Method for regulating and controlling TC4 titanium alloy structure performance based on ultrasonic energy field and alloy

Abstract

The invention relates to the field of alloy structure performance regulation and control, in particular to a method for regulating and controlling TC4 titanium alloy structure performance based on an ultrasonic energy field and an alloy. 2, deposition powder is prepared; step 3, preparing a laser melting deposition additive; and 4, the Mo / TC4 alloy is prepared. The Mo / TC4 alloy is prepared through the laser melting deposition additive manufacturing and ultrasonic impact technology, columnar crystals in the TC4 titanium alloy are equiaxed, the anisotropic performance of the TC4 titanium alloy is reduced, and the Mo / TC4 alloy has higher tensile strength and yield strength.

Description

Technical Field

[0001] The present invention relates to the field of alloy microstructure and performance regulation, and in particular to a method and alloy for regulating the microstructure and performance of a TC4 titanium alloy based on an ultrasonic energy field. Background Art

[0002] TC4 titanium alloy is widely used in aerospace, mainly for manufacturing aircraft structural parts and engine parts. The room temperature strength of TC4 titanium alloy is low and usually cannot be strengthened by heat treatment. TC4 titanium alloy is usually an α+β phase alloy. If the composition is uneven, it will cause abnormalities in its macro and micro structure, resulting in uneven performance, which will lead to reduced strength and plasticity of the material. Secondly, there are a large number of columnar crystals and needle-shaped martensite inside TC4 titanium alloy, which will increase the anisotropy of the material and reduce the plasticity of the material.

[0003] Therefore, the problems existing in the prior art such as the presence of a large amount of columnar crystals and needle-shaped martensite inside the TC4 titanium alloy, the high anisotropy of the TC4 titanium alloy, and the low tensile strength and yield strength of the TC4 titanium alloy are urgently to be solved by those skilled in the art. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide an effective method for regulating the microstructure and properties of Mo / TC4 alloy, which is simple to operate, easy to form materials, and can effectively solve the defect of insufficient strength of TC4 titanium alloy materials in existing additive manufacturing.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, comprising the following steps: Step 1: Clean the substrate and use industrial anhydrous ethanol to clean the surface of the substrate to remove oil and impurities on the surface of the substrate; Step 2: preparing a deposition powder, wherein the deposition powder includes TC4 titanium alloy powder and Mo powder, and the TC4 titanium alloy powder and Mo powder are prepared by a centrifugal atomization method; Step 3: Prepare laser melting deposition additives, configure TC4 titanium alloy powders with different Mo contents by controlling different powder feeding rates, lay the TC4 mixed titanium alloy powder containing Mo powder on the substrate, and use laser melting deposition additives; Step 4: Prepare Mo / TC4 alloy, adjust ultrasonic parameters, and use ultrasound to perform ultrasonic impact treatment on the laser melting deposition additive layer by layer to obtain Mo / TC4 alloy.

[0006] In the above-mentioned method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, in the deposited powder in step 2, the mass fraction of Mo powder is 0.1~10%, the mass fraction of TC4 titanium alloy powder is 92%, and the TC4 titanium alloy powder includes Ti, Al, and V, wherein the atomic percentages of Ti, Al, and V are: Ti≥90%, Al5%-5.5%, and V3.5%-4.5%.

[0007] In the above-mentioned method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, the particle size of the TC4 titanium alloy powder is 45 μm-105 μm, and the particle size of the Mo powder is 45 μm-105 μm.

[0008] In the above-mentioned method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, in step 3, the powder feeding rate is 20g / min-30g / min, the laser power is 1800W-2100W, and the scanning speed is 600mm / min-1000mm / min.

[0009] In the above method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, in step 4, the ultrasonic parameters are adjusted to power: 1800W-2400W, and ultrasonic amplitude 10μm-25μm.

[0010] In the above method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, in step 4, the ultrasonic impact comprises: Step 4-1: After the TC4 titanium alloy powder and the Mo powder are formed into a layer of laser melting deposition additive material by laser melting deposition, the first layer of laser melting deposition additive material is treated by ultrasonic impact; Step 4-2: The deposited powder is then laser treated to perform a second layer of laser melting deposition additive forming, and then the second layer of laser melting deposition additive is subjected to ultrasonic impact treatment, and the treatments are stacked layer by layer in sequence until the Mo / TC4 alloy is formed.

[0011] An alloy with TC4 titanium alloy microstructure and properties regulated by ultrasonic energy field, wherein the alloy is treated using any of the methods described above for regulating TC4 titanium alloy microstructure and properties, and an in-situ TiAl3 phase is generated inside the treated alloy, wherein the in-situ TiAl3 phase has a DO22 ordered tetragonal structure.

