Titanium alloy part and machining method thereof

Abstract

The invention relates to a titanium alloy part and a machining method thereof, and relates to the technical field of titanium alloys. According to the main technical scheme, the machining method of the titanium alloy part comprises the following steps that a titanium alloy material is heated to 950 + / -2 DEG C, after heat preservation is conducted for set time, hot rolling treatment is conducted, and a hot-rolled part is obtained; wherein the deformation of the hot rolling treatment is 5-60%; the hot-rolled part is subjected to heat treatment, and the titanium alloy part is obtained; wherein the temperature of the heat treatment is 840 + / -2 DEG C. The method is mainly used for reducing the anisotropy of the titanium alloy part and improving the overall mechanical property of the titanium alloy part.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy technology, and in particular to a titanium alloy part and its processing method. Background Technology

[0002] Large ring forgings have important applications in machinery, energy, and national defense equipment, such as aero-engine casings and wind turbine tower flanges. They are key components ensuring the safe and reliable operation of major equipment and require excellent resistance to high-temperature creep, low-temperature impact, and corrosion. Currently, ring rolling technology has been gradually applied to the production of large rings with diameters of 1-5m in China. However, process design relies heavily on experience and trial and error, and process control involves a high degree of manual intervention. This not only consumes a lot of manpower and resources but also results in low precision, poor consistency of microstructure and properties in the rolled rings, and an inability to achieve high-quality and stable production, which seriously restricts the development of major equipment in my country.

[0003] In aerospace, energy equipment, and other fields, large ring-shaped components serve as critical load-bearing structural parts, and their performance directly determines the reliability and service life of the equipment. Taking the aero-engine casing as an example, this component must withstand complex conditions of high temperature, high pressure, and alternating loads, requiring materials to possess high strength, high toughness, and fatigue resistance. Titanium alloys, due to their high specific strength (σb / ρ≈17-20), excellent corrosion resistance, and fatigue resistance, have become the preferred material for manufacturing such core components.

[0004] During the rolling and subsequent heat treatment of large titanium alloy rings, the complex cross-section and enormous size of the rings result in varying deformation and heat transfer conditions in different areas, leading to uneven strain and temperature distribution across different regions of the ring's cross-section. Furthermore, titanium alloys are extremely sensitive to deformation and temperature; these multiple factors contribute to significant differences in the microstructure and mechanical properties of different parts of the ring. This inhomogeneity greatly affects the overall mechanical properties of the large titanium alloy rings. Summary of the Invention

[0005] In view of this, the present invention provides a titanium alloy part and a processing method thereof, the main purpose of which is to reduce the anisotropy of the mechanical properties of the titanium alloy part.

[0006] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0007] On one hand, embodiments of the present invention provide a method for processing titanium alloy parts, characterized by comprising the following steps:

[0008] Hot rolling process: The titanium alloy material is heated to 950℃±2℃, held at that temperature for a set time, and then hot rolled to obtain the hot rolled part; the deformation of the hot rolling process is 5-60%;

[0009] Heat treatment step: The hot-rolled part is subjected to heat treatment to obtain a titanium alloy part; wherein the heat treatment temperature is 840℃±2℃.

[0010] Preferably, in the hot rolling process, the titanium alloy material is a titanium alloy sheet.

[0011] Preferably, in the hot rolling process, the hot rolling time is 30 min ± 2 min.

[0012] Preferably, in the heat treatment step, the heat treatment time is 30 min ± 2 min.

[0013] Preferably, in the heat treatment step, the heating rate of the hot-rolled part to the heat treatment temperature is 300℃ / h ± 2℃ / h.

[0014] Preferably, the titanium alloy part is made of TC4 titanium alloy.

[0015] Preferably, the titanium alloy part is a hot-rolled sheet metal part.

[0016] On the other hand, embodiments of the present invention provide a titanium alloy part, characterized in that the titanium alloy part is obtained by processing the titanium alloy part by any of the above-described processing methods.

[0017] Preferably, the microstructure of the titanium alloy part comprises a composite structure of equiaxed α phase and continuous layered β phase, wherein the size of αs is 0.8–1.0 μm.

