A rare earth alloyed high-performance copper-nickel-silicon alloy material and a preparation method thereof

Abstract

The present application belongs to the technical field of alloy, and mainly relates to a rare earth alloyed high-performance copper-nickel-silicon alloy material and a preparation method thereof. The copper-nickel-silicon alloy material contains, in percentage by weight, 1.0-3.5wt% Ni, 0.2-1.0wt% Si, 0.02-0.15wt% Mg, 0.01-0.1wt% Zn, 0-0.65wt% La, and the rest is copper. The preparation method comprises smelting, hot forging, solid solution, cold rolling and subsequent aging, wherein the solid solution temperature is 780-980 DEG C, the holding time is 0-24h; the aging temperature is 400-500 DEG C, and the holding time is 0-24h. Meanwhile, the alloy is subjected to multi-pass cold rolling according to the comprehensive performance requirements. The finished product obtained by the present application has a hardness of 190-240Hv, a tensile strength of 580-680MPa, and an electrical conductivity of 35-55% IACS, and can better meet the comprehensive performance requirements of the electronic industry and other fields for high-performance copper alloys.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, and mainly relates to a rare-earth alloyed high-performance copper-nickel-silicon alloy material and its preparation method. It is suitable for lead frame materials used in large-scale and very large-scale integrated circuits, contact wires, connectors, and contact springs used in various circuit systems. Background Technology

[0002] With the advent of the intelligent era, high-end manufacturing and the electronics industry have developed rapidly, with chips being the most crucial component. Leadframe materials are an indispensable part of chip manufacturing. Currently, the high-performance copper-based alloy materials developed by various countries mainly include CuNiSi, CuFeP, CuCr, and CuCrZr systems. The Cu-Ni-Si alloy, developed in the 21st century, possesses excellent comprehensive properties such as high strength, high electrical conductivity, and high thermal conductivity, making it more aligned with the future miniaturization and high integration trends in the electronics industry. Many countries worldwide are accelerating the research and development of CuNiSi alloys and their performance.

[0003] High-performance copper-based alloy materials discussed in domestic and international patent literature mostly involve controlling the atomic ratio of added Ni and Si, adding other components, or adjusting the process to improve a specific property. For example:

[0004] Chinese patent document CN113308622A describes a copper alloy containing 2.7–3.8 wt% Ni, 0.8–1.3 wt% Si, <0.01 wt% Fe, <0.02 wt% Zn, <0.015 wt% Pb, 0.1–0.4 wt% Mn, 0.01–0.05 wt% Ga, 0.01–0.03 wt% Al, 0.003–0.006 wt% Ba, <0.1 wt% Sn, and 0.005–0.01 wt% rare earth elements, with the balance being Cu. This type of alloy is characterized by the addition of mixed rare earth elements, but its overall performance is poor, with an electrical conductivity of 55–63% IACS and a hardness of only 165–178 Hv.

[0005] Chinese patent document CN103205600A describes two copper alloys: one containing 3.52–4.04 wt% Ni, 0.93–1.18 wt% Si, and 0.19–0.43 wt% Fe, with an electrical conductivity of 13–36% IACS and a hardness of 240–285 Hv; and another containing 3.51–4.04 wt% Ni, 0.93–1.18 wt% Si, and 0.32–0.73 wt% Mo, with an electrical conductivity of 13–35% IACS and a hardness of 212–244 Hv. The characteristic of these alloys is that the addition of Mo increases the alloy's hardness but deteriorates its electrical conductivity.

[0006] Chinese patent document CN107419132A describes a copper alloy containing 2.3–3.2 wt% Ni, 0.3–0.6 wt% Si, 0.01–0.015 wt% P, 0.1–0.25 wt% Sr, 0.05–0.15 wt% Y, 0.12–0.14 wt% Ag, with the balance being Cu. This type of alloy has poor overall performance, with an electrical conductivity of 61–68% IACS, but a hardness of only 160–180 Hv. Summary of the Invention

[0007] The purpose of this invention is to provide a rare-earth alloyed high-performance copper-nickel-silicon alloy material and its preparation method. By adding rare-earth elements, the matrix is ​​made purer, further improving the performance controllability of the alloy and meeting the performance requirements of copper alloy materials such as lead frame materials.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A rare earth alloyed high-performance copper-nickel-silicon alloy material, by weight percentage, contains: 1.0-3.5 wt% nickel, 0.2-1.0 wt% silicon, 0.02-0.15 wt% magnesium, 0.01-0.1 wt% zinc, 0-0.65 wt% lanthanum, with the remainder being copper.

