A method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, and the alloy

Abstract

This invention relates to the field of alloy microstructure and property control, specifically to a method and alloy for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, comprising: step 1: cleaning the substrate; step 2: preparing deposition powder; step 3: preparing laser melting deposition additive manufacturing; and step 4: preparing a Mo / TC4 alloy. The Mo / TC4 alloy was prepared by combining laser melting deposition additive manufacturing with ultrasonic impact technology, achieving equiaxed columnar crystals in the TC4 titanium alloy, reducing the anisotropic properties of the TC4 titanium alloy, and resulting in a Mo / TC4 alloy with higher tensile strength and yield strength.

Description

Technical Field

[0001] This invention relates to the field of alloy microstructure and property control, specifically to a method and alloy for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field. Background Technology

[0002] TC4 titanium alloy is widely used in aerospace, primarily for manufacturing aircraft structural components and engine parts. TC4 titanium alloy has low room temperature strength and typically cannot be strengthened through heat treatment. It is usually an α+β phase alloy; if the composition is inhomogeneous, it can cause abnormalities in its macroscopic and microscopic structure, leading to inhomogeneous properties and consequently reducing the material's strength and plasticity. Furthermore, the presence of numerous columnar and acicular martensite crystals within TC4 titanium alloy increases its anisotropy and reduces its plasticity.

[0003] Therefore, the problems of TC4 titanium alloy having a large number of columnar and acicular martensite, high anisotropy, and low tensile and yield strength are problems that urgently need 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 this invention is to provide an effective method for controlling the microstructure and properties of Mo / TC4 alloy that is easy 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 objectives, the technical solution adopted by the present invention is: a method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, comprising the following steps:

[0006] Step 1: Clean the substrate. Use industrial anhydrous ethanol to clean the surface of the substrate and remove oil and impurities.

[0007] Step 2: Prepare the deposited powder, which includes TC4 titanium alloy powder and Mo powder. The TC4 titanium alloy powder and Mo powder are prepared by centrifugal atomization.

[0008] Step 3: Prepare laser melting deposition additive manufacturing. By controlling different powder feeding rates, TC4 titanium alloy powder with different Mo contents is prepared. The TC4 mixed titanium alloy powder containing Mo powder is laid on the substrate, and laser melting deposition additive manufacturing is performed.

[0009] 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.

[0010] In the above-mentioned method for controlling 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%.

[0011] The above-mentioned method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, wherein the TC4 titanium alloy powder has a particle size of 45μm-105μm and the Mo powder has a particle size of 45μm-105μm.

[0012] In the above-mentioned method for controlling 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.

[0013] In the above-mentioned method for controlling 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.

[0014] In the above-mentioned method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field, step 4, the ultrasonic impact includes:

[0015] Step 4-1: After the TC4 titanium alloy powder and Mo powder are laser melted and deposited to form a laser melted deposition additive layer, the first laser melted deposition additive layer is treated with ultrasonic impact.

[0016] Step 4-2: Subsequently, laser treatment is used to deposit the powder for the second layer of laser melting deposition additive forming. Then, the second layer of laser melting deposition additive is subjected to ultrasonic impact treatment. This process is repeated layer by layer until the Mo / TC4 alloy is formed.

[0017] An alloy based on ultrasonic energy field modulation of the microstructure and properties of TC4 titanium alloy, wherein the alloy is treated using the method described above for ultrasonic energy field modulation of the microstructure and properties of TC4 titanium alloy, and an in-situ TiAl3 phase is generated inside the treated alloy, wherein the in-situ TiAl3 phase has a DO22 ordered tetragonal structure.

[0018] The beneficial effects of this invention's method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field are as follows: Mo / TC4 alloys are prepared using laser melting deposition additive manufacturing combined with ultrasonic impact technology. This preparation method avoids the limitations of traditional processes, such as complexity and high cost, and achieves a good balance between microstructure and properties, making it a commonly used method for preparing Mo / TC4 alloys. By employing laser melting deposition additive manufacturing combined with an ultrasonic energy field, the columnar crystals in the TC4 titanium alloy are made equiaxed, reducing the anisotropic properties of the TC4 titanium alloy. This Mo / TC4 alloy exhibits higher tensile strength and yield strength. Attached Figure Description

[0019] Figure 1 Laser-deposited TC4 tissues with varying Mo content;

[0020] Figure 2 Microstructure of Mo / TC4 alloy induced by ultrasonic energy field treatment with composite Mo;

[0021] Figure 3 Comparison of tensile properties of laser-deposited TC4 alloy under ultrasonic energy field treatment with composite Mo-modulated laser deposition.