[0012] The beneficial effect of the method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field of the present invention is that Mo / TC4 alloy is prepared by laser melting deposition additive manufacturing plus ultrasonic impact technology, and the preparation method avoids the limitations of traditional process complexity and high cost, and the good combination of microstructure and performance can be used as a common means of preparing Mo / TC4 alloy. The preparation method of laser melting deposition additive manufacturing plus ultrasonic energy field is adopted to realize the equiaxing of columnar crystals in TC4 titanium alloy, reduce the anisotropic performance of TC4 titanium alloy, and the Mo / TC4 alloy has higher tensile strength and yield strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Laser deposited TC4 structures regulated by different Mo contents; Figure 2 The microstructure of laser deposited Mo / TC4 alloy regulated by ultrasonic energy field treatment of composite Mo; Figure 3 Comparison of tensile properties of laser deposited TC4 alloy regulated by ultrasonic energy field treatment of composite Mo; Figure 4 XRD pattern of laser deposited TC4 alloy regulated by ultrasonic energy field treatment of composite Mo. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is described below in conjunction with specific implementation methods and drawings.

[0015] Figure 1 In the figure, a, b, c, d, and e respectively represent laser-deposited TC4 structures regulated by different Mo contents, which are used for comparison with the alloy products in this technical solution.

[0016] like Figure 2-4As shown, the technical solution adjusts the relative content of α phase and β phase by adding stabilizing elements of β phase, such as V, Mo, Fe, etc., to improve the strength and plasticity of TC4 titanium alloy, and can adjust the grain morphology to achieve the transformation from columnar crystal to equiaxed crystal. On the other hand, ultrasonic energy field treatment is performed layer by layer during the material forming process to micro-stir the molten pool, producing "cavitation effect" and "acoustic streaming effect". Among them, the "cavitation effect" breaks the grain dendrites by the stirring effect applied to the metal solution during solidification. These fine grains can be used as crystallization cores to increase the nucleation rate. The tiny bubbles inside the molten pool will experience rapid expansion, compression, oscillation and rapid collapse. During the bubble collapse process, a large temperature gradient and pressure gradient will be generated in a small volume. On the one hand, a large temperature gradient will lead to an increase in supercooling during the solidification process. On the other hand, instantaneous strong shock waves and strong convection will cause jets in the molten pool, accelerate the flow of the melt, and make the solute in the molten pool fully convect. The combination of the above two factors will increase the nucleation rate of the molten pool and refine the organization. The "acoustic streaming effect" reduces the temperature gradient of the molten pool solidification and homogenizes the temperature field of the molten pool solidification process, so that the coarse columnar crystals are transformed into fine equiaxed crystals. At the same time, the ultrasonic impact acts on the high-temperature solid deposition layer to produce ultrasonic impact, resulting in plastic deformation and inducing dynamic recrystallization, thereby making the αTi Widmanstatten structure and βTi grains equiaxed and refining, eliminating interlayer anisotropy and residual tensile stress, and achieving the purpose of making the laser deposited TC4 titanium alloy microstructure equiaxed and refining and improving the plasticity of the material.

[0017] Example 1 A method for regulating the microstructure and properties of TC4 titanium alloy based on an ultrasonic energy field comprises the following steps: Step 1: Clean the substrate and use industrial anhydrous ethanol to clean the surface of the substrate to remove oil and impurities on the surface of the substrate.

[0018] Step 2: preparing deposition powder, wherein the deposition powder includes TC4 titanium alloy powder and Mo powder, and the TC4 titanium alloy powder and Mo powder are prepared by centrifugal atomization method.

[0019] In the deposited powder, the mass fraction of Mo powder is 0.1-10%, and the remainder is TC4 titanium alloy powder. Specifically, in the optimal content, the mass fraction of Mo powder is 8%, and the mass fraction of TC4 titanium alloy powder is 92%.

[0020] The particle size of TC4 titanium alloy powder is 45μm-105μm, and the particle size of Mo powder is 45μm-105μm.

[0021] TC4 titanium alloy powder includes Ti, Al, and V, among which the atomic percentages of Ti, Al, and V are: Ti ≥ 90%, Al 5%-5.5%, and V 3.5%-4.5%.

[0022] Step 3: Prepare laser melting deposition additive materials, control the powder feeding rate, use laser to scan TC4 titanium alloy powder and Mo powder on the substrate, and deposit them to form laser melting deposition additive materials.

[0023] The powder feeding rate is 20g / min-30g / min, the laser power is 1800W-2100W, and the scanning speed is 600mm / min-1000mm / min.

[0024] Step 4: Prepare Mo / TC4 alloy, adjust ultrasonic parameters, and use ultrasound to perform ultrasonic impact treatment on the laser melting deposition additive layer by layer to obtain Mo / TC4 alloy.

