Ultra-fine-grained silver-copper alloy containing nano-precipitates and its preparation method and application

Abstract

The present application relates to the technical field of noble metal sputtering target material, and provides a kind of superfine grain silver copper alloy containing nano precipitated phase and its preparation method and application.The superfine grain silver copper alloy provided by the present application includes copper 0.1-3wt% and the balance Ag, and its phase composition includes silver-rich matrix phase and copper-rich nano precipitated phase dispersed in the silver-rich matrix phase, the average grain size of silver-rich matrix phase is 100-1000nm, and the average grain size of copper-rich nano precipitated phase is 10-50nm.The present application adopts microalloying method, combines large deformation plastic processing and lower annealing temperature, and prepares superfine grain silver copper alloy with excellent performance and submicron grain size, and the silver copper alloy of the present application is used as target material, which is beneficial to improve the sputtering rate and obtain silver copper alloy film with uniform thickness.

Description

Technical Field

[0001] This invention relates to the field of precious metal sputtering target technology, and in particular to an ultrafine-grained silver-copper alloy containing nano-precipitated phases, its preparation method, and its applications. Background Technology

[0002] Silver, a precious metal, possesses high electrical and thermal conductivity and excellent chemical stability. Its unique optical and electrical properties make it widely used in semiconductor devices and other fields. The preparation of the silver sputtering target is crucial for forming high-quality thin films. Typically, silver targets are required to have high purity (≥4N), high density (≥99% of theoretical density), and fine grain size (≤200μm) to obtain silver films with low defect density and uniform thickness during sputtering. With the miniaturization and increasing structural complexity of modern microelectronic devices, the number of sputtered thin films required is gradually increasing, making the sputtering process more complex and time-consuming. Therefore, improving the thin film sputtering deposition rate will improve production efficiency and significantly reduce costs. Fine-grained materials have small grain sizes and a significantly increased number of grain boundaries per unit volume. Grain boundaries are defect regions in the crystal structure, with irregular atomic arrangements leading to lower atomic binding energies. Because the atomic bonds at grain boundaries are incomplete, they are more easily bombarded and detached from the target surface by incident high-energy ions (such as argon ions). This localized weak bonding state increases sputtering yield. Compared to coarse-grained targets, targets with fine grains have a significantly increased number of grain boundaries, resulting in a markedly higher sputtering rate.

[0003] One related technology provides a high-purity silver sputtering target, in which a silver ingot is homogenized and heat-treated before forging, annealing, cold rolling, and heat treatment, resulting in a high-purity silver sputtering target with an average grain size of <15μm. Another related technology provides a silver alloy target, wherein indium accounts for 0.3%–0.6% of the mass, with the balance being silver; in its preparation, silver and indium are melted and slowly cooled to obtain a silver alloy ingot, which is then hot-forged, hot-rolled, cold-rolled, and heat-treated, ultimately yielding a silver alloy target with an average grain size of 10–40μm. While these methods achieve grain refinement to some extent, the resulting target grain size remains in the micrometer range, and the sputtering deposition rate still needs improvement. Summary of the Invention

[0004] In view of this, the present invention provides an ultrafine-grained silver-copper alloy containing nano-precipitates, its preparation method, and its application. The ultrafine-grained silver-copper alloy provided by the present invention has a grain size at the submicron level (≤1μm) and also has good electrical conductivity. When used as a target material, it is beneficial to improve the sputtering deposition rate and obtain a thin film with uniform thickness.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] An ultrafine-grained silver-copper alloy containing nano-precipitates comprises the following chemical composition by mass fraction: copper 0.1–3 wt%, with the balance being Ag;

[0007] The phase composition of the ultrafine-grained silver-copper alloy includes a silver-rich matrix phase and a copper-rich nano-precipitate phase dispersed in the silver-rich matrix phase; the average grain size of the silver-rich matrix phase is 100-1000 nm; and the average grain size of the copper-rich nano-precipitate phase is 10-50 nm.

[0008] Preferably, the volume fraction of copper-rich nano-precipitates in the phase composition of the ultrafine crystalline silver-copper alloy is 0.1-4%.