[0018] Compared with the prior art, the titanium alloy part and its processing method of the present invention have at least the following advantages:

[0019] Beneficial effects:

[0020] This invention provides a method for processing titanium alloy parts, comprising the following steps: heating the titanium alloy material to 950℃±2℃, holding it at that temperature for a set time, and then hot-rolling it to obtain a hot-rolled part; wherein the deformation amount of the hot rolling treatment is 5-60%; and heat-treating the hot-rolled part to obtain a titanium alloy part; wherein the heat treatment temperature is 840℃±2℃. The above scheme is explained as follows: Based on the above hot rolling temperature and hot rolling deformation amount, this invention achieves the synergistic effect of dynamic recrystallization and continuous β-phase layering by controlling the heat treatment temperature to 840℃±2℃. (It should be noted that dynamic recrystallization helps to form more uniform and finer grains, reduces slip barriers between different grains, and makes the mechanical behavior of the material more consistent in different directions. Continuous β-phase layering makes the β-phase more uniformly distributed in the material. Uniform β-phase distribution helps to enhance the isotropy of the titanium alloy (i.e., reduce forces in different directions). (Due to differences in mechanical properties), especially during hot rolling or heat treatment, when the material undergoes strain, the stability and uniform distribution of the β phase can reduce the fluctuations in mechanical properties caused by the inhomogeneity of the β phase, thereby further reducing anisotropy. This significantly reduces the strength difference between the titanium alloy parts in the RD and TD directions (RD represents the rolling direction, and TD represents the transverse direction), while maintaining high tensile strength. Furthermore, for hot-rolled parts with different hot rolling deformation amounts, at this heat treatment temperature, α phase refinement and β phase homogenization can be achieved, thereby effectively suppressing grain boundary orientation bias and improving microstructure stability. Therefore, the above-mentioned solution of the present invention can effectively reduce the anisotropy of the mechanical properties of titanium alloy parts and improve the overall mechanical properties of titanium alloy parts.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a dimensional diagram of the tensile specimen;

[0023] Figure 2 This is a microstructure diagram of the titanium alloy sheet provided in an embodiment of the present invention;

[0024] Figure 3 This is a microstructure diagram of the hot-rolled part in an embodiment of the present invention; wherein, Figure 3 Figure (a) shows the microstructure of a hot-rolled part with a deformation of 5%; Figure (b) shows the microstructure of a hot-rolled part with a deformation of 15%; Figure (c) shows the microstructure of a hot-rolled part with a deformation of 30%; Figure (d) shows the microstructure of a hot-rolled part with a deformation of 45%; and Figure (e) shows the microstructure of a hot-rolled part with a deformation of 60%.

[0025] Figure 4 These are the microstructures of titanium alloy parts after hot-rolled parts with different rolling deformation amounts and heat treatment at different temperatures; wherein, (a) corresponds to a deformation amount of 5% and a heat treatment temperature of 810℃; (b) corresponds to a deformation amount of 30% and a heat treatment temperature of 810℃; (c) corresponds to a deformation amount of 60% and a heat treatment temperature of 810℃; (d) corresponds to a deformation amount of 5% and a heat treatment temperature of 840℃; (e) corresponds to a deformation amount of 30% and a heat treatment temperature of 840℃; (f) corresponds to a deformation amount of 60% and a heat treatment temperature of 840℃; (g) corresponds to a deformation amount of 5% and a heat treatment temperature of 870℃; (h) corresponds to a deformation amount of 30% and a heat treatment temperature of 870℃; and (i) corresponds to a deformation amount of 60% and a heat treatment temperature of 870℃.

[0026] Figure 5 This is a comparison chart of the room temperature tensile strength of titanium alloy parts after hot-rolled parts with different rolling deformations and different heat treatment temperatures.

[0027] Figure 6 This is a comparison chart of the tensile strength at 400℃ of titanium alloy parts after hot-rolled parts with different rolling deformations and after being treated at different heat treatment temperatures. Detailed Implementation

[0028] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0029] This invention provides a method for processing titanium alloy parts, which mainly includes the following steps:

[0030] 1) Hot rolling process: The titanium alloy material is heated to 950℃±2℃, held at that temperature for a set time, and then hot rolled to obtain the hot rolled part; the deformation of the hot rolling process is 5-60%.

[0031] The hot rolling process takes 30 min ± 2 min.

[0032] Among them, the titanium alloy material is titanium alloy sheet.

[0033] The titanium alloy parts are made of TC4 titanium alloy.

[0034] 2) Heat treatment step: The hot-rolled part is heat-treated to obtain a titanium alloy part; wherein the heat treatment temperature is 840℃±2℃.

[0035] The heat treatment time is 30 min ± 2 min.

[0036] The heating rate for heating the hot-rolled part to the heat treatment temperature is 300℃ / h ± 2℃ / h.

[0037] The titanium alloy part is a ring-shaped part.

[0038] Regarding the above scheme, it should be noted that: by controlling the deformation amount during hot rolling and synergistically controlling the heat treatment temperature, the microstructure of the obtained titanium alloy material is as follows: a composite structure of uniform equiaxed α phase and continuous network β phase, with the αs phase size being 0.8–1.0 μm. This microstructure significantly reduces the anisotropy of the material's mechanical properties.

