A Ti-Al-V-Fe type high impact toughness α+β titanium alloy and its preparation method

Abstract

This invention belongs to the field of titanium alloy technology, specifically relating to a high-strength, high-impact-toughness titanium alloy and its preparation method. This high-strength, high-impact-toughness α+ α'+ β type titanium alloy is composed of the following components by mass percentage: Al 4-6%, V 2.3-2.7%, Fe 1-2%, with the balance being Ti and unavoidable impurities. This titanium alloy material has a simple composition and processing technology, low production cost, and significantly improves the alloy's strength and impact toughness while maintaining good processing plasticity. It can still maintain good impact performance under low-temperature conditions (ambient temperature approximately -40℃), showing broad application prospects in aerospace, deep-sea, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy technology, specifically relating to a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy and its preparation method. Background Technology

[0002] Titanium and titanium alloys are characterized by high strength, good ductility, and low density. However, the impact toughness of titanium alloys is not particularly outstanding. Furthermore, due to the bcc structure of the β phase in titanium alloys, they exhibit significant low-temperature brittleness, causing the impact toughness to decrease further as the temperature drops. This is a disadvantage for titanium alloys used in low-temperature environments. As structural materials, titanium alloys frequently face temperatures below 0°C or even lower in winter outdoor environments, aerospace environments, and marine environments, and are often subjected to impact loads, such as those from ocean waves. When the impact fracture toughness falls below a critical value, serious consequences may occur. Therefore, the service environment requires titanium alloys to possess both high strength and good impact toughness, as well as a certain level of low-temperature impact toughness. Overcoming the challenge of matching the impact toughness and strength of titanium alloys presents a significant challenge.

[0003] Currently, methods for improving the impact toughness of titanium alloys mainly focus on β-type titanium alloys. However, this improvement in impact toughness is limited, not exceeding 50 J / cm⁻², and often drops to only 20 J / cm⁻² when the temperature drops below 0°C, far below the safety requirements for component use. Furthermore, β-type titanium alloys have a high density, limiting their application range. Duplex titanium alloys, with their superior overall performance, are a better choice; however, research on improving the impact toughness of duplex titanium alloys is currently limited. Summary of the Invention

[0004] At least in response to the technical problems mentioned in the background art, the purpose of this invention is to provide a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy and its preparation method, the purpose of which is to improve the impact toughness of the titanium alloy while ensuring its strength.

[0005] 1. According to one aspect of the present invention, a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy is proposed. According to the mass percentage of alloying elements, the titanium alloy is composed of the following components: Al 4-6%, V 2.3-2.7%, Fe 1-2%, with the balance being Ti and unavoidable impurities.

[0006] 2. According to another aspect of the present invention, the present invention also provides a method for preparing the Ti-Al-V-Fe system high impact toughness α+β type titanium alloy described in the invention, comprising the following steps: Step 1: Prepare the raw materials according to the target alloy composition, press the electrodes, and melt them in a vacuum consumable arc furnace to obtain a titanium alloy ingot; the target alloy composition is as follows by mass percentage: Al 4-6%, V 2.3-2.7%, Fe 1-2%, with the balance being Ti and unavoidable impurities; Step 2: Heat the titanium alloy ingot to 50-100°C below the β phase transformation point and perform hot working deformation to obtain a deformed titanium alloy material. Step 3: The titanium alloy deformed material is solution treated at 30-70℃ below the β phase transformation point, and then water quenched after heat preservation to obtain the high-strength, high-impact-toughness α+ α'+ β type titanium alloy.

[0007] In step (2), the hot working deformation is rolling or forging.

[0008] In step (2), the hot working deformation temperature is 30-50℃ below the β phase transformation point.

[0009] In step (2), the total deformation amount of the hot working deformation is 80%-90%.

[0010] In step (3), the heat preservation time for the solution treatment is 0.5-2 hours.

[0011] The chemical composition of the titanium alloy, by mass percentage, is: Al 4-6%, V 2.3-2.7%, Fe 1-2%, with the balance being Ti and unavoidable impurities; and the room temperature Charpy V-notch impact toughness of the titanium alloy is not less than 60 J / cm². Beneficial effects

[0012] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: (1) The alloy of the present invention belongs to the Ti-Al-V-Fe system high impact toughness α+ β type titanium alloy. Through the alloy composition design, the alloy achieves high impact toughness and good strength matching. The α+ β type titanium alloy material of the present invention uses only four elements: Ti, Al, V and Fe. By controlling the addition of Fe element, the alloy cost is reduced, while the hardenability and weldability of the alloy are improved, and the processing capability of the alloy is improved.

[0013] (2) The titanium alloy of the present invention has a room temperature strength of >1000MPa and an impact toughness of >60 J / cm², achieving excellent strength-impact toughness matching.

[0014] (3) The Ti-Al-V-Fe system high impact toughness α+β type titanium alloy of the present invention has significant advantages in strength, plasticity, cost and density compared with commonly used titanium alloys, and is expected to become a candidate material for ultra-high strength titanium alloys in the aerospace field. Attached Figure Description

[0015] Figure 1 The image shows the microstructure (BC) of the titanium alloy EBSD in Example 1 of this invention.

