ingot after smelting;

Step (2): performing solid solution treatment on the rare earth copper-chromium-zirconium alloy ingot to obtain a rare-earth copper-chromium-zirconium alloy billet;

In step (3), the rare earth copper-chromium-zirconium alloy billet is alternately processed by rolling and aging, that is, a high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y is prepared.

The preparation method of the above-mentioned high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y, in the high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y, the mass percentages of chromium element and zirconium element are respectively 0.55wt% and 0.18wt%, the mass percentage of yttrium is 0.15wt%. After many tests, it was found that with the increase of the mass percentage of chromium and zirconium elements, the mechanical properties of the alloy increased significantly, but the solute atoms (chromium atoms, zirconium atoms) had a certain degree of damage to the electrical properties of the alloy, and in the present invention, the rare earth is used. The mass percentages of chromium and zirconium elements in the copper alloy are controlled at 0.55wt% and 0.18wt%, respectively, which can ensure that the prepared high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y has good mechanical properties. At the same time, it has good electrical properties. After many experiments, it is found that when the mass fraction of rare earth Y in the rare earth copper alloy Cu-Cr-Zr-Y is 0.15wt%, the grain structure of the alloy is composed of fine and uniform equiaxed grains, and the mechanical properties of the alloy at this time are better.

In the preparation method of the above-mentioned high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, in step (1), the purity of pure copper is greater than or equal to 99.95wt%, the chromium raw material is copper-chromium master alloy, and the zirconium raw material is copper-zirconium intermediate Alloy, yttrium raw material is copper-yttrium master alloy. In the present invention, the master alloy is selected as the chromium raw material, the zirconium raw material and the yttrium raw material, and the reason for not using the metal element is that the metal element has high cost and high burning loss rate, the cost of the master alloy is lower, and the impurity content of the three master alloys can be Negligible; in addition, adding a master alloy can make the elements in the alloy easier to disperse uniformly in the melt.

In the preparation method of the above-mentioned high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, in the copper-chromium master alloy, the mass fraction of chromium is 10wt%; in the copper-zirconium master alloy, the mass fraction of zirconium is 40wt%; In the copper-yttrium master alloy, the mass fraction of yttrium is 20wt%.

In the preparation method of the above-mentioned high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y, in step (1), the smelting method includes the following steps:

Step (1-1): adding pure copper into the graphite crucible and heating up with the furnace to melt the pure copper to obtain a copper melt;

Step (1-2): continue to heat up the copper melt, and then sequentially add the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy to the copper melt to make the The copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy are melted, and continue to be heated and kept warm to obtain a mixed melt;

Step (1-3): casting the mixed melt into a preheated graphite mold by a near-liquidus casting method to obtain the rare earth copper-chromium-zirconium alloy ingot.

In the preparation method of the above-mentioned high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y, in step (1), the smelting method includes the following steps:

Step (1-1): adding pure copper into the graphite crucible and heating up with the furnace to melt the pure copper to obtain a copper melt; the graphite crucible itself has good heat resistance, and compared with other crucibles, not only is the cost lower, Moreover, there is no possibility of C element reacting with other alloy elements within the temperature range of the smelting process of the present invention.

Step (1-2): continue heating the copper melt to 1240-1260° C., and then sequentially add the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy to the copper melt Alloy, melt the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy, and continue heating to 1300-1400 ° C. It is found through research that the alloying elements can be fully diffused in this temperature range without producing Severe burning loss, keep the temperature in this temperature range for 15 minutes to obtain a mixed melt; when adding three kinds of master alloys to the copper melt, the copper-chromium master alloy with a smaller burning loss rate is added first, and then the copper-chromium master alloy with a higher burning loss rate is added. Finally, the copper-yttrium master alloy with the most serious burning loss rate is added; the three alloys are added in order according to the burning loss rate from small to large, which can effectively reduce the burning loss rate of alloy elements and ensure the quality of the obtained alloy products. Effectively control production costs.