[0010] The rare earth alloyed high-performance copper-nickel-silicon alloy material, preferably, contains, by weight percentage: 2.0-3.5 wt% nickel, 0.4-0.6 wt% silicon, 0.07-0.12 wt% magnesium, 0.03-0.08 wt% zinc, 0.2-0.5 wt% lanthanum, with the remainder being copper.

[0011] The rare earth alloyed high-performance copper-nickel-silicon alloy material has a Ni to Si weight ratio controlled between 3.5 and 5.5.

[0012] The method for preparing the rare earth alloyed high-performance copper-nickel-silicon alloy material includes the following steps:

[0013] (1) Melt the raw materials at 1200-1400℃ under a protective atmosphere, and then pour the melted material into a mold;

[0014] (2) Hot forging of alloys: hot forging temperature is 700-950℃, holding time is 1-3 hours, forging ratio is 1-3;

[0015] (3) Hot rolling deformation of alloys: hot rolling temperature 700~900℃, rolling deformation amount 60~80%;

[0016] (4) Solution treatment of alloy: The solution temperature is 780~980℃, the total holding time is 0~24h, and then water quenching is performed;

[0017] (5) Cold rolling deformation of alloys: cold rolling deformation amount 50-95%;

[0018] (6) Aging process of alloy: aging temperature is 400-500℃, and holding time is 0-24h.

[0019] In the preparation method of the rare earth alloyed high-performance copper-nickel-silicon alloy material, in step (1), the protective atmosphere is nitrogen or argon.

[0020] In the preferred method for preparing the rare earth alloyed high-performance copper-nickel-silicon alloy material, the forging ratio in step (2) is 1.5 to 2.5.

[0021] In the preparation method of the rare earth alloyed high-performance copper-nickel-silicon alloy material, in step (3), the deformation amount of each rolling pass does not exceed 10%.

[0022] In the preferred method for preparing the rare earth alloyed high-performance copper-nickel-silicon alloy material, the solution treatment temperature in step (4) is 790–920°C, with a temperature error not exceeding ±5°.

[0023] In the preparation method of the rare earth alloyed high-performance copper-nickel-silicon alloy material, in step (5), the deformation of each rolling pass is no more than 20% compared with the previous pass.

[0024] The design concept of this invention is:

[0025] The copper-nickel-silicon alloy material proposed in this invention is a novel high-strength, medium-conductivity, high-performance copper alloy material with excellent comprehensive properties, uniform alloy microstructure, and fine precipitates. This alloy is an age-hardening alloy, and the precipitated second phases include Ni₂Si and LaNiSi compounds, with precipitate sizes ranging from approximately 30 to 300 nm. To ensure a relatively pure matrix after aging and thus achieve relatively high conductivity, an appropriate Ni / Si weight ratio is maintained between 3.5 and 5.5. Furthermore, considering the purifying effect of trace amounts of La on the copper matrix, La has a high melting point and very low solid solubility in the copper matrix. Undissolved La elements will form a second phase and affect the precipitation of Ni and Si atoms during the aging process, thereby impacting the material's strength and conductivity.

[0026] The advantages and beneficial effects of this invention are:

[0027] 1. The copper-nickel-silicon alloy material described in this invention is designed based on the traditional CuNiSi alloy. One of its key features is the addition of the rare earth element La, which extends the peak aging time, improves conductivity, and allows for better control of the material's performance. This material possesses excellent comprehensive properties such as high strength and high conductivity, and can well meet the performance requirements of lead frame materials for copper alloy materials.

[0028] 2. The rare earth alloyed high-performance copper-nickel-silicon alloy material of the present invention, when prepared by the above process, has a hardness of 190-240 Hv and an electrical conductivity of 35-55% IACS, which can better meet the comprehensive performance requirements of high-performance copper alloys used in the electronics industry and other fields such as lead frame materials. Detailed Implementation

[0029] In the specific implementation process, by weight percentage, the rare earth alloyed high-performance copper-nickel-silicon alloy material of this invention contains: 1.0–3.5 wt% Ni, 0.2–1.0 wt% Si, 0.02–0.15 wt% Mg, 0.01–0.1 wt% Zn, 0–0.65 wt% La, with the remainder being copper. Its preparation method includes smelting, hot forging, solution treatment, cold rolling, and subsequent aging, wherein: the solution treatment temperature is 780–980℃, and the holding time is 0–24 h; the aging temperature is 400–500℃, and the holding time is 0–24 h. Simultaneously, the alloy undergoes multiple cold rolling passes according to the comprehensive performance requirements.

[0030] The present invention will now be described in further detail with reference to the embodiments.

[0031] Example 1

[0032] By weight percentage, the copper-nickel-silicon alloy material of this embodiment contains: 2.48% Ni, 0.51% Si, 0.11% Mg, 0.048% Zn, 0.044% La, with the remainder being copper.

