Manufacturing method of TB9 titanium alloy with grain size bimodal distribution

Abstract

The invention relates to the technical field of metal material processing and forming, in particular to a manufacturing method of TB9 titanium alloy with grain size bimodal distribution. The method comprises the following steps that (1) a TB9 titanium alloy cast ingot is subjected to hot forging to form a cylindrical forging material, and the diameter of the forging material is 20-40 mm; (2) the forged material is subjected to solution treatment, and the solution temperature ranges from 950 DEG C to 1150 DEG C; (3) the forged material subjected to solid solution treatment is subjected to axial rolling treatment to be rolled into a plate, and the thickness is 6-15 mm; (4) the rolled plate is subjected to annealing treatment, and the annealing temperature ranges from 400 DEG C to 500 DEG C; (5) after annealing, the titanium alloy plate is immediately subjected to secondary (asynchronous) rolling to form a thin plate, and the pressing amount is 50%-80%; and (6) the rolled titanium alloy sheet is subjected to recrystallization annealing for a short time, and the annealing temperature ranges from 680 DEG C to 710 DEG C. The method solves or partially solves the problem that the obdurability of the uniform grain titanium alloy cannot be synchronously improved due to a traditional processing technology, and the obdurability of the titanium alloy material is synchronously improved by introducing a grain size bimodal distribution structure.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing and forming, and in particular to a method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution. Background Art

[0002] The inherent strength and ductility of traditional metal materials have a certain restrictive relationship (i.e., inversion of strength and toughness), which limits their application range as structural parts in actual engineering. The introduction of a bimodal distribution structure of grain size in TB9 titanium alloy can obtain excellent mechanical properties and functionality, and has gradually attracted attention from the outside world. In terms of mechanical properties, this heterogeneous structure enables titanium alloys to have both the high strength of fine grains and the high ductility of coarse grains, thereby simultaneously improving their strength and toughness, providing an innovative approach for the development of high-performance lightweight metal structural materials. Summary of the Invention

[0003] The present invention aims to provide a method for manufacturing TB9 titanium alloy with a bimodal distribution of grain size, which solves or partially solves the problem that the strength and toughness of uniform-grained titanium alloys caused by traditional processing techniques cannot be simultaneously improved, and the strength and toughness of the titanium alloy material are simultaneously improved by introducing a bimodal distribution structure of grain size.

[0004] The technical solution of the present invention is:

[0005] A method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution comprises the following steps:

[0006] (1) Hot forging the TB9 titanium alloy ingot into a cylindrical forging with a diameter of 20 mm to 40 mm;

[0007] (2) subjecting the forging material to solution treatment at a solution temperature of 950-1150°C and a holding time of ≥30 min;

[0008] (3) subjecting the forged material after solid solution to axial rolling to be rolled into a titanium alloy plate with a thickness of 6 mm to 15 mm;

[0009] (4) Annealing the rolled plate at a temperature of 400-500°C for a holding time of ≥30 min;

[0010] (5) Immediately after annealing, the upper and lower surfaces of the titanium alloy plate are asynchronously rolled into thin plates with a downward pressure of 50% to 80%;

[0011] (6) The titanium alloy sheet after rolling is subjected to short-time recrystallization annealing, the annealing temperature is 680℃~710℃, and the annealing time is 3~5min.

[0012] The method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution comprises the following steps: in step (1), the metal raw material is melted in an induction furnace and then cast into a metal ingot with a diameter of 100 mm to 200 mm and a height of 200 mm to 400 mm; after the surface oxide scale of the metal ingot is mechanically removed by a lathe, the metal ingot is hot forged into a cylindrical forging with a final size of 20 mm to 40 mm in diameter and a length greater than 100 mm.

[0013] The method for manufacturing the TB9 titanium alloy with a bimodal grain size distribution, in step (2), the forging material is cut into sections with a length of 100 to 200 mm, and then solution treated in a vacuum environment, the forging material is kept at a temperature of 950 to 1150° C. for 30 to 60 minutes, and then water quenched to room temperature.

[0014] In the method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution, in step (5), the annealed titanium alloy plate is rolled, and the rolling process adopts asynchronous rolling at room temperature, that is, the driving speeds of the upper roller and the lower roller are 1 m / s and 1.2 m / s, respectively, to introduce non-uniform deformation.