[0039] The present invention will be further illustrated below with specific embodiments:

[0040] Example 1

[0041] The material used in this embodiment is TC4 titanium alloy ingot produced by Wuxi Parker New Material Technology Co., Ltd. First, the titanium alloy ingot is machined into a 30×60×200mm titanium alloy sheet, and then the following processing is performed:

[0042] 1) Hot rolling process: The titanium alloy sheet is held at 950℃ for 30 minutes (to ensure uniform heating) and then hot rolled to obtain the hot-rolled part. The deformation is 5%.

[0043] 2) Heat treatment steps: The hot-rolled part is heated to 840℃ at a heating rate of 300℃ / h, then held at that temperature for 30min, and then air-cooled to room temperature to obtain titanium alloy rolled plate.

[0044] The chemical composition of the titanium alloy ingot is shown in Table 1:

[0045] Table 1. Composition of TC4 Alloy Ingot

[0046] element Al V Fe H C N O Ti Quality fraction (%) 6.6 4.6 0.2 0.0017 0.02 0.009 0.16 margin

[0047] Example 2

[0048] This embodiment processes titanium alloy sheet to prepare titanium alloy parts; the difference between Embodiment 2 and Embodiment 1 is as follows:

[0049] The deformation during the hot rolling process is 30%.

[0050] Other parameters and steps are the same as in Example 1.

[0051] Example 3

[0052] This embodiment processes titanium alloy sheet to prepare titanium alloy parts; the difference between Example 3 and Example 1 is as follows:

[0053] The deformation during the hot rolling process is 60%.

[0054] Other parameters and steps are the same as in Example 1.

[0055] Example 4

[0056] This embodiment processes titanium alloy sheet to prepare titanium alloy parts; the difference between Example 4 and Example 1 is as follows:

[0057] The deformation during the hot rolling process is 15%.

[0058] Other parameters and steps are the same as in Example 1.

[0059] Example 5

[0060] This embodiment processes titanium alloy sheets to prepare titanium alloy parts; the difference between Example 5 and Example 1 is as follows:

[0061] The deformation during the hot rolling process is 45%.

[0062] Other parameters and steps are the same as in Example 1.

[0063] Comparative Example 1

[0064] Comparative Example 1 involves processing titanium alloy sheet to prepare titanium alloy parts; the difference between Comparative Example 1 and Example 1 is as follows:

[0065] The heat treatment temperature in the heat treatment step is 780℃.

[0066] Other parameters and steps are the same as in Example 1.

[0067] Comparative Example 2

[0068] Comparative Example 2 involves processing titanium alloy sheets to prepare titanium alloy parts; the difference between Comparative Example 2 and Comparative Example 1 is as follows:

[0069] The deformation during the hot rolling process is 30%.

[0070] Other parameters and steps are the same as in Comparative Example 1.

[0071] Comparative Example 3

[0072] Comparative Example 3 involves processing titanium alloy sheet to prepare titanium alloy parts; the difference between Comparative Example 3 and Comparative Example 1 is as follows:

[0073] The deformation during the hot rolling process is 60%.

[0074] Other parameters and steps are the same as in Comparative Example 1.

[0075] Comparative Example 4

[0076] Comparative Example 4 involves processing titanium alloy sheets to prepare titanium alloy parts; the difference between Comparative Example 1 and Example 1 is as follows:

[0077] The heat treatment temperature in the heat treatment step is 810℃.

[0078] Other parameters and steps are the same as in Example 1.

[0079] Comparative Example 5

[0080] Comparative Example 5 involves processing titanium alloy sheets to prepare titanium alloy parts; the difference between Comparative Example 5 and Comparative Example 4 is as follows:

[0081] The deformation during the hot rolling process is 30%.

[0082] Other parameters and steps are the same as in Comparative Example 4.

[0083] Comparative Example 6

[0084] Comparative Example 6 involves processing titanium alloy sheets to prepare titanium alloy parts; the difference between Comparative Example 6 and Comparative Example 4 is as follows:

[0085] The deformation during the hot rolling process is 60%.

[0086] Other parameters and steps are the same as in Comparative Example 4.

[0087] Comparative Example 7

[0088] Comparative Example 7 involves processing titanium alloy sheet to prepare titanium alloy parts; the difference between Comparative Example 7 and Example 1 is as follows:

[0089] The heat treatment temperature in the heat treatment step is 870℃.

[0090] Other parameters and steps are the same as in Example 1.

[0091] Comparative Example 8

[0092] Comparative Example 8 involves processing titanium alloy sheet to prepare titanium alloy parts; the difference between Comparative Example 8 and Comparative Example 7 is as follows:

[0093] The deformation during the hot rolling process is 30%.

