High-strength and high-plasticity titanium bronze alloy and preparation method thereof

Abstract

The invention provides a high-strength and high-plasticity titanium bronze alloy and a preparation method thereof, and relates to the technical field of alloys. The preparation method comprises the following steps: smelting and casting prepared raw materials in sequence to obtain a cast ingot; and the cast ingot is sequentially subjected to hot rolling, solution treatment, electric pulse treatment and aging treatment, and the high-strength and high-plasticity titanium bronze alloy is obtained. Cr is added into the titanium bronze alloy, Cr and Ti form a TiCr phase, the strength and conductivity of the alloy are improved, the nucleation of a metastable state strengthening phase is effectively promoted by adopting an electric pulse induced precipitation and aging treatment method, so that the strengthening phase density of the titanium bronze alloy in the aging process is improved, the size distribution of the metastable state strengthening phase is improved, and the strength and conductivity of the titanium bronze alloy are improved. And the formation of a discontinuous precipitated phase is inhibited. The comprehensive performance of the titanium bronze alloy can be greatly improved, the obtained titanium bronze alloy has high strength and high plasticity, and the tensile strength and the elongation can reach 782-889 MPa and 17-35%.

Description

Technical Field

[0001] The invention relates to the technical field of alloys, and in particular to a high-strength and high-plasticity titanium bronze alloy and a preparation method thereof. Background Art

[0002] Titanium bronze alloys are widely used in electronic elastic components, connectors, and frame materials due to their excellent mechanical properties, electrical conductivity, and stress relaxation resistance. Among the currently used ultra-high-strength copper alloys, titanium bronze is expected to replace environmentally harmful beryllium bronze alloys and become a key material in the field of the next generation of ultra-high-strength conductive copper alloys. Among them, the dispersion precipitation of nanoscale β'-Cu4Ti phases during the aging process provides the alloy with an excellent precipitation strengthening effect. As a typical precipitation-type copper alloy, titanium bronze is the key to further improving the strength and plasticity of the alloy by controlling the size and distribution of the nanoscale strengthening phase and increasing the nucleation density of the precipitated phase. However, the diffusion rate of the Ti element during the aging process is slow, and it is difficult to effectively control the precipitation behavior of the Ti element with traditional aging treatment. The early nucleation of the β'-Cu4Ti phase comes from the Ti-rich and Ti-poor regions formed by the diffusion of Ti atoms, which provides a compositional basis for the aggregation and precipitation of the β'-Cu4Ti phase. The increase in aging temperature accelerates the precipitation of supersaturated Ti atoms, but also promotes the discontinuous precipitation transformation of the metastable β'-Cu4Ti phase to the stable β-Cu4Ti phase, which has an extremely adverse effect on the strength and plasticity of titanium bronze alloys. The introduction of cold deformation can effectively improve the mechanical properties of the alloy and accelerate the nucleation of the β'-Cu4Ti phase, but it will inevitably reduce the plasticity of the alloy. Therefore, under the traditional production method, it is often difficult to achieve a synchronous improvement in the strength and plasticity of titanium bronze alloys.

[0003] With the unprecedented development of electronic information technology and new energy fields, improving the plasticity of alloys while increasing strength is the key to developing a new generation of high-performance elastic component materials. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a high-strength and high-plasticity titanium bronze alloy and a preparation method thereof. The titanium bronze alloy prepared by the present invention has both high strength and high 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 a method for preparing a high-strength and high-plasticity titanium bronze alloy, comprising the following steps:

[0007] According to the composition and ingredients of the high-strength and high-plasticity titanium bronze alloy; the high-strength and high-plasticity titanium bronze alloy includes the following elements in percentage by mass: Ti 1.5-5.0%, Cr 0.3-0.65%, and the balance Cu;

[0008] The prepared raw materials are melted and casted in sequence to obtain an ingot;

[0009] The ingot is sequentially subjected to hot rolling, solution treatment, electric pulse treatment and aging treatment to obtain a high-strength and high-plasticity titanium bronze alloy.

