A method for multi-directional reversing forging of Ti80 titanium alloy based on dynamic organization regulation

Abstract

The application provides a titanium alloy multi-directional reversing forging method based on dynamic organization regulation, which comprises the following steps: pretreating and initially regulating the organization of a titanium alloy ingot to obtain a pretreated titanium alloy ingot; performing multi-parameter coupling forging of the reversing frequency-deformation-temperature field on the pretreated titanium alloy ingot to obtain a forged piece; performing dynamic recrystallization and solid solution-ageing strengthening on the forged piece and cooling to obtain a titanium alloy. The method realizes the coupling refining effect of the dynamic recrystallization in the beta phase area and the alpha phase lamellar structure through the multi-parameter coupling forging of the reversing frequency-deformation-temperature field on the titanium alloy ingot, and significantly improves the comprehensive performance of the titanium alloy forged piece, such as the tensile strength, toughness and fatigue performance.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material preparation technology, and particularly relates to a method for multi-directional reversible forging of Ti80 titanium alloy based on dynamic microstructure control. Background Technology

[0002] Titanium alloys possess high strength, low density, excellent corrosion resistance, and high-temperature performance, making them widely used in numerous critical fields such as aerospace, defense, automotive manufacturing, and biomedicine. Meanwhile, Ti80 titanium alloy, as a high-performance titanium alloy, has become the preferred material for manufacturing high-precision products such as aircraft and aero-engine components due to its superior comprehensive properties.

[0003] However, traditional Ti80 titanium alloy forging processes have significant limitations. Conventional forging methods struggle to precisely control the microstructure of Ti80 titanium alloys, leading to large fluctuations in the mechanical properties of titanium alloy forgings. This prevents the full realization of the potential advantages of Ti80 titanium alloys and makes it difficult to meet the stringent requirements of high-end equipment manufacturing for consistent and stable material properties. Furthermore, traditional forging processes often require numerous machining steps, resulting in low production efficiency, high energy consumption, and unsatisfactory material utilization. This not only increases production costs but also limits the large-scale application of Ti80 titanium alloys in a wider range of fields. With the continued growth in demand for high-performance titanium alloys across various industries, developing a new forging process that can effectively overcome the drawbacks of traditional forging processes, achieve precise control over the microstructure of Ti80 titanium alloys, and improve product quality and production efficiency is urgently needed. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for multi-directional reversing forging of titanium alloys based on dynamic microstructure control, which significantly improves the overall performance of titanium alloy forgings.

[0005] This invention provides a method for multi-directional reversible forging of titanium alloys based on dynamic microstructure control, comprising the following steps:

[0006] Pretreated titanium alloy ingots are obtained by pretreatment and initial microstructure control.

[0007] The pretreated titanium alloy ingot is subjected to multi-parameter coupled forging of reversal number, deformation amount, and temperature field to obtain a forging;

[0008] The forging was subjected to dynamic recrystallization and solution-aging strengthening, followed by cooling to obtain a titanium alloy.

[0009] Preferably, the pretreatment and initial microstructure control of the titanium alloy ingot include:

[0010] The titanium alloy ingot is held at 30-50℃ above the β phase transformation point for 2-5 hours and then water-quenched to obtain a martensitic structure. The Ti80 titanium alloy ingot is then pre-deformed by 30-45% using a triaxial anvil to break the original coarse grains to below 200-400μm.

[0011] Preferably, the pretreated titanium alloy ingot undergoes multi-parameter coupled forging involving reversal number, deformation amount, and temperature field, including:

[0012] The process employs a cycle of 3 forging passes in the Z-axis direction, 2 forging passes in the Y-axis direction, and 1 forging pass in the X-axis direction. During the alternating forging process of the ZYX axes, the deformation amount in each pass exhibits a gradient distribution, with 15-18% in the first forging pass and decreasing to 8-10% in subsequent passes. The reversal angle can be dynamically adjusted to a reversal angle of 70°-90° between adjacent passes. In the β single-phase region, the forging process is set to 2-4 heat treatments, with a forging temperature gradient of 30-60°C.