[0022] Figure 4 XRD patterns of TC4 alloy laser-deposited with composite Mo regulated by ultrasonic energy field processing. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described below in conjunction with specific embodiments and accompanying drawings.

[0024] Figure 1 In the figure, a, b, c, d, and e represent laser-deposited TC4 microstructures with different Mo contents, used for comparison with the alloy products in this technical solution.

[0025] like Figure 2-4As shown, this technical solution improves the strength and plasticity of TC4 titanium alloy by adding stabilizing elements of the β phase, such as V, Mo, and Fe, to regulate the relative content of the α and β phases and control the grain morphology, achieving the transformation from columnar crystals to equiaxed crystals. On the other hand, ultrasonic energy field treatment is applied layer by layer during material forming to micro-stir the molten pool, generating "cavitation effect" and "acoustic flow effect." The "cavitation effect" causes the dendrites to break up due to the stirring action applied during the solidification of the molten metal. These fine grains can then act as nucleation nuclei, increasing the nucleation rate. The tiny bubbles inside the molten pool undergo rapid expansion, compression, oscillation, and rapid collapse. During bubble collapse, a large temperature and pressure gradient is generated within a small volume. On the one hand, the large temperature gradient leads to an increase in undercooling during solidification; on the other hand, the instantaneous strong shock wave and strong convection cause jets within the molten pool, accelerating the flow of the melt and allowing for sufficient convection of the solute. The combination of these two factors increases the nucleation rate of the molten pool, thereby refining the microstructure. The "acoustic flow effect" reduces the temperature gradient during molten pool solidification, homogenizes the temperature field during solidification, and promotes the transformation of coarse columnar crystals into fine equiaxed crystals. Simultaneously, ultrasonic impact on the high-temperature solid deposited layer generates ultrasonic shock, leading to plastic deformation and inducing dynamic recrystallization. This results in the equiaxed refinement of the αTi Widmanstätten structure and βTi grains, elimination of interlayer anisotropy and residual tensile stress, achieving the goal of refining the microstructure of laser-deposited TC4 titanium alloy and improving the material's plasticity.

[0026] Example 1

[0027] A method for controlling the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field includes the following steps:

[0028] Step 1: Clean the substrate. Use industrial anhydrous ethanol to clean the surface of the substrate and remove oil and impurities.

[0029] Step 2: Prepare the deposited powder, which includes TC4 titanium alloy powder and Mo powder. The TC4 titanium alloy powder and Mo powder are prepared by centrifugal atomization.

[0030] In the deposited powder, the mass fraction of Mo powder is 0.1~10%, and the balance is TC4 titanium alloy powder. Specifically, the optimal content is 8% Mo powder and 92% TC4 titanium alloy powder.

[0031] The particle size of TC4 titanium alloy powder is 45μm-105μm, and the particle size of Mo powder is 45μm-105μm.

[0032] TC4 titanium alloy powder contains Ti, Al, and V, with the atomic percentages of Ti, Al, and V being: Ti ≥ 90%, Al 5%-5.5%, and V 3.5%-4.5%.

[0033] Step 3: Prepare laser melting deposition additive. Control the powder feeding rate and use a laser to scan TC4 titanium alloy powder and Mo powder onto the substrate to deposit and form laser melting deposition additive.

[0034] The powder feeding rate is 20g / min-30g / min, the laser power is 1800W-2100W, and the scanning speed is 600mm / min-1000mm / min.

[0035] 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.

[0036] The ultrasound parameters were adjusted to power: 1800W-2400W, and ultrasound amplitude: 10μm-25μm.

[0037] Ultrasonic shock includes:

[0038] Step 4-1: After the TC4 titanium alloy powder and Mo powder are laser melted and deposited to form a laser melted deposition additive layer, the first laser melted deposition additive layer is treated with ultrasonic impact.

