A low-cost high-toughness titanium alloy material and a preparation method thereof

Abstract

The application belongs to the technical field of titanium alloy materials, and specifically discloses a low-cost high-strength and high-toughness titanium alloy material and a preparation method thereof; the titanium alloy material is composed of an alpha single phase, 4-8 wt.% of Al, 1-5 wt.% of Si, and the balance of Ti. 85 Al 12 Si3, and is based on inexpensive aluminum, silicon and pure titanium particles; a low-cost high-strength and high-toughness titanium alloy Ti 85 Al 12 Si3 is designed, and the prepared titanium alloy material exhibits significant advantages in mechanical properties, cost-effectiveness and process feasibility.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of titanium alloy preparation, in particular to a low-cost high-strength and high-toughness titanium alloy material and a preparation method thereof. BACKGROUND

[0002] Titanium alloy has been widely used in many fields due to its low density, high specific strength, excellent corrosion resistance and good mechanical properties. The density of titanium alloy is generally 4.51 g / cm3, which is only 60% of that of steel, but its strength can be comparable to that of many high-strength alloy steels, or even higher. Such high specific strength (ratio of strength to density) makes titanium alloy an ideal material for manufacturing lightweight, high-strength and rigid components. In the field of aerospace, titanium alloy is used to manufacture key components such as aircraft engine blades and fuselage structural parts; in the field of armored vehicles and shipbuilding, titanium alloy is widely used in protective structures and propulsion systems due to its impact resistance and corrosion resistance; in the field of equipment, the high strength and light weight of titanium alloy significantly improve the mobility and protection capability of equipment.

[0003] Although titanium alloy exhibits unique advantages in specific strength, corrosion resistance and the like, its mechanical properties still have significant shortcomings. Taking the typical gamma-TiAl-based alloy Ti-48Al-2Nb-2Cr (Ti4822) as an example, although the alloy can still maintain a strength of more than 500 MPa at a high temperature of 600°C, exhibiting good high-temperature performance, it has been widely used in low-pressure turbine blades of aircraft engines, but its room temperature plasticity is generally less than 2%, and there is a significant brittleness problem. Under high-temperature or extreme load working conditions, the room temperature brittleness and narrow hot working window (about 50°C) of the Ti4822 alloy seriously restrict its application in key components such as compressor blades of new-generation aircraft engines. In addition, the high cost problem of the Ti4822 alloy is also prominent. The niobium (Nb) and chromium (Cr) metals contained in the formula account for about 35% of the cost of raw materials, and the processing cost caused by vacuum consumable melting, precision forging and other processes makes the price of Ti4822 components far exceed that of traditional structural materials. This dual restriction of “performance-cost” prompts the titanium alloy research and development to break through in the direction of “high strength and toughness-low cost” synergistic optimization.

[0004] The application aims to provide a low-cost high-strength and high-toughness titanium alloy and a preparation method thereof, to improve the mechanical properties of titanium alloy materials and to be suitable for popularization and application in the fields of aerospace, automobile manufacturing, building structure and the like. SUMMARY

[0005] The application aims to provide a low-cost high-strength and high-toughness titanium alloy material and a preparation method thereof, to improve the mechanical properties of titanium alloy materials and to be suitable for popularization and application in the fields of aerospace, automobile manufacturing, building structure and the like. 85 Al12 Si3, the titanium alloy material prepared has significant advantages in mechanical properties, cost-effectiveness and process feasibility.

[0006] To achieve the above object, the application provides a low-cost high-toughness titanium alloy material, the phase composition of the titanium alloy material is alpha single phase, and the atomic ratio chemical expression of the titanium alloy material is Ti 85 Al 12 Si3, and the titanium alloy material comprises the following raw materials in percentage by mass: 4-8wt.% of Al, 1-5wt.% of Si, and the balance of Ti.

[0007] Preferably, the titanium alloy material comprises 7.2wt.% of Al, 1.8wt.% of Si, and the balance of Ti.

[0008] Preferably, the purity of Al, Si and Ti is not less than 99.9%.

[0009] The application further provides a preparation method of the low-cost high-toughness titanium alloy material, comprising the following steps:

[0010] Step one: uniformly mixing raw materials according to percentage by mass;

[0011] Step two: pretreating a smelting device, and the smelting device is a vacuum arc furnace;

[0012] Step three: performing multiple smelting on the alloy mixture obtained in step one in the smelting device, and obtaining the titanium alloy material Ti 85 Al 12 Si3 after cooling.

