Precipitation strengthening type multi-element copper alloy and ultrasonic-assisted preparation method thereof

Abstract

The invention provides a precipitation strengthening type multi-element copper alloy and an ultrasonic-assisted preparation method thereof, and relates to the technical field of metal material processing. The preparation method comprises the following steps: firstly, smelting metal raw materials to obtain an alloy melt; casting the obtained alloy melt in an ultrasonic field, and cooling to obtain an as-cast alloy; then the obtained as-cast alloy is subjected to solution treatment, and a solid solution alloy is obtained; and finally, the obtained solid solution alloy is subjected to aging treatment, and the precipitation strengthening type multi-element copper alloy is obtained. According to the precipitation strengthening type multi-element copper alloy prepared through the preparation method, the strength is greatly improved, and plasticity is synergistically optimized.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material processing, and in particular relates to a precipitation-strengthened multi-component copper alloy and an ultrasonic-assisted preparation method thereof. Background Art

[0002] Copper alloy is a metal material widely used in industry. It has a series of advantages such as high conductivity and strength, wear resistance and corrosion resistance, excellent ductility and electromagnetic shielding ability, and abundant resources. Therefore, it is increasingly widely used in the fields of electronic and electrical industry, communication electronics industry, and aerospace industry. Among them, typical precipitation-strengthened multi-element copper alloys represented by Cu-Ni-Mn, Cu-Ni-Si, Cu-Cr-Zr and other alloys are widely used due to their good corrosion resistance, high strength and high conductivity.

[0003] The prior art generally adopts the "casting-rolling-heat treatment precipitation strengthening" process to prepare precipitation-strengthened multinary copper alloys. Hot rolling is performed after casting, and the coarse dendrites can be refined by inducing dynamic recovery and recrystallization. Although the plasticity can be improved, the strength improvement is limited because the grain size after recrystallization is still large and the dislocation density is low; cold rolling is performed after casting, and the strength of the alloy can be significantly improved by introducing dislocations, but high-density dislocations will cause the material to become brittle and the plasticity of the alloy will be significantly deteriorated. It can be seen that the strength and plasticity of the precipitation-strengthened copper alloys prepared by the prior art are in serious conflict. Therefore, how to simultaneously improve the strength and plasticity of precipitation-strengthened multinary copper alloys has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a precipitation-strengthened multinary copper alloy and an ultrasonic-assisted preparation method thereof. The precipitation-strengthened multinary copper alloy prepared by the preparation method provided by the present invention has greatly improved strength and synergistically optimized plasticity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides an ultrasonic-assisted preparation method of a precipitation-strengthened multi-element copper alloy, comprising the following steps:

[0007] (1) smelting metal raw materials to obtain alloy melt;

[0008] (2) casting the alloy melt obtained in step (1) in an ultrasonic field and then cooling it to obtain a cast alloy;

[0009] (3) subjecting the cast alloy obtained in step (2) to a solid solution treatment to obtain a solid solution alloy;

[0010] (4) subjecting the solid solution alloy obtained in step (3) to aging treatment to obtain a precipitation-strengthened multinary copper alloy.

[0011] Preferably, the precipitation-strengthened multi-element copper alloy is a Cu-Ni-Mn alloy, a Cu-Ni-Si alloy or a Cu-Cr-Zr alloy.

[0012] Preferably, the melting temperature in step (1) is 1200-1500 °C.

[0013] Preferably, the ultrasonic mode in the ultrasonic field in step (2) is continuous ultrasound or pulsed ultrasound, and the ultrasonic dimension is three-dimensional ultrasound.

[0014] Preferably, the sound pressure of the ultrasound in the alloy melt in the ultrasonic field in step (2) is higher than the cavitation threshold of the melt.

[0015] Preferably, the ultrasonic action time t1 and the ultrasonic stop time t2 of each pulse period of the pulsed ultrasound satisfy t1 / t2 > 2, and the ultrasonic action time t1 of each pulse period and the number of pulse periods n satisfy n×t1 > 3 s.

[0016] Preferably, the solution treatment temperature in step (3) is 500-680 °C, and the holding time is 2-9 h.

[0017] Preferably, the aging treatment temperature in step (4) is 400-450 °C.

