Forming method of high-strength and high-toughness zirconium-based amorphous alloy hat-shaped flexible gear blank

Abstract

The invention relates to a forming method of a high-strength and high-toughness zirconium-based amorphous alloy hat-shaped flexible gear blank, which comprises the following steps: quickly heating a zirconium-based amorphous alloy to a supercooled liquid interval to obtain supercooled liquid of the zirconium-based amorphous alloy; the supercooled liquid is subjected to rapid superplastic forming, and a hat-shaped flexible gear blank is obtained; the hat-shaped flexible gear blank is rapidly cooled to the temperature below the glass transition temperature of the zirconium-based amorphous alloy; the blank cooled to the temperature below the glass transition temperature is demolded; and naturally cooling a flexible gear blank obtained after demolding to room temperature. According to the forming method, the high-strength and high-toughness zirconium-based amorphous alloy is selected, the superplasticity of supercooled liquid is utilized, near-net forming of the amorphous alloy flexible gear is achieved, the size and shape of the formed flexible gear are close to the final size of a part, the machining amount is greatly reduced, the defects of a traditional die-casting technology are overcome, and the internal quality of a flexible gear blank is improved; the process and quality problems existing in steel flexible gear production are solved.

Description

Technical Field

[0001] The invention belongs to the field of metal material processing and forming, and relates to a forming method of a high-strength and high-toughness zirconium-based amorphous alloy top-hat-shaped flexible wheel blank. Background Art

[0002] Harmonic reducer is an advanced reduction device, which consists of three parts: rigid wheel, flexwheel and wave generator. Compared with traditional reducers, it has the advantages of compact structure, small size, light weight, large reduction ratio, high transmission efficiency and high transmission accuracy. It is widely used in industrial robots, aerospace, national defense, precision machine tools, medical equipment and other fields. Flexwheel is a key core component of harmonic reducer, and the requirements for materials, processing equipment and processing technology are extremely stringent. At present, the material used to prepare flexwheel is high-strength alloy steel, such as SNCM439 alloy steel, with a density of about 7830kg / m 3 , yield strength 835MPa, fracture toughness about 100MPa·m 1 / 2 , hardness 393HV, elastic limit 0.2%, processed by high-precision CNC machine tools, not only difficult to process, but also long process flow and high processing cost. The more serious problem is that SNCM439 alloy steel is prone to cracks during the forging process of the top hat-shaped flexible wheel blank, which reduces product quality and increases manufacturing costs, becoming a pain point for manufacturing companies. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a forming method for a high-strength and high-toughness zirconium-based amorphous alloy top-hat-shaped flexible wheel blank. The high-strength and high-toughness zirconium-based amorphous alloy selected in the forming method has better mechanical properties than SNCM439 alloy steel, with a tensile yield strength of ≥1600Mpa and a fracture toughness of ≥130Mpa·m 1 / 2 , elastic limit ≥ 2%; using the superplasticity of supercooled liquid, the near-net forming of the amorphous alloy flexible wheel is achieved. The size and shape of the formed flexible wheel are close to the final size of the part, which greatly reduces the processing flow and solves the existing process technology and quality problems of steel flexible wheels.

[0004] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0005] The object of the present invention is to provide a method for forming a high-strength and high-toughness zirconium-based amorphous alloy top-hat-shaped flexible wheel blank, the forming method comprising:

[0006] The zirconium-based amorphous alloy is heated to a supercooled liquid range to obtain a supercooled liquid of the zirconium-based amorphous alloy;

[0007] The supercooled liquid is subjected to superplastic forming to obtain a top-hat-shaped flexible wheel blank;

[0008] The top-hat-shaped flexible wheel blank is rapidly cooled to below the glass transition temperature of the zirconium-based amorphous alloy;

[0009] The blank cooled to below the glass transition temperature is demoulded, and then naturally cooled to room temperature to obtain a top-hat shaped flexible wheel.

