A high-strength and toughness titanium alloy and its preparation method
By adding CrMnFeCoNi high-entropy alloy powder to the titanium alloy and using discharge plasma sintering technology, the problems of low density and poor plasticity of titanium alloy materials are solved, and high-strength and tough titanium alloy preparation is achieved, which improves the tensile strength and plastic deformation ability.
Patent Information
- Application Number
- CN202210519951.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-13
- Publication Date
- 2025-08-26
- Estimated Expiration
- 2042-05-13
AI Technical Summary
The existing titanium alloy materials have defects such as low density, unconverted particle interface and pores during the preparation of powder metallurgy, resulting in poor plasticity of the material, especially the room temperature elongation is less than 8%.
The high-entropy alloy powder CrMnFeCoNi is mixed with titanium powder, and the instantaneous liquid phase sintering is carried out in a vacuum environment through discharge plasma sintering technology to form a quasi-continuous distribution of the titanium alloy sintered body with enhanced phase along the particle boundary. The sintering temperature is 1050~1150℃, the insulation time is 2 minutes, and the cooling method is to cool with the furnace.
The tensile strength and plastic deformation capacity of titanium alloy are significantly improved. The room temperature tensile strength exceeds 700MPa and the plastic deformation amount exceeds 12.5%. At the same time, the preparation process is simplified and the cost is reduced.
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Figure CN117107111B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of titanium alloys and relates to a high-strength and toughness powder metallurgy titanium alloy and a preparation method thereof. Background Art
[0002] Titanium and titanium alloys are important structural metal materials with many excellent properties, such as high specific strength, low density, excellent corrosion resistance and high temperature resistance, and good machinability. They are widely used in many fields such as aerospace, chemical industry, and biomedicine, and are known as the modern metal of the 21st century.
[0003] The literature (PANIGRAHI B B. Sintering behavior of Ti–2Ni and Ti–5Nielemental powders [J]. Materials Letters, 2007, 61(1): 152-5) mentions that powder metallurgy titanium alloys are prone to defects such as low density, unconverted particle interfaces, and pores. These defects can have a significant impact on the plasticity of the material. For example, the room temperature elongation of powder metallurgy TC4 titanium alloy is generally less than 8%. Summary of the Invention
[0004] In view of the shortcomings of the current titanium and titanium alloy materials, such as complex preparation process and poor mechanical properties, the present invention proposes a HEA-Ti series titanium alloy with high strength and toughness, which has a simple preparation process and excellent mechanical properties.
[0005] The present invention is achieved through the following technical solutions:
[0006] A high-strength and toughness titanium alloy and a preparation method thereof, wherein the chemical composition of the alloy is as follows by mass: Ti: 92.5% to 97.5%, CrMnFeCoNi: 2.5% to 7.5%, and the remainder being unavoidable impurity elements;
[0007] The specific steps include:
[0008] (1) Prepare the raw materials required for titanium alloy according to the designed composition and mix them evenly by ball milling;
[0009] (2) In a vacuum environment, the raw materials prepared in step (1) are subjected to spark plasma sintering, and the principle of continuous instantaneous liquid phase sintering is used to obtain a titanium alloy sintered body in which the reinforcement phase is quasi-continuously distributed along the particle boundaries.
[0010] Preferably, in step (1), Ti powder and CrMnFeCoNi powder required for the titanium alloy are configured according to the designed composition.
[0011] Preferably, in step (2), the spark plasma sintering heating rate is 50°C / min, the sintering temperature is 1050-1150°C, the holding time is 2 minutes, and the cooling method is furnace cooling.
[0012] Preferably, the room temperature tensile strength of the titanium alloy prepared by spark plasma sintering exceeds 700 MPa and the plastic deformation exceeds 12.5%.
[0013] Compared with the prior art, the present invention has the following beneficial effects:
[0014] (1) The alloy has good plastic deformation ability and greatly improved tensile strength. In the sintered state, the room temperature tensile strength of the titanium alloy is greater than 700 MPa, and the plastic deformation exceeds 12.5%.
[0015] (2) The titanium alloy provided by the present invention has good performance, low cost and simple preparation process. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is the microstructure diagram of Example 1.
[0017] Figure 2 This is the microstructure diagram of Example 2.
[0018] Figure 3 This is the microstructure diagram of Example 3. DETAILED DESCRIPTION
[0019] In order to better understand the technical content of the present invention, specific embodiments are given and described below with reference to the accompanying drawings.
[0020] Various aspects of the present invention are described herein with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. The embodiments of the present invention are not necessarily intended to encompass all aspects of the present invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, may be implemented in any of a number of ways, as the concepts and embodiments disclosed herein are not limited to any particular implementation. In addition, some aspects disclosed herein may be used alone or in any appropriate combination with other aspects disclosed herein.
