Copper alloy and preparation method and application thereof

Abstract

The invention discloses a copper alloy and a preparation method and application thereof, and belongs to the technical field of alloys. The copper alloy comprises the components of Cu, Al, Cr, Zr, Ni, Mg, Ti, Si, rare earth elements, Zn and the like, through the innovative design of Al-Cr-Si oxidation film synergistic protection, Zr-Ti-Mg nanophase strengthening, rare earth grain boundary purification and the like of the copper alloy, the breakthrough improvement of the high-temperature strength, the complex corrosion resistance, the machining performance and the environmental protection performance is achieved through the combination of the low-burning-loss smelting, rapid solidification and multi-stage heat treatment processes, and the copper alloy can be used for manufacturing the high-temperature-resistant alloy. The copper alloy can be widely applied to the fields of aerospace high-temperature parts, ocean engineering corrosion-resistant structural parts, high-end die-casting dies and the like, and fills the blank of the existing copper alloy technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloys, and particularly relates to a copper alloy, a preparation method thereof, and an application thereof. Background Art

[0002] Due to their excellent electrical conductivity, thermal conductivity, corrosion resistance, and processing performance, copper alloys are widely used in the fields of power electronics, aerospace, marine engineering, high-temperature molds, etc. However, with the complexity of the industrial environment (such as high temperature, high humidity, sulfur / chlorine-containing media, etc.), the limitations of traditional copper alloys have become increasingly prominent, mainly reflected in the following aspects:

[0003] 1. High-temperature oxidation and insufficient strength: Ordinary pure copper and brass (Cu-Zn system) undergo significant oxidation softening above 200 °C, and their high-temperature strength drops sharply, making it difficult to meet the requirements of engine components, die-casting molds, etc. for the high-temperature stability of materials. Although aluminum bronze (Cu-Al system) can raise the anti-oxidation temperature to about 500 °C through the Al 2 O 3 film, a high aluminum content (>10%) leads to deteriorated processing performance and insufficient anti-sulfide corrosion ability.

[0004] 2. Limitations in corrosion resistance: Existing corrosion-resistant copper alloys (such as cupronickel Cu-Ni system, beryllium copper Cu-Be system) have obvious defects in specific environments; for example, cupronickel is prone to sulfide corrosion in sulfur-containing media, while beryllium copper, although having high strength and high conductivity, has a highly toxic beryllium element, and the processing and waste treatment costs are high; in addition, brass is prone to dezincification corrosion in seawater environments, and aluminum bronze has insufficient corrosion resistance in acidic media, all of which limit their application ranges.

[0005] 3. Insufficient multi-component synergistic effect: In recent years, research on improving the performance of copper alloys by adding elements such as Cr, Ni, Si, etc. has gradually increased, but the selection and ratio of elements lack systematic optimization. For example, a prior art discloses a Cu-Cr-Zr alloy, which has a certain high-temperature strength, but does not introduce oxidation film-forming elements such as Al and Si, resulting in an insufficient upper limit of the anti-oxidation temperature; a prior art also discloses a Cu-Ni-Si-Mg alloy, which improves the corrosion resistance, but does not consider the role of rare earth elements in purifying grain boundaries, and has a low high-temperature creep resistance. In addition, the element addition in the prior art is mostly limited to 3-4 kinds, making it difficult to simultaneously improve the high-temperature strength, corrosion resistance, and processing performance.

[0006] 4. Defects in preparation processes: During the melting process of traditional copper alloys, highly active elements (such as Mg, Zr) are easily oxidized and burned out, resulting in composition deviation and performance fluctuations. For example, CN110616361A prepares a Zr-containing copper alloy by non-vacuum melting. Due to severe oxidation loss of Zr, the actual Zr content is difficult to accurately control; when the casting cooling rate is insufficient, the problems of grain coarsening and segregation are prominent, affecting the homogeneity of the material.

[0007] In view of the above problems, it is urgent to develop a new type of multi-component copper alloy. By scientifically designing the element composition and ratio, and combining with an efficient preparation process, while maintaining high thermal and electrical conductivity, the bottlenecks of high-temperature strength, corrosion resistance in complex media, and processing performance are broken through to meet the urgent needs of the high-end equipment manufacturing field for high-performance copper alloys. Summary of the Invention

[0008] In view of the above-mentioned prior art, the present invention provides a copper alloy, a preparation method thereof, and an application thereof to solve the technical problem of poor comprehensive performance of existing copper alloys.