[0010] As a preferred technical solution of the present invention, the composition of the zirconium-based amorphous alloy is Zr x Cu a Ni b Al c Ti d Re y , Re is a rare earth element;

[0011] Wherein, a, b, c, d and y are all atomic percentages, and the value ranges of a, b, c, d, x and y are: 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.15, 0≤d≤0.05, 0≤ <y≤0.05;x=1-a-b-c-d-y。

[0012] The value of a can be 0, 0.1, 0.2 or 0.3, etc., the value of b can be 0, 0.1, 0.2 or 0.3, etc., the value of c can be 0, 0.05, 0.10 or 0.15, etc., the value of d can be 0, 0.01, 0.02, 0.03, 0.04 or 0.05, etc., the value of y can be 0.01, 0.02, 0.03, 0.04 or 0.05, etc., but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] As a preferred technical solution of the present invention, the rare earth element includes any one of Ce, La, Y, Dy, Gd or Er, or a combination of two or more thereof.

[0014] As a preferred technical solution of the present invention, the mechanical properties of the zirconium-based amorphous alloy are: yield strength ≥ 1600Mpa, fracture toughness ≥ 130Mpa·m 1 / 2 , elastic limit ≥2%.

[0015] As a preferred technical solution of the present invention, the structure of the zirconium-based amorphous alloy is characterized before rapid heating.

[0016] As a preferred technical solution of the present invention, the glass transition temperature T of the zirconium-based amorphous alloy rod before rapid heating g , crystallization temperature T x , melting point T m Conduct a test.

[0017] As a preferred technical solution of the present invention, the temperature range of the supercooled liquid is T g <T<T m , Tg is the glass transition temperature of zirconium-based amorphous alloy, T m is the melting point of zirconium-based amorphous alloy.

[0018] As a preferred technical solution of the present invention, the superplastic forming method includes causing the supercooled liquid to generate thixotropic flow under the action of external force, and completing superplastic forming under the action of pressure.

[0019] As a preferred technical solution of the present invention, the rapid cooling method includes forced convection cooling.

[0020] As a preferred technical solution of the present invention, the forming method of the high-strength and high-toughness zirconium-based amorphous composite top-hat-shaped flexible wheel blank comprises:

[0021] Glass transition temperature T of zirconium-based amorphous alloy rod g , crystallization temperature T x , melting point T m Conduct testing;

[0022] The zirconium-based amorphous alloy is rapidly heated to the supercooled liquid range, and the temperature range of the supercooled liquid is T g <T<T m , obtaining a supercooled liquid of a zirconium-based amorphous alloy;

[0023] The composition of zirconium-based amorphous alloy is Zr x Cu a Ni b Al c Ti d Re y , Re is a rare earth element; wherein a, b, c, d, x and y are all atomic percentages, and the value ranges of a, b, c, d, x and y are: 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.15, 0≤d≤0.05, 0 <y≤0.05;x=1-a-b-c-d-y;

[0024] The supercooled liquid is made to flow thixotropically under the action of external force, and is superplastically formed under the action of pressure to obtain a top-hat-shaped flexible wheel blank.

[0025] The top-hat-shaped flexible wheel blank is subjected to forced convection cooling until the temperature is below the glass transition temperature of the zirconium-based amorphous alloy, and then removed from the mold, and cooled to room temperature to obtain the top-hat-shaped flexible wheel.

[0026] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0027] The present invention provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible wheel. The zirconium-based amorphous alloy selected in the molding method has excellent mechanical properties, a yield strength of ≥1600Mpa, and a fracture toughness of ≥130Mpa·m 1 / 2, elastic limit ≥ 2%; at the same time, the superplasticity of the supercooled liquid is used to achieve near-net forming of the amorphous alloy flexible wheel. The size and shape of the formed flexible wheel are close to the final size of the part, which greatly reduces the processing flow and solves the existing process technology and quality problems of steel flexible wheels. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic flow chart of a method for forming a top-hat-shaped flexible wheel provided in a specific embodiment of the present invention.