[0009] This invention also provides a method for preparing the ultrafine-grained silver-copper alloy containing nano-precipitated phases as described above, comprising the following steps:

[0010] Copper and silver are melted and then cast to obtain ingots;

[0011] The ingot is forged to obtain a forging; the side length deformation during forging is 75-90%; the side length deformation during forging is expressed as the rate of change of the side length of the cross-section of the forging relative to the side length of the cross-section of the ingot.

[0012] The forging is rolled to obtain a billet; the total thickness deformation during rolling is 40-90%.

[0013] The billet is annealed to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates; the annealing temperature is 200-350℃.

[0014] Preferably, the smelting is medium-frequency induction smelting; the power of the smelting furnace during the casting process is 20-30kW, and the casting rate is 0.3-0.8Kg / s.

[0015] Preferably, the forging is cold forging; the single-pass side length deformation of the forging is 10-30%.

[0016] Preferably, the rolling process is cold rolling; the thickness deformation per pass of the rolling process is 10-30%.

[0017] Preferably, the annealing is vacuum annealing; the vacuum degree of the annealing is 1×10⁻⁶. -2 ~1×10 -3 Pa.

[0018] Preferably, the holding time for annealing is 30 to 120 minutes; the heating rate to the annealing temperature is 1 to 10 °C / min.

[0019] Preferably, the purity of the copper and silver is 4N or higher.

[0020] The present invention also provides the application of the ultrafine-grained silver-copper alloy containing nano-precipitates as described in the above-described scheme or the ultrafine-grained silver-copper alloy containing nano-precipitates prepared by the preparation method described in the above-described scheme in sputtering targets.

[0021] This invention provides an ultrafine-grained silver-copper alloy containing nano-precipitates, comprising the following chemical composition by mass fraction: copper 0.1–3 wt%, with the balance being Ag; the phase composition of the ultrafine-grained silver-copper alloy includes a silver-rich matrix phase and a copper-rich nano-precipitate dispersed in the silver-rich matrix phase; the average grain size of the silver-rich matrix phase is 100–1000 nm; the average grain size of the copper-rich nano-precipitate is 10–50 nm. The ultrafine-grained silver-copper alloy provided by this invention has a submicron-level grain size and good electrical conductivity, which is beneficial for improving the sputtering deposition rate and obtaining thin films with uniform thickness when used as a sputtering target.

[0022] The present invention also provides a method for preparing the ultrafine-grained silver-copper alloy containing nano-precipitates as described above, comprising the following steps: melting copper and silver and casting them to obtain an ingot; forging the ingot to obtain a forging; the total side length deformation of the forging is 75-90%; the total side length deformation of the forging is expressed as the rate of change of the cross-sectional side length of the forging relative to the cross-sectional side length of the ingot; rolling the forging to obtain a billet; the total thickness deformation of the rolling is 40-90%; annealing the billet to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates; the annealing temperature is 200-350°C. The advantages of the preparation method provided by this invention are as follows: First, by employing a microalloying method, copper, which has a higher melting point than silver, is added to generate a solid solution strengthening effect, effectively increasing the recrystallization temperature of the alloy. Simultaneously, because the added copper, like silver, has good electrical conductivity, the alloy maintains good electrical conductivity after the addition of copper. Second, according to materials science, the microstructural deformation of silver-copper alloys during plastic deformation is controlled by the generation and annihilation of dislocations. This invention controls a larger deformation amount during forging and rolling, which is beneficial to the generation and aggregation of dislocations, thereby producing a higher dislocation density. First, by storing more deformation energy, recrystallization can occur at a lower temperature during subsequent annealing, forming uniform and fine grains. Second, through low-temperature annealing, nanoscale copper-rich phases precipitate in the silver-rich matrix. These copper-rich phases precipitate at the grain boundaries and within the silver-rich matrix. The copper-rich phase precipitated within the grains of the silver-rich matrix effectively hinders dislocation movement, increasing the alloy strength. The copper-rich phase precipitated at the grain boundaries of the silver-rich matrix effectively pins the grain boundaries, thus hindering grain boundary migration. This allows the material to suppress recrystallization at higher temperatures, further maintaining the stability of the ultrafine grains of the alloy. In summary, this invention uses a microalloying method, combined with large deformation plastic processing and a lower annealing temperature, to prepare a high-performance ultrafine-grained silver-copper alloy containing nanoprecipitates. Furthermore, the preparation method provided by this invention is simple, with mild and easily controllable conditions, which can greatly improve production efficiency and significantly reduce preparation costs. Attached Figure Description