[0018] Preferably, the aging treatment is ultrasonic aging treatment, and the vibration frequency f and the maximum amplitude A of the alloy during the ultrasonic aging treatment satisfy f×A≥2 cm / s and ρ×(2πf) 2 ×A×L < σ.

[0019] The present invention also provides a precipitation-strengthened multi-element copper alloy prepared by the preparation method described in the above technical solution.

[0020] The present invention provides an ultrasonic-assisted preparation method for a precipitation-strengthened multi-element copper alloy, comprising the following steps: (1) melting metal raw materials to obtain an alloy melt; (2) casting the alloy melt obtained in step (1) in an ultrasonic field and then cooling it to obtain an as-cast alloy; (3) subjecting the as-cast alloy obtained in step (2) to solution treatment to obtain a solution-state alloy; (4) subjecting the solution-state alloy obtained in step (3) to aging treatment to obtain a precipitation-strengthened multi-element copper alloy. In the present invention, the alloy melt is cast and cooled in an ultrasonic field, and a series of non-linear effects such as cavitation and acoustic streaming of the ultrasonic wave in the ultrasonic field are utilized to produce effects such as grain refinement and tissue homogenization; the low-angle grain boundaries generated during ultrasonic solidification can inhibit the nucleation and growth of discontinuous phases during subsequent aging treatment, thereby optimizing the precipitation of the second phase; the increase in the content of the precipitated phase and its uniform and dispersed distribution greatly improve the strength of the alloy, and the plasticity is synergistically optimized. Experimental results show that in the as-cast alloy prepared by the present invention, the α-Cu dendrites undergo an equiaxed transformation, and the grain size is significantly refined; the precipitation-strengthened multi-element copper alloy prepared by ultrasonic solidification combined with ordinary aging for 48 hours has a tensile strength of 1345 MPa and an elongation of 3.6%; the precipitation-strengthened multi-element copper alloy prepared by ultrasonic solidification combined with ultrasonic aging for 12 hours has a tensile strength of 904 MPa and an elongation of 6.7%. Description of the Drawings

[0021] Figure 1 It is a process schematic diagram for preparing a precipitation-strengthened multi-element copper alloy in an embodiment of the present invention;

[0022] Figure 2 It is an electron microscope image of the solidification structure of the as-cast alloy prepared in Comparative Example 1 of the present invention;

[0023] Figure 3 It is an electron microscope image of the solidification structure of the as-cast alloy prepared in Comparative Example 2 of the present invention;

[0024] Figure 4 It is an electron microscope image of the solidification structure of the as-cast alloy prepared in Comparative Example 3 of the present invention;

[0025] Figure 5 It is an electron microscope image of the solidification structure of the as-cast alloy prepared in Example 1 of the present invention;

[0026] Figure 6 It is a tensile property test of the precipitation-strengthened multi-element copper alloys prepared in Comparative Examples 1-3 and Example 1 of the present invention;

[0027] Figure 7 It is a tensile property test of the precipitation-strengthened multi-element copper alloys prepared in Examples 2-3 of the present invention. Detailed Embodiments

[0028] The present invention provides an ultrasonic-assisted preparation method for a precipitation-strengthened multi-element copper alloy, comprising the following steps:

[0029] (1) Melting metal raw materials to obtain an alloy melt;

[0030] (2) Casting the alloy melt obtained in step (1) in an ultrasonic field and then cooling to obtain a as-cast alloy;

[0031] (3) Subjecting the as-cast alloy obtained in step (2) to solution treatment to obtain a solution-treated alloy;

[0032] (4) Subjecting the solution-treated alloy obtained in step (3) to aging treatment to obtain a precipitation-strengthened multi-element copper alloy.

[0033] The ultrasonic-assisted preparation method for a precipitation-strengthened multi-element copper alloy provided by the present invention can be used to improve the strength and plasticity of precipitation-strengthened multi-element copper alloys with all compositions. In the present invention, the precipitation-strengthened multi-element copper alloy is preferably a Cu-Ni-Mn alloy, a Cu-Ni-Si alloy or a Cu-Cr-Zr alloy. As an implementation mode of the present invention, the precipitation-strengthened multi-element copper alloy can be a Cu-Ni-Mn alloy, and the composition of the Cu-Ni-Mn alloy can be 5-40 wt.% of Ni, 5-40 wt.% of Mn and the balance of Cu. The above composition is designed according to the calculated phase diagram for the alloy composition, which can ensure the precipitation of precipitation strengthening phases during the solution aging treatment process.

