Processing method of high-toughness matched multi-layer heterostructure TC21 titanium alloy plate

Abstract

The invention relates to the technical field of titanium alloy plate processing, in particular to a processing method of a high-toughness matched multilayer heterostructure TC21 titanium alloy plate, which is realized by adopting the following steps of: 1, putting a TC21 titanium alloy cast ingot into a heating furnace for pre-heat treatment, and keeping the temperature at 30 DEG C below beta transformation temperature for a period of time; secondly, the TC21 titanium alloy cast ingot obtained in the first step is rapidly heated to the temperature higher than the beta transformation temperature, heat preservation is conducted for a short time, and after a structure is subjected to amplitude modulation decomposition, rapid transferring is conducted for hot rolling; thirdly, the titanium alloy sample obtained in the second step is rapidly transferred to preheated rolling equipment to be subjected to one-pass rolling; and 4, the titanium alloy sample obtained in the step 3 is put into a heating furnace to be subjected to aging treatment, so that the structure generates a multi-layer heterostructure. The method effectively solves the problem that products manufactured through an existing titanium alloy plate machining method are poor in toughness matching performance, and is suitable for machining of titanium alloy plates.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy plate processing, and in particular to a method for processing a high-strength-toughness matched multi-layer heterogeneous structure TC21 titanium alloy plate. Background Art

[0002] At present, titanium alloy plates are mainly produced by plastic processing methods such as rolling, forging, stamping and extrusion. Among them, the rolling process is the most widely used among various plastic processing methods due to its high production efficiency, large output and a wide variety of products. However, due to the poor plastic deformation ability of titanium alloys below the β transformation temperature, and the production of plates by rolling technology, the plates are prone to serious anisotropy, resulting in the problem of poor strength-toughness matching of products made by existing titanium alloy plate processing methods. Based on this, it is necessary to invent a multi-layer heterogeneous structure TC21 titanium alloy plate processing method with high strength-toughness matching to solve the problem of poor strength-toughness matching of products made by existing titanium alloy plate processing methods. Summary of the invention

[0003] In order to solve the problem of poor strength-toughness matching of products produced by existing titanium alloy plate processing methods, the present invention provides a processing method for a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength-toughness matching.

[0004] The present invention is achieved by adopting the following technical solutions: A method for processing a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

[0005] Furthermore, in the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 925° C. to 935° C., and the preliminary heat treatment time is 60 min to 90 min.

[0006] Furthermore, in the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping warm for 3 minutes.

[0007] Furthermore, in the step 2, the process parameters of hot rolling are: the reduction amount per pass is 20% to 40%.

[0008] Furthermore, in step 4, the process parameters of the aging treatment are: isothermal aging treatment at 600° C. to 700° C., and the isothermal aging treatment time is 60 min to 90 min.

[0009] Compared with the existing titanium alloy plate processing method, the present invention has the following advantages: First, the present invention realizes the control of the organizational composition of TC21 titanium alloy. It uses a preliminary heat treatment process to homogenize the composition of the titanium alloy so that the elements in the alloy are evenly distributed. By controlling the heat treatment time, the grains will not grow too large, which is convenient for the subsequent large plastic forming process and helps to improve the performance of the finished plate. At the same time, the preliminary heat treatment can eliminate component segregation, and the uniform organization can improve the plastic forming ability of the TC21 titanium alloy ingot. An excellent preliminary heat treatment process can allow the TC21 titanium alloy ingot to reach the optimal state required for amplitude modulation decomposition and hot rolling, which helps the finished plate to achieve the ultimate performance. Simple and reasonable preliminary heat treatment parameter settings can greatly help realize the standardized industrial production of titanium alloy plates.

[0010] Secondly, the present invention rapidly heats to above the β transition temperature and keeps the temperature at 1000°C for 3 minutes, so that the α phase changes to a molten state, and a spinodal decomposition phenomenon occurs. α solute atom-enriched areas and depleted areas appear in the titanium alloy structure. The molten α phases in these α solute atom-enriched areas are the α phases distributed in the residual β phase in the multilayer heterogeneous structure. The uniformly alternating α solute atom-enriched areas and depleted areas are the basis of the titanium alloy heterogeneous structure. After the spinodal decomposition, the morphology of the α element-enriched area after rolling is mainly composed of short rod-shaped and spherical α phases. Some α solute atoms form multiple α solute atom-enriched areas in a small range, which show short strip-shaped morphologies adjacent to each other after rolling. The orientation relationship of the α phase distributed in the same residual β phase matrix is ​​roughly the same, but the orientation relationship with the α phase in the adjacent residual β phase matrix is ​​different. The lamellar residual β phase matrix and α phases of different sizes together constitute a heterogeneous structure. The formation of a heterogeneous structure can maintain high strength while allowing the material to have a certain toughness, so that the strength and toughness of the finished plate are highly matched.

[0011] Thirdly, the present invention uses a one-pass hot rolling process to hot-roll the TC21 titanium alloy in which the β phase is solid and the α phase is molten, so that the molten α phase deforms in coordination with the β phase under stress, and the deformation product is a residual β phase matrix and an α phase with different sizes and morphologies uniformly distributed in the β phase matrix. During the hot rolling process, as the temperature decreases, the α phase solidifies into a short rod, a sphere or a short strip.