Step (1-3): using the near-liquidus casting method to cast the mixed melt into a preheated graphite mold at 1100°C-1150°C, and the mold preheating temperature is 300°C, to obtain the rare earth copper-chromium Zirconium alloy ingots. Since the liquidus temperature of the copper-chromium-zirconium alloy changes with the content of each element in the alloy, in the high-strength and high-conductivity rare-earth copper alloy to be prepared in the present invention, when the casting temperature is in the range of 1100°C-1150°C, the rare-earth copper The chromium-zirconium alloy has a large degree of undercooling and a finer crystal structure, especially when the casting temperature is 1120 °C, the crystal structure of the alloy is finer. In addition, during casting, the preheating temperature of the mold should not be too high. When the preheating temperature of the mold is 300 °C, the internal and external crystal structure of the rare earth copper-chromium-zirconium alloy prepared by casting is relatively uniform.

In the preparation method of the above-mentioned high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, in step (2), the solution treatment method is as follows: placing the rare earth copper-chromium-zirconium alloy ingot in a heat treatment furnace, and at 900 ℃ -980℃ for 30-180min, then water quenching. It has been proved by experimental research that the solid solution treatment is carried out at 900-980 ° C and 30-180 min. Under this solid solution condition, the elements of chromium and zirconium can be dissolved into the copper matrix to form a supersaturated solid solution. And when the solid solution treatment condition of rare earth copper alloy is 920℃×1h, the solid solution effect is the best; if the temperature is too high, the mechanical properties of the alloy will be significantly reduced, and a good solid solution strengthening effect cannot be produced. The solution-treated alloy is quenched in cold water at room temperature; the quenching process is to ensure that the alloy elements will not be naturally aged and precipitated after the solution treatment, so quenching in water at room temperature can be selected.

In the preparation method of the above-mentioned high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, in step (3), the alternate treatment of rolling and aging includes the following steps:

Step (3-1): rolling the rare earth copper-chromium-zirconium alloy billet at room temperature for the first time at room temperature with a deformation of 60%; rolling the rare-earth copper-chromium-zirconium alloy billet for the first time First-level aging treatment at 360℃×30min;

Step (3-2): The rare earth copper-chromium-zirconium alloy billet after primary aging treatment is rolled at room temperature for the second time, and the deformation amount is 50%; The copper-chromium-zirconium alloy billet is subjected to secondary aging treatment at 340℃×30min;

Step (3-3): the rare earth copper-chromium-zirconium alloy billet after the secondary aging treatment is rolled at room temperature for the third time, and the deformation amount is 40%; The copper-chromium-zirconium alloy billet is subjected to three-stage aging treatment at 320℃×30min.

In the preparation method of the above-mentioned high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, in step (1), the purity of pure copper is greater than or equal to 99.95wt%, the chromium raw material is copper-chromium master alloy, and the zirconium raw material is copper-zirconium intermediate Alloy, the yttrium raw material is copper-yttrium master alloy; in the copper-chromium master alloy, the mass fraction of chromium is 10wt%; in the copper-zirconium master alloy, the mass fraction of zirconium is 40wt%; in the copper-yttrium master alloy, The mass fraction of yttrium is 20wt%;

In step (1), the smelting method comprises the steps:

Step (1-1): adding pure copper into the graphite crucible and heating up with the furnace to melt the pure copper to obtain a copper melt;

Step (1-2): continue heating the copper melt to 1250° C., and then sequentially add the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy into the copper melt, Melting the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy, continuing to heat to 1350° C., and keeping the temperature within this temperature range for 15 minutes to obtain a mixed melt;

Step (1-3): using near liquidus casting method to cast the mixed melt into a preheated graphite mold at 1120°C, and the mold preheating temperature is 300°C to obtain the rare earth copper-chromium-zirconium alloy cast. ingot;

In step (2), the solution treatment method is as follows: placing the rare earth copper-chromium-zirconium alloy ingot in a heat treatment furnace, keeping the temperature at 920° C. for 60 minutes, and then performing water quenching, and the temperature during water quenching is room temperature;

In the high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, the mass percentage of chromium element and zirconium element are 0.55wt% and 0.18wt% respectively, and the mass percentage of yttrium is 0.15wt%.