[0094] Other parameters and steps are the same as in Comparative Example 7.

[0095] Comparative Example 9

[0096] Comparative Example 9 processed titanium alloy sheet to prepare titanium alloy parts; the difference between Comparative Example 9 and Comparative Example 7 is as follows:

[0097] The deformation during the hot rolling process is 60%.

[0098] Other parameters and steps are the same as in Comparative Example 7.

[0099] The process parameters for Examples 1-4 and Comparative Examples 1-9 are shown in Table 2:

[0100] Table 2

[0101] Deformation amount of hot rolling Heat treatment temperature Example 1 5％ 840℃ Example 2 30％ 840℃ Example 3 60％ 840℃ Example 4 15％ 840℃ Example 5 45％ 840℃ Comparative Example 1 5％ 780℃ Comparative Example 2 30％ 780℃ Comparative Example 3 60％ 780℃ Comparative Example 4 5％ 810℃ Comparative Example 5 30％ 810℃ Comparative Example 6 60％ 810℃ Comparative Example 7 5％ 870℃ Comparative Example 8 30％ 870℃ Comparative Example 9 60％ 870℃

[0102] Microstructure observation and mechanical property testing were performed on the hot-rolled and titanium alloy samples prepared in Examples 1-5 and Comparative Examples 1-9. The tensile test samples used adopted the national standard sample size M10-Φ5, and the tensile sample dimensions are as follows: Figure 1 As shown ( Figure 1 The drawings used are for the national standard M10-Φ5 tensile bar (dimensions in mm). To improve data reliability, two tensile specimens were taken for each test. Room temperature tensile testing and 400℃ high-temperature tensile testing were performed according to GB / T 228.1 and GB / T 4338, respectively. The microstructure of the longitudinal section of the tensile fracture surface was observed using a TESCAN MIRA3 scanning electron microscope (SEM). Electron backscatter diffraction (EBSD) measurements and analysis were performed on the hot-rolled and annealed plates using a Verios scanning electron microscope with an EBSD system. The collected data were then analyzed and processed using Aztec Crystal software.

[0103] Furthermore, it should be noted that in the above embodiments and comparative examples, titanium alloy ingots were processed into titanium alloy plates for subsequent hot rolling. The microstructure of the titanium alloy plates is as follows: Figure 2 As shown in the figure. Where RD represents the rolling direction, TD represents the transverse direction, and ND represents the normal phase.

[0104] The test results are as follows:

[0105] First, Figure 3 This is a microstructure diagram of the hot-rolled part in an embodiment of the present invention; wherein, Figure 3Figure (a) shows the microstructure of a hot-rolled part with a deformation of 5% (corresponding to the hot-rolled part in Example 1); Figure (b) shows the microstructure of a hot-rolled part with a deformation of 15% (corresponding to the hot-rolled part in Example 4); Figure (c) shows the microstructure of a hot-rolled part with a deformation of 30% (corresponding to the hot-rolled part in Example 2); Figure (d) shows the microstructure of a hot-rolled part with a deformation of 45% (corresponding to the hot-rolled part in Example 5); and Figure (e) shows the microstructure of a hot-rolled part with a deformation of 60% (corresponding to the hot-rolled part in Example 3).

[0106] Because TC4 titanium alloy undergoes high-temperature deformation in the two-phase region, i.e., the temperature range of 800℃-1000℃ during the coexistence of α phase and β phase, dynamic recrystallization will occur, resulting in a biphasic structure in the deformed morphology. However, due to the different amounts of deformation, there are certain differences in the morphology of the structure.

[0107] When the deformation is 5%, a large amount of equiaxed structure is transformed into lamellar structure. Due to the small amount of deformation, most of the αp phase is equiaxed, and the βt phase is distributed between the αp phases.

[0108] As the amount of deformation increases (see...) Figure 3 In Figure (b), some equiaxed αp phases are elongated, gradually showing a tendency to become elongated.

[0109] When the deformation reaches 30% (see...) Figure 3 (c) In the figure: Most of the equiaxed αp phases are transformed into elongated shapes. This is because the flow and deformation direction of the material during hot rolling is consistent with the hot rolling direction. Furthermore, as the amount of deformation increases, the thermal activation energy of deformation increases, making it easier for grain boundaries and phase boundaries to migrate within the alloy, resulting in the grains being elongated along the rolling direction.