[0016] Figure 2 The image shows the microstructure (BC) of the titanium alloy EBSD in Example 2 of this invention.

[0017] Figure 3 This is a SEM image of the microstructure of the titanium alloy EBSD in Example 3 of the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments.

[0019] In the following embodiments: Example

[0020] A Ti-Al-V-Fe system high impact toughness α+β type titanium alloy is composed of the following components by mass percentage: Al 6%, V 2.5%, Fe 2%, with the balance being Ti and unavoidable impurities.

[0021] The preparation method of a Ti-Al-V-Fe system high impact toughness α+ β type titanium alloy in this embodiment includes the following steps: (1) Melt the titanium alloy and then homogenize it.

[0022] (2) The casting obtained by casting is hot rolled at 820°C with a deformation of 80% to obtain hot rolled plate.

[0023] (3) The obtained plate was subjected to solution treatment at 870℃ for 1 hour and then cooled to room temperature to obtain a high-strength and high-impact toughness titanium alloy.

[0024] The mechanical properties of a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy in this embodiment are as follows: tensile strength 1100MPa, impact toughness 71J / cm2. Example

[0025] A Ti-Al-V-Fe system high impact toughness α+β type titanium alloy is composed of the following components by mass percentage: Al 4%, V 2.5%, Fe 1.5%, with the balance being Ti and unavoidable impurities.

[0026] The preparation method of a Ti-Al-V-Fe system high impact toughness α+ β type titanium alloy in this embodiment includes the following steps: (1) Melt the titanium alloy and then homogenize it.

[0027] (2) The casting obtained by casting is hot rolled at 830°C with a deformation of 80% to obtain hot rolled plate.

[0028] (3) The obtained plate was solution treated at 850℃ for 1 hour, and then water-quenched to room temperature to obtain a high-strength and high-impact toughness titanium alloy.

[0029] The mechanical properties of a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy in this embodiment are as follows: tensile strength 1080MPa, impact toughness 61J / cm2. Example

[0030] A Ti-Al-V-Fe system high impact toughness α+β type titanium alloy is composed of the following components by mass percentage: Al 4%, V 2.5%, Fe 15%, with the balance being Ti and unavoidable impurities.

[0031] The preparation method of a Ti-Al-V-Fe system high impact toughness α+ β type titanium alloy in this embodiment includes the following steps: (1) Melt the titanium alloy and then homogenize it.

[0032] (2) The casting obtained by casting is hot forged at 850°C with a deformation of 85% to obtain a hot forging.

[0033] (3) The obtained plate was subjected to solution treatment at 850℃ for 1 hour and then cooled to room temperature to obtain a high-strength and high-impact toughness titanium alloy.

[0034] The mechanical properties of a Ti-Al-V-Fe system high impact toughness α+β type titanium alloy in this embodiment are as follows: tensile strength 1000MPa, impact toughness 69 J / cm2.

[0035] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a high-strength high-impact toughness α + α' + β type titanium alloy, characterized by, Based on the total mass of the raw material components of the material being 100%, the components and their mass percentages are as follows: Al: 3.7-4.2%, V: 2.3-2.7%, Fe: 1.2-1.7%, with the balance being Ti and unavoidable impurities.

2. A method of producing a high-strength high-impact toughness α + α' + β type titanium alloy according to claim 1, characterized by: Includes the following steps: Step 1: Prepare the raw materials according to the target alloy composition, press the electrodes, and melt them in a vacuum arc remelting furnace to obtain a titanium alloy ingot; the target alloy composition, by mass percentage, is: Al: 3.7-4.2%, V: 2.3-2.7%, Fe: 1.2-1.7%, Ti and unavoidable impurities, wherein the total content of unavoidable impurities is ≤0.3%; Step 2: Heat the titanium alloy ingot to 50-100°C below the β phase transformation point and perform hot working deformation to obtain a deformed titanium alloy material. Step 3: The titanium alloy deformed material is solution treated at 30-70℃ below the β phase transformation point, and then water quenched after heat preservation to obtain the high-strength, high-impact-toughness α+ α'+ β type titanium alloy.

3. The production method according to claim 2, characterized by, In step (2), the hot working deformation is rolling or forging.

4. The production method according to claim 2, characterized by, When the hot working deformation is forging, the forging end temperature is 30-50°C below the β phase transformation point.

5. The preparation method according to claim 2, characterized in that, In step (2), the total deformation amount of the hot working deformation is 80%-90%.

6. The preparation method according to claim / 2, characterized in that, In step (3), the heat preservation time for the solution treatment is 0.5-2 hours.

7. A high-strength, high-impact-toughness titanium alloy, characterized in that, The chemical composition of the titanium alloy, by mass percentage, is as follows: Al: 3.7-4.2%, V: 2.3-2.7%, Fe: 1.2-1.7%, with the balance being Ti and unavoidable impurities; and the room temperature Charpy V-notch impact toughness of the titanium alloy is not less than 60 J / cm².

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