A high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y is prepared by using the above-mentioned preparation method of the high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y.

The technical scheme of the present invention has achieved the following beneficial technical effects:

(1) The rare earth copper alloy prepared by the invention has excellent performance, the tensile strength exceeds 700MPa, and the relative conductivity is higher than 80% IACS, which can meet the performance requirements of the industry for high-strength and high-conductivity copper alloys and meet the needs of high-performance cutting-edge technology. The copper-chromium-zirconium alloy prepared by the traditional method cannot meet the requirements of today's industrial production, and the preparation and processing process of the present invention is beneficial to the industrialized large-scale production of high-strength and high-conductivity copper-chromium-zirconium alloy.

(2) The method of the present invention prepares a new type of rare earth copper alloy, which can keep the strength at a high level while ensuring the high electrical conductivity of the material, which benefits from the effect of different sizes of precipitation phases. It breaks through the contradiction that the high strength and high conductivity of ordinary copper-chromium-zirconium alloys are difficult to coexist, and realizes the real high strength and high conductivity.

(3) In the present invention, the rare earth Y element is added to the copper-chromium-zirconium alloy, which can effectively refine the crystal grains. At the same time, the rare earth element can react with impurities to purify the matrix. The Y element can promote the precipitation of the Cr phase during the aging process and inhibit the Cr phase. grow.

(4) At room temperature, the solubility of chromium and zirconium in copper-chromium-zirconium alloy is very low. Excess chromium and zirconium atoms in the alloy will precipitate out of the supersaturated solid solution to strengthen the matrix and improve conductivity. At the same time, when the alloy is rolled, the second phase precipitated by aging will have a dislocation pinning effect on the alloy, which can greatly increase the tensile strength of the alloy and reduce its electrical conductivity. In the present invention, the rare earth copper-chromium-zirconium alloy billet is treated by the method of multiple rolling and multi-stage aging alternate treatment. This treatment method is introduced into the rolling process before aging, which is beneficial to make the obtained rare earth copper alloy Cu-Cr-Zr -Y has good mechanical properties. Due to the large amount of distortion energy generated during rolling, these distortion energies promote the precipitation of second-phase atoms. At the same time, point defects such as vacancies and line defects such as dislocations will occur in the rolling process with large deformation. The existence of these defects will provide nucleation sites for the precipitation of solute atoms in the alloy during the aging process. Therefore, it can be said that rolling The defects introduced in the manufacturing process provide conditions for the precipitation of solute atoms, which is conducive to the formation of different sizes of precipitation phases in the alloy during the alternate process. While obtaining high strength, the influence of the second relative conductivity of the precipitation by aging treatment is weakened. , to ensure that the prepared copper-chromium-zirconium alloy can achieve an effective combination of high strength (≥700MPa) and high conductivity (≥80% IACS).

Description of drawings

Fig. 1 microstructure diagram of non-vacuum melting near liquidus casting copper-chromium-zirconium alloy Cu-Cr-Zr in comparative example of the present invention;

Fig. 2 is a microstructure diagram of non-vacuum melting near liquidus casting rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y in the embodiment of the present invention;

3 is a microstructure diagram of the rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y after the first rolling (room temperature, deformation amount of 60%) in the embodiment of the present invention;

4 is a microstructure diagram of the rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y first-order aging (360°C × 30min) in the embodiment of the present invention;

5 is a microstructure diagram of the rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y after the second rolling (room temperature, deformation amount of 50%) in the embodiment of the present invention;

6 is a microstructure diagram of rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y secondary aging (340°C×30min) in the embodiment of the present invention;

7 is a microstructure diagram of the rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y after the third rolling (room temperature, deformation amount of 40%) in the embodiment of the present invention;

8 is a microstructure diagram of the rare earth copper-chromium-zirconium alloy Cu-Cr-Zr-Y three-stage aging (320°C × 30min) in the embodiment of the present invention;

9 is a graph of the tensile strength at room temperature of the alloy materials prepared in the embodiment of the present invention and the comparative example in different states;

FIG. 10 is a graph of the relative conductivity of the alloy materials prepared in the embodiment of the present invention and the comparative example in different states.