[0110] When the deformation reaches 45% (see...) Figure 3 (Figure (d) in the diagram): The greater deformation produces higher distortion energy, which further increases the degree of dynamic recrystallization, causing the elongated αp phase to begin to transform into an equiaxed shape. Furthermore, as the deformation increases to 45%, the size of αs phase decreases significantly. This is because the increased degree of dynamic recrystallization leads to the formation of new, fine αs phase grains (it should be noted here that αs phase grains usually refer to needle-like α phase grains present in the layered β phase in the microstructure diagram, which are small in size and contribute to improving mechanical properties).

[0111] When the deformation increases to 60% (see...) Figure 3(Figure (e)): Greater deformation produces higher distortion energy, leading to complete dynamic recrystallization. Under these conditions, most of the elongated αp phase transforms into a distinct equiaxed structure, and the content of the βt phase increases significantly. This is because greater distortion energy may cause strain-induced phase transformation, resulting in a more pronounced partitioning of the α and β phases. The equiaxed structure becomes unstable and begins to undergo phase transformation, gradually transforming into a lamellar structure and generating more and finer αs phases.

[0112] second, Figure 4 The figures show the microstructures of hot-rolled parts with different rolling deformations after being treated at different heat treatment temperatures; (a) corresponds to a deformation of 5% and a heat treatment temperature of 810℃ (Comparative Example 4); (b) corresponds to a deformation of 30% and a heat treatment temperature of 810℃ (Comparative Example 5); (c) corresponds to a deformation of 60% and a heat treatment temperature of 810℃ (Comparative Example 6); and (d) corresponds to a deformation of 5% and a heat treatment temperature of 840℃ (Example 1). (e) The deformation amount corresponding to the figure is 30% and the heat treatment temperature is 840℃ (Example 2); (f) The deformation amount corresponding to the figure is 60% and the heat treatment temperature is 840℃ (Example 3); (g) The deformation amount corresponding to the figure is 5% and the heat treatment temperature is 870℃ (Comparative Example 7); (h) The deformation amount corresponding to the figure is 30% and the heat treatment temperature is 870℃ (Comparative Example 8); (i) The deformation amount corresponding to the figure is 60% and the heat treatment temperature is 870℃ (Comparative Example 9).

[0113] from Figure 4 It can be seen that:

[0114] Under low deformation (5%) conditions, the effect of heat treatment temperature is relatively limited. Specifically, at a heat treatment temperature of 810℃, the microstructure mainly consists of incompletely recrystallized coarse α phase and a small amount of β phase, and the dislocation structure caused by residual rolling deformation is still quite obvious. When the heat treatment temperature rises to 840℃, fine equiaxed α grains begin to appear in some areas, indicating that the recrystallization process is gradually activated. When the heat treatment temperature rises to 870℃, although the temperature increase promotes phase boundary migration, the grain coarsening phenomenon is not significant due to insufficient driving force provided by the low deformation.

[0115] Under a deformation of 30%, the temperature sensitivity of the microstructure is significantly enhanced. Specifically, at a heat treatment temperature of 810℃, the deformation-induced increase in dislocation density provides more nucleation sites for recrystallization, forming fine lamellar α structures. When the heat treatment temperature rises to 840℃, recrystallization tends to be complete, the α phase exhibits uniform equiaxed characteristics, and the β phase distribution is more continuous, reflecting a typical dynamic recrystallization morphology. However, at a high temperature of 870℃, although recrystallization is complete, the grain size increases significantly, especially with local coarsening in the β phase region, suggesting the occurrence of over-annealing.

[0116] Under high deformation (60%) conditions, intense plastic deformation leads to significant distortion of the initial microstructure. Specifically, at a heat treatment temperature of 810℃, significant recrystallization behavior is observed, forming a composite structure of ultrafine equiaxed α grains and dispersed β phases. Heat treatment at 840℃ further optimizes the microstructure homogeneity, stabilizing the α grain size at the micrometer level and achieving optimal phase distribution matching; at this point, the material exhibits both high strength and good plasticity. When the heat treatment temperature rises to 870℃, although the high deformation delays the grain coarsening process, the abnormal growth of the β phase region still leads to a decrease in microstructure homogeneity, with some areas showing an imbalance in the α / β phase ratio.

[0117] In summary, for titanium alloy parts with low deformation (5%), increasing the heat treatment temperature mainly helps to activate the recrystallization process, refine the grains, and uniformly distribute the β phase, but it is still affected by grain coarsening. For titanium alloy parts with medium deformation (30%) and high deformation (60%), the heat treatment temperature is more important because it promotes dynamic recrystallization and continuous layering of the β phase, significantly improving the microstructure uniformity and mechanical properties. Especially at a heat treatment temperature of 840℃, the anisotropy of the material is significantly reduced, achieving optimal performance. Therefore, a heat treatment temperature of 840℃ and a hot rolling deformation of 5-60% (preferably 30-60%) correspond to excellent microstructure, resulting in excellent material uniformity and properties.