[0013] The temperature distribution of the forging is set as a temperature gradient field, with the core temperature at 1000–1060℃ and the surface temperature at 950–1010℃, so that the temperature difference between the core and the surface is 40–60℃. The low-temperature zone is rapidly heated at 50–100℃ / s in the ZYX axis reversal gap by induction local heating. The temperature of the forging is stepped during the final forging, and the temperature of the forging is reduced to 920–960℃ 5–10 minutes before the final forging.

[0014] Preferably, the temperature gradient field of the forging is controlled to dynamically precipitate in the β phase region, thereby achieving a bimodal distribution of α phase grain size, with the size of the fine lamellar α phase being less than 1 μm and the grain size of the spherical α phase being 3 to 5 μm.

[0015] Preferably, the dynamic recrystallization employs a reaction rate of 0.05–0.20 s. -1 The Zener-Hollomon parameter ranges from 3.0×10¹² to 8.0×10¹³.

[0016] Preferably, the proportion of dynamic recrystallization reaches 60-80%.

[0017] Preferably, the solution-aging strengthening process employs double annealing, with the first annealing temperature at 900–940°C and a holding time of 1–3 h; and the second annealing temperature at 750–780°C and a holding time of 4–6 h.

[0018] Preferably, the aging strengthening temperature is 550–600℃, and the aging strengthening holding time is 8–12 hours.

[0019] Preferably, the cooling rate is 40–60 °C / min.

[0020] Preferably, the titanium alloy is a Ti80 alloy.

[0021] This invention provides a method for multi-directional reversing forging of titanium alloys based on dynamic microstructure control, comprising the following steps: pre-treating and initially controlling the microstructure of a titanium alloy ingot to obtain a pre-treated titanium alloy ingot; performing multi-parameter coupled forging of the reversing number, deformation amount, and temperature field of the pre-treated titanium alloy ingot to obtain a forging; and subjecting the forging to dynamic recrystallization and solution-aging strengthening, followed by cooling to obtain a titanium alloy. This invention achieves the coupled refinement of dynamic recrystallization in the β-phase region and the lamellar structure of the α-phase through multi-parameter coupled forging of the reversing number, deformation amount, and temperature field of the titanium alloy ingot, significantly improving the comprehensive properties of the titanium alloy forging, including tensile strength, toughness, and fatigue performance. Attached Figure Description

[0022] Figure 1 Flowchart of multi-directional reversible forging process for titanium alloys;

[0023] Figure 2 This is a schematic diagram illustrating the optimization of the multi-directional reversing forging path;

[0024] Figure 3 This is a schematic diagram of the solution-aging heat treatment of titanium alloy forgings in an embodiment of the present invention;

[0025] Figure 4 The image shows the metallographic structure of the Ti80 titanium alloy prepared according to an embodiment of the present invention. Detailed Implementation

[0026] This invention provides a method for multi-directional reversible forging of titanium alloys based on dynamic microstructure control, comprising the following steps:

[0027] Pretreated titanium alloy ingots are obtained by pretreatment and initial microstructure control.

[0028] The pretreated titanium alloy ingot is subjected to multi-parameter coupled forging of reversal number, deformation amount, and temperature field to obtain a forging;

[0029] The forging was subjected to dynamic recrystallization and solution-aging strengthening, followed by cooling to obtain a titanium alloy.

[0030] This invention addresses the problems of coarse β-grains, uneven α-phase distribution, anisotropy, and unstable mechanical properties that easily occur in the traditional forging process of Ti80 titanium alloy (Ti-6Al-3Nb-2Zr-1Mo). It proposes a novel forging process that integrates multi-directional deformation path optimization, gradient temperature field control, and dynamic recrystallization synergistic control. By establishing a multi-parameter coupled model of commutation number, deformation amount, and temperature field, the coupled refinement effect of dynamic recrystallization in the β-phase region and the lamellar structure of the α-phase is achieved, significantly improving the overall performance of the titanium alloy forgings.