[0015] The method for manufacturing the TB9 titanium alloy with a bimodal grain size distribution is to subject the titanium alloy sheet after asynchronous rolling to vacuum recrystallization annealing at 680°C to 710°C for 3 to 5 minutes, and then water-cool it to room temperature to achieve local recrystallization, while the grain size of the recrystallized grains still maintains an ultrafine grain scale.

[0016] The method for manufacturing the TB9 titanium alloy with a bimodal distribution of grain size has an ultrafine grain size of 1 to 10 μm.

[0017] The design concept of the present invention is:

[0018] The present invention realizes the construction of heterogeneous (grain) structure through a reasonable process combination of rolling and annealing. Theoretically, the size of recrystallized grains after annealing is determined by the nucleation rate and the grain growth rate. The larger the nucleation rate and the smaller the growth rate, the smaller the grain size. Nucleation usually requires a pre-deformation of the material. When the stored distortion can meet the recrystallization nucleation energy conditions of the local area, nucleation may occur. Moreover, the larger the pre-deformation, the higher the nucleation rate. The asynchronous rolling treatment enables the material to obtain a larger pre-deformation and local strain gradient. Therefore, through a short recrystallization annealing, recrystallization is preferentially carried out in the local large deformation area of ​​the material, and the remaining areas retain the rolled state organization, forming a bimodal distribution of grain size TB9 titanium alloy heterogeneous structure.

[0019] The advantages and beneficial effects of the present invention are:

[0020] 1. This invention provides a method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution. Through asymmetric rolling followed by a brief recrystallization heat treatment, the alloy achieves a heterogeneous structure consisting of a dispersed distribution of ultrafine grains and as-rolled nanocrystals. By manipulating the grain size and its distribution, the alloy achieves optimized mechanical properties.

[0021] 2. The present invention aims to maximize the comprehensive mechanical properties of structurally heterogeneous materials by constructing a TB9 titanium alloy with a bimodal grain size distribution, which is expected to simultaneously enhance the strength and toughness of the alloy and reduce the material cost for the large-scale application of TB9 titanium alloy.

[0022] 3. The present invention is applicable to many fields such as aerospace, automotive industry and biomedicine. Titanium alloys have good mechanical properties and biocompatibility, which are of great help to the requirements of lightweight and high strength of aerospace materials and the functionality of biological implants, thus providing a new idea and new path for the development and manufacture of metal materials and components with both high strength and high toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1-Figure 2 It is a schematic diagram of the core process of the invention; wherein, Figure 1 Asymmetric plate rolling, 1 upper roller, 2 plates, 3 lower rollers; Figure 2 Heat treatment process.

[0024] Figure 3 Figure 1 shows the internal microstructure of TB9 titanium alloy after manufacturing with a bimodal grain size distribution and the removal of the unrecrystallized area. (a) and (b) are the BC and EBSD maps of the heterogeneous microstructure, and (c) is the EBSD map after the unrecrystallized area is removed. DETAILED DESCRIPTION

[0025] In the specific implementation process, the present invention proposes a method for manufacturing a TB9 titanium alloy with a bimodal distribution of grain size. Figure 1-Figure 2As shown, the method includes the following steps: (1) hot forging the TB9 titanium alloy ingot into a cylindrical forging material with a diameter of 20mm to 40mm; (2) subjecting the forging material to a solution treatment at a solution temperature of 950 to 1150°C and a holding time of ≥30min; (3) subjecting the forging material after the solution treatment to an axial rolling treatment to be rolled into a plate 2 with a thickness of 6 to 15mm; (4) subjecting the rolled plate to an annealing treatment at a temperature of 400 to 500°C and a holding time of ≥30min; (5) immediately after annealing, the titanium alloy plate 2 is subjected to a secondary (asynchronous) rolling (with a downward pressure of 50% to 80%) to be formed into a thin plate using an upper roller 1 and a lower roller 3; (6) subjecting the rolled titanium alloy thin plate to a short-time recrystallization annealing treatment at a temperature of 680°C to 710°C and an annealing time of 3 to 5min. After the manufacturing process of the TB9 titanium alloy with a bimodal grain size distribution is completed, the TB9 titanium alloy plate presents a heterogeneous structure in which completely recrystallized ultrafine grains are dispersed in the unrecrystallized nanocrystalline layer, forming a TB9 titanium alloy with a grain heterogeneous structure.

[0026] The technical solution of the present invention is described and explained in detail below with reference to the accompanying drawings.

[0027] Example

[0028] This embodiment provides a method for manufacturing a TB9 titanium alloy with a bimodal grain size distribution. The specific process is as follows:

[0029] (1) A typical TB9 titanium alloy (Ti-38644) was selected as the substrate, with a nominal composition of Ti-3Al-8V-6Cr-4Mo-4Zr.