[0034] The present invention melts metal raw materials to obtain an alloy melt.

[0035] The present invention has no special requirements for the types of the metal raw materials, and the raw materials well-known to those skilled in the art can be selected according to the target composition. The metal raw materials are preferably pure metals or master alloy raw materials. In the embodiments of the present invention, the metal raw materials are copper blocks, nickel particles and electrolytic manganese, and the purities of the copper blocks, nickel particles and electrolytic manganese are preferably 99.9%.

[0036] In the present invention, it is preferred to add the raw materials in batches during the melting. The present invention solves the problem that it is difficult to melt and homogenize high-melting-point alloy elements by adding the raw materials in batches during the melting.

[0037] In the present invention, the temperature of the smelting is preferably 1200 to 1500 °C. As an embodiment of the present invention, the smelting specifically includes: performing a first smelting on copper blocks, adding nickel particles for a second smelting, adding electrolytic manganese for a third smelting, and then performing heat preservation and refining. The temperature of the first smelting is preferably 1200 to 1400 °C, more preferably 1200 °C; the heat preservation time of the first smelting is preferably 5 to 10 min, more preferably 6 min; the temperature of the second smelting is preferably 1450 to 1500 °C, more preferably 1450 °C; the heat preservation time of the second smelting is preferably 2 to 5 min, more preferably 2 min; the temperature of the third smelting is preferably 1300 to 1500 °C, more preferably 1400 °C; the heat preservation time of the third smelting is preferably 2 to 5 min, more preferably 2 min; the temperature of the heat preservation and refining is preferably 1200 to 1400 °C, more preferably 1300 °C; the heat preservation time of the heat preservation and refining is preferably 5 min. By controlling the temperature of the smelting within the above range in the present invention, it can not only ensure complete melting of the raw materials, but also enable the alloy melt to have good fluidity, which is conducive to uniform mixing of each component, and further reduces the smelting time.

[0038] In the present invention, the smelting is preferably carried out in a vacuum, and the vacuum degree is preferably 1e -5 Pa. By reducing the gas pressure on the surface of the melt in the present invention, the gas removal ability is enhanced. By smelting in a vacuum, the gas solubility is reduced and the impurity content is decreased, which can prevent oxidation of the alloy raw materials and reduce casting defects such as shrinkage porosity.

[0039] After obtaining the alloy melt, in the present invention, the alloy melt is cast in an ultrasonic field and then cooled to obtain a cast alloy.

[0040] In the present invention, before casting the alloy melt in an ultrasonic field, the mold is preferably preheated; the preheating temperature is preferably 400 to 700 °C, more preferably 700 °C; the preheating time is preferably 2 to 4 min, more preferably 4 min; the preheating is achieved by putting a heating resistor or a high-frequency coil into the mold. The heating resistor or the high-frequency coil is preferably coaxial and at the same height as the inner wall of the mold, and the high-frequency coil is preferably not in direct contact with the inner wall of the mold.

[0041] In the present invention, the sound pressure of the ultrasonic wave in the ultrasonic field in the alloy melt is preferably higher than the cavitation threshold of the melt; the calculation method of the cavitation threshold of the melt is shown in Equation I:

[0042] P B = P0[1 + [(4S 3 ) / (27(1 + S))] 0.5 (Equation I),

[0043] In the said Equation I, P Brepresents the melt cavitation threshold, S is a dimensionless parameter, S = 2σ L / P0R0, σ L is the surface pressure of the alloy melt, which is 1.3 N / m, P0 is the atmospheric static pressure, with a value of 101325 Pa, and R0 is the initial radius of the bubble in the melt, which is 10 μm. It can be calculated that the cavitation threshold in the CuNiMn alloy melt is 1.9×10 5 Pa.