[0010] Preferably, the high-strength and high-plasticity titanium bronze alloy comprises the following elements in percentage by mass: Ti 2.5-4%, Cr 0.5-0.65%, and the balance Cu.

[0011] Preferably, the smelting temperature is 1150-1250°C.

[0012] Preferably, after the smelting, the obtained melt is kept at a temperature of 1200-1250° C. for 20 minutes and then cast.

[0013] Preferably, the initial temperature of the hot rolling is 820-880° C., the final temperature is greater than 750° C., and the deformation amount is 50-90%.

[0014] Preferably, the temperature of the solution treatment is 800-860° C., and the holding time is 60-120 min.

[0015] Preferably, the electric pulse frequency applied in the electric pulse treatment is 100-300 Hz, and the current density is 60-180 A / mm 2 The processing time is 30 to 120 seconds.

[0016] Preferably, the temperature of the alloy during the electric pulse treatment is 100-600°C.

[0017] Preferably, the aging treatment temperature is 450-500° C., and the holding time is 1-48 hours.

[0018] The present invention provides a high-strength and high-plasticity titanium bronze alloy prepared by the preparation method described in the above technical solution, wherein the average grain size of the high-strength and high-plasticity titanium bronze alloy is 20 to 100 μm, and the alloy has a submicron primary Cr phase and a Cr2Ti phase, and the size of the submicron primary Cr phase and the Cr2Ti phase is less than 1 μm.

[0019] The invention provides a preparation method of a high-strength and high-plasticity titanium bronze alloy, comprising the following steps: preparing ingredients according to the composition of the high-strength and high-plasticity titanium bronze alloy; the high-strength and high-plasticity titanium bronze alloy comprises the following elements in percentage by mass: 1.5-5.0% Ti, 0.3-0.65% Cr, and the remainder Cu; smelting and casting the prepared raw materials in sequence to obtain an ingot; and hot rolling, solution treatment, electric pulse treatment and aging treatment are performed on the ingot in sequence to obtain the high-strength and high-plasticity titanium bronze alloy. The present invention adds Cr to the titanium bronze alloy, Cr and Ti form a TiCr phase, which forms a pinning effect on the movement of dislocations and the migration of grain boundaries, and simultaneously improves the strength and electrical conductivity of the alloy; the present invention adopts a copper-titanium alloy modification method of "electric pulse pretreatment and aging treatment", and uses electric pulse treatment as a pretreatment method before aging of titanium bronze, which effectively promotes the nucleation of the metastable strengthening phase, thereby increasing the nucleation density of the β'-Cu4Ti metastable strengthening phase in the titanium bronze alloy, and uses aging treatment to fully precipitate Ti atoms, thereby improving the size and distribution of the nano-scale strengthening phase in the titanium bronze alloy, inhibiting the formation of discontinuous precipitation phases, and realizing efficient preparation of high-strength and high-toughness titanium bronze alloys. The present invention effectively alleviates the problems of low metastable strengthening phase nucleation rate, structural thermal sensitivity, slow precipitation rate, etc. faced by titanium bronze in traditional aging treatment, and the strength and plasticity are significantly improved without relying on severe plastic deformation, which can effectively meet the actual application requirements of materials in complex structural parts and high-temperature service environments.

[0020] The results of the embodiments show that the titanium bronze alloy prepared by the present invention has both high strength and high plasticity, and the tensile strength and elongation can reach 782-889 MPa and 17-35%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the HAADF-STEM image of the β'-Cu4Ti phase after 1.9V electric pulse treatment and aging treatment in Example 5;

[0022] Figure 2 This is the HAADF-STEM image of the β'-Cu4Ti phase in the titanium bronze alloy after direct aging treatment in Comparative Example 6. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a high-strength and high-plasticity titanium bronze alloy, comprising the following steps:

[0024] According to the composition and ingredients of the high-strength and high-plasticity titanium bronze alloy; the high-strength and high-plasticity titanium bronze alloy includes the following elements in percentage by mass: Ti 1.5-5.0%, Cr 0.3-0.65%, and the balance Cu;

[0025] The prepared raw materials are melted and casted in sequence to obtain an ingot;

[0026] The ingot is sequentially subjected to hot rolling, solution treatment, electric pulse treatment and aging treatment to obtain a high-strength and high-plasticity titanium bronze alloy.