[0029] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0031] The specific embodiment of the present invention provides a method for forming a high-strength and high-toughness zirconium-based amorphous composite top-hat-shaped flexible wheel blank, the forming method comprising:

[0032] The zirconium-based amorphous alloy is heated to a supercooled liquid range to obtain a supercooled liquid of the zirconium-based amorphous alloy;

[0033] The supercooled liquid is subjected to superplastic forming to obtain a top-hat-shaped flexible wheel blank;

[0034] The top-hat-shaped flexible wheel blank is rapidly cooled to below the glass transition temperature of the zirconium-based amorphous alloy;

[0035] The blank cooled to below the glass transition temperature is demoulded, and then naturally cooled to room temperature to obtain a top-hat shaped flexible wheel.

[0036] In a specific embodiment of the present invention, a method for preparing a zirconium-based amorphous alloy may include: selecting sponge zirconium particles, sponge titanium particles, granular yttrium, electrolytic copper, electrolytic nickel and electrolytic aluminum, mixing them according to atomic percentages, and performing induction melting in a protective gas atmosphere, and repeating the melting for no less than three times.

[0037] In a specific embodiment of the present invention, the method for preparing the zirconium-based amorphous alloy rod may include: pouring the alloy liquid into a copper mold, and rapidly cooling it to obtain the zirconium-based amorphous alloy rod.

[0038] In a specific embodiment of the present invention, induction melting is carried out in a vacuum furnace. After the raw materials are added, vacuum is evacuated, and then a protective gas, such as argon, is introduced to carry out induction melting in a protective atmosphere.

[0039] In one specific embodiment of the present invention, the crystal structure of the zirconium-based amorphous alloy rod is tested, such as by using XRD, to determine that it is amorphous.

[0040] In one embodiment of the present invention, the glass transition temperature T of the zirconium-based amorphous alloy rod is measured using DSC. g , crystallization temperature T x , melting point T m Conduct a test.

[0041] In a specific embodiment of the present invention, the compressive mechanical properties and fracture toughness of the zirconium-based amorphous alloy rod are tested, such as using a universal mechanical testing machine to characterize the compressive mechanical properties and using a three-point bending method to characterize the zirconium-based amorphous alloy rod.

[0042] In one embodiment of the present invention, the method for heating the zirconium-based amorphous alloy to the supercooled liquid range comprises: placing the zirconium-based amorphous alloy rod in a sprue with a pulse current heating function; discharging the capacitor to generate a pulse current to quickly and uniformly heat the amorphous rod (≥10 4 K / S) to supercooled liquid temperature range.

[0043] In a specific embodiment of the present invention, the superplastic forming method includes: a supercooled liquid generates thixotropic flow under the action of an electromagnetic driving force.

[0044] In a specific embodiment of the present invention, superplastic forming of the top-hat flexspline is completed under the pressure generated by the electromagnetic driving force.

[0045] In a specific embodiment of the present invention, rapid superplastic forming refers to completing superplastic forming within 1 millisecond.

[0046] In a specific embodiment of the present invention, the rapid cooling method includes: providing a cooling channel in the mold and using a coolant with strong cooling capacity for forced convection cooling. The coolant with strong cooling capacity can be specifically selected according to the properties of the coolant and the cooling needs, and is not further limited here.

[0047] In a specific embodiment of the present invention, rapid cooling refers to cooling at a cooling rate of not less than 50K / S.

[0048] In a specific embodiment of the present invention, the cooling channel and high thermal conductivity mold material of the injection mold can be selected according to the thermophysical parameters of different mold materials; considering that the temperature of the supercooled liquid is much lower than the melting point, materials with relatively large heat transfer coefficients, such as brass (H06 C21000 and H03 C21000) and beryllium copper (TF00C17500 copper and TF00C17510 coppe), can be selected to manufacture the molding mold.