Detailed ways

Example

A preparation method of high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, comprising the following steps:

Step (1): place pure copper, chromium raw material, zirconium raw material and yttrium raw material in a medium-frequency induction smelting furnace after proportioning, smelting under atmospheric environment, and obtain rare earth copper-chromium-zirconium alloy ingot after smelting;

Step (2): performing solid solution treatment on the rare earth copper-chromium-zirconium alloy ingot to obtain a rare-earth copper-chromium-zirconium alloy billet;

In step (3), the rare earth copper-chromium-zirconium alloy billet is alternately processed by rolling and aging, that is, a high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y is prepared.

The microstructure of the high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y prepared in this example is shown in FIG. 2 . It can be seen from Figure 2 that the grain structure of the alloy is composed of uniform and fine equiaxed grains with an average grain size of about 11 μm, which has the characteristics of rapid solidification. Significant refinement with fewer defects.

In step (1), the purity of pure copper is greater than 99.95wt%, the chromium raw material is a copper-chromium master alloy, the zirconium raw material is a copper-zirconium master alloy, and the yttrium raw material is a copper-yttrium master alloy; in the copper-chromium master alloy, the chromium The mass fraction is 10wt%; in the copper-zirconium master alloy, the mass fraction of zirconium is 40wt%; in the copper-yttrium master alloy, the mass fraction of yttrium is 20wt%. The three master alloys in this example were purchased from the official website of Zhongnuo New Materials Co., Ltd.

In step (1), the smelting method comprises the steps:

Step (1-1): adding pure copper into the graphite crucible and heating up with the furnace to melt the pure copper to obtain a copper melt;

Step (1-2): continue heating the copper melt to 1250° C., and then sequentially add the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy into the copper melt, Melting the copper-chromium master alloy, the copper-zirconium master alloy and the copper-yttrium master alloy, and continuing to heat to 1350° C. for 15 minutes to obtain a mixed melt;

Step (1-3): using near liquidus casting method to cast the mixed melt into a preheated graphite mold at 1120°C, and the mold preheating temperature is 300°C to obtain the rare earth copper-chromium-zirconium alloy cast. ingot.

In step (2), the solution treatment method is as follows: placing the rare earth copper-chromium-zirconium alloy ingot in a heat treatment furnace, keeping the temperature at 920° C. for 1 hour, and then performing water quenching, and the temperature of the water during water quenching is room temperature .

In step (3), the alternate treatment of rolling and aging includes the following steps:

Step (3-1): rolling the rare earth copper-chromium-zirconium alloy billet at room temperature for the first time at room temperature with a deformation of 60%; rolling the rare-earth copper-chromium-zirconium alloy billet for the first time The first-level aging treatment at 360℃×30min; the microstructure of the rolled billet is shown in Figure 3. It can be seen from Figure 3 that the alloy is obviously deformed after rolling, and the large deformation causes the alloy grains to be oriented; the treated billet The microstructure of the alloy is shown in Figure 4. It can be seen from Figure 4 that the deformed grains of the alloy partially recover after aging treatment, and recrystallization occurs;

Step (3-2): The rare earth copper-chromium-zirconium alloy billet after primary aging treatment is rolled at room temperature for the second time, and the deformation amount is 50%; The copper-chromium-zirconium alloy billet was subjected to secondary aging treatment at 340°C × 30min; the microstructure of the rolled billet is shown in Figure 5. After reducing the rolling amount, the grain deformation of the alloy is smaller than that of the first rolling at room temperature. The grain deformation is weak; the microstructure of the treated billet is shown in Figure 6. Compared with the first-order aging, some twins are generated inside the alloy, and the recrystallized grains are smaller in size due to temperature;

Step (3-3): the rare earth copper-chromium-zirconium alloy billet after the secondary aging treatment is rolled at room temperature for the third time, and the deformation amount is 40%; The copper-chromium-zirconium alloy billet was subjected to three-stage aging treatment at 320℃×30min; the microstructure of the billet after rolling is shown in Figure 7, the rolling amount is further reduced, and the change of the microstructure and morphology of the alloy is not obvious; the microstructure of the treated billet As shown in Figure 8, the number of twins increases after the third-level aging, and the precipitation of solute atoms in the rare earth copper alloy is relatively complete at this time.