[0009] To achieve the above object, the technical solution adopted by the present invention is to provide a copper alloy, which comprises the following components in mass percentage:

[0010] Cu 50-60%, Al 1-3%, Cr 0.5-2%, Zr 0.05-0.2%, Ni 2-5%, Mg 0.1-0.3%, Ti 0.5-2%, Si 0.5-1%, rare earth element 0.02-0.05%, and the balance is zinc.

[0011] On the basis of the above technical solution, the present invention can be further improved as follows.

[0012] Further, the copper alloy comprises the following components in mass percentage:

[0013] Cu 58%, Al 2%, Cr 1.3%, Zr 0.13%, Ni 3%, Mg 0.2%, Ti 1%, Si 0.7%, rare earth element 0.03%, and the balance is zinc.

[0014] Further, the rare earth element is at least one of Y, Sc, Ce, and La.

[0015] The present invention also discloses a preparation method of the above copper alloy, which comprises the following steps:

[0016] S1: Charge electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio, evacuate the vacuum induction melting furnace to ≤10 -2 Pa and then fill it with argon; then heat it up to 1250-1300 °C and melt for 20-30 min to obtain a metal base liquid;

[0017] S2: Cool the metal base liquid to 1150 °C, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, keep warm and stir for 5 min; then heat it up to 1250-1300 °C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain an intermediate alloy liquid;

[0018] S3: Cool the master alloy liquid to 1150 °C, then add pure Mg foil and Cu-Re master alloy according to the element ratio, keep warm and stir for 3 - 5 min, then add Zn grains according to the element ratio, continue to keep warm and stir for 3 min, and then keep warm and stand for 5 min;

[0019] S4: Cool the alloy liquid obtained in S3 to 1000 - 1050 °C, then add a refining agent, keep warm and stir for 3 min, then stand for 10 min, remove the surface melting slag to obtain the casting alloy liquid;

[0020] S5: Adjust the temperature of the casting alloy liquid to 1080 - 1120 °C, then pour it into the mold at a pouring speed of 0.5 - 1 kg / s, and then water-cool it to room temperature to obtain an alloy ingot;

[0021] S6: Heat the alloy ingot to 850 - 900 °C in an inert atmosphere and keep warm for 6 - 12 h; then cool it with the furnace to 500 °C, and then air-cool it to room temperature;

[0022] S7: Heat the ingot after being treated in S6 to 850 - 900 °C and keep warm for 2 h; then carry out hot rolling, the total hot rolling deformation is 60 - 80%, the pass deformation is 10 - 15%, and the final hot rolling temperature is 750 °C; then use the method of upsetting + drawing out for forging, the cumulative forging deformation is ≥70%; then air-cool it to room temperature to obtain a forging;

[0023] S8: Heat the forging to 900 - 950 °C, keep warm for 1 - 2 h and then water-quench; then heat the water-quenched forging to 450 - 550 °C, keep warm for 4 - 8 h, and then air-cool it to room temperature, thus obtaining.

[0024] Furthermore, the cooling rate in S2, S3 and S4 is 10 - 15 °C / min.

[0025] Furthermore, the refining agent is hexachloroethane.

[0026] Furthermore, the addition amount of the refining agent is 0.1% of the mass of the alloy liquid.

[0027] Furthermore, the water-cooling rate in S5 is 50 - 70 °C / s.

[0028] Furthermore, the heating rate in S6, S7 and S8 is 10 - 15 °C / min.

[0029] The present invention also discloses the application of the above copper alloy in manufacturing high-temperature resistant metal parts.

[0030] The beneficial effects of the present invention are:

[0031] 1. The elemental composition of the copper alloy in the present invention is Cu - Al - Cr - Zr - Ni - Mg - Ti - Si - rare earth - Zn. Among them, Al preferentially oxidizes at high temperatures to form α - Al 2 O 3 (dense layer), inhibiting the diffusion of oxygen into the alloy interior; Cr oxidizes to form Cr 2 O 3 , filling the cracks in the Al 2 O 3 film, enhancing the continuity of the oxide film; Si oxidizes to form SiO 2 glass - like layer, covering the surface pores and reducing the risk of oxide film spalling. The combined action of the three oxide films reduces the oxidation rate of the alloy at 500 - 800 °C to ≤0.1 g / (m 2 ·h), which is more than 50% higher than that of traditional aluminum bronze (C95400). Ni in the alloy can inhibit sulfide corrosion (forming Ni 3 S 2 , rather than Cu 2 S), endowing the alloy with excellent sulfide corrosion resistance. Cr can block the penetration of chloride ions, making the alloy have excellent chloride ion corrosion resistance. Moreover, Ni and Cr are dissolved in the alloy matrix, which can increase the binding energy between atoms, thereby delaying high - temperature softening and enhancing the alloy's anti - deformation ability. Zr in the alloy can form nanoscale (20 - 50 nm) Cu 5 Zr with Cu, pinning dislocations. Ti combines with Al to form TiAl 3 precipitation phase (≤30 nm), which can inhibit high - temperature grain - boundary slip, enabling the alloy to have a room - temperature tensile strength of 650 - 800 MPa, a tensile strength of ≥400 MPa at 500 °C, and a high - temperature strength retention rate of ≥60% at 500 °C, being suitable for repeated thermal shock environments (such as die - casting molds). Additionally, Zr can refine grains, effectively reducing thermal stress concentration. Mg in the alloy can inhibit grain - boundary segregation, and rare earth can purify grain boundaries. The combined action of the two can improve the plasticity of the alloy, endowing the alloy with excellent shaping properties at room temperature.

[0032] 2. When preparing the copper alloy in the present invention, a vacuum melting + master alloy pre - melting method is used to prepare the metal base liquid, which can control the burn - out rate of active elements (such as Zr, Mg, etc.) below 3% (the burn - out rate of traditional non - vacuum melting is >10%), ensuring the uniformity of composition. In the present invention, after alloy pouring, a rapid water - cooling method (cooling rate ≥50 °C / s) is used for cooling. Rapid solidification can effectively inhibit dendrite growth. The final obtained alloy has a grain size ≤50 μm and a as - cast porosity ≤0.5%. Moreover, through homogenization annealing + solution treatment + aging treatment, internal segregation of the alloy can be eliminated, and the obtained alloy has a low defect rate, thus having excellent comprehensive properties.

[0033] 3. Through innovative designs such as the synergistic protection of the Al-Cr-Si oxide film, the strengthening of the Zr-Ti-Mg nano-phase, and the purification of the rare earth grain boundaries in the copper alloy of the present invention, combined with the low-loss melting + rapid solidification + multi-stage heat treatment process, a breakthrough improvement in high-temperature strength, complex corrosion resistance, processing performance, and environmental friendliness has been achieved. It can be widely applied to high-temperature components in aerospace, corrosion-resistant structural components in ocean engineering, high-end die-casting molds, etc., filling the gap in the existing copper alloy technology. Detailed Embodiments

[0034] The following will describe in detail the specific embodiments of the present invention in conjunction with the embodiments.

[0035] Embodiment 1

[0036] A copper alloy, which comprises the following components in mass percentage:

[0037] Cu 58%, Al 2%, Cr 1.3%, Zr 0.13%, Ni 3%, Mg 0.2%, Ti 1%, Si 0.7%, Y 0.03%, and the balance is zinc.

[0038] The copper alloy in this embodiment is prepared through the following steps:

[0039] S1: Load electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio. Vacuumize the vacuum induction melting furnace to ≤10 -2 Pa and then fill it with argon; then heat up to 1300°C and melt for 25 minutes to obtain a metal substrate liquid;

[0040] S2: Cool the metal substrate liquid to 1150°C at a cooling rate of 10°C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, and keep it warm and stir for 5 minutes; then heat up to 1300°C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain an intermediate alloy liquid;

[0041] S3: Cool the intermediate alloy liquid to 1150°C at a cooling rate of 10°C / min, then add pure Mg foil and Cu-Y master alloy according to the element ratio, keep it warm and stir for 3 minutes, then add Zn pellets according to the element ratio, continue to keep it warm and stir for 3 minutes, and then keep it warm and stand for 5 minutes;

[0042] S4: Cool the alloy liquid obtained in S3 to 1050°C at a cooling rate of 10°C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), keep it warm and stir for 3 minutes, then stand for 10 minutes, remove the surface melting slag to obtain a casting alloy liquid;