[0023] Figure 1 The images shown are TEM images of the ultrafine-grained silver-copper alloy prepared in Example 1, where (a) is the EBSD image of the silver-copper alloy, (a1) is the bright-field image of Cu-rich particles, (a2) is the EDS image of Cu element distribution, and (a3) ​​is the EDS image of Ag element distribution. Detailed Implementation

[0024] This invention provides an ultrafine-grained silver-copper alloy containing nano-precipitated phases, comprising the following chemical composition by mass fraction: copper 0.1-3 wt%, balance Ag;

[0025] The phase composition of the ultrafine-grained silver-copper alloy includes a silver-rich matrix phase and a copper-rich nano-precipitate phase dispersed in the silver-rich matrix phase; the average grain size of the silver-rich matrix phase is 100-1000 nm; and the average grain size of the copper-rich nano-precipitate phase is 10-50 nm.

[0026] In this invention, the mass fraction of copper in the ultrafine-grained silver-copper alloy containing nano-precipitates is 0.1–3 wt%, specifically 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%. Silver has a melting point of 961.9 °C, and its recrystallization temperature after large deformation is approximately 220 °C. Therefore, it is difficult to obtain sub-micron grains in pure silver after large deformation. This invention adds an appropriate amount of Cu as an alloying element, which helps to increase the recrystallization temperature of the alloy, thereby refining the grain size.

[0027] In this invention, the average grain size of the silver-rich matrix phase is 100–1000 nm, preferably 300–800 nm; the average grain size of the copper-rich nanoprecipitates is 10–50 nm, preferably 10–30 nm; the volume fraction of the copper-rich nanoprecipitates in the phase composition of the ultrafine-grained silver-copper alloy is preferably 0.1–4 vol%, specifically 0.1 vol%, 0.5 vol%, 1 vol%, 2 vol%, 3 vol%, or 4 vol%; the copper-rich nanoprecipitates are specifically precipitated at the grain boundaries and within the grains of the silver-rich matrix phase.

[0028] This invention also provides a method for preparing the ultrafine-grained silver-copper alloy containing nano-precipitated phases as described above, comprising the following steps:

[0029] Copper and silver are melted and then cast to obtain ingots;

[0030] The ingot is forged to obtain a forging; the side length deformation during forging is 75-90%; the side length deformation during forging is expressed as the rate of change of the side length of the cross-section of the forging relative to the side length of the cross-section of the ingot.

[0031] The forging is rolled to obtain a billet; the total thickness deformation during cold rolling is 40-90%.

[0032] The billet is annealed to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates; the annealing temperature is 200-350℃.

[0033] This invention involves melting copper and silver and then casting them to obtain ingots. In this invention, the purity of the copper and silver is preferably 4N or higher; the melting is preferably carried out using medium-frequency induction melting, specifically in a medium-frequency induction melting furnace; the power of the melting furnace during casting is preferably 20–30 kW, specifically 20 kW, 25 kW, or 30 kW, and the casting rate is preferably 0.3–0.8 kg / s, specifically 0.3 kg / s, 0.5 kg / s, 0.6 kg / s, or 0.8 kg / s. In this invention, the ingot is preferably a square ingot, specifically a square ingot with a square cross-section.

[0034] After obtaining the ingot, the present invention forges the ingot to obtain a forging. In the present invention, the forging is preferably die forging, and the forging is preferably cold forging; the side length deformation of the forging is 75-90%; the side length deformation of the forging is measured by the rate of change of the side length of the cross-section of the forging relative to the side length of the cross-section of the ingot; the side length deformation per pass of the forging is preferably 10-30%, specifically 10%, 15%, 20%, 25%, or 30%; the forging is preferably a square bar, specifically a bar with a square cross-section; the side length ratio of the square ingot to the square bar's square cross-section is preferably 4-10:1, specifically 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1.