A high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y is prepared by the above preparation method; in the prepared high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, the mass percentages of chromium element and zirconium element are respectively are 0.55wt% and 0.18wt%, the mass percentage of yttrium element is 0.15wt%, and the mass percentage of copper element is 99.12wt%.

The high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y material prepared in this example has good comprehensive properties, the room temperature tensile strength is 730.96MPa, the room temperature elongation is 7.1%, and the room temperature conductivity is 82.10% IACS. The rare earth copper alloy prepared by the preparation method described in this embodiment solves the contradictory relationship between high electrical conductivity and high strength of the alloy, and achieves a better match between the mechanical properties and electrical properties of the alloy.

In this example, the mass percentage of Cr and Zr elements in the alloy ingot cast by the non-vacuum melting near liquidus casting method are 0.55% and 0.18% respectively, and the mass percentage of Y element is 0.15%. The smelting conditions are atmospheric environment, the smelting temperature is controlled at 1350°C, and the casting temperature is 1120°C. The as-cast Cu-Cr-Zr-Y alloy was solution treated at 920℃×1h. The alternating process of multiple rolling and multi-stage aging is alternating between room temperature rolling and low temperature aging: the deformation amount is 60% (the first room temperature rolling), the aging treatment temperature/time is 360℃/30min, and the deformation amount is 50% (The second room temperature rolling), the aging treatment temperature/time is 340°C/30min, the deformation amount is 40% (the third room temperature rolling), the aging treatment temperature/time is 320°C/30min; the rolling deformation amount decrease in turn, and the temperature of aging treatment decreases in turn, and the aging time of each stage remains unchanged at 30min. The rare earth copper alloy cast by non-vacuum melting near liquidus casting method, through the orderly combination of solution-rolling-aging, obtains a new type of integrated structure and function with a tensile strength of more than 700MPa and a relative conductivity of more than 80% ICSA Rare earth copper alloy.

Comparative ratio

The difference between this comparative example and the embodiment is that the prepared copper-chromium-zirconium alloy does not contain rare earth yttrium element. The specific preparation method is as follows:

Step (1): placing pure copper, chromium raw material and zirconium raw material in an intermediate frequency induction melting furnace, smelting under atmospheric environment, and obtaining a copper-chromium-zirconium alloy ingot after smelting;

Step (2): performing solution treatment on the copper-chromium-zirconium alloy ingot to obtain a copper-chromium-zirconium alloy billet;

In step (3), the copper-chromium-zirconium alloy billet is alternately processed by rolling and aging treatment, that is, the copper-chromium-zirconium alloy Cu-Cr-Zr is prepared (see Fig. 1 for its microstructure diagram).

In step (1), the purity of pure copper is greater than 99.95wt%, the chromium raw material is a copper-chromium master alloy, and the zirconium raw material is a copper-zirconium master alloy; in the copper-chromium master alloy, the mass fraction of chromium is 10wt%; the In the copper-zirconium master alloy, the mass fraction of zirconium is 40wt%. The two master alloys in this comparative example were purchased from the official website of Zhongnuo New Materials Co., Ltd.

In step (1), the smelting method comprises the steps:

Step (1-1): adding pure copper into the graphite crucible and heating up with the furnace to melt the pure copper to obtain a copper melt;

Step (1-2): continue heating the copper melt to 1250° C., and then add the copper-chromium master alloy and the copper-zirconium master alloy to the copper melt in sequence to make the copper-chromium master alloy. Melt with the copper-zirconium master alloy, continue to heat to 1350°C, and keep the temperature for 15min to obtain a mixed melt;

Step (1-3): using the near liquidus casting method to cast the mixed melt into a preheated graphite mold at 1120°C, and the mold preheating temperature is 300°C to obtain the copper-chromium-zirconium alloy ingot .

