A micro-nano dual-scale particle reinforced nickel-silicon brass and its preparation method

Abstract

The present invention belongs to the technical field of metal materials, and relates to a high-strength and wear-resistant copper alloy, specifically to a micro-nano dual-scale particle-reinforced nickel-silicon brass and a preparation method thereof. The present invention innovatively proposes a method for improving the mechanical properties of nickel-silicon brass by forming micro-nano dual-scale hard-phase particles in the nickel-silicon brass. First, micron-sized NiAl(Si) primary-phase particles are in-situ generated in the nickel-silicon brass by the melt reaction method, and then nano-sized NiAl(Si) precipitation-phase particles are formed in the Cu-Zn solid-solution matrix by combining the isothermal heat treatment and quenching processes. Finally, a microscopic organizational structure in which the micron-sized NiAl(Si) primary-phase particles and the nano-sized NiAl(Si) precipitation-phase particles synergistically reinforce is formed, realizing a significant improvement in the strength, toughness, and wear resistance of the nickel-silicon brass. The micro-nano dual-scale particle-reinforced nickel-silicon brass prepared by the present invention has a relatively high tensile strength (580-670 MPa) and elongation (4.0-5.3%), which is of great significance for the design and development of new high-strength and wear-resistant nickel-silicon brass.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal materials, and relates to a high-strength and wear-resistant copper alloy, specifically to a micro-nano dual-scale particle-reinforced nickel-silicon brass and a preparation method thereof. Background Art

[0002] Nickel-silicon brass refers to a multi-element alloy system formed by adding a small amount of alloying elements such as Ni, Al, Mn, Si, and Fe on the basis of a Cu-Zn alloy. It has a composite structure composed of a Cu-Zn solid solution matrix and hard-phase particles, showing excellent mechanical properties, thermal conductivity, and wear resistance, and has a wide and urgent application demand in the field of high-strength and wear-resistant components such as transmission synchronizer rings, bearing bushes, shaft sleeves, and brake pads. Among them, the matrix, as the main component of nickel-silicon brass, plays a role in dispersing loads and protecting hard-phase particles during service, and transfers loads to the hard phase in the form of shear force. Therefore, the strength and plasticity of the matrix directly affect the mechanical properties of nickel-silicon brass.

[0003] However, the currently prepared nickel-silicon brass has a single Cu-Zn solid solution matrix, which has good plasticity but insufficient strength and toughness. The reason is that a large number of alloying elements in the Cu-Zn solid solution only improve the alloy strength through solid solution strengthening, which is not enough for the service requirements of products. Summary of the Invention

[0004] In view of this, to solve this problem, the present invention discloses a micro-nano dual-scale particle-reinforced nickel-silicon brass and a preparation method thereof. On the basis of in-situ self-generation method for preparing micron-sized NiAl(Si) particle-reinforced nickel-silicon brass, uniform nano-sized NiAl(Si) precipitated phase particles are formed in the Cu-Zn solid solution matrix by combining isothermal heat treatment and quenching process, significantly improving the strength and toughness of the matrix. The present invention finally forms a microscopic organizational structure with synergistic strengthening of micron-sized NiAl(Si) primary phase particles and nano-sized NiAl(Si) precipitated phase particles, realizing a significant improvement in the strength, toughness, and wear resistance of nickel-silicon brass.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first object of the present invention is to provide a preparation method of a micro-nano dual-scale particle-reinforced nickel-silicon brass. First, micron-sized NiAl(Si) primary phase particles are synthesized in nickel-silicon brass by in-situ self-generation method, and then uniform nano-sized NiAl(Si) precipitated phase particles are formed in the Cu-Zn solid solution matrix by combining isothermal heat treatment and quenching process to prepare a high-strength and high-elongation micro-nano dual-scale particle-reinforced nickel-silicon brass; the method specifically includes the following steps:

[0007] 1) Pre-alloying composition of micro-nano dual-scale particle-reinforced nickel-silicon brass: Cu with a content of 53.5 - 58.5 wt.%, Al with a content of 3.5 - 3.8 wt.%, Ni with a content of 5.0 - 8.5 wt.%, Si with a content of 1.5 - 2.5 wt.%, Mn with a content of 0.2 - 0.4 wt.%, Fe with a content of 0.4 - 0.6 wt.%, and the balance being Zn;

[0008] 2) Charge pure Cu, pure Al, pure Zn, pure Ni, pure Fe, Cu-Mn master alloy, and Cu-Si master alloy with the surface oxide scale removed according to the mass percentages in step 1), and place them in a drying oven at a temperature of 60 - 80 °C for drying;