[0039] Step 4-2: Subsequently, laser treatment is used to deposit the powder for the second layer of laser melting deposition additive forming. Then, the second layer of laser melting deposition additive is subjected to ultrasonic impact treatment. This process is repeated layer by layer until the Mo / TC4 alloy is formed.

[0040] Example 2

[0041] The key technical point of this embodiment is: using Mo elemental 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 and β phases, improve the strength and plasticity of 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 cylinders, TC4 titanium alloy powders with different Mo contents can be prepared, with the added Mo content ranging from 0-8%. During the layer-by-layer laser deposition additive process, ultrasonic energy field regulation is applied simultaneously. Utilizing the "cavitation" and "acoustic flow" effects of ultrasound on the molten pool, as well as the plastic deformation and recovery recrystallization effects of ultrasonic impact on the deposited layer, the grains are further refined and made equiaxed, thereby improving the performance of the TC4 alloy.

[0042] This embodiment provides a method for controlling the microstructure and properties of TC4 titanium alloy by designing a composite ultrasonic energy field. This method uses laser melting deposition additive manufacturing combined with an ultrasonic energy field to improve the microstructure and properties of TC4 titanium alloy.

[0043] The technical solution of this embodiment is as follows:

[0044] Ultrasonic impaction was used to process Mo / TC4 alloys manufactured by laser melting deposition additive manufacturing layer by layer. After the Mo / TC4 alloy was formed by laser deposition, the deposited layer was treated with ultrasonic impaction at a power of 1800W-2400W and an amplitude of 10μm-25μm. A second layer of Mo / TC4 alloy was then formed by laser melting deposition, followed by ultrasonic impaction. This process of laser melting deposition followed by ultrasonic impaction was repeated to achieve layer-by-layer control of the microstructure and properties of Mo / TC4 alloys manufactured by laser melting deposition additive manufacturing. The specific steps are as follows:

[0045] S1. Explore appropriate forming parameters for laser melting deposition of Mo / TC4 alloys and form Mo / TC4 alloys using laser melting deposition technology.

[0046] S2. Layer-by-layer processing of laser-melted deposited Mo / TC4 alloy was performed using ultrasonic shock. The ultrasonic shock parameters were: power: 1800W-2400W, ultrasonic amplitude: 10μm-25μm.

[0047] This embodiment includes the following features:

[0048] The Mo powder and TC4 titanium alloy powder selected in step S1 are thoroughly mixed and dried using a ball mill, and then produced by gas atomization. The mass fraction of the Mo powder is 8%, and the mass percentage of the TC4 titanium alloy powder is:

[0049] Ti: ≥90%

[0050] Al: 5%-5.5%

[0051] V: 3.5%-4.5%

[0052] The laser melting deposition additive manufacturing process parameters in step S1 include: laser power, scanning speed, powder feeding rate, etc.

[0053] The particle size of Mo powder and TC4 titanium alloy powder is 45μm-105μm.

[0054] The laser power control range of the laser melting deposition additive manufacturing system is 1800W-2100W.

[0055] The scanning speed control range of the laser melting deposition additive manufacturing system is 400 mm / min to 800 mm / min.

[0056] The powder feeding rate of the laser melting deposition additive manufacturing system is controlled within the range of 20g / min-30g / min.

[0057] This invention prepares Mo / TC4 alloys by laser melting deposition additive manufacturing combined with ultrasonic impaction technology. This preparation method avoids the limitations of traditional processes such as complexity and high cost. At the same time, the good combination of microstructure and properties makes it a common method for preparing Mo / TC4 alloys.

[0058] Example 3

[0059] This embodiment uses the preparation of Mo / TC4 alloy by laser melting deposition additive manufacturing combined with ultrasonic impaction technology as an example to provide a full understanding and description of the present invention. However, it should be stated that the laser melting deposition additive manufacturing method combined with ultrasonic impaction 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. Furthermore, the terminology used in this invention, unless otherwise specified, generally has the meaning commonly understood by those skilled in the art.

[0060] The first step is the preparation work 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 from the substrate surface to prevent contaminants from affecting the formed Mo / TC4 alloy.