[0021] The present invention provides a high-strength and tough HEA-Ti series titanium alloy. A small amount of CrMnFeCoNi high-entropy alloy powder is added to the titanium alloy to produce a quasi-continuously distributed strengthening phase surrounding the boundaries of the titanium matrix particles. This significantly improves the tensile strength of the titanium alloy while maintaining good plasticity. The specific reason is that during the deformation of the alloy, after the elastic stage ends, as the stress continues to increase, local deformation bands appear in the material structure and expand rapidly. If there are no other conditions to hinder it, plastic instability will occur quickly. However, the presence of micron-sized precipitation phases actually enhances the work hardening ability. When the deformation band in the alloy structure expands to the precipitation phase, it is suppressed and difficult to continue to expand instably. The overall plastic instability of the material is suppressed and more new deformation bands are formed, thereby significantly improving the plasticity of the alloy.
[0022] The high-strength and tough HEA-Ti series titanium alloy described in the present invention has the following chemical composition by mass: Ti powder: 92.5% to 97.5%, CrMnFeCoNi powder (purchased from Hebei Qinbang New Materials Co., Ltd.): 2.5% to 7.5%, and the remainder are unavoidable impurities. The raw materials required for the titanium alloy are first prepared according to the designed composition and ball-milled to mix uniformly. Then, spark plasma sintering is used to obtain a high-strength and tough titanium alloy material with a quasi-continuous network distribution of the reinforcement phase. The spark plasma sintering method uses a heating rate of 50°C / min, a sintering temperature of 1050-1150°C, a holding time of 2 minutes, and a cooling method of furnace cooling.
[0023] Comparative Example 1:
[0024] Pure titanium material, including unavoidable impurity elements.
[0025] The pure titanium material preparation method involves first ball-milling pure titanium powder, followed by spark plasma sintering to prepare the sample. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0026] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests conducted at room temperature revealed a tensile strength of 382 MPa and a plastic deformation of 39.4%. The material density was measured to be 87.2%.
[0027] Comparative Example 2:
[0028] A titanium alloy material, the chemical composition of which is as follows by mass percentage: Ti: 92.5%, AlCoCrFeNi 2.1 : 7.5%, the rest are inevitable impurity elements.
[0029] The titanium alloy material was prepared by ball-milling the raw material powders, followed by spark plasma sintering to produce the sample. The sintering process was performed in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling. The material density was measured to be 92.2%.
[0030] Standard tensile specimens were cut from the center of the sintered sample using wire cutting. Tensile tests at room temperature showed that the alloy material had a tensile strength of 474 MPa and a plastic deformation of 8.4%.
[0031] Comparative Example 3:
[0032] A titanium alloy material, whose chemical composition by mass percentage is: Ti: 98.0%, CrMnFeCoNi: 2.0%, and the rest are inevitable impurity elements.
[0033] The alloy material is prepared by ball-milling the raw material powders, followed by spark plasma sintering to prepare the sample. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0034] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 524 MPa and a plastic deformation of 19.2%.
[0035] Comparative Example 4:
[0036] A titanium alloy material, whose chemical composition by mass percentage is: Ti: 92.0%, CrMnFeCoNi: 8.0%, and the rest are inevitable impurity elements.
[0037] The alloy material is prepared by ball-milling the raw material powders, followed by spark plasma sintering to prepare the sample. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0038] Standard tensile specimens were cut from the center of the sintered sample using wire cutting. Tensile tests at room temperature showed that the alloy material had a tensile strength of 425 MPa and a plastic deformation of 3.2%.
[0039] Comparative Example 5:
[0040] A titanium alloy material, whose chemical composition by mass percentage is: Ti: 92.5%, CrMnFeCoNi: 7.5%, and the rest are inevitable impurity elements.
[0041] The alloy material is prepared by ball-milling the raw material powders, followed by spark plasma sintering to prepare the sample. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 900°C, a holding time of 2 minutes, and subsequent cooling.
[0042] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 322 MPa and a plastic deformation of 3.4%.
[0043] Comparative Example 6:
[0044] A titanium alloy material, whose chemical composition by mass percentage is: Ti: 92.5%, CrMnFeCoNi: 7.5%, and the rest are inevitable impurity elements.
[0045] The alloy material is prepared by first ball-milling the raw material powders, followed by spark plasma sintering to prepare the sample. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1200°C, a holding time of 2 minutes, and subsequent cooling.
[0046] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 682 MPa and a plastic deformation of 11.3%.
[0047] Example 1:
[0048] A high-strength and tough powder metallurgy titanium alloy has the following chemical compositions by mass percentage: Ti: 97.5%, CrMnFeCoNi: 2.5%, and the remainder being unavoidable impurity elements.