[0031] This invention pre-treats and controls the initial microstructure of titanium alloy ingots to obtain pre-treated titanium alloy ingots. The invention pre-treats and controls the initial microstructure of titanium alloy ingots that have undergone three vacuum consumable melting processes: the titanium alloy ingot is held at 30–50°C above the β-phase transformation point for 2–5 hours, followed by water quenching to obtain a martensitic microstructure; the titanium alloy ingot is then pre-deformed by 30–45% using a triaxial anvil, breaking the original coarse grains to below 200–400 μm.

[0032] This invention optimizes the multi-directional reversing forging path design for pretreated titanium alloy ingots: a ZYX triaxial alternating forging path design is established, and the reversing process adopts a 3-2-1 reversing mode cycle: that is, 3 passes in the Z-axis direction → 2 passes in the Y-axis direction → 1 pass in the X-axis direction in a cycle; and the deformation amount of each pass in the ZYX triaxial alternating forging process shows a gradient distribution, with 15-18% in the first forging pass and decreasing to 8-10% in subsequent passes; the reversing angle can be dynamically adjusted to a reversing angle of 70°-90° between adjacent passes; the forging process in the β single-phase region is set to 2-4 heats, and the forging temperature shows a temperature gradient of 30-60℃.

[0033] This invention provides precise temperature control of the forging process: the temperature distribution of the forging is set as a temperature gradient field, with the core temperature at 1000–1060°C and the surface temperature at 950–1010°C, resulting in a temperature difference of 40–60°C between the core and the surface; rapid heating of the low-temperature zone at 50–100°C / s is achieved through induction local heating in the ZYX axis reversal gap; and the temperature of the forging is stepped during final forging, with the temperature reduced to 920–960°C 5–10 minutes before final forging, thereby inducing dynamic precipitation of the forging microstructure.

[0034] This invention controls the temperature gradient field of forgings to dynamically precipitate α phase in the β phase region, thereby achieving a bimodal distribution of α phase grain size. The size of the fine lamellar α phase is less than 1 μm, and the grain size of the spherical α phase is 3–5 μm. Specifically, when the material undergoes plastic deformation in the high-temperature β phase region (temperature higher than the β transformation temperature), by controlling deformation parameters (temperature, strain rate, cooling rate, etc.), the α phase is induced to precipitate in situ from the β phase matrix during dynamic deformation, and its morphology (fine lamellar or spherical) and distribution are further controlled to ultimately achieve a bimodal grain size distribution.

[0035] This invention solves the problems of anisotropy and unstable mechanical properties caused by traditional reversing forging processes by optimizing the multi-directional reversing forging path and gradient distribution of deformation amount in each pass.

[0036] This invention optimizes the parameters for dynamic recrystallization of grains during forging: the strain rate is set to 0.05–0.20 s during forging in the β single-phase region. -1Adjust the Zener-Hollomon parameter to 3.0 × 10⁻⁶. 12 ~8.0×10 13 This ensures that the dynamic recrystallization ratio of the forging reaches 60-80%; to promote the reaction and recombination between crystal defects during forging (such as dislocations, stacking faults and twin structures), the pressure is held for 1-2 minutes after each deformation pass.

[0037] This invention provides solution-aging strengthening for forged titanium alloy forgings: preferably, a double annealing process is used. The titanium alloy forgings undergo a first annealing heat treatment at a temperature of 900–940°C for 1–3 hours, followed by air cooling. A second annealing heat treatment is then performed at a temperature of 750–780°C for 4–6 hours, followed by furnace cooling. Finally, the forgings undergo aging treatment at a temperature of 550–600°C for 8–12 hours, followed by gradient cooling at a rate of 40–60°C / hour to 200°C, and then air cooling, resulting in a titanium alloy with excellent mechanical properties.

[0038] This invention establishes a titanium alloy forging process system by optimizing technical parameters such as forging path, deformation parameters, and microstructure evolution control, which is suitable for the mass production of titanium alloy structural parts.

[0039] This invention provides a complete process for the preparation of titanium alloys, but is not limited to Ti80 titanium alloys.