[0044] As an embodiment of the present invention, the sound pressure of the ultrasound in the alloy melt can be adjusted by controlling the amplitude of the ultrasound; the amplitude A of the ultrasound is preferably 22 μm. In the present invention, the sound pressure of the ultrasound in the alloy melt is adjusted by controlling the amplitude of the ultrasound. The sound pressure in the alloy melt can be detected in real time by a high-temperature sound field detection system. The detection results show that the greater the amplitude, the higher the sound pressure of the ultrasound in the alloy melt, and the easier it is to exceed the cavitation threshold. When the amplitude of the ultrasound reaches 22 μm, it can ensure that the sound pressure of the ultrasound in the alloy melt is higher than the melt cavitation threshold, which can significantly refine the microstructure, improve the mechanical properties, reduce the porosity, and promote the uniform distribution of components.

[0045] In the present invention, the ultrasound in the ultrasound field is preferably continuous ultrasound or pulsed ultrasound. In the present invention, for the pulsed ultrasound, the ultrasound action time t1 and the ultrasound stop time t2 of each pulse cycle satisfy t1 / t2 > 2; the ultrasound action time t1 of each pulse cycle and the number of pulse cycles n satisfy n×t1 > 3 s.

[0046] In the present invention, the ultrasound field is preferably a three-dimensional orthogonal ultrasound field. As an embodiment of the present invention, the three-dimensional ultrasound field can be generated by an ultrasound vibration component and monitored in real time by a high-temperature sound field detection system. The three-dimensional ultrasound field can be regulated by setting the power supply for the amplitude of the transmitting end.

[0047] The present invention has no special requirements for the casting device, and any device well-known to those skilled in the art that can implement the ultrasound field can be used. As an embodiment of the present invention, the casting device may include a mold and an X-axis anti-pusher, a Y-axis anti-pusher, an X-axis ultrasound vibration component, and a Y-axis ultrasound vibration component provided on the side wall of the mold; the mold is a hollow groove structure; the X-axis ultrasound vibration component and the X-axis anti-pusher are oppositely arranged; the Y-axis ultrasound vibration component and the Y-axis anti-pusher are oppositely arranged; the solidification device further includes a Z-axis ultrasound vibration component provided at the bottom of the mold and a pressing plate fixed above the mold by a screw.

[0048] In the present invention, the cooling rate is preferably 1 - 20 K / s.

[0049] After obtaining the as-cast alloy, the present invention performs a solution treatment on the as-cast alloy to obtain a solution-treated alloy.

[0050] In the present invention, the solution treatment temperature is preferably 500 - 680 °C, more preferably 630 °C; the holding time is preferably 2 - 9 h, more preferably 2 h. The above temperature and time can control the grain size and optimize the strength and toughness of the alloy.

[0051] As an embodiment of the present invention, the solution treatment can be carried out in a muffle furnace; during the solution treatment process, the as-cast alloy can be wrapped with copper foil and charcoal can be added for protection.

[0052] In the present invention, the cooling method during the solution treatment is preferably water cooling; in the examples of the present invention, the temperature of the water used for water cooling is below 25 °C, and the cooling rate is 750 °C / s.

[0053] After obtaining the solution-treated alloy, the present invention subjects the solution-treated alloy to aging treatment to obtain a precipitation-strengthened multi-element copper alloy.

[0054] In the present invention, the aging treatment temperature is preferably 400 - 450 °C, more preferably 400 °C. The present invention controls the aging temperature not to be lower than 400 °C to effectively prevent the formation of brittle discontinuous precipitation phases.

[0055] In the present invention, the aging treatment is preferably ordinary aging or ultrasonic aging treatment.

[0056] In one technical solution of the present invention, the aging treatment is ordinary aging; the time of the ordinary aging is preferably 12 - 72 h, more preferably 48 h.

[0057] In one technical solution of the present invention, the aging treatment is ultrasonic aging treatment, and the time of the ultrasonic aging treatment is preferably 12 h. Ultrasonic aging can introduce a periodic stress field and a micro-strain field, increase the nucleation sites, accelerate the solute diffusion, promote the precipitation of θ-MnNi, and can regulate the solidification structure and application properties of the alloy, obtaining a very high strength improvement in a very short aging time.