[0035] After obtaining the forging, the present invention rolls the forging to obtain a billet. In the present invention, the rolling is preferably cold rolling; the total thickness deformation during rolling is 40-90%, specifically 40%, 50%, 60%, 70%, 80%, or 90%; the thickness deformation per single pass during rolling is preferably 10-30%, specifically 10%, 15%, 20%, 25%, or 30%. In the present invention, the billet is preferably a sheet metal. The present invention controls a large amount of deformation during forging and rolling, which is beneficial for generating a higher dislocation density and storing more deformation energy, thereby facilitating the formation of uniform and fine grains during subsequent annealing.

[0036] After obtaining the billet, the present invention anneals the billet to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates. In the present invention, the annealing temperature is preferably 200–350°C, specifically 200°C, 250°C, 300°C, or 350°C; the annealing is preferably vacuum annealing; and the vacuum degree of the annealing is preferably 1×10⁻⁶. -2 ~1×10 -3Pa; the holding time for annealing is preferably 30-120 min, specifically 30 min, 60 min, 90 min, or 120 min; the heating rate to the annealing temperature is preferably 1-10 °C / min, specifically 1 °C / min, 3 °C / min, 5 °C / min, or 10 °C / min. In a specific embodiment of the present invention, it is preferable to first evacuate to 1 × 10⁻⁶ Pa. -2 ~1×10 -3 The temperature is then raised to the annealing temperature for annealing. After annealing, the furnace is cooled to room temperature before removal. This invention precipitates a nanoscale copper-rich phase in a silver-rich matrix by annealing at a relatively low temperature.

[0037] After annealing, the present invention preferably further includes machining the ultrafine-grained silver-copper alloy containing nano-precipitates to obtain a product of the desired size. The present invention does not specify a particular machining method; any method well-known to those skilled in the art can be used.

[0038] This invention also provides the application of the ultrafine-grained silver-copper alloy containing nano-precipitates described in the above-described scheme, or the ultrafine-grained silver-copper alloy containing nano-precipitates prepared by the above-described method, in sputtering targets. The ultrafine-grained silver-copper alloy containing nano-precipitates provided by this invention has a grain size reaching the sub-micron level and also exhibits good conductivity. Using it as a target material is beneficial for improving the sputtering deposition rate and obtaining thin films with uniform thickness.

[0039] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] Example 1

[0041] This embodiment provides an ultrafine-grained silver-copper alloy containing nano-precipitates, with the chemical composition by mass fraction as follows: 2wt% copper and the balance being Ag.

[0042] The preparation method is as follows:

[0043] (1) Silver and copper raw materials with a purity of 4N or above are added to a medium-frequency induction melting furnace for melting. After the raw materials are completely melted, they are cast to obtain square ingots. During the casting process, the power of the medium-frequency induction melting furnace is maintained at 25kW and the casting rate is maintained at 0.5kg / s.

[0044] (2) The square ingot is cold-forged into a square bar by die forging. The side length ratio of the square ingot and the square bar is 5:1. The side length deformation per pass during the forging process is 10%.

[0045] (3) The square bar is cold rolled, and the total thickness deformation is controlled to be 60% and the single-pass thickness deformation is 10% to obtain silver-copper alloy plate.

[0046] (4) Vacuum annealing is performed on the silver-copper alloy sheet. First, a vacuum is drawn to a vacuum degree of 1×10⁻⁶. -2 Pa, then heat to the annealing temperature at a rate of 5℃ / min, the annealing temperature is 300℃, and the annealing time is 60min. After the annealing time is reached, cool to room temperature in the furnace and then remove it. Then perform machining to obtain the product of the required size, denoted as AgCu2wt%.

[0047] Example 2

[0048] This embodiment provides an ultrafine-grained silver-copper alloy containing nano-precipitates, with a chemical composition of 1 wt% copper and the balance being Ag.