[0040] Figure 1 The flowchart of the multi-directional reversing forging process of titanium alloy in this embodiment of the invention includes: pretreatment of titanium alloy ingots: holding at 30-50℃ above the β phase transformation point for 2-5 hours followed by water quenching and 30-35% pre-deformation; optimization of the multi-directional reversing forging path: 3-2-1 reversing mode cycle and gradient distribution of deformation amount, 15-18% for the first forging pass, decreasing by 8-10% in subsequent passes; control of the gradient temperature field of the forging: the temperature difference between the core and the surface is 40-60℃, and the reversing gap rapidly heats the low-temperature zone at 50-100℃ / s; dynamic recrystallization: the strain rate is 0.05-0.2s. -1 The Zener-Hollomon parameter is 3.0 × 10. 12 ~8.0×10 13 Solution aging: The double annealing temperatures are 900–940℃ and 750–780℃, respectively, and the aging temperature is set to 550–600℃.

[0041] To further illustrate the present invention, the following detailed description of a method for multi-directional reversing forging of titanium alloys based on dynamic microstructure control is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1

[0043] This invention establishes a multi-parameter coupled model of commutation number, deformation amount, and temperature field to achieve the coupled refinement effect of dynamic recrystallization in the β-phase region and lamellar structure of the α-phase, significantly improving the overall performance of Ti80 titanium alloy forgings. The specific invention steps are as follows:

[0044] First, the Ti80 titanium alloy ingot, which has undergone three vacuum consumable melting processes, needs to be pretreated and its initial microstructure controlled: the Ti80 ingot is held at 50°C above the β phase transformation point for 3 hours and then water-quenched to obtain a martensitic microstructure; the Ti80 titanium alloy ingot is pre-deformed by 30% using a triaxial anvil to break the original coarse grains to below 400μm.

[0045] The pretreated titanium alloy ingot undergoes optimized design for a multi-directional reversing forging path, such as... Figure 2 As shown: A ZYX triaxial alternating forging path design is established, and the reversing process adopts a 3-2-1 reversing mode cycle (3 passes in the Z-axis direction → 2 passes in the Y-axis direction → 1 pass in the X-axis direction cycle); the deformation amount of each pass in the ZYX triaxial alternating forging presents a gradient distribution, with 15% in the first forging pass and decreasing to 8% in subsequent passes; the reversing angle can be dynamically adjusted to a reversing angle of 70° between adjacent passes; the forging process in the β single-phase region is set to 3 heats, and the temperature gradient of each heat is set to 40℃.

[0046] Precise control of the gradient temperature field of the forging during the forging process: The temperature distribution of the forging is set as a temperature gradient field, with the core temperature at 1050℃ and the surface temperature at 1000℃, so that the temperature difference between the core and the surface is about 50℃; through induction local heating technology, the low temperature zone is rapidly heated at 100℃ / s in the ZYX axis reversal gap; the temperature of the forging is stepped during the final forging, and the temperature of the forging is reduced to 950℃ 5 minutes before the final forging, thereby inducing dynamic precipitation of the forging structure.

[0047] Parameter optimization was performed on the dynamic recrystallization of grains during forging: the strain rate was set to 0.10 s⁻¹ during forging in the β single-phase region. -1 Adjust the Zener-Hollomon parameter to 1.0 × 10⁻⁶. 13 This ensures that the dynamic recrystallization ratio of the forging reaches 60%; to promote the reaction and recombination between crystal defects during the forging process (such as dislocations, stacking faults and twin structures), the pressure is held for 1 minute after each deformation pass.

[0048] Solution-aging strengthening of the forged Ti80 parts, such as... Figure 3As shown: First, a double annealing process is performed. The Ti80 forging is first annealed at 920℃ for 2 hours, followed by air cooling. Then, the titanium alloy forging is further annealed at 750℃ for 5 hours, followed by furnace cooling. Finally, the forging is aged at 580℃ for 8 hours, followed by gradient cooling at a rate of 50℃ / h to 200℃, and then air cooling is performed to obtain the Ti80 titanium alloy.

[0049] This embodiment achieves a bimodal distribution of α-phase grain size by controlling the dynamic precipitation in the β-phase region. The size of the fine lamellar α-phase is less than 1 μm, and the grain size of the spherical α-phase is 4 μm. The metallographic structure is as follows: Figure 4 As shown, the prepared Ti80 titanium alloy exhibits a room temperature tensile strength exceeding 1000 MPa, an elongation exceeding 15%, and a fracture toughness reaching 65 MPa·m. 1 / 2 .