[0009] 3) Under argon protection, heat the pure Cu in step 2) to melting in an intermediate-frequency induction furnace. When the melt temperature reaches 1200 - 1300 °C, sequentially add pure Ni, pure Fe, Cu-Mn master alloy, Cu-Si master alloy, and pure Al;

[0010] 4) Continue heating until the materials added in step 3) are completely melted, then keep the melt temperature at 1200 - 1300 °C and apply electromagnetic stirring for 40 - 50 s to ensure that the alloying elements are evenly diffused in the alloy melt;

[0011] 5) Control the alloy melt temperature at 1080 - 1130 °C by adjusting the heating power. Wrap the pure Zn block in step 2) with Cu foil and press it into the alloy melt in multiple batches to avoid direct contact between the Zn block and the high-temperature melt, which may cause burning loss. During this process, strictly control the melt temperature to avoid excessive temperature causing serious spouting of the melt and significant burning loss of Zn;

[0012] 6) After the pure Zn block is completely added to the alloy melt, apply electromagnetic stirring for 40 - 50 s, and raise the alloy melt temperature to 1140 - 1150 °C twice for spouting degassing;

[0013] 7) Let the melt stand for 10 - 20 s after spouting, and pour the alloy melt into a cylindrical graphite mold preheated to 200 - 250 °C for cooling;

[0014] 8) Place the alloy ingot obtained in step 7) in a muffle furnace at a temperature of 830 - 870 °C for isothermal heat treatment for 0.5 - 1 h. After the isothermal heat treatment, place the ingot in water for rapid cooling to obtain the target nickel-silicon brass.

[0015] It should be noted that the present invention innovatively proposes a method for improving the mechanical properties of nickel-silicon brass by forming micro-nano dual-scale hard phase particles in nickel-silicon brass. First, in-situ self-generation method is used to prepare nickel-silicon brass strengthened by micron-sized NiAl(Si) primary phase, and then spherical NiAl(Si) precipitation phase particles with a size of about dozens of nanometers are formed in the Cu-Zn solid solution matrix by combining isothermal heat treatment and quenching process, significantly improving the strength and toughness of the matrix, and combining with NiAl(Si) primary phase particles to synergistically improve the strength, hardness and wear resistance of nickel-silicon brass. The micro-nano dual-scale particle-reinforced nickel-silicon brass prepared by the present invention has a relatively high tensile strength (580-670 MPa) and elongation (4.0-5.3%), which is of great significance for the design and development of new high-strength and wear-resistant nickel-silicon brass.

[0016] The second object of the present invention is to provide a micro-nano dual-scale particle-reinforced nickel-silicon brass prepared by the method as described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The nickel-silicon brass prepared by the present invention has a microscopic structure with synergistic strengthening of micron-sized NiAl(Si) primary phase particles and nano-sized NiAl(Si) precipitation phase particles. Among them, the micron-sized primary phase provides higher hardness and wear resistance for the alloy, while the nano-sized precipitation phase further improves the strength and toughness of the matrix, realizing the synergistic strengthening of the alloy. Through mechanical property testing, it is found that the micro-nano dual-scale particle-reinforced nickel-silicon brass prepared has relatively high tensile strength and elongation.

[0019] (2) The present invention innovatively designs and obtains a synergistic strengthening microstructure of dual-scale hard phase particles in nickel-silicon brass through isothermal heat treatment combined with quenching process, realizing the effective improvement of the strength and toughness of nickel-silicon brass, which has a significant promoting effect on the development and preparation of new high-strength and wear-resistant nickel-silicon brass. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0021] Figure 1 Microscopic structure pictures of the micro-nano dual-scale particle-reinforced nickel-silicon brass prepared for Example 1: (a) Low-magnification microscopic structure picture, (b) High-magnification microscopic structure picture.

[0022] Figure 2Prepare the stress-strain curve of the micro-nano dual-scale particle reinforced nickel-silicon brass for Example 1.

[0023] Figure 3 Prepare the microstructures of the micro-nano dual-scale particle reinforced nickel-silicon brass for Example 2: (a) low-magnification microstructure picture, (b) high-magnification microstructure picture.

[0024] Figure 4 Prepare the stress-strain curve of the micro-nano dual-scale particle reinforced nickel-silicon brass for Example 2. Detailed implementation manners

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] The special term "embodiment" used here, any embodiment described as "exemplary" does not have to be interpreted as superior to or better than other embodiments. For the performance index tests in the embodiments of this application, unless otherwise specified, the conventional test methods in the art are adopted. It should be understood that the terms described in this application are only used to describe specific embodiments and are not used to limit the content disclosed in this application.

[0027] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which this application belongs; the test methods and technical means not specifically mentioned in this application are all the experimental methods and technical means commonly adopted by those of ordinary skill in the art.