[0027] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

[0028] The present invention is based on the composition of high-strength and high-plasticity titanium bronze alloy. In the present invention, the high-strength and high-plasticity titanium bronze alloy includes the following elements in percentage by mass: Ti 1.5-5.0%, Cr 0.3-0.65%, and the balance Cu; the mass percentage of Ti in the high-strength and high-plasticity titanium bronze alloy is preferably 2.5-4%, more preferably 3-3.5%, and the mass percentage of Cr is preferably 0.5-0.65%, more preferably 0.6-0.65%. The present invention adds Cr to the titanium bronze alloy, Cr and Ti form a TiCr phase, which forms a pinning effect on the movement of dislocations and the migration of grain boundaries, and simultaneously improves the strength and electrical conductivity of the alloy. In an embodiment of the present invention, the raw materials used in the ingredients are pure copper, pure titanium and Cu-20Cr master alloy.

[0029] After batching, the present invention sequentially melts and casts the prepared raw materials to obtain an ingot. In the present invention, the smelting temperature is preferably 1150-1250°C; after the smelting, the present invention preferably keeps the obtained melt at 1200-1250°C for 20 minutes before casting. In the present invention, the smelting and heat preservation are preferably carried out in a vacuum high-frequency induction melting furnace, that is, the present invention adopts vacuum casting. After the casting, it is preferably cooled to room temperature to obtain an ingot.

[0030] After obtaining the ingot, the present invention sequentially performs hot rolling, solution treatment, electric pulse treatment and aging treatment on the ingot to obtain a high-strength and high-plasticity titanium bronze alloy.

[0031] In the present invention, the initial temperature of the hot rolling is preferably 820-880°C, more preferably 850-860°C, the final temperature is preferably greater than 750°C, and the deformation is preferably 50-90%, more preferably 75-85%. The present invention preferably places the ingot in a box-type resistance furnace, heats the ingot to 820-880°C, keeps the ingot warm for 60-120 minutes (preferably 60-100 minutes), and then takes it out for hot rolling. After the hot rolling, the present invention preferably air cools the obtained alloy to room temperature.

[0032] In the present invention, the temperature of the solution treatment is preferably 800-860°C, more preferably 820-850°C, and the holding time is preferably 60-120 min, more preferably 60-100 min. In the present invention, the solution treatment is preferably carried out in a box-type resistance furnace, and after the solution treatment is completed, the obtained alloy is taken out and quickly water-cooled.

[0033] In the present invention, the electric pulse treatment is to apply a pulse current to the titanium bronze alloy in the solid solution state after the solution treatment; the electric pulse frequency applied in the electric pulse treatment is preferably 100 to 300 Hz, more preferably 200 to 250 Hz, and the current density is preferably 60 to 180 A / mm 2 (voltage 1 to 2.4 V), more preferably 100 to 150 A / mm 2 , more preferably 125 to 145 A / mm 2 , the treatment time is preferably 30 to 120 seconds, more preferably 60 to 90 seconds. The present invention performs electric pulse induced pre-nucleation treatment on the titanium bronze alloy after solid solution, and uses the thermal effect and electron wind effect generated when the pulse current is applied to the metal material to control the aging precipitation behavior of the alloy. Among them, the thermal effect comes from the spontaneous heat generation of the metal material under the external electric field, which is equivalent to a short-term heat treatment in actual production; and the electron wind effect comes from the interaction between high-speed electrons and atoms in the material, which can effectively improve the migration ability and diffusion rate of atoms. In the present invention, the energy required for the nucleation of the metastable β'-Cu4Ti phase can be effectively reduced by pulse current pretreatment, thereby increasing the nucleation density of the β'-Cu4Ti phase. Therefore, the titanium bronze alloy after pulse current pretreatment has a higher precipitation phase density and better size control, and the discontinuous precipitation transformation is also significantly suppressed in the subsequent long-term aging and heat preservation process. This makes the titanium bronze alloy after electric pulse pretreatment significantly higher in tensile strength and elongation than the traditional aging titanium bronze alloy.