[0043] S5: Adjust the temperature of the molten alloy to 1110 °C, then pour it into the mold at a pouring rate of 0.5 kg / s, and then water-cool it to room temperature at a rate of 60 °C / s to obtain an alloy ingot;

[0044] S6: In a nitrogen atmosphere, heat the alloy ingot from room temperature to 900 °C at a heating rate of 10 °C / min and hold for 10 h; then cool it in the furnace to 500 °C, and then air-cool it to room temperature;

[0045] S7: Heat the ingot after S6 treatment to 900 °C at a heating rate of 10 °C / min and hold for 2 h; then perform hot rolling with a total deformation of 70% and a per-pass deformation of 12%, and the final temperature of hot rolling is 750 °C; then forge it by upsetting + drawing with a cumulative deformation of ≥70%; then air-cool it to room temperature to obtain a forged part;

[0046] S8: Heat the forged part to 920 °C at a heating rate of 10 °C / min, hold for 1.5 h and then water-quench; then heat the water-quenched forged part to 500 °C, hold for 6 h, and then air-cool it to room temperature to obtain the product.

[0047] Example 2

[0048] A copper alloy, the copper alloy comprises the following components in mass percentage:

[0049] Cu 50%, Al 3%, Cr 0.5%, Zr 0.2%, Ni 2%, Mg 0.3%, Ti 0.5%, Si 1%, Ce 0.02%, and the balance is zinc.

[0050] The copper alloy in this example is prepared through the following steps:

[0051] S1: Charge electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio, evacuate the vacuum induction melting furnace to ≤10 -2 Pa and then fill it with argon; then heat it to 1250 °C and melt for 30 min to obtain a metal base liquid;

[0052] S2: Cool the metal base liquid to 1150 °C at a cooling rate of 10 °C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio and hold for stirring for 5 min; then heat it to 1250 °C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain an intermediate alloy liquid;

[0053] S3: Cool the master alloy liquid to 1150°C at a cooling rate of 10°C / min, then add pure Mg foil and Cu-Ce master alloy according to the element ratio, hold and stir for 3 min, then add Zn granules according to the element ratio, continue to hold and stir for 3 min, and then hold and stand for 5 min;

[0054] S4: Cool the alloy liquid obtained in S3 to 1000°C at a cooling rate of 10°C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), hold and stir for 3 min, then stand for 10 min, remove the surface melting slag to obtain the casting alloy liquid;

[0055] S5: Adjust the temperature of the casting alloy liquid to 1080°C, then pour it into the mold at a pouring speed of 0.5 kg / s, and then water-cool it to room temperature at a rate of 50°C / s to obtain an alloy ingot;

[0056] S6: Heat the alloy ingot to 850°C at a heating rate of 10°C / min in a nitrogen atmosphere and hold for 12 h; then cool it in the furnace to 500°C and then air-cool it to room temperature;

[0057] S7: Heat the ingot treated in S6 to 850°C at a heating rate of 10°C / min and hold for 2 h; then perform hot rolling, the total hot rolling deformation is 60%, the pass deformation is 10%, and the final hot rolling temperature is 750°C; then forge it by the method of upsetting + drawing, and the cumulative forging deformation is ≥70%; then air-cool it to room temperature to obtain a forging;

[0058] S8: Heat the forging to 900°C at a heating rate of 10°C / min, quench it after holding for 2 h; then heat the quenched forging to 450°C, hold for 8 h, and then air-cool it to room temperature to obtain the product.

[0059] Example 3

[0060] A copper alloy, the copper alloy comprises the following components in mass percentage:

[0061] Cu 60%, Al 1%, Cr 2%, Zr 0.05%, Ni 5%, Mg 0.1%, Ti 2%, Si 0.5%, Ce 0.03%, La 0.02%, and the balance is zinc.

[0062] The copper alloy in this example is prepared through the following steps:

[0063] S1: Load electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio, evacuate the vacuum induction melting furnace to ≤10 -2 Pa and then fill it with argon; then heat it to 1300°C and melt for 30 min to obtain a metal base liquid;

[0064] S2: Cool the molten metal base liquid to 1150 °C at a cooling rate of 15 °C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, hold and stir for 5 min; then heat up to 1300 °C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain the master alloy liquid.