[0028] To better illustrate the content of this application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that this application can still be implemented without some specific details. In the embodiments, some methods, means, instruments, equipment, etc. well-known to those skilled in the art are not described in detail to highlight the gist of this application.

[0029] On the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the obtained technical solutions belong to the content disclosed in the embodiments of this application.

[0030] The present invention discloses a high-strength and high-elongation micro-nano dual-scale particle reinforced nickel-silicon brass and its preparation method.

[0031] To better understand the present invention, the following specific embodiments are used to further elaborate the present invention, but it should not be construed as a limitation of the present invention. For those skilled in the art, some non-essential improvements and adjustments made based on the above-mentioned invention content are also considered to fall within the protection scope of the present invention.

[0032] Example 1

[0033] A preparation method of micro-nano dual-scale particle reinforced nickel-silicon brass, the method comprising the following steps:

[0034] 1) The pre-alloy composition of micro-nano dual-scale particle reinforced nickel-silicon brass: 57.5 wt.% of Cu, 3.5 wt.% of Al, 7.5 wt.% of Ni, 2.1 wt.% of Si, 0.4 wt.% of Mn, 0.5 wt.% of Fe, and the balance is Zn;

[0035] 2) Remove the surface oxide scale of pure Cu, pure Al, pure Zn, pure Ni, pure Fe, Cu-Mn master alloy and Cu-Si master alloy, proportion them according to the mass percentages in step 1), and place them in a drying oven at 80 °C for drying;

[0036] 3) Under argon protection, heat the pure Cu in step 2) to melting in an intermediate frequency induction furnace. When the melt temperature reaches 1290 °C, successively add pure Ni, pure Fe, Cu-Mn master alloy, Cu-Si master alloy and pure Al;

[0037] 4) Continue heating until the materials added in step 3) are completely melted, keep the melt temperature at 1290 °C, apply electromagnetic stirring for 50 s to fully diffuse the solutes in the alloy melt;

[0038] 5) Control the alloy melt temperature at 1100 °C by adjusting the heating power. Wrap the pure Zn block in step 2) with Cu foil and press it into the alloy melt in multiple times. During this period, strictly control the melt temperature to avoid serious sputtering of the melt due to too high temperature, resulting in a large amount of Zn loss;

[0039] 6) After the pure Zn block is completely added to the alloy melt, apply electromagnetic stirring for 40 s, and raise the alloy melt temperature to 1140 °C twice for sputtering degassing;

[0040] 7) Let the melt stand for 20 s after sputtering, and pour the alloy melt into a cylindrical graphite mold preheated to 200 °C for cooling;

[0041] 8) Place the alloy ingot obtained in step 7) in a muffle furnace at 840 °C for isothermal heat treatment for 0.5 h. After the isothermal heat treatment is completed, place the ingot in water for rapid cooling to obtain the target nickel-silicon brass.

[0042] In the nickel-silicon brass prepared according to Example 1, a microscopic organizational structure with synergistic strengthening of micro-nano dual-scale particles was formed, where the size of the micron-sized primary phase particles was 10 - 20 μm, and the size of the nano-sized precipitated phase was 80 - 120 nm; the prepared micro-nano dual-scale particle-reinforced nickel-silicon brass had excellent mechanical properties with a tensile strength of 623 MPa and an elongation of 4.3%, providing a basis for its excellent wear resistance.

[0043] Example 2

[0044] A preparation method of micro-nano dual-scale particle-reinforced nickel-silicon brass, the method comprising the following steps:

[0045] 1) The prefabricated alloy composition of the micro-nano dual-scale particle-reinforced nickel-silicon brass: 59.5 wt.% of Cu, 3.8 wt.% of Al, 4.0 wt.% of Ni, 1.2 wt.% of Si, 0.4 wt.% of Mn, 0.4 wt.% of Fe, and the balance being Zn;

[0046] 2) Charge pure Cu, pure Al, pure Zn, pure Ni, pure Fe, Cu-Mn master alloy, and Cu-Si master alloy with the surface oxide scale removed according to the mass percentages in step 1), and place them in a drying oven at 80 °C for drying;

[0047] 3) Under argon protection, heat the pure Cu in step 2) to melting in an intermediate frequency induction furnace. When the melt temperature reaches 1270 °C, sequentially add pure Ni, pure Fe, Cu-Mn master alloy, Cu-Si master alloy, and pure Al;

[0048] 4) Continue heating until the materials added in step 3) are completely melted, keep the melt temperature at 1270 °C, and apply electromagnetic stirring for 50 s to fully diffuse the solutes in the alloy melt;

[0049] 5) Control the alloy melt temperature at 1090 °C by adjusting the heating power. Wrap the pure Zn block in step 2) with Cu foil and press it into the alloy melt in multiple times, and strictly control the melt temperature during this period to avoid excessive temperature causing serious spouting of the melt and a large amount of Zn burning loss;

[0050] 6) After the pure Zn block is completely added to the alloy melt, apply electromagnetic stirring for 40 s, and raise the alloy melt temperature to 1145 °C twice for spouting degassing;

[0051] 7) After the melt spouts, let it stand for 20 s, and pour the alloy melt into a cylindrical graphite mold preheated to 220 °C for cooling;

[0052] 8) Place the alloy ingot obtained in step 7) in a muffle furnace at 850 °C for isothermal heat treatment for 1.0 h. After the isothermal heat treatment is completed, place the ingot in water for rapid cooling to obtain the target nickel-silicon brass.