[0058] In the present invention, when performing the ultrasonic aging treatment, the vibration frequency f of the alloy and the maximum amplitude A satisfy f×A≥2 cm / s and ρ×(2πf) 2 ×A×L < σ, where ρ is the alloy density of 8.6 g / cm 3 , L is the alloy length of 5 cm, and σ is the alloy fatigue strength of about 400 MPa, that is, f 2 ×A < 2.3×10 6 m / s 2 When this condition is met, fatigue fracture of the alloy during the ultrasonic aging process can be avoided, ensuring the mechanical properties of the alloy.

[0059] As an embodiment of the present invention, the ultrasonic aging treatment can regulate the amplitude of the transmitting end through power settings. By synergistically regulating the three variables of ultrasonic amplitude, aging temperature, and aging time, the content and distribution of precipitation strengthening phases are optimized, and finally a high-strength and high-toughness multi-element copper-based alloy material is obtained.

[0060] In the present invention, the cooling method of the aging treatment is preferably natural cooling to room temperature.

[0061] In the present invention, the aging treatment is preferably carried out in an ultrasonic aging device. The present invention has no special limitation on the device for the ultrasonic aging treatment, and any device well-known to those skilled in the art can be used to achieve ultrasonic treatment.

[0062] As an embodiment of the present invention, the preparation process of the precipitation-strengthened multi-element copper alloy is as Figure 1 shown: Configure metal raw materials, heat and hold them for melting to obtain an alloy melt. After preheating the mold, pour the alloy melt, turn on three-dimensional pulsed ultrasound in the ultrasonic field, and obtain a as-cast alloy after solidification. Perform solution treatment on the as-cast alloy, and finally perform ordinary aging or ultrasonic aging treatment.

[0063] The present invention also provides a precipitation-strengthened multi-element copper alloy prepared by the preparation method described in the above technical solution. In the present invention, the strength of the precipitation-strengthened multi-element copper alloy is greatly improved, and the plasticity is synergistically optimized. The elongation can reach 3.6% when the tensile strength is 1345 MPa, and the elongation can reach 6.7% when the tensile strength is 904 MPa.

[0064] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0065] Example 1

[0066] (1) Prepare metal raw materials by mixing copper blocks with a purity of 99.9%, nickel particles, and electrolytic manganese in a mass ratio of 60:20:20; perform the first melting on the copper blocks, hold for melting at 1200 °C for 6 min; add nickel particles for the second melting, hold for melting at 1450 °C for 2 min; add electrolytic manganese for the third melting, hold for melting at 1400 °C for 2 min; lower the melting temperature to 1300 °C, and hold for refining for 5 min. The first melting, second melting, and third melting are carried out in a vacuum environment with a vacuum degree of 1e -5 Pa.

[0067] (2) Before casting the alloy melt in a three-dimensional ultrasonic field, preheat the mold. The preheating temperature is 700 °C and the preheating time is 4 min. After casting the alloy melt obtained in step (1) in the three-dimensional ultrasonic field, cool it to obtain the as-cast alloy. The mold material is graphite, the shape is a cube, the inner side length is 20 mm, the inner height is 50 mm, and the wall thickness is 10 mm.

[0068] The ultrasonic wave in the three-dimensional ultrasonic field is pulsed ultrasonic wave. The amplitude A of the ultrasonic wave is 22 μm, and the sound pressure in the alloy melt is 2.4×10 5 Pa, which is higher than the melt cavitation threshold of 1.9×10 5 Pa. The ultrasonic action time t1 for each pulse cycle is 3 s, and the ultrasonic stop time t2 is 1 s; the ultrasonic action time t1 for each pulse cycle is 3 s, and the number of pulse cycles n is 8 (satisfying t1 / t2 > 2, n×t1 > 3 s).

[0069] (3) Wrap the as-cast alloy with copper foil and perform solution treatment on the as-cast alloy in a muffle furnace to obtain the solution-treated alloy. The solution treatment temperature is 630 °C, and the holding time is 2 h. After solution treatment, place it in water below 25 °C for water cooling, and the cooling rate is 750 °C / s.