[0049] The preparation method is as follows:

[0050] (1) Silver and copper raw materials with a purity of 4N or above are added to a medium-frequency induction melting furnace for melting. After the raw materials are completely melted, they are cast to obtain square ingots. During the casting process, the power of the medium-frequency induction melting furnace is maintained at 30kW and the casting rate is maintained at 0.8kg / s.

[0051] (2) The square ingot is cold-forged into a square bar by die forging. The side length ratio of the square ingot and the square bar is 4:1. The side length deformation of a single pass during the forging process is 15%.

[0052] (3) The square bar is cold rolled to control the total thickness deformation to 80% and the single-pass thickness deformation to 20% to obtain silver-copper alloy plate.

[0053] (4) Vacuum annealing is performed on the silver-copper alloy sheet. First, a vacuum is drawn to a vacuum degree of 1×10⁻⁶. -3 Pa, then heat to the annealing temperature at a rate of 10℃ / min, annealing temperature of 250℃, annealing time of 90min. After the annealing time is reached, cool to room temperature in the furnace and remove, then perform machining to obtain the product of the required size, denoted as AgCu1wt%.

[0054] Example 3

[0055] This embodiment provides an ultrafine-grained silver-copper alloy containing nano-precipitates, with the chemical composition by mass fraction as follows: copper 3wt%, balance Ag.

[0056] The preparation method is as follows:

[0057] (1) Silver and copper raw materials with a purity of 4N or above are added to a medium-frequency induction melting furnace for melting. After the raw materials are completely melted, they are cast to obtain square ingots. During the casting process, the power of the medium-frequency induction melting furnace is maintained at 20kW and the casting rate is maintained at 0.3kg / s.

[0058] (2) The square ingot is cold-forged into a square bar by die forging. The side length ratio of the square ingot and the square bar is 10:1. The side length deformation of a single pass during the forging process is 30%.

[0059] (3) The square bar is cold rolled, and the total thickness deformation is controlled to be 90% and the single-pass thickness deformation is 30% to obtain silver-copper alloy plate.

[0060] (4) Vacuum annealing is performed on the silver-copper alloy sheet. First, a vacuum is drawn to a vacuum degree of 1×10⁻⁶. -3 Pa, then heat to the annealing temperature at a rate of 10℃ / min, annealing temperature of 250℃, annealing time of 50min. After the annealing time is reached, cool to room temperature in the furnace and remove, then perform machining to obtain the product of the required size, denoted as AgCu3wt%.

[0061] Example 4

[0062] This embodiment provides an ultrafine-grained silver-copper alloy containing nano-precipitates, with a chemical composition of: 0.1 wt% copper and the balance being Ag.

[0063] The preparation method is as follows:

[0064] (1) Silver and copper raw materials with a purity of 4N or above are added to a medium-frequency induction melting furnace for melting. After the raw materials are completely melted, they are cast to obtain square ingots. During the casting process, the power of the medium-frequency induction melting furnace is maintained at 28kW and the casting rate is maintained at 0.6kg / s.

[0065] (2) The square ingot is cold-forged into a square bar by die forging. The side length ratio of the square ingot and the square bar is 9:1. The side length deformation per pass during the forging process is 22%.

[0066] (3) The square bar is cold rolled, and the total thickness deformation is controlled to be 40% and the single-pass thickness deformation is 10% to obtain silver-copper alloy plate.

[0067] (4) Vacuum annealing is performed on the silver-copper alloy sheet. First, a vacuum is drawn to a vacuum degree of 1×10⁻⁶. -3Pa, then heat to the annealing temperature at a rate of 5℃ / min, the annealing temperature is 200℃, and the annealing time is 120min. After the annealing time is reached, cool to room temperature in the furnace and then take it out. Then perform machining to obtain the product of the required size, denoted as AgCu0.1wt%.

[0068] Example 5

[0069] This embodiment provides an ultrafine-grained silver-copper alloy containing nano-precipitates, with a chemical composition of 1.5 wt% copper and the balance being Ag.