In step (2), the solution treatment method is as follows: placing the copper-chromium-zirconium alloy ingot in a heat treatment furnace, keeping the temperature at 920° C. for 1 hour, and then performing water quenching, and the water temperature during water quenching is room temperature.

In step (3), the alternate treatment of rolling and aging includes the following steps:

Step (3-1): rolling the copper-chromium-zirconium alloy billet at room temperature for the first time at room temperature with a deformation of 60%; rolling the copper-chromium-zirconium alloy billet at 360°C for the first time ×30min first-level aging treatment;

Step (3-2): The copper-chromium-zirconium alloy billet after the primary aging treatment is rolled at room temperature for the second time at room temperature, and the deformation amount is 50%; The zirconium alloy billet is subjected to secondary aging treatment at 340℃×30min;

Step (3-3): the copper-chromium-zirconium alloy billet after the secondary aging treatment is rolled at room temperature for the third time at room temperature, and the deformation amount is 40%; The zirconium alloy billet is subjected to three-stage aging treatment at 320℃×30min.

In the copper-chromium-zirconium alloy prepared by the above method, the mass percentages of chromium element and zirconium element are respectively 0.55wt% and 0.18wt%, and the balance is copper.

The room temperature tensile strength of the copper-chromium-zirconium alloy material prepared in this comparative example is 405.91 MPa, the room temperature elongation is 26%, and the room temperature relative conductivity is 88.21% IACS.

Compared with the example, the room temperature tensile strength of the copper-chromium-zirconium alloy material prepared in the comparative example is much lower than that of the high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y prepared in the example, but the relative conductivity at room temperature is different between the two. The room temperature elongation of the high-strength and high-conductivity rare-earth copper alloy Cu-Cr-Zr-Y is significantly lower than that of the copper-chromium-zirconium alloy material of the comparative example. This shows that adding the rare earth element yttrium to the copper-chromium-zirconium alloy can significantly improve the room temperature tensile strength of the alloy material, but also significantly reduce the room temperature elongation of the copper-chromium-zirconium alloy, and also affect the room temperature conductivity of the material to a certain extent. Therefore, in order to improve the strength of the copper-chromium-zirconium alloy material by adding the rare earth element yttrium to the copper-chromium-zirconium alloy, it is necessary to control the addition amount of the yttrium element. It can be seen from Figure 9 and Figure 10 that the alternating treatment of room temperature rolling and aging can significantly improve the tensile strength and relative conductivity of high-strength and high-conductivity rare earth copper alloy Cu-Cr-Zr-Y and copper-chromium-zirconium alloy materials , which shows that this preparation process of alternating rolling and aging treatment can reduce the adverse effects of chromium, zirconium and yttrium elements on the tensile strength and electrical conductivity of alloy materials, especially the adverse effects on the electrical conductivity of the alloy. The formation of precipitates of different sizes can be promoted under the alternate conditions of room temperature rolling and aging in this embodiment, and the multi-size grades of precipitates and twins significantly improve the mechanical properties of the alloy. The effect of crystals on electron scattering is not strong, thereby weakening the influence of the second relative conductivity precipitated by the aging treatment, so the alloy can maintain high strength and high conductivity at the same time after the alternating process of room temperature rolling and aging.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. However, the obvious changes or changes derived from this are still within the protection scope of the claims of this patent application.