[0030] (2) The TB9 titanium alloy raw material was melted in an induction furnace and cast into an ingot with a diameter of 100 mm and a height of 200 mm.

[0031] (3) After the surface oxide scale of the ingot is removed by lathe, the TB9 titanium alloy ingot is hot forged into a cylindrical forging with a diameter of 20 mm.

[0032] (4) The forging material is cut into 100 mm sections. Then, solution treatment is performed in a vacuum environment at a heating temperature of 1000°C for 30 min and water quenching is performed to room temperature.

[0033] (5) The solution-treated forged material was axially rolled into a titanium alloy plate with a thickness of 8 mm.

[0034] (6) Annealing the rolled plate at a temperature of 450°C for 30 minutes;

[0035] (7) Figure 1As shown, the plate 2 is rolled into a thin plate for the second time with a downward pressing amount of 60%. The rolling process adopts asynchronous rolling at room temperature, that is, the driving speeds of the upper roller 1 and the lower roller 3 are 1m / s and 1.2m / s respectively, introducing non-uniform deformation.

[0036] (8) The plate obtained by asymmetric rolling was subjected to vacuum recrystallization annealing at a temperature of 705 °C for a holding time of 5 min, and then water-cooled to room temperature.

[0037] like Figure 3 As shown in the figure, after the manufacturing process of the titanium alloy with bimodal grain size distribution is completed, the TB9 titanium alloy presents structural heterogeneity. Completely recrystallized ultrafine grains are dispersed in the unrecrystallized nanocrystalline area, and the ultrafine grain size is 1 to 10 μm.

[0038] The results of the examples show that the present invention provides a way for the preparation of high-strength and high-toughness metal materials and the production of components, and is applicable to TB9 titanium alloy, as well as other metal and alloy systems.

[0039] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for producing a TB9 titanium alloy with a bimodal grain size distribution, characterized in that: The following steps are involved: (1) Hot forging the TB9 titanium alloy ingot into a cylindrical forging with a diameter of 20 mm to 40 mm; (2) subjecting the forging material to solution treatment at a solution temperature of 950-1150°C and a holding time of ≥30 min; (3) subjecting the forged material after solid solution to axial rolling to be rolled into a titanium alloy plate with a thickness of 6 mm to 15 mm; (4) Annealing the rolled plate at a temperature of 400-500°C for a holding time of ≥30 min; (5) Immediately after annealing, the upper and lower surfaces of the titanium alloy plate are asynchronously rolled into thin plates with a downward pressure of 50% to 80%; (6) The titanium alloy sheet after rolling is subjected to short-time recrystallization annealing, the annealing temperature is 680℃~710℃, and the annealing time is 3~5min.

2. The method for producing a TB9 titanium alloy with a bimodal grain size distribution according to claim 1, wherein: In step (1), the metal raw material is melted in an induction furnace and then cast into a metal ingot with a diameter of 100 mm to 200 mm and a height of 200 mm to 400 mm; after the surface oxide scale of the metal ingot is removed by a lathe, the metal ingot is hot forged into a cylindrical forging material with a final size of 20 mm to 40 mm in diameter and a length greater than 100 mm.

3. The method for producing a TB9 titanium alloy with a bimodal grain size distribution according to claim 2, wherein: In step (2), the forging material is cut into sections of 100 to 200 mm in length, and then solution treated in a vacuum environment at a temperature of 950 to 1150° C. for 30 to 60 minutes, and then water quenched to room temperature.

4. The method for producing a TB9 titanium alloy with a bimodal grain size distribution according to claim 3, wherein: In step (5), the annealed titanium alloy plate is rolled, and the rolling process adopts asynchronous rolling at room temperature, that is, the driving speeds of the upper roller and the lower roller are 1m / s and 1.2m / s respectively, introducing non-uniform deformation.

5. The method for producing a TB9 titanium alloy with a bimodal grain size distribution according to claim 4, wherein: The titanium alloy sheet after asynchronous rolling is subjected to vacuum recrystallization annealing at 680℃~710℃ for 3~5min, and then water-cooled to room temperature to achieve local recrystallization, and the grain size of the recrystallized grains still maintains an ultrafine grain scale.

6. The method for producing a TB9 titanium alloy with a bimodal grain size distribution according to claim 5, characterized in that: The ultrafine grain size is 1 to 10 μm.

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