[0070] (4) Perform aging treatment on the solution-treated alloy in a muffle furnace. The aging treatment temperature is 400 °C, and the holding time is 48 h. Naturally cool it to room temperature to obtain the Cu-20wt.%Ni-20wt.%Mn precipitation-strengthened multi-element copper alloy.

[0071] Example 2

[0072] The difference between Example 2 and Example 1 lies in that step (4) is different:

[0073] (4) Perform aging treatment on the solution-treated alloy in a muffle furnace. The aging treatment temperature is 400 °C, and the holding time is 12 h. Naturally cool it to room temperature to obtain the precipitation-strengthened multi-element copper alloy.

[0074] Example 3

[0075] The difference between Example 3 and Example 1 lies in that step (4) is different:

[0076] (4) Perform ultrasonic aging treatment on the solution-treated alloy in a muffle furnace. The aging treatment temperature is 400 °C, and the holding time is 12 h. When performing ultrasonic aging treatment, the vibration frequency f of the alloy is 20 kHz, and the maximum amplitude A is 4 μm (satisfying f×A≥2 cm / s, ρ×(2πf) 2 ×A×L < σ).

[0077] Comparative Example 1

[0078] The difference between Comparative Example 1 and Example 1 lies in that step (2) is different:

[0079] Turn off the three-dimensional ultrasonic field in step (2).

[0080] Comparative Example 2

[0081] The difference between Comparative Example 2 and Example 1 lies in that step (2) is different:

[0082] The amplitude A of the ultrasonic vibration component is set to 14 μm, and the sound pressure of the ultrasonic wave in the alloy melt is 4.2×10 4 Pa, which is lower than the melt cavitation threshold of 1.9×10 5 Pa.

[0083] Comparative Example 3

[0084] The difference between Comparative Example 3 and Example 1 lies in that step (2) is different:

[0085] The amplitude A of the ultrasonic vibration component is set to 18 μm, and the sound pressure of the ultrasonic wave in the alloy melt is 1.8×10 5 Pa, slightly lower than the melt cavitation threshold of 1.9×10 5 Pa.

[0086] Observe the as-cast alloys prepared in Comparative Examples 1-3 and Example 1 under an electron microscope

[0087] The electron microscope images of the solidification structures of the as-cast alloys prepared in Comparative Examples 1-3 and Example 1 of the present invention are respectively shown in Figures 2 to 5 .

[0088] Conduct tensile tests on the precipitation-strengthened multi-element copper alloys prepared in Comparative Examples 1-3 and Examples 1-3

[0089] Use an Instron 3382 universal electronic testing machine to conduct tensile tests on the precipitation-strengthened multi-element copper alloys prepared in Comparative Examples 1-3 and Examples 1-3 at room temperature at a strain rate of 5.0×10 -4 s -1 .

[0090] The tensile property test diagrams of the precipitation-strengthened multi-element copper alloys prepared in Comparative Examples 1-3 and Example 1 of the present invention are shown in Figure 6 .

[0091] The tensile property test diagrams of the precipitation-strengthened multi-element copper alloys prepared in Example 2 and Example 3 of the present invention are shown in Figure 7 .

[0092] From Figures 2 to 5It can be seen that in Comparative Example 1 (the three-dimensional ultrasonic field is turned off, A = 0 μm), in the absence of an ultrasonic field, relatively coarse α-Cu dendritic microstructures exist in the Cu-Ni-Mn multi-element alloy. In Comparative Example 2 (A = 14 μm), Comparative Example 3 (A = 18 μm), and Example 1 (A = 22 μm), as the ultrasonic amplitude increases, the grain size of α-Cu dendrites is refined, and the size distribution becomes more uniform. In Example 1, under the action of ultrasonic waves with an amplitude of A = 22 μm, the solidified structure of the Cu-Ni-Mn multi-element alloy presents a fine α-Cu equiaxed crystal structure.