[0065] S3: Cool the master alloy liquid to 1150 °C at a cooling rate of 15 °C / min, then add pure Mg foil, Cu-Ce master alloy and Cu-La master alloy according to the element ratio, hold and stir for 3 min, then add Zn grains according to the element ratio, continue to hold and stir for 3 min, and then hold and stand for 5 min.

[0066] S4: Cool the alloy liquid obtained in S3 to 1050 °C at a cooling rate of 15 °C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), hold and stir for 3 min, then stand for 10 min, remove the surface melting slag to obtain the casting alloy liquid.

[0067] S5: Adjust the temperature of the casting alloy liquid to 1120 °C, then pour it into the mold at a pouring speed of 1 kg / s, and then water-cool it to room temperature at a rate of 70 °C / s to obtain the alloy ingot.

[0068] S6: Heat the alloy ingot to 900 °C at a heating rate of 15 °C / min in a nitrogen atmosphere and hold for 6 h; then cool it in the furnace to 500 °C and then air-cool it to room temperature.

[0069] S7: Heat the ingot after S6 treatment to 900 °C at a heating rate of 15 °C / min and hold for 2 h; then carry out hot rolling, the total hot rolling deformation is 80%, the pass deformation is 15%, and the final hot rolling temperature is 750 °C; then use the upsetting + drawing method for forging, the cumulative forging deformation is ≥70%; then air-cool it to room temperature to obtain the forging.

[0070] S8: Heat the forging to 950 °C at a heating rate of 15 °C / min, quench it in water after holding for 1 h; then heat the quenched forging to 550 °C, hold for 4 h, and then air-cool it to room temperature to obtain the product.

[0071] Comparative Example 1

[0072] A copper alloy, the copper alloy comprises the following components in mass percentage:

[0073] Cu 59.3%, Al 2%, Zr 0.13%, Ni 3%, Mg 0.2%, Ti 1%, Si 0.7%, Y 0.03%, and the balance is zinc.

[0074] The copper alloy in this comparative example was prepared through the following steps:

[0075] S1: Load electrolytic copper, Cu-Zr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio. Evacuate the vacuum induction melting furnace to ≤10 -2 Pa and then fill it with argon; then heat it up to 1300 °C and melt for 25 min to obtain a metal base liquid;

[0076] S2: Cool the metal base liquid to 1150 °C at a cooling rate of 10 °C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, and keep it warm and stir for 5 min; then heat it up to 1300 °C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain an intermediate alloy liquid;

[0077] S3: Cool the intermediate alloy liquid to 1150 °C at a cooling rate of 10 °C / min, then add pure Mg foil and Cu-Y master alloy according to the element ratio, keep it warm and stir for 3 min, then add Zn grains according to the element ratio, continue to keep it warm and stir for 3 min, and then keep it warm and stand for 5 min;

[0078] S4: Cool the alloy liquid obtained in S3 to 1050 °C at a cooling rate of 10 °C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), keep it warm and stir for 3 min, then stand for 10 min, and remove the surface melting slag to obtain a casting alloy liquid;

[0079] S5: Adjust the temperature of the casting alloy liquid to 1110 °C, then pour it into a mold at a pouring speed of 0.5 kg / s, and then water-cool it to room temperature at a rate of 60 °C / s to obtain an alloy ingot;

[0080] S6: Heat the alloy ingot to 900 °C at a heating rate of 10 °C / min in a nitrogen atmosphere and keep it warm for 10 h; then cool it with the furnace to 500 °C, and then air-cool it to room temperature;

[0081] S7: Heat the ingot after S6 treatment to 900 °C at a heating rate of 10 °C / min and keep it warm for 2 h; then carry out hot rolling, the total hot rolling deformation is 70%, the pass deformation is 12%, and the final hot rolling temperature is 750 °C; then use the upsetting + drawing method for forging, and the cumulative forging deformation is ≥70%; then air-cool it to room temperature to obtain a forging;

[0082] S8: Heat the forging to 920 °C at a heating rate of 10 °C / min, quench it after keeping it warm for 1.5 h; then heat the quenched forging to 500 °C, keep it warm for 6 h, and then air-cool it to room temperature to obtain the product.

[0083] Comparative Example 2

[0084] A copper alloy, the copper alloy comprising the following components by mass percentage:

[0085] Cu 59.13%, Al 2%, Cr 1.3%, Ni 3%, Mg 0.2%, Si 0.7%, Y 0.03%, the balance being zinc.