Claims (5)

1. A preparation method of a high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y is characterized by comprising the following steps:

step (1): placing pure copper, a chromium raw material, a zirconium raw material and an yttrium raw material in a medium-frequency induction smelting furnace, smelting in an atmospheric environment, and obtaining a rare earth copper chromium zirconium alloy ingot after smelting;

step (2): carrying out solid solution treatment on the rare earth copper chromium zirconium alloy ingot to obtain a rare earth copper chromium zirconium alloy blank;

step (3) rolling and aging the rare earth copper chromium zirconium alloy blank alternately to obtain high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y;

in the high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, the mass percentages of chromium element and zirconium element are respectively 0.55wt% and 0.18wt%, and the mass percentage of yttrium is 0.15 wt%;

in the step (1), the purity of pure copper is more than or equal to 99.95wt%, the chromium raw material is a copper-chromium intermediate alloy, the zirconium raw material is a copper-zirconium intermediate alloy, and the yttrium raw material is a copper-yttrium intermediate alloy;

in step (1), the smelting process comprises the steps of:

step (1-1): adding pure copper into a graphite crucible, and heating along with the furnace to melt the pure copper to obtain a copper melt;

step (1-2): continuously heating the copper melt, then sequentially adding the copper-chromium intermediate alloy, the copper-zirconium intermediate alloy and the copper-yttrium intermediate alloy into the copper melt to melt the copper-chromium intermediate alloy, the copper-zirconium intermediate alloy and the copper-yttrium intermediate alloy, and continuously heating and preserving heat to obtain a mixed melt;

step (1-3): casting the mixed melt into a preheated graphite mold by adopting a near liquidus casting method to obtain the rare earth copper chromium zirconium alloy cast ingot;

in step (3), the alternating process of rolling and aging comprises the following steps:

step (3-1): rolling the rare earth copper chromium zirconium alloy blank at room temperature for the first time at the room temperature, wherein the deformation is 60%; carrying out primary aging treatment on the rare earth copper chromium zirconium alloy blank rolled for the first time at 360 ℃ for 30 min;

step (3-2): carrying out secondary room temperature rolling on the rare earth copper chromium zirconium alloy blank subjected to the primary aging treatment at room temperature, wherein the deformation amount is 50%; carrying out secondary aging treatment on the rare earth copper chromium zirconium alloy blank rolled for the second time at 340 ℃ for 30 min;

step (3-3): carrying out third room temperature rolling on the rare earth copper chromium zirconium alloy blank subjected to the secondary aging treatment at room temperature, wherein the deformation amount is 40%; and carrying out three-stage aging treatment on the rare earth copper chromium zirconium alloy blank rolled for the third time at 320 ℃ for 30 min.

2. The method for preparing the high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y according to claim 1, wherein the mass fraction of chromium in the copper-chromium intermediate alloy is 10 wt%; in the copper-zirconium intermediate alloy, the mass fraction of zirconium is 40 wt%; in the copper-yttrium master alloy, the mass fraction of yttrium is 20 wt%.

3. The method for preparing the high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y according to claim 1, wherein in the step (1), the smelting method comprises the following steps:

step (1-1): adding pure copper into a graphite crucible, and heating along with the furnace to melt the pure copper to obtain a copper melt;

step (1-2): continuously heating the copper melt to 1240-1260 ℃, then sequentially adding the copper-chromium intermediate alloy, the copper-zirconium intermediate alloy and the copper-yttrium intermediate alloy into the copper melt to melt the copper-chromium intermediate alloy, the copper-zirconium intermediate alloy and the copper-yttrium intermediate alloy, continuously heating to 1300-1400 ℃, and preserving heat for 15min within the temperature range to obtain a mixed melt;

step (1-3): and casting the mixed melt into a preheated graphite mold at 1100-1150 ℃ by adopting a near liquidus casting method, wherein the preheating temperature of the mold is 300 ℃, and thus obtaining the rare earth copper-chromium-zirconium alloy ingot.

4. The method for preparing the high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y according to claim 1, wherein in the step (2), the solution treatment method comprises: and (3) placing the rare earth copper chromium zirconium alloy ingot in a heat treatment furnace, preserving the heat for 30-180min at the temperature of 980 ℃ of 900-.

5. A high-strength high-conductivity rare earth copper alloy Cu-Cr-Zr-Y, which is prepared by the method of any one of claims 1 to 4.

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