[0025] The ultrasonic parameters were adjusted to power: 1800W-2400W, ultrasonic amplitude 10μm-25μm.

[0026] Ultrasonic shock includes: Step 4-1: After the TC4 titanium alloy powder and the Mo powder are formed into a layer of laser melting deposition additive material by laser melting deposition, the first layer of laser melting deposition additive material is processed by ultrasonic impact.

[0027] Step 4-2: The deposited powder is then laser treated to perform a second layer of laser melting deposition additive forming, and then the second layer of laser melting deposition additive is subjected to ultrasonic impact treatment, and the treatments are stacked layer by layer in sequence until the Mo / TC4 alloy is formed.

[0028] Example 2 The technical key points of this embodiment are: using Mo element composition to design a composite ultrasonic energy field to regulate the microstructure and properties of laser-added TC4 titanium alloy. Mo is a stabilizing element of the β phase, which can regulate the relative content of the α phase and the β phase, improve the strength and plasticity of the TC4 titanium alloy, and regulate the grain morphology to achieve the transformation from columnar crystals to equiaxed crystals. By controlling the powder feeding rate of the two powder barrels, the preparation of TC4 titanium alloy powders with different Mo contents can be achieved, and the added Mo content is between 0-8%. In the layer-by-layer laser deposition additive process, ultrasonic energy field regulation is applied synchronously, and the "cavitation" and "acoustic streaming" effects of ultrasound on the molten pool, as well as the plastic deformation and recovery recrystallization effects of ultrasonic impact on the deposited layer, are utilized to further achieve grain refinement and equiaxed, thereby improving the performance of the TC4 alloy.

[0029] This embodiment provides a method for controlling the microstructure and properties of TC4 titanium alloy by using a composition design and a composite ultrasonic energy field. The method improves the microstructure and properties of TC4 titanium alloy by using a laser melting deposition additive manufacturing and ultrasonic energy field technology.

[0030] The technical solution of this embodiment is as follows: Ultrasonic impact is used to treat the laser melt deposition additive manufacturing Mo / TC4 alloy layer by layer. After the Mo / TC4 alloy is formed by laser deposition, the deposition layer is treated with ultrasonic impact power of 1800W-2400W and ultrasonic amplitude of 10μm-25μm. Then, laser melt deposition is used to form the second layer of Mo / TC4 alloy, and then ultrasonic impact treatment is performed. In this way, laser melt deposition and ultrasonic impact treatment are performed in sequence to achieve ultrasonic impact layer by layer control of the microstructure and properties of the laser melt deposition additive manufacturing Mo / TC4 alloy. The specific steps are as follows:

[0031] S1. Explore appropriate laser melting deposition forming parameters of Mo / TC4 alloy and form Mo / TC4 alloy using laser melting deposition technology.

[0032] S2. The laser melt-deposited Mo / TC4 alloy was treated layer by layer by ultrasonic impact. The ultrasonic impact parameters were: power: 1800W-2400W, ultrasonic amplitude 10μm-25μm.

[0033] This embodiment includes the following features: The Mo powder and TC4 titanium alloy powder selected in step S1 are fully mixed and dried in a ball mill, and then prepared by a gas atomization method. The mass fraction of the Mo powder is 8%, and the mass percentage of the TC4 titanium alloy powder is: Ti: ≥90% Al: 5%-5.5% V: 3.5%-4.5% In step S1, the laser melting deposition additive manufacturing process parameters include: laser power, scanning speed, powder feeding rate and other parameters.

[0034] The particle size of Mo powder and TC4 titanium alloy powder is 45μm-105μm.

[0035] The laser power control range of the laser melting deposition additive manufacturing system is 1800W-2100W.

[0036] The scanning speed control range of the laser melting deposition additive manufacturing system is 400mm / min-800mm / min.

[0037] The powder feeding rate control range of the laser melting deposition additive manufacturing system is 20g / min-30g / min.

[0038] The present invention prepares Mo / TC4 alloy by laser melting deposition additive manufacturing plus ultrasonic impact technology. This preparation method avoids the limitations of traditional processes such as complexity and high cost. At the same time, the good combination of structure and performance can be used as a common means of preparing Mo / TC4 alloy.

[0039] Example 3 This embodiment takes the preparation of Mo / TC4 alloy by laser melting deposition additive manufacturing plus ultrasonic impact technology as an example to fully understand and describe the present invention, but it should be stated that the laser melting deposition additive manufacturing plus ultrasonic impact method of the present invention is applicable to different types of titanium alloys. Therefore, the following embodiments are only for illustrating the present invention, and are not intended to limit the scope of the present invention in any way. In addition, the terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by ordinary technicians in the field.