[0086] The copper alloy in this comparative example was prepared through the following steps:

[0087] S1: Load electrolytic copper, Cu-Cr master alloy, and Cu-Ni master alloy into a vacuum induction melting furnace according to the element ratio, evacuate the vacuum induction melting furnace to ≤ 10 -2 Pa and then fill it with argon; then raise the temperature to 1300 °C and melt for 25 min to obtain a metal base liquid;

[0088] S2: Cool the metal base liquid to 1150 °C at a cooling rate of 10 °C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, keep warm and stir for 5 min to obtain an intermediate alloy liquid;

[0089] S3: Cool the intermediate alloy liquid to 1150 °C at a cooling rate of 10 °C / min, then add pure Mg foil and Cu-Y master alloy according to the element ratio, keep warm and stir for 3 min, then add Zn granules according to the element ratio, continue to keep warm and stir for 3 min, and then keep warm and stand for 5 min;

[0090] S4: Cool the alloy liquid obtained in S3 to 1050 °C at a cooling rate of 10 °C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), keep warm and stir for 3 min, then stand for 10 min, remove the surface melting slag to obtain a casting alloy liquid;

[0091] S5: Adjust the temperature of the casting alloy liquid to 1110 °C, then pour it into a mold at a pouring speed of 0.5 kg / s, and then water-cool it to room temperature at a rate of 60 °C / s to obtain an alloy ingot;

[0092] S6: Heat the alloy ingot in a nitrogen atmosphere to 900 °C at a heating rate of 10 °C / min and keep warm for 10 h; then cool it in the furnace to 500 °C and then air-cool it to room temperature;

[0093] S7: Heat the ingot after being treated in S6 to 900 °C at a heating rate of 10 °C / min and keep warm for 2 h; then perform hot rolling, the total hot rolling deformation is 70%, the pass deformation is 12%, and the final hot rolling temperature is 750 °C; then perform forging in the way of upsetting + drawing, the cumulative forging deformation is ≥ 70%; then air-cool it to room temperature to obtain a forging;

[0094] S8: Heat the forging to 920 °C at a heating rate of 10 °C / min, hold for 1.5 h and then water quench; then heat the water-quenched forging to 500 °C, hold for 6 h, and then air cool to room temperature to obtain the product.

[0095] Comparative Example 3

[0096] A copper alloy, the copper alloy comprises components in the following mass percentages:

[0097] Cu 58%, Al 2%, Cr 1.3%, Zr 0.13%, Ni 3%, Mg 0.2%, Ti 1%, Si 0.7%, Y 0.03%, and the balance is zinc.

[0098] The copper alloy in this comparative example is obtained through the following steps:

[0099] S1: Charge electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy, and Cu-Ni master alloy into a melting furnace according to the element ratio, heat to 1300 °C, and melt for 25 min to obtain a metal base liquid;

[0100] S2: Cool the metal base liquid to 1150 °C at a cooling rate of 10 °C / min, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, hold and stir for 5 min; then heat to 1300 °C, add pure Ti particles according to the element ratio, and stir until completely melted to obtain an intermediate alloy liquid;

[0101] S3: Cool the intermediate alloy liquid to 1150 °C at a cooling rate of 10 °C / min, then add pure Mg foil and Cu-Y master alloy according to the element ratio, hold and stir for 3 min, then add Zn granules according to the element ratio, continue to hold and stir for 3 min, and then hold and stand for 5 min;

[0102] S4: Cool the alloy liquid obtained in S3 to 1050 °C at a cooling rate of 10 °C / min, then add hexachloroethane (the addition amount is 0.1% of the mass of the alloy liquid), hold and stir for 3 min, then stand for 10 min, remove the surface melting slag to obtain a casting alloy liquid;

[0103] S5: Adjust the temperature of the casting alloy liquid to 1110 °C, then pour it into a mold at a pouring speed of 0.5 kg / s, and then air cool to room temperature to obtain an alloy ingot;

[0104] S6: Heat the alloy ingot in a nitrogen atmosphere to 900 °C at a heating rate of 10 °C / min, hold for 10 h; then cool with the furnace to 500 °C, and then air cool to room temperature to obtain the product.

[0105] Experimental Example

[0106] The high-temperature oxidation performance of the copper alloys prepared in the above examples and comparative examples was tested by the method described in GB / T 13303-1991, and the room-temperature tensile strength of the copper alloys was tested by the method described in GB / T 228.1-2021. The results are shown in Table 1.