[0049] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0050] Example 1

[0051] This embodiment provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible pulley, wherein the composition is Zr 0.609 Cu 0.25 Al 0.12 Ti 0.02 Y 0.001 , and its preparation method comprises:

[0052] Sponge Zr particles (purity 99.5%), electrolytic copper (purity 99.9%), electrolytic aluminum (purity 99.9%), and sponge titanium (purity 99.5%) were placed in a vacuum furnace according to atomic percentage and evacuated to 1×10 -3 After Pa, high-purity argon gas is introduced, and induction melting is carried out in an argon atmosphere. After the charge is completely melted and evenly melted, the power of the induction furnace is increased to 10KW for overheating, and the heat is kept for one minute. The power is reduced to 8KW, and the alloy liquid is cast into a water-cooled copper mold and rapidly cooled to obtain a non-gold alloy rod;

[0053] XRD was used to determine that the non-gold alloy rod was amorphous, and DSC was used to determine the glass transition temperature T of the non-gold alloy rod. g , crystallization temperature T x , melting point T m .

[0054] Example 2

[0055] This embodiment provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible pulley, wherein the composition is Zr 0.577 Cu 0.28 Al 0.12 Ti 0.02 Y 0.003 , and its preparation method is the same as that of Example 1.

[0056] XRD was used to determine that the non-gold alloy rod was amorphous, and DSC was used to determine the glass transition temperature T of the non-gold alloy rod. g , crystallization temperature T x , melting point T m .

[0057] Example 3

[0058] This embodiment provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible pulley, wherein the composition is Zr 0.615 Cu 0.26 Al 0.10 Ti 0.02 Y 0.005 , and its preparation method is the same as that of Example 1.

[0059] XRD was used to determine that the non-gold alloy rod was amorphous, and DSC was used to determine the glass transition temperature T of the non-gold alloy rod. g , crystallization temperature T x , melting point T m .

[0060] Example 4

[0061] This embodiment provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible pulley, wherein the composition is Zr 0.599 Cu 0.27 Al 0.08 Ti 0.05 Y 0.001 , and its preparation method is the same as that of Example 1.

[0062] XRD was used to determine that the non-gold alloy rod was amorphous, and DSC was used to determine the glass transition temperature T of the non-gold alloy rod. g , crystallization temperature T x , melting point T m .

[0063] Example 5

[0064] This embodiment provides a high-strength and high-toughness zirconium-based amorphous alloy for preparing a top-hat-shaped flexible pulley, wherein the composition is Zr 0.615 Cu 0.23 Al 0.10 Ti 0.05 Y 0.005 , and its preparation method is the same as that of Example 1.

[0065] XRD was used to determine that the non-gold alloy rod was amorphous, and DSC was used to determine the glass transition temperature T of the non-gold alloy rod. g , crystallization temperature T x , melting point T m .

[0066] Example 6

[0067] This embodiment provides a method for forming a high-strength and high-toughness zirconium-based amorphous alloy top-hat-shaped flexible wheel blank, and the process is as follows: Figure 1 As shown, the molding method includes:

[0068] The non-gold alloy rods prepared in Examples 1-5 were placed in a sprue with a pulse current heating function, and the capacitor was discharged to generate a pulse current to quickly and evenly heat the amorphous rods (≥10 4 K / S) to the supercooled liquid region (Tg <T<Tm);

[0069] The alloy liquid heated to the supercooled liquid zone generates thixotropic flow under the action of the electromagnetic driving force; under the pressure generated by the electromagnetic driving force, the top-hat-shaped flexible wheel is superplasticly formed to obtain a top-hat-shaped flexible wheel blank;

[0070] A cooling channel is set in the injection mold, and the coolant is used for forced convection cooling to cool the top hat flexspline blank to the glass transition temperature T g The mold is then removed and naturally cooled to room temperature to obtain a top-hat shaped flexible wheel.