[0070] The preparation method is as follows:

[0071] (1) Silver and copper raw materials with a purity of 4N or above are added to a medium-frequency induction melting furnace for melting. After the raw materials are completely melted, they are cast to obtain square ingots. During the casting process, the power of the medium-frequency induction melting furnace is maintained at 20kW and the casting rate is maintained at 0.4kg / s.

[0072] (2) The square ingot is cold-forged into a square bar by die forging. The side length ratio of the square ingot and the square bar is 8:1. The side length deformation per pass during the forging process is 10%.

[0073] (3) The square bar is cold rolled to control the total thickness deformation to 80% and the single-pass thickness deformation to 20% to obtain silver-copper alloy plate.

[0074] (4) Vacuum annealing is performed on the silver-copper alloy sheet. First, a vacuum is drawn to a vacuum degree of 1×10⁻⁶. -3 Pa, then heat to the annealing temperature at a rate of 5℃ / min, annealing temperature of 350℃, annealing time of 30min. After the annealing time is reached, cool to room temperature in the furnace and then remove it. Then perform machining to obtain the product of the required size, denoted as AgCu1.5wt%.

[0075] Comparative Example 1

[0076] Other conditions are the same as in Example 1, except that the side length ratio of the square cross-section of the square ingot and the square bar is controlled to be 3:1 during forging; and the single-pass side length deformation during forging is 10%.

[0077] Comparative Example 2

[0078] Other conditions are the same as in Example 1, except that the total thickness deformation is controlled to be 20% and the thickness deformation per pass is controlled to be 10% during rolling.

[0079] Comparative Example 3

[0080] The other conditions are the same as in Example 1, except that the annealing temperature is controlled at 400°C.

[0081] Comparative Example 4

[0082] The other conditions are the same as in Example 1, except that the annealing temperature is controlled at 150°C.

[0083] Performance testing:

[0084] 1. Phase composition test

[0085] The ultrafine-grained silver-copper alloy prepared in Example 1 was subjected to TEM testing, and the results are as follows: Figure 1 As shown, Figure 1 In the image, (a) is the EBSD image of the silver-copper alloy, (a1) is the bright-field image of Cu-rich particles, (a2) is the EDS image of Cu element distribution, and (a3) ​​is the EDS image of Ag element distribution. According to... Figure 1 It can be seen that the ultrafine-grained silver-copper alloy prepared by the present invention uses a silver-rich phase as the matrix, and copper-rich nano-precipitates are dispersed in the matrix. The copper-rich nano-precipitates are located at the grain boundaries and within the grains of the silver-rich matrix phase, and the grain size of the silver-rich phase is 100-800 nm, while the grain size of the copper-rich nano-precipitates is 10-30 nm.

[0086] The ultrafine-grained silver-copper alloys prepared in Examples 2-5 were subjected to the same TEM test. The results showed that the obtained ultrafine-grained silver-copper alloys all had a silver-rich phase as the matrix, and copper-rich nano-precipitates were precipitated at the grain boundaries and within the grains of the silver-rich matrix phase. At the same time, the grain size of the silver-rich matrix phase was submicron, and the grain size of the copper-rich nano-precipitates was in the range of 10-40 nm.

[0087] The silver-copper alloys prepared in Comparative Examples 1–4 were subjected to the same TEM tests. The results showed that the deformation during the forging or rolling process of Comparative Examples 1–2 was relatively small, and the grain size of the silver-rich phase in the prepared silver-copper alloy was 10–30 μm, while the grain size of the copper-rich precipitate was in the range of 10–50 nm. The annealing temperature of Comparative Example 3 was too high, and the grain size of the silver-rich phase in the obtained silver-copper alloy was 20–50 μm, while the grain size of the copper-rich precipitate was in the range of 200–500 nm. The annealing temperature of Comparative Example 4 was too low, and the silver-rich phase in the obtained silver-copper alloy was at the micrometer level, containing a large number of dislocation cell structures, and there was no copper-rich precipitate.