[0049] The titanium alloy material preparation method involves first ball-milling the raw material powders, followed by spark plasma sintering to produce the titanium alloy. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0050] The metallographic specimen was made by cutting the center of the sintered sample by wire cutting. After coarse grinding, fine grinding, polishing and corrosion, it was found that the microstructure of the alloy was composed of α titanium matrix and granular β reinforcement phase. Figure 1 During the sintering process, the two powders first form a liquid phase to fill the pores between the powders, and gradually form a reinforcement phase at the boundary around the titanium matrix.
[0051] Standard tensile specimens were cut from the center of the sintered sample using wire cutting. Tensile tests at room temperature showed that the alloy material had a tensile strength of 701 MPa and a plastic deformation of 15.8%.
[0052] Example 2:
[0053] A high-strength and tough titanium alloy has the following chemical compositions by mass percentage: Ti: 95.0%, CrMnFeCoNi: 5%, and the remainder being unavoidable impurity elements.
[0054] The titanium alloy material preparation method involves first ball-milling the raw material powders, followed by spark plasma sintering to produce the titanium alloy. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0055] The metallographic specimen was made by cutting the center of the sintered sample by wire cutting. After coarse grinding, fine grinding, polishing and corrosion, it was found that the microstructure of the alloy was composed of α titanium matrix and granular β reinforcement phase. Figure 2 During the sintering process, the two powders first form a liquid phase to fill the pores between the powders, and gradually form a reinforcement phase at the boundary around the titanium matrix, forming a quasi-continuous distribution network structure.
[0056] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 712 MPa and a plastic deformation of 14.3%.
[0057] Example 3:
[0058] A high-strength and tough titanium alloy, whose chemical composition by mass percentage is Ti: 92.5%, CrMnFeCoNi: 7.5%, and the rest are inevitable impurity elements.
[0059] The titanium alloy material preparation method involves first ball-milling the raw material powders, followed by spark plasma sintering to produce the titanium alloy. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1100°C, a holding time of 2 minutes, and subsequent cooling.
[0060] The metallographic specimen was made by cutting the center of the sintered sample by wire cutting. After coarse grinding, fine grinding, polishing and corrosion, it was found that the microstructure of the alloy was composed of α titanium matrix and granular β reinforcement phase. Figure 3 During the sintering process, the two powders first form a liquid phase to fill the pores between the powders, and gradually form a reinforcement phase at the boundary around the titanium matrix, forming a quasi-continuous distribution network structure.
[0061] Standard tensile specimens were cut from the center of the sintered sample using wire cutting. Tensile tests at room temperature revealed a tensile strength of 735 MPa and a plastic deformation of 13.6%. The material density was measured to be 97.8%.
[0062] Example 4:
[0063] A high-strength and tough titanium alloy, whose chemical composition by mass percentage is Ti: 92.5%, CrMnFeCoNi: 7.5%, and the rest are inevitable impurity elements.
[0064] The titanium alloy material preparation method involves first ball-milling the raw material powders, followed by spark plasma sintering to produce the titanium alloy. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1050°C, a holding time of 2 minutes, and subsequent cooling.
[0065] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 727 MPa and a plastic deformation of 12.8%.
[0066] Example 5:
[0067] A high-strength and tough titanium alloy, whose chemical composition by mass percentage is Ti: 92.5%, CrMnFeCoNi: 7.5%, and the rest are inevitable impurity elements.
[0068] The titanium alloy material preparation method involves first ball-milling the raw material powders, followed by spark plasma sintering to produce the titanium alloy. The sintering process is carried out in a vacuum environment, with a heating rate of 50°C / min, a sintering temperature of 1150°C, a holding time of 2 minutes, and subsequent cooling.
[0069] Standard tensile specimens were prepared by wire cutting the center of the sintered sample. Tensile tests at room temperature showed that the alloy material had a tensile strength of 715 MPa and a plastic deformation of 12.5%.
Claims
1. A method for preparing a high-strength and tough titanium alloy, wherein the chemical composition of the alloy is as follows: Ti: 92.5% to 97.5%, CrMnFeCoNi: 2.5% to 7.5% by mass; The specific steps include: (1) Prepare the raw materials required for titanium alloy according to the alloy composition and mix them evenly by ball milling; (2) spark plasma sintering the mixed powder obtained in step (1) under a vacuum environment to obtain a titanium alloy sintered body in which the reinforcement phase is quasi-continuously distributed along the particle boundaries; in, In step (1), Ti powder and CrMnFeCoNi powder required for titanium alloy are prepared according to the alloy composition; In step (2), the spark plasma sintering heating rate is 50°C / min, the sintering temperature is 1050~1150°C, the holding time is 2min, and the cooling method is furnace cooling.
2. A high-strength and tough titanium alloy prepared by the method according to claim 1.
3. The high-strength and toughness titanium alloy according to claim 2, wherein the room temperature tensile strength of the titanium alloy exceeds 700 MPa and the plastic deformation exceeds 12.5%.