[0071] The amorphous alloy top-hat-shaped flexible pulley blank is prepared by the method provided in Example 6. Compared with the flexible pulley blank made of SNCM439 alloy steel forging steel, the wall thickness of the blank is thinned from 7 mm to 1 mm, the utilization rate of the product is greatly improved, and the qualified rate of the product is also significantly improved.

[0072] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0073] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0074] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0075] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for forming a high-strength and high-toughness zirconium-based amorphous alloy top-hat-shaped flexible wheel blank, characterized in that: The molding method comprises: Rapidly heating the zirconium-based amorphous alloy to a supercooled liquid range to obtain a supercooled liquid of the zirconium-based amorphous alloy; The supercooled liquid is subjected to rapid superplastic forming to obtain a top-hat-shaped flexible wheel blank; The top-hat-shaped flexible spline blank is rapidly cooled to a temperature below the glass transition temperature of the zirconium-based amorphous alloy, and then removed from the mold, and then cooled to room temperature to obtain the top-hat-shaped flexible spline.

2. The zirconium-based amorphous alloy according to claim 1, characterized in that: The zirconium-based amorphous alloy is composed of Zr x Cu a Ni b Al c Ti d Re y , Re is a rare earth element; Wherein, a, b, c, d, x and y are all atomic percentages, and the value ranges of a, b, c, d, x and y are: 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.15, 0≤d≤0.05, 0≤ <y≤0.05;x=1-a-b-c-d-y。 3. The zirconium-based amorphous alloy according to claim 2, characterized in that: The rare earth element includes any one of Ce, La, Y, Dy, Gd or Er, or a combination of at least two of them.

4. The zirconium-based amorphous alloy according to claim 2, characterized in that: The mechanical properties of the zirconium-based amorphous alloy are: yield strength ≥ 1600Mpa, fracture toughness ≥ 130Mpa·m 1 / 2 , elastic limit ≥ 2%.

5. The molding method according to claim 1, characterized in that: Before the rapid heating, the zirconium-based amorphous alloy is subjected to structural characterization.

6. The molding method according to claim 1, characterized in that: Before the rapid heating, the glass transition temperature T g , crystallization temperature T x , melting point T m Conduct a test.

7. The molding method according to claim 1, characterized in that: The temperature range of the supercooled liquid is T g <T<T m , the T g is the glass transition temperature of the zirconium-based amorphous alloy, T m is the melting point of the zirconium-based amorphous alloy.

8. The molding method according to claim 1, characterized in that: The superplastic forming method comprises causing the supercooled liquid to generate thixotropic flow under the action of external force, and completing superplastic forming under the action of pressure.

9. The molding method according to claim 1, characterized in that: The rapid cooling method includes forced convection cooling.

10. The molding method according to claim 1, characterized in that: The molding method comprises: Glass transition temperature T of zirconium-based amorphous alloy rod g , crystallization temperature T x , melting point T m Conduct testing; The zirconium-based amorphous alloy is rapidly heated to a supercooled liquid range, wherein the temperature range of the supercooled liquid is T g <T<T m , obtaining a supercooled liquid of the zirconium-based amorphous alloy; The zirconium-based amorphous alloy is composed of Zr x Cu a Ni b Al c Ti d Re y , Re is a rare earth element; wherein a, b, c, d and y are all atomic percentages, and the value ranges of a, b, c, d, x and y are: 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.15, 0≤d≤0.05, 0 <y≤0.05;x=1-a-b-c-d-y; The supercooled liquid is made to flow thixotropically under the action of external force, and is superplastically formed under the action of pressure to obtain a top-hat-shaped flexible wheel blank; The top-hat-shaped flexible wheel blank is subjected to forced convection cooling until the temperature is below the glass transition temperature of the zirconium-based amorphous alloy, and then removed from the mold, and cooled to room temperature to obtain the top-hat-shaped flexible wheel.

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