[0034] In the present invention, the temperature of the alloy during the electric pulse treatment is preferably 100 to 600°C (temperature rise is generated by the electric field thermal effect). At this temperature, Ti atoms tend to precipitate in the form of a metastable β'-Cu4Ti phase. However, under the action of traditional heat treatment, the Ti atoms of titanium bronze have a slower precipitation rate, which indicates that relying solely on the thermal effect is far from enough to complete the nucleation and precipitation of the β'-Cu4Ti phase within 120s. However, under the action of the electron wind effect, the nucleation energy of the β'-Cu4Ti phase is significantly reduced, and the diffusion rate of Ti atoms is accelerated. Therefore, the nucleation efficiency of the β'-Cu4Ti phase during the electric pulse treatment is much greater than that of the traditional aging treatment under the same time. At the same time, the temperature rise generated by the thermal effect during the electric pulse treatment should not be too high. If the actual heat generation exceeds 650°C, the titanium bronze alloy is prone to form a stable β-Cu4Ti phase that is unfavorable to strength and plasticity, resulting in a significant reduction in alloy performance.

[0035] In the present invention, the temperature of the aging treatment is preferably 450-500°C, and can be 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, and the holding time is preferably 1-48h, and can be 1h, 2h, 4h, 8h, 12h or 24h. In the present invention, the aging treatment is preferably carried out in a box-type resistance furnace, and after the aging treatment is completed, it is taken out and air-cooled. As Ti atoms are fully precipitated, the β'-Cu4Ti phase grows further during the aging process, and its size is 4-10nm along the length direction and 2-6nm along the width direction. After the aging treatment, no discontinuous precipitation phase harmful to strong plasticity is formed in the matrix.

[0036] The present invention cooperates with the electric pulse treatment and the aging treatment, which is helpful to promote the nucleation of the strengthening phase and improve the aging precipitation behavior of the alloy, and has the following beneficial effects:

[0037] (1) It can effectively improve the aging precipitation behavior of titanium bronze, refine the size of the β'-Cu4Ti phase, and promote the uniform distribution of the strengthening phase: the electric pulse can effectively increase the nucleation sites of the β'-Cu4Ti phase and increase the density of the strengthening phase after aging treatment, thereby simultaneously improving the strength and plasticity of titanium bronze after aging. The tensile strength and elongation of the titanium bronze alloy prepared by this method are about 14% and 58% higher than those of the traditional solid solution-aged titanium bronze alloy;

[0038] (2) It can effectively delay the over-aging softening of titanium bronze: the coarsening of the β'-Cu4Ti phase and the formation of discontinuous precipitation phase in the late aging period are not conducive to the performance improvement of titanium bronze alloy. The β'-Cu4Ti phase in the present invention shows excellent size control after electric pulse pretreatment, and the discontinuous precipitation transformation is significantly inhibited, which also enables the comprehensive performance of titanium bronze alloy to be further exerted in the late aging period;

[0039] (3) No additional plastic deformation is required, and the size and structure of the material itself are not changed. It is green and efficient: electric pulse and aging treatment do not require additional plastic deformation, which can effectively avoid the residual stress, plasticity and residual stress reduction caused by lattice distortion. The high-strength and high-toughness titanium bronze material obtained by this method is widely used in plates, strips, bars and wires, and complex structural parts. It improves the strength and plasticity of the alloy without destroying the external size and structure of the material.

[0040] (4) It can significantly shorten the peak aging time of titanium bronze, improve the production efficiency of titanium bronze alloy, and broaden the heat treatment process range; at the same time, the equipment of this method is simple, easy to carry out continuous production and online control, and does not require the introduction of additional production processes, which can effectively shorten the production cycle of titanium bronze.