[0012] Fourthly, the present invention performs isothermal aging treatment at 600°C to 700°C to make the α phase component and structure in the residual β phase matrix in the above heterogeneous structure more stable, increase the content of spherical α phase, coordinate the proportion of α phase content with different morphologies, and finally generate a heterogeneous structure in which α phases with different sizes, morphologies and orientations are evenly distributed in adjacent lamellar residual β phase matrices. This heterogeneous structure has high strength and toughness and excellent comprehensive performance.

[0013] In summary, the present invention realizes spinodal decomposition in the titanium alloy structure by combining the optimal heat treatment process with the subsequent deformation process, and obtains α solute atom-enriched areas and depleted areas that are alternately and evenly distributed in the residual β phase matrix, thereby forming a multilayer heterogeneous structure (such as Figure 1 As shown), the expected high strength and toughness matching is achieved.

[0014] In addition, the operation steps of the present invention are easy to promote, the process flow is very simple, and the equipment used are all common equipment in titanium alloy plate processing factories, which is of great help in promoting and realizing industrialized production.

[0015] The invention effectively solves the problem of poor strength-toughness matching of products produced by the existing titanium alloy plate processing method, and is suitable for processing titanium alloy plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a metallographic structure diagram of the product made by the present invention. DETAILED DESCRIPTION Embodiment 1

[0017] A method for processing a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

[0018] In the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 935° C. and the preliminary heat treatment time is 60 minutes.

[0019] In the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping the temperature for 3 minutes.

[0020] In the step 2, the process parameters of hot rolling are: the reduction amount per pass is 30%.

[0021] In the step 4, the process parameters of the aging treatment are: isothermal aging treatment at 600° C., and the isothermal aging treatment time is 90 minutes. Embodiment 2

[0022] A method for processing a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

[0023] In the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 925° C. and the preliminary heat treatment time is 90 minutes.

[0024] In the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping the temperature for 3 minutes.

[0025] In the step 2, the process parameters of hot rolling are: the reduction amount per pass is 20%.

[0026] In the step 4, the process parameters of the aging treatment are: isothermal aging treatment at 650° C., and the isothermal aging treatment time is 60 minutes. Embodiment 3

[0027] A method for processing a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

[0028] In the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 935° C. and the preliminary heat treatment time is 70 minutes.

[0029] In the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping the temperature for 3 minutes.

[0030] In the step 2, the process parameters of hot rolling are: the reduction amount per pass is 40%.

[0031] In the step 4, the process parameters of the aging treatment are: isothermal aging treatment at 700° C., and the isothermal aging treatment time is 70 minutes. Embodiment 4

[0032] A method for processing a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

[0033] In the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 930° C. and the preliminary heat treatment time is 80 minutes.

[0034] In the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping the temperature for 3 minutes.

[0035] In the step 2, the process parameters of hot rolling are: the reduction amount per pass is 25%.

[0036] In the step 4, the process parameters of the aging treatment are: isothermal aging treatment at 680° C., and the isothermal aging treatment time is 80 minutes.

[0037] Through the tensile test of the product made by the present invention, it can be concluded that the strength and toughness of the product made by the present invention are highly matched, the comprehensive mechanical properties are very excellent, the tensile strength is above 1200MPa, and the elongation is above 14%. The tensile test results are shown in Table 1: .

[0038] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for processing a multi-layer heterogeneous structure TC21 titanium alloy sheet with high strength and toughness matching, characterized in that: This method is implemented by the following steps: Step 1: polishing the prepared TC21 titanium alloy ingot so that its surface has no obvious defects and presents obvious metallic luster; then, placing the TC21 titanium alloy ingot in a heating furnace for preliminary heat treatment, and keeping it at 30°C below the β transformation temperature for a period of time; Step 2: Rapidly heat the TC21 titanium alloy ingot obtained in step 1 to above the β transformation temperature, keep the temperature for a short time, and quickly transfer it for hot rolling after the microstructure undergoes spinodal decomposition, thereby obtaining a titanium alloy sample; Step 3: quickly transferring the titanium alloy sample obtained in step 2 to a preheated rolling device for one-pass rolling, thereby obtaining a titanium alloy sample; Step 4: Place the titanium alloy sample obtained in step 3 into a heating furnace for aging treatment to produce a multi-layer heterogeneous structure, thereby obtaining a multi-layer heterogeneous structure TC21 titanium alloy plate with high strength and toughness matching.

2. The method for processing a multi-layer heterogeneous structure TC21 titanium alloy sheet with high strength and toughness matching according to claim 1, characterized in that: In the step 1, the process parameters of the preliminary heat treatment are: the preliminary heat treatment is carried out at 925° C. to 935° C., and the preliminary heat treatment time is 60 min to 90 min.

3. The method for processing a multi-layer heterogeneous structure TC21 titanium alloy sheet with high strength and toughness matching according to claim 1, characterized in that: In the step 2, the process parameters of rapid heating are: heating to 1000° C. within 3 minutes and keeping the temperature for 3 minutes.

4. The method for processing a multi-layer heterostructure TC21 titanium alloy sheet with high strength and toughness matching according to claim 1, characterized in that: In the step 2, the process parameters of hot rolling are: the reduction amount per pass is 20% to 40%.

5. The method for processing a multi-layer heterogeneous structure TC21 titanium alloy sheet with high strength and toughness matching according to claim 1, characterized in that: In the step 4, the process parameters of the aging treatment are: isothermal aging treatment at 600° C. to 700° C., and the isothermal aging treatment time is 60 min to 90 min.

Images