[0107] Table 1 High-temperature oxidation performance and room-temperature tensile strength of copper alloys

[0108] Highest antioxidant temperature (°C) Room temperature tensile strength (MPa) Example 1 804 793 Example 2 793 764 Example 3 798 772 Comparative Example 1 684 699 Comparative Example 2 607 603 Comparative Example 3 711 704

[0109] Although the specific implementation manners of the present invention have been described in detail in combination with the embodiments, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of this patent.

Claims

1. A copper alloy, characterized in that: The copper alloy includes the following components in percentage by mass: Cu 50~60%, Al 1~3%, Cr 0.5~2%, Zr 0.05~0.2%, Ni 2~5%, Mg 0.1~0.3%, Ti 0.5~2%, Si 0.5~1%, rare earth elements 0.02~0.05%, and the balance is zinc.

2. The copper alloy according to claim 1, characterized in that The copper alloy includes the following components in percentage by mass: Cu 58%, Al 2%, Cr 1.3%, Zr 0.13%, Ni 3%, Mg 0.2%, Ti 1%, Si 0.7%, rare earth elements 0.03%, and the balance is zinc.

3. The copper alloy according to claim 1 or 2, characterized in that: The rare earth element is at least one of Y, Sc, Ce and La.

4. The method for preparing a copper alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Place electrolytic copper, Cu-Cr master alloy, Cu-Zr master alloy and Cu-Ni master alloy into a vacuum induction melting furnace according to the proportion of the elements, and evacuate the vacuum induction melting furnace to ≤10 -2 Pa, argon gas is filled in; then the temperature is raised to 1250-1300°C, and smelted for 20-30 minutes to obtain a metal base liquid; S2: Cool the metal base liquid to 1150°C, then add Cu-Al master alloy and Cu-Si master alloy according to the element ratio, keep warm and stir for 5 minutes; then heat it to 1250-1300°C, add pure Ti particles according to the element ratio, stir until completely melted, and obtain the master alloy liquid; S3: Cool the master alloy liquid to 1150°C, then add pure Mg foil and Cu-Re master alloy according to the proportion of elements, keep warm and stir for 3 to 5 minutes, then add Zn particles according to the proportion of elements, continue to keep warm and stir for 3 minutes, and then keep warm and stand for 5 minutes; S4: lowering the temperature of the alloy liquid obtained in S3 to 1000-1050°C, then adding a refining agent, stirring at the temperature for 3 minutes, and then standing for 10 minutes to remove the surface smelting slag to obtain a pouring alloy liquid; S5: adjusting the temperature of the alloying liquid to 1080-1120° C., then pouring it into a mold at a pouring speed of 0.5-1 kg / s, and then water-cooling it to room temperature to obtain an alloy ingot; S6: heating the alloy ingot to 850-900°C in an inert atmosphere and keeping the temperature for 6-12 hours; then cooling the ingot to 500°C with the furnace and then air cooling it to room temperature; S7: heating the ingot after S6 treatment to 850-900°C and keeping it at this temperature for 2h; Then hot rolling is performed, the total deformation of hot rolling is 60-80%, the deformation of each pass is 10-15%, and the final temperature of hot rolling is 750°C; then forging is performed by upsetting + drawing, and the cumulative deformation of forging is ≥70%; then air cooling is performed to room temperature to obtain a forged piece; S8: Heat the forged piece to 900-950°C, keep it at that temperature for 1-2 hours, and then water quench it; then heat the forged piece after water quenching to 450-550°C, keep it at that temperature for 4-8 hours, and then air-cool it to room temperature.

5. The preparation method according to claim 4, characterized in that: The cooling rates in S2, S3 and S4 are all 10-15°C / min.

6. The preparation method according to claim 4, characterized in that: The refining agent is hexachloroethane.

7. The preparation method according to claim 6, characterized in that: The amount of the refining agent added is 0.1% of the mass of the alloy liquid.

8. The preparation method according to claim 4, characterized in that: The water cooling rate in S5 is 50-70°C / s.

9. The preparation method according to claim 4, characterized in that: The heating rates in S6, S7 and S8 are all 10-15°C / min.

10. Use of the copper alloy according to any one of claims 1 to 3 in manufacturing high temperature resistant metal parts.