[0040] The first step is the preparation for laser melting deposition forming of Mo / TC4 alloy. Before laser melting deposition forming of Mo / TC4 alloy, the substrate surface is cleaned with industrial anhydrous ethanol to remove oil and impurities on the substrate surface to prevent the pollutants from affecting the formed Mo / TC4 alloy.

[0041] In the second step, laser melting deposition forming plus ultrasonic impact treatment is used to prepare the Mo / TC4 alloy deposition layer. After the Mo / TC4 alloy is formed by laser melting deposition, it is treated by ultrasonic impact, and then the second layer of Mo / TC4 alloy is formed by laser melting deposition, and then ultrasonic impact treatment is performed again. In this way, laser melting deposition and ultrasonic impact treatment are carried out in sequence to achieve the control of the microstructure and properties of the laser melting deposition additively manufactured Mo / TC4 alloy by ultrasonic impact layer by layer. The experimental substrate is a pure Ti plate, the Mo powder particle size is 45μm-105μm, and the TC4 powder particle size is 45μm-105μm. The Mo / TC4 alloy deposition layer is formed using the same experimental parameters, and the specific parameters are laser power of 1800W, scanning speed of 400mm / min, powder feeding rate of 20g / min, ultrasonic power of 1800W, and ultrasonic amplitude of 20μm. At the same time, the Mo / TC4 alloy is formed using the same laser melting deposition process parameters.

[0042] Example 4 like Figure 2 As shown, an alloy based on ultrasonic energy field to regulate the microstructure and properties of TC4 titanium alloy, the alloy is treated using the methods in Example 1, Example 2, and Example 3, and the grains of the Mo / TC4 alloy prepared after the treatment are fine equiaxed grains with a grain area of ​​0.17μm2-4.21μm2.

[0043] A small amount of TiAl3 phase is generated inside the alloy. TiAl3 phase is a δ phase of an intermetallic compound with a DO22 ordered tetragonal structure. This in-situ TiAl3 particle can significantly improve the strength and hardness of the material while maintaining a good elongation, thereby improving the overall performance of the material.

[0044] The tensile strength of the Mo / TC4 alloy prepared after treatment is ≥1080MPa, the yield strength is ≥910MPa, and the elongation is approximately 9.5%.

[0045] The above embodiments are only for illustrating the inventive concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, characterized in that: The following steps are involved: Step 1: Clean the substrate and use industrial anhydrous ethanol to clean the surface of the substrate to remove oil and impurities on the surface of the substrate; Step 2: preparing a deposition powder, wherein the deposition powder includes TC4 titanium alloy powder and Mo powder, and the TC4 titanium alloy powder and Mo powder are prepared by a centrifugal atomization method; Step 3: Prepare laser melting deposition additives, configure TC4 titanium alloy powders with different Mo contents by controlling different powder feeding rates, lay the TC4 mixed titanium alloy powder containing Mo powder on the substrate, and use laser melting deposition additives; Step 4: Prepare Mo / TC4 alloy, adjust ultrasonic parameters, and use ultrasound to perform ultrasonic impact treatment on the laser melting deposition additive layer by layer to obtain Mo / TC4 alloy.

2. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field according to claim 1 is characterized in that: In the deposited powder of step 2, the mass fraction of Mo powder is 0.1-10%, and the remainder is TC4 titanium alloy powder. The TC4 titanium alloy powder includes Ti, Al, and V, wherein the mass percentages of Ti, Al, and V are: Ti≥90%, Al5%-5.5%, and V3.5%-4.5%.

3. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field according to claim 2 is characterized in that: The particle size of the TC4 titanium alloy powder is 45 μm-105 μm, and the particle size of the Mo powder is 45 μm-105 μm.

4. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field according to claim 1, characterized in that: In step 3, the powder feeding rate is 20 g / min-30 g / min, the laser power is 1800 W-2100 W, and the scanning speed is 600 mm / min-1000 mm / min.

5. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field according to claim 1, characterized in that: In step 4, the ultrasonic parameters are adjusted to power: 1800W-2400W, and ultrasonic amplitude 10μm-25μm.

6. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field according to claim 5, characterized in that: In step 4, the ultrasonic impact includes: Step 4-1: After the TC4 titanium alloy powder and the Mo powder are formed into a layer of laser melting deposition additive material by laser melting deposition, the first layer of laser melting deposition additive material is treated by ultrasonic impact; Step 4-2: The deposited powder is then laser treated to perform a second layer of laser melting deposition additive forming, and then the second layer of laser melting deposition additive is subjected to ultrasonic impact treatment, and the treatments are stacked layer by layer in sequence until the Mo / TC4 alloy is formed.

7. An alloy for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, characterized in that The alloy is treated using the method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field as described in any one of claims 1 to 6, and an in-situ TiAl3 phase is generated inside the treated alloy, and the in-situ TiAl3 phase has a DO22 ordered tetragonal structure.

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