[0050] As can be seen from the above embodiments, the present invention provides a method for multi-directional reversing forging of titanium alloys based on dynamic microstructure control, comprising the following steps: pre-treating and initially controlling the microstructure of a titanium alloy ingot to obtain a pre-treated titanium alloy ingot; performing multi-parameter coupled forging of the pre-treated titanium alloy ingot with reversal number, deformation amount, and temperature field to obtain a forging; and performing dynamic recrystallization and solution-aging strengthening on the forging, followed by cooling to obtain a titanium alloy. Using this method, on the one hand, the quality of titanium alloy products can be improved. Through dynamic microstructure control, the internal microstructure of the titanium alloy can be precisely controlled, significantly improving the strength, toughness, and fatigue performance of the forgings, meeting the stringent requirements of high-end fields. On the other hand, production efficiency can be improved. Multi-directional reversing forging optimizes the process, reduces forging steps and processing time, and makes the production process more efficient and streamlined. Increased production efficiency reduces energy consumption and labor costs, and improved material utilization also reduces raw material loss costs. Compared with existing forging processes, it has significant competitive advantages, and using the method of the present invention can generate substantial economic benefits.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for multi-directional reversible forging of titanium alloys based on dynamic microstructure control, comprising the following steps: Titanium alloy ingots are cast in β After holding at 30-50℃ above the phase transformation point for 2-5 hours, the Ti80 titanium alloy ingot is quenched in water to obtain a martensitic structure. Then, the Ti80 titanium alloy ingot is pre-deformed by 30-45% using a triaxial anvil to break the original coarse grains to below 200-400 μm, thus obtaining a pretreated titanium alloy ingot. The pretreated titanium alloy ingot is subjected to multi-parameter coupled forging of reversal number, deformation amount, and temperature field to obtain a forging; The pretreated titanium alloy ingot undergoes multi-parameter coupled forging involving reversal frequency, deformation amount, and temperature field, including: The process involves a cycle of 3 forging passes in the Z-axis direction, 2 forging passes in the Y-axis direction, and 1 forging pass in the X-axis direction. During the ZYX triaxial alternating forging process, the deformation amount in each pass exhibits a gradient distribution, with 15-18% in the first pass and decreasing to 8-10% in subsequent passes; the reversal angle can be dynamically adjusted to 70°-90° between adjacent passes; β The single-phase forging process is set to 2 to 4 heat passes, with a forging temperature gradient of 30 to 60°C. The temperature distribution of the forging is set as a temperature gradient field, with the core temperature at 1000~1060℃ and the surface temperature at 950~1010℃, so that the temperature difference between the core and the surface is 40~60℃; the low-temperature zone is rapidly heated at 50~100℃ / s in the ZYX axis reversal gap by induction local heating; the temperature of the forging is stepped during the final forging, and the temperature of the forging is reduced to 920~960℃ 5~10 minutes before the final forging. The forging was subjected to dynamic recrystallization and solution-aging strengthening, followed by cooling to obtain a titanium alloy. The dynamic recrystallization process employs a reaction rate of 0.05–0.20 s. -1 The Zener-Hollomon parameter is 3.0 × 10. 12 ~8.0×10 13 The proportion of dynamic recrystallization reaches 60-80%. The solution-aging strengthening process employs double annealing. The first annealing temperature is 900~940℃, and the holding time is 1~3h. The second annealing temperature is 750~780℃, and the holding time is 4~6h. The aging strengthening temperature is 550~600℃, and the aging strengthening holding time is 8~12h.

2. The method according to claim 1, characterized in that, Temperature gradient field control of forgings enables dynamic precipitation in the β phase region, achieving... α Bimodal distribution of phase grain size, fine lamellar α The phase size is less than 1 μm, spherical α The grain size of the phase is 3~5μm.

3. The method according to claim 1, characterized in that, The cooling rate used is 40~60℃ / min.

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