[0033] The preparation method of the copper-nickel-silicon alloy material in this embodiment is as follows: After weighing the raw materials according to the above weight percentages, electrolytic copper plates, electrolytic nickel plates, and industrial silicon are placed into a crucible. Mg, Zn, and La are suspended. Mg and Zn are wrapped with copper foil to prevent them from being oxidized at high temperatures. The crucible is evacuated to about 10 Pa and then heated to about 1300°C. After the raw materials in the crucible are completely melted, they are refined for 20 minutes at a temperature of about 1200°C. After refining, 0.08 MPa argon gas is introduced, and Mg, Zn, and La alloy materials are added in sequence until they are completely melted. After stirring for 1 minute, the temperature is adjusted and cast at approximately 1300°C. The casting is then cooled to room temperature to obtain an ingot. Before hot forging, the ingot is held at 950°C for 2 hours. The forging temperature is ≥700℃, and the forging ratio is 2.1 to obtain a hot-forged material with a thickness of 30mm. The hot-forged material is then hot-rolled at an initial rolling temperature of 890℃, through 5 passes to a thickness of approximately 6mm, with a final rolling temperature ≥700℃. The hot-rolled material is then solution-treated in a box-type resistance furnace at 800℃ for 1 hour, followed by water quenching to room temperature to obtain a cold material. This cold material is then milled, followed by cold rolling with a deformation of 83.3%, through six passes to a thickness of 0.3mm. The surface of the resulting material is then polished. The material is then sealed in a tube, evacuated, and filled with nitrogen for aging treatment at 450℃ for 4 hours, followed by water cooling to room temperature. The resulting copper-nickel-silicon alloy material, obtained through the above treatment, has a hardness of 235Hv, a tensile strength of 670.5MPa, and an electrical conductivity of 39% IACS.

[0034] Example 2

[0035] By weight percentage, the copper-nickel-silicon alloy material of this embodiment contains: 2.42% Ni, 0.48% Si, 0.093% Mg, 0.071% Zn, 0.22% La, with the remainder being copper.

[0036] The preparation method of the copper-nickel-silicon alloy material in this embodiment is as follows: After weighing the raw materials according to the above weight percentages, electrolytic copper plates, electrolytic nickel plates, and industrial silicon are placed into a crucible. Mg, Zn, and La are suspended. Mg and Zn are wrapped with copper foil to prevent them from being oxidized at high temperatures. The crucible is evacuated to about 10 Pa and then heated to about 1300°C. After the raw materials in the crucible are completely melted, they are refined for 20 minutes at a temperature of about 1200°C. After refining, 0.08 MPa argon gas is introduced, and Mg, Zn, and La alloy materials are added in sequence until they are completely melted. After stirring for 1 minute, the temperature is adjusted and the mixture is cast at approximately 1300°C. After cooling to room temperature, an ingot is obtained. Before hot forging, the ingot is held at 950°C for 2 hours. The final forging temperature is ≥700℃, and the forging ratio is 2.1 to obtain a hot-forged material with a thickness of 30mm. The hot-forged material is then hot-rolled at an initial rolling temperature of 890℃, through 5 passes to a thickness of approximately 6mm, with a final rolling temperature ≥700℃. The hot-rolled material is then solution-treated in a box-type resistance furnace at 800℃ for 1 hour, followed by water quenching to room temperature to obtain a cold material. This cold material is then milled, followed by cold rolling with a deformation of 80%, through six passes to a thickness of 0.3mm. The surface of the resulting material is then polished. Finally, the material is sealed in a tube, evacuated, and filled with nitrogen for aging treatment at 450℃ for 4 hours, followed by water cooling to room temperature. The resulting copper-nickel-silicon alloy material, obtained through the above treatment, achieves a hardness of 220Hv and an electrical conductivity of 45% IACS.

[0037] The DSC curves of the solid solution at different heating rates show that the endothermic peak of the Ni2Si phase gradually shifts to higher temperatures as the heating rate increases. This indicates that the presence of the La phase influences the precipitation behavior of the Ni2Si phase, thereby altering the alloy's electrical conductivity and strength properties.

[0038] Example 3

[0039] By weight percentage, the copper-nickel-silicon alloy material of this embodiment contains: 2.5% Ni, 0.47% Si, 0.1% Mg, 0.063% Zn, 0.45% La, and the remainder is copper.