[0118] Third, Table 3 shows the width of the αs phase in the microstructure of titanium alloy parts after hot-rolled parts with different deformation amounts have been treated at different heat treatment temperatures.

[0119] Table 3

[0120] 780℃ 810℃ 840℃ 870℃ 5％ 1.276μm 1.185μm 1.134μm 1.252μm 30％ 1.129μm 1.061μm 0.929μm 1.115μm 60％ 0.727μm 0.722μm 0.862μm 0.884μm

[0121] It should be noted that fine αs phases in the microstructure of titanium alloy parts, especially those with a size in the range of 0.8-1.0 μm, can significantly improve the mechanical properties of titanium alloys.

[0122] Fourth, Table 4 shows the relative content of the α phase in the microstructure of titanium alloy parts after hot-rolled parts with different deformation amounts have been treated at different heat treatment temperatures.

[0123] Table 4

[0124] 780℃ 810℃ 840℃ 870℃ 5％ 72.66％ 73.72％ 70.26％ 71.31％ 30％ 66.12％ 66.36％ 62.63％ 67.33％ 60％ 73.24％ 71.78％ 67.64％ 69.16％

[0125] Table 4 shows that the proportion of the α phase in the microstructure of TC4 alloy exhibits a dynamic evolution closely related to the deformation amount, with changes in heat treatment temperature. At an annealing temperature of 780℃, the relative content of the α phase first decreases and then increases with increasing deformation. As deformation occurs, the α phase content gradually decreases, possibly because when the deformation amount is small, the phase transformation process inside the alloy may be insufficient, leading to a higher relative content of the αp phase and limiting the formation and refinement of the αs phase. However, as the deformation amount continues to increase, the proportion of the α phase gradually increases. This may be due to the deformation-induced phase transformation of the β phase in the two-phase region into the α phase. With increasing deformation, more β phases transform into a higher content of the α phase. Simultaneously, large deformation may also lead to an increase in recrystallization, further refining the grains and changing the phase ratio, resulting in an increase in the proportion of the α phase. As the temperature increased to 810℃, the α-phase proportion in the 5% deformation sample increased to 73.72%, possibly because the partial recrystallization process stabilized the α-phase structure by releasing residual stress. However, when the deformation increased to 30% and 60%, the α-phase proportion decreased to 66.36% and 71.78%, respectively, reflecting that the dislocation density introduced by the higher deformation accelerated dynamic recrystallization, promoting the transformation of some α-phase to β-phase. At annealing at 840℃, the α-phase proportion generally decreased to its lowest level, indicating that the synergistic effect of recrystallization and phase transformation was most active in this temperature range. The 60% deformation sample, due to the sufficient driving force provided by the intense plastic deformation, promoted the refinement of the α-phase and its partial dissolution in the β matrix, while the low deformation sample had a relatively high α-phase retention ratio due to insufficient recrystallization. When the temperature was further increased to 870℃, the proportion of the α phase showed differentiated responses: the 5% deformation sample saw a slight increase in the α phase proportion to 71.31% due to grain boundary migration and enhanced β phase stability at high temperatures; the 30% deformation sample experienced a rebound in the α phase proportion to 67.33% due to a non-equilibrium phase transformation caused by over-annealing; while the 60% deformation sample saw a continuous decrease in the α phase proportion to 69.16% due to high recrystallization completion and a more stable phase distribution. Notably, the increase in deformation significantly improved the efficiency of temperature in controlling the α phase proportion. The change in the α phase proportion caused by temperature increase was relatively small at 5% deformation (approximately 2.5%), while the change reached 5.6% at 60% deformation. This is attributed to the high-density defects introduced by high deformation accelerating atomic diffusion and phase boundary migration.

[0126] Because the α phase of the HCP (hexagonal close-packed) structure has higher strength than the β phase of the BCC (body-centered cubic) structure, the dense atomic arrangement and strong intercrystalline interactions within the HCP structure make it more robust under external stress and less prone to slippage. In contrast, the atomic arrangement of the BCC structure is relatively loose, making the β phase more susceptible to slippage during deformation, resulting in a smoother deformation process and thus lower strength. The relatively small number of slip systems in the α phase allows for effective stress distribution to stronger deformation modes during plastic deformation, thereby increasing its strength. The β phase in the BCC structure has more slip systems, making it more prone to slippage under the same stress conditions, thus resulting in relatively lower strength. The increased strength of titanium alloys as the proportion of the α phase increases is due to the fact that more α phase allows the alloy to withstand greater stress under external forces and exhibit better resistance to deformation. Especially at high temperatures, the α phase maintains its high strength, while the β phase is prone to softening. Therefore, by increasing the content of the α phase, the overall strength of titanium alloys is enhanced, especially when subjected to external forces such as tension, compression and torsion, exhibiting better resistance to deformation.