[0041] In view of the problem that the strength and plasticity of titanium bronze alloys are difficult to control simultaneously during traditional heat treatment, the present invention has developed an efficient and low-cost titanium bronze preparation method to achieve the regulation of the alloy's microstructure and comprehensive properties, and prepare a titanium bronze alloy with both high strength and high plasticity (i.e., high strength and high toughness) to meet the application needs of advanced electronics, elastic components and complex structural parts.

[0042] The present invention provides a high-strength and high-plasticity titanium bronze alloy prepared by the preparation method described in the above technical solution, wherein the average grain size of the high-strength and high-plasticity titanium bronze alloy is 20 to 100 μm, and the alloy has a submicron primary Cr phase and a Cr2Ti phase, and the size of the submicron primary Cr phase and the Cr2Ti phase is less than 1 μm.

[0043] In order to further illustrate the present invention, the high-strength and high-plasticity titanium bronze alloy and the preparation method thereof provided by the present invention are described in detail below in conjunction with examples, but they should not be construed as limiting the protection scope of the present invention.

[0044] Example 1

[0045] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy (that is, the element composition of the titanium bronze alloy is Ti 3.1wt.%, Cr0.6wt.% and the balance Cu).

[0046] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0047] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0048] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0049] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0050] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 1 h, and then air-cooled.

[0051] Example 2

[0052] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0053] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0054] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0055] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0056] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0057] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 2 h, and then air-cooled.

[0058] Example 3

[0059] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0060] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0061] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0062] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0063] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0064] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450°C for 4 hours, and then air-cooled after being taken out.

[0065] Example 4

[0066] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0067] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0068] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0069] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0070] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0071] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450°C for 8 hours, and then air-cooled after being taken out.

[0072] Example 5

[0073] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0074] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0075] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0076] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0077] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0078] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 12 h, and then air-cooled.

[0079] Example 6

[0080] In this embodiment, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0081] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0082] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0083] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0084] (4) Electric pulse: A pulse current is applied to the solid solution titanium bronze alloy in (3). The electric pulse frequency is 200 Hz, the voltage is 1.9 V, and the actual current density is 144.25 A / mm 2 , the sample temperature was 400 °C, and the electric pulse was applied for 90 s;

[0085] (5) Aging: The titanium bronze alloy pretreated by electric pulse in step (4) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 24 h, and then air-cooled.

[0086] Comparative Example 1

[0087] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0088] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0089] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0090] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat to 850°C, and keep at this temperature for 60 min. After taking out, quickly cool with water.

[0091] Comparative Example 2

[0092] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0093] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0094] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0095] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0096] (4) Aging: The titanium bronze alloy after solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 1 h, and then air-cooled after being taken out.

[0097] Comparative Example 3

[0098] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0099] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0100] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0101] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0102] (4) Aging: The titanium bronze alloy after solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for a holding time of 2 h, and then air-cooled after being taken out.

[0103] Comparative Example 4

[0104] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0105] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0106] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0107] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0108] (4) Aging: The titanium bronze alloy after solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 4 h, and then air-cooled after being taken out.

[0109] Comparative Example 5

[0110] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0111] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0112] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0113] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0114] (4) Aging: The titanium bronze alloy after the solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 8 h, and then air-cooled after being taken out.

[0115] Comparative Example 6

[0116] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0117] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0118] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0119] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0120] (4) Aging: The titanium bronze alloy after the solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 12 h, and then air-cooled after being taken out.

[0121] Comparative Example 7

[0122] In this comparative example, pure copper, pure titanium and Cu-20Cr master alloy are used as raw materials, and the actual composition of the prepared alloy is Cu-3.1Ti-0.6Cr (wt.%) alloy.

[0123] (1) Vacuum casting: According to the composition of titanium bronze alloy, the raw material is heated to 1150°C in a high-frequency vacuum induction melting furnace. After the melt is completely melted, it is evenly stirred. The casting temperature is controlled at 1200°C. After keeping the temperature for 20 minutes, casting is performed and cooled to room temperature to obtain an ingot.