[0088] 2. Tensile strength, resistivity and sputtering tests

[0089] The tensile strength and resistivity of the silver-copper alloys prepared in Examples 1-5 and Comparative Examples 1-4 were tested. Subsequently, using the prepared silver-copper alloys as targets, silver-copper alloy thin films were prepared by magnetron sputtering. The sputtering rate and thickness tolerance of the resulting films were tested. The magnetron sputtering conditions were as follows: sputtering was performed using a magnetron sputtering machine at a sputtering pressure of 3 Pa and a sputtering power of 200 W. The results showed that, compared with the comparative examples, the silver-copper alloy target of the present invention had higher tensile strength and lower resistivity. Simultaneously, under the above magnetron sputtering conditions, the sputtering rate of the silver-copper alloy target of the present invention was significantly faster than that of the comparative examples, and the resulting silver-copper alloy had a uniform thickness. The main results are shown in Table 1.

[0090] Table 1 Performance evaluation results of different embodiments and comparative examples

[0091]

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultrafine-grained silver-copper alloy containing nano-precipitated phases, characterized in that, The chemical composition includes the following mass fractions: copper 0.1~3wt%, balance Ag; The phase composition of the ultrafine-grained silver-copper alloy includes a silver-rich matrix phase and a copper-rich nano-precipitate phase dispersed in the silver-rich matrix phase; the average grain size of the silver-rich matrix phase is 100~1000nm; the average grain size of the copper-rich nano-precipitate phase is 10~50nm. The preparation method of the ultrafine-grained silver-copper alloy containing nano-precipitated phases includes the following steps: Copper and silver are melted and then cast to obtain ingots; The ingot is forged to obtain a forging; the side length deformation during forging is 75-90%; the side length deformation during forging is measured by the rate of change of the cross-sectional side length of the forging relative to the cross-sectional side length of the ingot; the forging is cold forging. The forging is rolled to obtain a billet; the total thickness deformation during rolling is 40-90%; the rolling process is cold rolling. The billet is annealed to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates; the annealing temperature is 200~350℃.

2. The ultrafine-grained silver-copper alloy containing nano-precipitated phases according to claim 1, characterized in that, The volume fraction of copper-rich nanoprecipitates in the phase composition of the ultrafine crystalline silver-copper alloy is 0.1~4 vol%.

3. The method for preparing the ultrafine-grained silver-copper alloy containing nano-precipitated phases according to any one of claims 1 to 2, characterized in that, Includes the following steps: Copper and silver are melted and then cast to obtain ingots; The ingot is forged to obtain a forging; the side length deformation during forging is 75-90%; the side length deformation during forging is measured by the rate of change of the cross-sectional side length of the forging relative to the cross-sectional side length of the ingot; the forging is cold forging. The forging is rolled to obtain a billet; the total thickness deformation during rolling is 40-90%; the rolling process is cold rolling. The billet is annealed to obtain the ultrafine-grained silver-copper alloy containing nano-precipitates; the annealing temperature is 200~350℃.

4. The preparation method according to claim 3, characterized in that, The smelting is a medium-frequency induction smelting; the power of the smelting furnace during the casting process is 20~30kW, and the casting rate is 0.3~0.8Kg / s.

5. The preparation method according to claim 3, characterized in that, The deformation of the side length in a single pass of the forging is 10-30%.

6. The preparation method according to claim 3, characterized in that, The thickness deformation per pass during rolling is 10-30%.

7. The preparation method according to claim 3, characterized in that, The annealing is vacuum annealing; the vacuum degree of the annealing is 1×10⁻⁶. -2 ~1×10 -3 Pa.

8. The preparation method according to claim 3 or 7, characterized in that, The holding time for annealing is 30~120 min; the heating rate to the annealing temperature is 1~10℃ / min.

9. The preparation method according to claim 3, characterized in that, The purity of the copper and silver is above 4N.

10. The application of the ultrafine-grained silver-copper alloy containing nano-precipitates as described in claim 1 or 2, or the ultrafine-grained silver-copper alloy containing nano-precipitates prepared by the preparation method according to any one of claims 3 to 9, in sputtering targets.

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