[0093] It can be seen from Figure 6 that the tensile strength of the precipitation-strengthened multi-element copper alloy in Comparative Example 1 is 824 MPa and the elongation is 0.9%. The tensile strength of the precipitation-strengthened multi-element copper alloy in Comparative Example 2 is 903 MPa, and the elongation is 2.3%. The tensile strength of the precipitation-strengthened multi-element copper alloy in Comparative Example 3 is 1034 MPa, and the elongation is 3.7%. The tensile strength of the precipitation-strengthened multi-element copper alloy in Example 1 is 1345 MPa and the elongation is 3.6%. There is no ultrasonic field in Comparative Example 1. After ultrasonic solidification in Example 1, the tensile strength of the Cu-Ni-Mn multi-element alloy is increased from 824 MPa to 1345 MPa, and the elongation is increased from 0.9% to 3.6%. This shows that ultrasonic solidification has greatly improved the mechanical properties of the Cu-Ni-Mn multi-element alloy.

[0094] It can be seen from Figure 7 that the tensile strength of the precipitation-strengthened multi-element copper alloy in Example 2 is 499 MPa and the elongation is 20.6%. The tensile strength of the precipitation-strengthened multi-element copper alloy in Example 3 is 904 MPa and the elongation is 6.7%. Compared with Example 2 with ordinary aging treatment, after ultrasonic aging treatment in Example 3, the tensile strength of the Cu-Ni-Mn multi-element alloy is increased from 499 MPa to 904 MPa, and the elongation is decreased from 20.6% to 6.7%. This shows that ultrasonic aging treatment has greatly improved the strength of the Cu-Ni-Mn multi-element alloy. Although the plasticity has decreased, it still has significant comprehensive mechanical property advantages.

[0095] It can be seen from the above examples and comparative examples that the alloy strength of the precipitation-strengthened multi-element copper alloy provided by the present invention has been greatly improved, and the plasticity has been synergistically optimized. The precipitation-strengthened multi-element copper alloy prepared by ultrasonic solidification combined with ordinary aging for 48 hours has a tensile strength of 1345 MPa and an elongation of 3.6%. The precipitation-strengthened multi-element copper alloy prepared by ultrasonic solidification combined with ultrasonic aging for 12 hours has a tensile strength of 904 MPa and an elongation of 6.7%.

[0096] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An ultrasonic-assisted preparation method of a precipitation-strengthened multi-element copper alloy, characterized in that, It includes the following steps: (1) Melting metal raw materials to obtain an alloy melt; (2) Casting the alloy melt obtained in step (1) in an ultrasonic field and then cooling it to obtain an as-cast alloy; (3) Subjecting the as-cast alloy obtained in step (2) to solution treatment to obtain a solution-treated alloy; (4) Subjecting the solution-treated alloy obtained in step (3) to aging treatment to obtain a precipitation-strengthened multi-element copper alloy.

2. The preparation method according to claim 1, characterized in that, The precipitation-strengthened multi-element copper alloy is a Cu-Ni-Mn alloy, a Cu-Ni-Si alloy or a Cu-Cr-Zr alloy.

3. The preparation method according to claim 1 or 2, characterized in that, The melting temperature in step (1) is 1200-1500 °C.

4. The preparation method according to claim 1, wherein, In step (2), the sound pressure of the ultrasonic wave in the ultrasonic field in the alloy melt is higher than the melt cavitation threshold.

5. The preparation method according to claim 1 or 4, characterized in that, In step (2), the ultrasonic wave in the ultrasonic field is continuous ultrasonic wave or pulsed ultrasonic wave.

6. The preparation method according to claim 5, characterized in that, For the pulsed ultrasonic wave, the ultrasonic wave action time t1 of each pulse cycle and the ultrasonic wave stop time t2 satisfy t1 / t2>2, and the ultrasonic wave action time t1 of each pulse cycle and the number of pulse cycles n satisfy n×t1>3s.

7. The preparation method according to claim 1 or 2, characterized in that, In step (3), the solution treatment temperature is 500-680 °C, and the holding time is 2-9 h.

8. The preparation method according to claim 1 or 2, characterized in that In step (4), the aging treatment temperature is 400-450 °C.

9. The preparation method according to claim 8, characterized in that, The aging treatment is ultrasonic aging treatment. When performing ultrasonic aging treatment, the vibration frequency f and the maximum amplitude A of the alloy satisfy f×A≥2 cm / s and ρ×(2πf) 2 ×A×L < σ.

10. A precipitation-strengthened multi-element copper alloy prepared by the preparation method according to any one of claims 1-9.

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