[0127] In this embodiment of the invention, the suitable content of the α phase is mainly determined under the conditions of a deformation amount of 30% to 60% and a heat treatment temperature of 840°C. Within this range, the α phase content of the titanium alloy... s Refining the α phase to 0.8–1.0 μm achieves a good balance between the material's strength and toughness, while reducing anisotropy problems caused by grain inhomogeneity. Therefore, an appropriate α phase content can effectively improve the mechanical properties of titanium alloys, especially playing a key role in reducing anisotropy and improving microstructure uniformity.

[0128] fifth, Figure 5 This is a comparison chart of the room temperature tensile strength of hot-rolled parts with different rolling deformations and titanium alloy parts treated at different heat treatment temperatures.

[0129] from Figure 5 It can be seen that as the heat treatment temperature increases, the difference between the rolling direction (RD) and transverse direction (TD) properties decreases significantly. Among them, the 840℃ heat treatment process shows the best comprehensive control effect.

[0130] The optimal solution in this embodiment of the invention (5-60% deformation and a heat treatment temperature of 840℃±2℃) is that, under these conditions, the titanium alloy can fully utilize dynamic recrystallization to refine the α phase and form a continuous layered β phase, thereby achieving homogenization of the microstructure and optimization of mechanical properties. The 840℃ heat treatment temperature ensures optimal microstructural stability and mechanical properties, particularly demonstrating a significant advantage in reducing anisotropy. This heat treatment temperature effectively promotes the recrystallization process, resulting in uniform and refined grains in the titanium alloy, while ensuring a balance between strength and plasticity. Therefore, a 5-60% deformation and a 840℃ heat treatment temperature are key process parameters for achieving optimal performance.

[0131] At a heat treatment temperature of 780℃, the microstructure of the titanium alloy ring-shaped component cannot be effectively optimized, making it unable to meet the requirements for high performance and stability. Due to the inhomogeneous grains, uneven phase distribution, and significant differences in mechanical properties, the reliability of the material under complex working conditions cannot be guaranteed.

[0132] At a heat treatment temperature of 810℃, the tensile strength of the sample with a deformation of 5% reached 1025MPa in the TD direction, but there was still obvious anisotropy in the RD direction due to residual work hardening and uneven distribution of coarse α phase; while the sample with a deformation of 60% formed a composite structure of ultrafine equiaxed α grains and dispersed β phase through dynamic recrystallization, which partially alleviated the anisotropy, but the synergistic strengthening of the two phases has not yet reached equilibrium.

[0133] At a heat treatment temperature of 840℃, the αs phase size in the 30% deformation sample reached its minimum value. The continuous distribution of the β phase and the uniform refinement of the α phase formed an efficient two-phase synergistic strengthening mechanism. The tensile strength in the TD direction stabilized at 1017 MPa, and due to sufficient dynamic recrystallization, the strength difference between the RD direction and the TD direction was reduced to within 15 MPa. The anisotropy index was reduced by about 15% compared with the heat treatment at 810℃. For the 60% deformation sample, the heat treatment at 840℃ accelerated the dynamic recrystallization process, suppressed the orientation preference caused by grain boundary migration, further weakened the mechanical difference between the rolling and normal directions, and maintained the αs phase size refinement to 0.862 μm, achieving a balance between high strength and low anisotropy.

[0134] In contrast, although the heat treatment temperature of 870℃ reduced the anisotropy difference of the 30% deformation sample by increasing the proportion of α phase and the dispersed distribution of β phase, the grain coarsening and over-tempering effect caused by high temperature significantly weakened the overall strength.

[0135] In summary, the 840℃ heat treatment process, by optimizing the dynamic recrystallization process, refining the α-phase size, and controlling the β-phase distribution, significantly reduces the anisotropy in the rolling and normal directions while maintaining high tensile strength, making it the optimal annealing temperature for balancing the microstructure stability and mechanical property homogenization of TC4 alloy.

[0136] sixth, Figure 6 This is a comparison chart of the tensile strength at 400℃ of titanium alloy parts after hot rolling with different deformation amounts and after being treated at different heat treatment temperatures.

[0137] from Figure 6 It can be seen that as the heat treatment temperature increases, the performance difference between the RD and TD directions gradually decreases. Among them, the 840℃ heat treatment process becomes the key node for balancing high-temperature strength and anisotropy by optimizing the microstructure coordination.