[0061] The second step involves preparing a Mo / TC4 alloy deposition layer using laser melting deposition followed by ultrasonic impact treatment. After laser melting deposition of one layer of Mo / TC4 alloy, it is treated with ultrasonic impact. A second layer of Mo / TC4 alloy is then formed using laser melting deposition, followed by another ultrasonic impact treatment. This process of laser melting deposition followed by ultrasonic impact treatment allows for layer-by-layer control of the microstructure and properties of the laser melting deposition additive manufacturing of Mo / TC4 alloy. The experimental substrate is a pure Ti plate, with Mo powder and TC4 powder having particle sizes of 45μm-105μm. The same experimental parameters are used to form the Mo / TC4 alloy deposition layer: laser power of 1800W, scanning speed of 400mm / min, powder feed rate of 20g / min, ultrasonic power of 1800W, and ultrasonic amplitude of 20μm. Simultaneously, the same laser melting deposition process parameters are used to form the Mo / TC4 alloy.

[0062] Example 4

[0063] like Figure 2As shown, an alloy based on ultrasonic energy field regulation of the microstructure and properties of TC4 titanium alloy is prepared by treating the alloy using the methods in Examples 1, 2 and 3. The Mo / TC4 alloy prepared after treatment has fine equiaxed grains with a grain area of ​​0.17 μm2-4.21 μm2.

[0064] A small amount of TiAl3 phase is generated inside the alloy. TiAl3 phase is a δ phase of an intermetallic compound with an ordered tetragonal structure of DO22. These in-situ TiAl3 particles can significantly improve the strength and hardness of the material while maintaining good elongation, thereby improving the overall performance of the material.

[0065] The Mo / TC4 alloy prepared after treatment has a tensile strength ≥1080MPa, a yield strength ≥910MPa, and an elongation of approximately 9.5%.

[0066] The above embodiments are merely illustrative of the inventive concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the present invention should be covered within the scope of protection 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 method comprises the following steps: Step 1: cleaning the substrate, using industrial anhydrous ethanol to clean the surface of the substrate to remove oil stains and impurities on the surface of the substrate; Step 2: preparing deposition powder, the deposition powder comprising TC4 titanium alloy powder and Mo powder, the TC4 titanium alloy powder and Mo powder being prepared by centrifugal atomization method; Step 3: preparing laser melting deposition additive, by controlling different powder feeding rates to configure TC4 titanium alloy powder with different Mo contents, laying TC4 mixed titanium alloy powder containing Mo powder on the substrate, and using laser to perform melting deposition additive; Step 4: preparing Mo / TC4 alloy, adjusting ultrasonic parameters, using ultrasonic to perform layer-by-layer ultrasonic impact treatment on the laser melting deposition additive, obtaining Mo / TC4 alloy, the ultrasonic parameters being adjusted to power: 1800W-2400W, ultrasonic amplitude 10μm-25μm, the ultrasonic impact comprising: Step 4-1: after the TC4 titanium alloy powder and Mo powder are laser melted and deposited to form a layer of laser melting deposition additive, the first layer of laser melting deposition additive is treated by ultrasonic impact; Step 4-2: then, the deposition powder is treated by laser to form a second layer of laser melting deposition additive, and then the second layer of laser melting deposition additive is treated by ultrasonic impact, and the layer-by-layer treatment is sequentially performed until the Mo / TC4 alloy is formed.

2. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field of claim 1, characterized in that, In the deposition powder of step 2, the mass fraction of Mo powder is 0.1-10%, and the balance is TC4 titanium alloy powder, the TC4 titanium alloy powder comprising Ti, Al and V, wherein the mass percentage of Ti, Al and V is: Ti≥90%, Al 5%-5.5%, and V 3.5%-4.5%.

3. The method of claim 2, wherein the ultrasonic energy field is applied at a frequency of 20-40 kHz, a power of 0.5-2 kW, and a duty cycle of 10-50%. The particle size of the TC4 titanium alloy powder is 45μm-105μm, and the particle size of the Mo powder is 45μm-105μm.

4. The method for regulating the microstructure and properties of TC4 titanium alloy based on ultrasonic energy field of claim 1, characterized in that, 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.

5. A kind of alloy based on ultrasonic energy field regulation TC4 titanium alloy organization performance, it is characterized by The alloy is treated by the method for regulating the microstructure and performance of TC4 titanium alloy based on ultrasonic energy field according to any one of claims 1-4, in-situ TiAl3 phase is generated in the treated alloy, and the in-situ TiAl3 phase has DO22 ordered tetragonal structure.

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