[0124] (2) Hot rolling: the ingot in (1) is placed in a box-type resistance furnace, heated to 850°C, and kept at this temperature for 60 min. After being taken out, it is quickly hot rolled, with the thickness being deformed from 20 mm to 5 mm, and the total deformation being 75%. The final rolling temperature is greater than 750°C, and after hot rolling, it is air-cooled to room temperature.

[0125] (3) Solution treatment: Place the hot-rolled titanium bronze alloy prepared in (2) into a box-type resistance furnace, heat it to 850°C, and keep it at this temperature for 60 min. After taking it out, quickly cool it with water.

[0126] (4) Aging: The titanium bronze alloy after the solid solution in step (3) is further subjected to aging treatment in a box-type resistance furnace at an aging temperature of 450° C. for 24 h, and then air-cooled after being taken out.

[0127] Table 1 Properties of titanium bronze alloys obtained in Examples and Comparative Examples

[0128]

[0129] It can be seen from the data in Table 1 that during the aging and heat preservation process at 450°C, the titanium bronze alloy after electric pulse pretreatment always maintains more excellent mechanical properties. The tensile strength and elongation of the alloys in Examples 1 to 6 are significantly improved compared with the direct aging alloys under the same heat treatment process in Comparative Examples 2 to 7.

[0130] Figure 1 This is the HAADF-STEM image of the β'-Cu4Ti phase after 1.9V electric pulse treatment and aging treatment in Example 5. Figure 2 This is the HAADF-STEM image of the β'-Cu4Ti phase in the titanium bronze alloy after direct aging treatment in Comparative Example 6. Figure 1 From the TEM microstructure in Figure 1, it can be seen that the Cu-Ti-Cr alloy after electric pulse pretreatment has a more finely dispersed continuous precipitate phase during the aging treatment, among which the size of the β'-Cu4Ti phase is significantly smaller than that of the Figure 2 The dimensions of the direct aging treatment.

[0131] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a high-strength and high-plasticity titanium bronze alloy, characterized in that: The following steps are involved: According to the composition and ingredients of the high-strength and high-plasticity titanium bronze alloy; the high-strength and high-plasticity titanium bronze alloy includes the following elements in percentage by mass: Ti 1.5-5.0%, Cr 0.3-0.65%, and the balance Cu; The prepared raw materials are melted and casted in sequence to obtain an ingot; The ingot is sequentially subjected to hot rolling, solution treatment, electric pulse treatment and aging treatment to obtain a high-strength and high-plasticity titanium bronze alloy.

2. The preparation method according to claim 1, characterized in that: The high-strength and high-plasticity titanium bronze alloy comprises the following elements in percentage by mass: Ti 2.5-4%, Cr 0.5-0.65%, and the balance Cu.

3. The preparation method according to claim 1 or 2, characterized in that: The smelting temperature is 1150-1250°C.

4. The preparation method according to claim 3, characterized in that: After the smelting, the obtained melt is kept at a temperature of 1200-1250° C. for 20 minutes and then cast.

5. The preparation method according to claim 1, characterized in that: The initial temperature of the hot rolling is 820-880° C., the final temperature is greater than 750° C., and the deformation amount is 50-90%.

6. The preparation method according to claim 1, characterized in that: The temperature of the solution treatment is 800-860° C., and the holding time is 60-120 minutes.

7. The preparation method according to claim 1, characterized in that: The electric pulse frequency applied in the electric pulse treatment is 100-300 Hz, and the current density is 60-180 A / mm 2 The processing time is 30 to 120 seconds.

8. The preparation method according to claim 7, characterized in that: The temperature of the alloy during the electric pulse treatment is 100-600°C.

9. The preparation method according to claim 1, characterized in that: The temperature of the aging treatment is 450-500° C., and the insulation time is 1-48 hours.

10. The high-strength and high-plasticity titanium bronze alloy prepared by the preparation method according to any one of claims 1 to 9, wherein the average grain size of the high-strength and high-plasticity titanium bronze alloy is 20 to 100 μm, and the alloy has submicron primary Cr phase and Cr2Ti phase, and the size of the submicron primary Cr phase and Cr2Ti phase is less than 1 μm.

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