[0138] In the 810℃ heat treatment, the sample with 60% deformation formed fine αs phase and a high α phase ratio due to dynamic recrystallization, achieving a TD direction strength of 705 MPa. However, the uneven distribution of the β phase in the RD direction limited the synergistic strengthening between the two phases, resulting in a high anisotropy index. In contrast, with the 840℃ heat treatment, the αs phase size in the 60% deformation sample increased to 0.862 μm. However, after recrystallization, the β phase formed a continuous layered structure, significantly enhancing the phase boundary bonding force. This stabilized the TD direction strength at 702 MPa, and the RD direction strength simultaneously increased to 695 MPa, reducing the difference between the two directions to less than 7 MPa. The anisotropy index decreased by approximately 50% compared to the 810℃ condition.

[0139] For the 5% deformation sample, although the 840℃ heat treatment process reduced the TD direction strength to 665MPa due to the decrease in the proportion of α phase, the improved uniformity of β phase distribution effectively suppressed the performance degradation in the RD direction, keeping the anisotropy difference within 30MPa, highlighting the regulatory effect of heat treatment temperature on the homogenization of the microstructure of the low deformation sample.

[0140] When the annealing temperature reached 870℃, although the high deformation sample delayed grain coarsening through deformation energy storage and maintained a TD direction strength of 702MPa, the local imbalance of the dispersed β phase distribution led to increased strength fluctuations in the RD direction, and the anisotropy difference rose back to 20MPa. Meanwhile, the low deformation sample experienced a simultaneous decrease in both α phase coarsening and β phase aggregation, resulting in a bidirectional strength drop to 665MPa. This indicates that high-temperature annealing has limited homogenization capabilities for low deformation samples.

[0141] In summary, the 840℃±2℃ heat treatment process is the optimal choice for optimizing the overall performance and anisotropy control of titanium alloys. At room temperature and 400℃, the 840℃±2℃ heat treatment process significantly reduces the strength difference between the RD and TD directions through the synergistic effect of dynamic recrystallization and continuous layering of the β phase, while maintaining high tensile strength. For samples with different deformation amounts, the refinement of the α phase and the homogenization of the β phase distribution at this heat treatment temperature effectively suppress grain boundary orientation bias and improve microstructural stability. In contrast, the microstructure obtained by the 780℃ heat treatment process exhibits significant coarseness and large deformation of the incompletely recrystallized α phase, resulting in substantial anisotropy. The 810℃ heat treatment process results in residual anisotropy due to insufficient recrystallization, while the 870℃ heat treatment process weakens both strength and homogenization effects due to high-temperature grain coarsening. In summary, the 840℃±2℃ heat treatment process achieves the preparation of titanium alloy parts that balance high strength and low anisotropy through balanced grain refinement strengthening, phase distribution regulation and thermal softening suppression mechanisms.

[0142] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for processing titanium alloy parts, characterized in that, It includes the following steps: Hot rolling process: The titanium alloy material is heated to 950℃±2℃, held at that temperature for a set time, and then hot rolled to obtain the hot rolled part; the deformation of the hot rolling process is 5-60%; Heat treatment step: The hot-rolled part is subjected to heat treatment to obtain a titanium alloy part; wherein the heat treatment temperature is 840℃±2℃.

2. The processing method for titanium alloy parts according to claim 1, characterized in that, In the hot rolling process, the titanium alloy material is a titanium alloy sheet.

3. The processing method for titanium alloy parts according to claim 1 or 2, characterized in that, In the hot rolling process, the set time is 30 min ± 2 min.

4. The processing method for titanium alloy parts according to any one of claims 1-3, characterized in that, In the heat treatment step: the heat treatment time is 30 min ± 2 min.

5. The processing method for titanium alloy parts according to any one of claims 1-4, characterized in that, In the heat treatment step, the heating rate of the hot-rolled part to the heat treatment temperature is 300℃ / h ± 2℃ / h.

6. The processing method for titanium alloy parts according to any one of claims 1-5, characterized in that, The titanium alloy component is made of TC4 titanium alloy.

7. The processing method for titanium alloy parts according to any one of claims 1-6, characterized in that, The titanium alloy part is a hot-rolled sheet metal part.

8. A titanium alloy part, characterized in that, The titanium alloy part is obtained by processing the titanium alloy part according to any one of claims 1-7.

9. The titanium alloy part according to claim 8, characterized in that, The microstructure of the titanium alloy part includes a composite structure of equiaxed α phase and continuous layered β phase, wherein the αs phase is distributed between the continuous layered β phase.

10. The titanium alloy part according to claim 9, characterized in that, The size of the αs phase is 0.8–1.0 μm.

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