[0040] The preparation method of the copper-nickel-silicon alloy material in this embodiment is as follows: After weighing the raw materials according to the above weight percentages, electrolytic copper plates, electrolytic nickel plates, and industrial silicon are placed into a crucible. Mg, Zn, and La are suspended. Mg and Zn are wrapped with copper foil to prevent them from being oxidized at high temperatures. The crucible is evacuated to about 10 Pa and then heated to about 1300°C. After the raw materials in the crucible are completely melted, they are refined for 20 minutes at a temperature of about 1200°C. After refining, 0.08 MPa argon gas is introduced, and Mg, Zn, and La alloy materials are added in sequence until they are completely melted. After stirring for 1 minute, the temperature is adjusted and the mixture is cast at approximately 1300°C. After cooling to room temperature, an ingot is obtained. Before hot forging, the ingot is held at 950°C for 2 hours. The final forging temperature is ≥700℃, and the forging ratio is 2.1 to obtain a hot-forged material with a thickness of 30mm. The hot-forged material is then hot-rolled at an initial rolling temperature of 890℃, through 5 passes to a thickness of approximately 6mm, with a final rolling temperature ≥700℃. The hot-rolled material is then solution-treated in a box-type resistance furnace at 800℃ for 1 hour, followed by water quenching to room temperature to obtain a cold material. This cold material is then milled, followed by cold rolling with a deformation of 80%, through six passes to a thickness of 0.3mm. The surface of the resulting material is then polished. Finally, the material is sealed in a tube, evacuated, and filled with nitrogen for aging treatment at 450℃ for 4 hours, followed by water cooling to room temperature. The resulting copper-nickel-silicon alloy material, obtained through the above treatment, achieves a hardness of 200Hv, a tensile strength of 598MPa, and an electrical conductivity of 44% IACS.

[0041] In Examples 1-3, Cu, Ni, Si, Mg, Zn, and La were melted and cast into qualified ingots according to the proportions in Table 1. The ingots were then hot-forged at 700-890℃, followed by solution treatment, cold rolling deformation, and aging treatment to obtain copper alloy materials with excellent comprehensive properties. The comprehensive properties are shown in Table 1.

[0042] Table 1 Comprehensive Properties of Cu-Ni-Si-Mg-Zn-La Alloys

[0043]

[0044] The test data shows that this invention, through the rational allocation of alloying elements and the improvement of process steps and the adjustment of process parameters, enables the copper alloy material for the lead frame to possess excellent mechanical and electrical properties. The performance of this copper alloy is superior to that of the commonly available R620 temper C7025 copper alloy, which has a conductivity ≥40% IACS and a hardness of 180–220 Hv.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art who makes equivalent substitutions or changes to the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a rare-earth alloyed high-performance copper-nickel-silicon alloy material, characterized in that, By weight percentage, this copper-nickel-silicon alloy material contains: 2.0~2.5wt% nickel, 0.47~0.6wt% silicon, 0.07~0.1wt% magnesium, 0.063~0.071wt% zinc, 0.2~0.5wt% lanthanum, with the remainder being copper. The weight ratio of Ni and Si is controlled between 3.5 and 5.

5. This alloy is an age-hardening alloy, and the precipitated second phases are Ni2Si and LaNiSi compounds, with the size of the precipitated phases being 30~300nm. The method for preparing the rare earth alloyed high-performance copper-nickel-silicon alloy material includes the following steps: (1) Melt the raw materials at 1200~1400℃ under a protective atmosphere, and then pour the melted material into a mold; (2) Hot forging of alloys: hot forging temperature is 700~950℃, holding time is 1~3 hours, forging ratio is 1~3; (3) Hot rolling deformation of alloys: hot rolling temperature 700~900℃, rolling deformation amount 60~80%; (4) Solution treatment of alloy: The solution temperature is 780~800℃, the total holding time is 0~24h, and then water quenching is performed; (5) Cold rolling deformation of alloys: cold rolling deformation amount 80~95%; (6) Aging process of alloy: aging temperature is 400~500℃, and holding time is 0~24h.

2. The method for preparing rare earth alloyed high-performance copper-nickel-silicon alloy material according to claim 1, characterized in that, In step (1), the protective atmosphere is nitrogen or argon.

3. The method for preparing rare earth alloyed high-performance copper-nickel-silicon alloy material according to claim 1, characterized in that, The forging ratio in step (2) is 1.5~2.

5.

4. The method for preparing rare earth alloyed high-performance copper-nickel-silicon alloy material according to claim 1, characterized in that, In step (3), the deformation amount of each rolling pass shall not exceed 10%.

5. The method for preparing rare earth alloyed high-performance copper-nickel-silicon alloy material according to claim 1, characterized in that, In step (4), the solution treatment temperature is 790~800℃, and the temperature error does not exceed ±5°.

6. The method for preparing rare earth alloyed high-performance copper-nickel-silicon alloy material according to claim 1, characterized in that, In step (5), the deformation of each rolling pass is no more than 20% compared to the previous pass.

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