[0053] In the nickel-silicon brass prepared according to Example 2, a microscopic structure with micro-nano dual-scale particle synergistic strengthening was formed. Among them, the size of the micron-scale primary phase particles was 7-15 μm, and the size of the nano-scale precipitated phase was 90-150 nm; the prepared micro-nano dual-scale particle-reinforced nickel-silicon brass had excellent mechanical properties with a tensile strength of 592 MPa and an elongation of 5.1%, providing a basis for its excellent wear resistance.

[0054] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing micro-nano dual-scale particle reinforced nickel-silicon brass, characterized in that: Firstly, micron-sized NiAl(Si) primary phase particles are synthesized in nickel-silicon brass by an in-situ autogenous method, and then uniformly distributed nano-sized NiAl(Si) precipitation phase particles are formed in a Cu-Zn solid solution matrix by a method combining isothermal heat treatment with a quenching process, so as to prepare a high-strength and high-elongation micro-nano dual-scale particle reinforced nickel-silicon brass; the method specifically comprises the following steps: 1) The prefabricated alloy composition of the micro-nano dual-scale particle reinforced nickel-silicon brass: 53.5-58.5wt.% Cu, 3.5-3.8wt.% Al, 5.0-8.5wt.% Ni, 1.5-2.5wt.% Si, 0.2-0.4wt.% Mn, 0.4-0.6wt.% Fe, and the balance is Zn; 2) pure Cu, pure Al, pure Zn, pure Ni, pure Fe, Cu-Mn master alloy and Cu-Si master alloy with surface oxide scale removed are prepared according to the mass percentage in step 1), and then dried for standby use; 3) Under argon protection, the pure Cu in step 2) is heated in a medium frequency induction furnace until it is melted, and pure Ni, pure Fe, Cu-Mn master alloy, Cu-Si master alloy and pure Al are added in sequence; heating is continued until the added materials are completely melted, and then the temperature is kept and electromagnetic stirring is applied to allow the solute in the alloy melt to fully diffuse; In the step 3), pure Ni, pure Fe, Cu-Mn master alloy, Cu-Si master alloy and pure Al are added in sequence when the melt temperature is 1200-1300° C.; after the materials are completely melted, they are kept at 1200-1300° C. and electromagnetic stirring is applied for 40-50 seconds to ensure that the alloy elements are evenly diffused in the alloy melt; 4) Wrapping the pure Zn block in step 2) with Cu foil and pressing it into the alloy melt in multiple times, during which the melt temperature must be strictly controlled to avoid excessive temperature causing severe flame spurting of the melt and causing a large amount of Zn burning; 5) After the pure Zn block is completely added to the alloy melt, electromagnetic stirring is applied, and the temperature is increased for flame spraying and degassing; 6) After the melt is sprayed with fire, it is allowed to stand still, and the alloy melt is cast into a preheated mold and cooled to obtain an alloy ingot; 7) subjecting the alloy ingot obtained in step 6) to isothermal heat treatment and then rapidly cooling it in water to obtain the target nickel-silicon brass; In the step 7), the isothermal heat treatment temperature is 830-870° C., and the isothermal heat treatment time is 0.5-1 h.

2. The method for preparing the micro-nano dual-scale particle reinforced nickel-silicon brass according to claim 1, characterized in that: In the step 4), the pure Zn block is wrapped with Cu foil and then pressed into the alloy melt, and the melt temperature is 1080-1130°C.

3. The method for preparing the micro-nano dual-scale particle reinforced nickel-silicon brass according to claim 1, characterized in that: In the step 5), the flame spraying degassing operation is as follows: the temperature of the alloy melt is increased twice to 1140-1150° C., and flame spraying degassing is performed.

4. The method for preparing the micro-nano dual-scale particle reinforced nickel-silicon brass according to claim 1, characterized in that: In the step 6), the standing time is 10 to 20 seconds, and the preheating mold is a cylindrical graphite mold preheated to 200 to 250°C.

5. A micro-nano dual-scale particle reinforced nickel-silicon brass prepared by the method according to any one of claims 1 to 4.

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