[0013] Preferably, in step two, the vacuum arc furnace comprises a tungsten rod and a crucible, and the pretreatment comprises tapering the working end of the tungsten rod by using sandpaper and wiping the surface of the crucible by using anhydrous ethanol.

[0014] Preferably, in step three, the specific method of smelting is as follows:

[0015] The alloy mixture is placed in a smelting station of the vacuum arc furnace, pure zirconium metal particles are placed on an oxygen absorption station of the vacuum arc furnace, and before smelting the alloy mixture each time, the pure zirconium metal particles are first smelted to play an oxygen absorption role.

[0016] Preferably, in step three, the inductive current is controlled to be between 300A and 350A during smelting, the magnetic stirring is started after the alloy mixture is melted into a liquid state, the magnetic stirring current is 10A, each smelting is performed for 3-4 minutes, each sample is smelted for 6 times, and the sample is vertically erected during the 2nd-5th smelting, so as to ensure that the alloy mixture is completely melted and the components are uniformly mixed.

[0017] The titanium alloy material and the preparation method thereof have the advantages and beneficial effects of the low-cost high-toughness titanium alloy material and the preparation method thereof.

[0018] 1、 The Ti 85 Al 12 Si3 alloy prepared by the method has significant advantages in mechanical properties, cost-effectiveness and process feasibility. 85 Al 12 The comprehensive advantages of the Ti 48 Al2Cr2Nb alloy in mechanical properties, cost control and process feasibility make it have broad application prospects in the fields of aerospace, automobile manufacturing, building structure and the like.

[0019] 2、 The titanium alloy material has a high room temperature compression strength of 1757 MPa, far exceeding the traditional commercial titanium alloy Ti 85 Al2Cr2Nb, and exhibits excellent plasticity, and meanwhile, the elongation rate reaches 35%, so that brittle fracture can be effectively avoided, and the titanium alloy material is suitable for application scenarios with high stress and high deformation requirements.

[0020] 3、 The titanium alloy material has a tensile strength of 870 MPa at room temperature, and the elongation rate can reach 3.5%. At a high temperature of 600°C, the tensile strength is 594 MPa, and the elongation rate is 10.5%; at a high temperature of 750°C, the tensile strength is 465 MPa, and the elongation rate is 12.6%; at a high temperature of 800°C, the tensile strength is 432 MPa, and the elongation rate is 34%.

[0021] 4、 The titanium alloy material is prepared by using inexpensive Al and Si as main alloying elements, instead of expensive Cr and Nb in traditional titanium alloys, so that the material cost is reduced; in the preparation process, the smelting process is optimized, and the operation steps are simplified, so that the energy consumption and production complexity are reduced, and the production efficiency is improved.

[0022] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a scanning electron microscope microstructure image of the Ti 12 Al 85 Si3 alloy of the present application;

[0024] Figure 2 is an XRD image of the Ti 12 Al 85 Si3 alloy of the present application;

[0025] Figure 3 is a Ti 12 Al2Cr2Nb intermetallic compound of the Ti48 Al2Cr2Nb(Ti-48Al-2Nb-2Cr) at different temperatures tensile mechanical properties comparison chart;

[0026] Figure 4 Ti 85 Al 12 Si3 and titanium aluminum intermetallic compound Ti 48 Al2Cr2Nb compression mechanical properties comparison chart. DETAILED DESCRIPTION

[0027] The technical solutions of the present application are further illustrated below by means of the drawings and examples.

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present application shall have the usual meaning understood by those skilled in the art to which the present application belongs.

[0029] Unless otherwise defined, the reagents, devices and other materials used in the present application are obtained from conventional commercial sources.

[0030] Example 1

[0031] A low-cost high-toughness titanium alloy material, the phase composition of the titanium alloy material is α single phase, including 7.2wt.% Al, 1.8wt.% Si, and the balance is Ti.

[0032] The purity of Al, Si and Ti is not less than 99.9%.

[0033] A preparation method of a low-cost high-toughness titanium alloy material, comprising the following steps:

[0034] Step one: mix each raw material uniformly according to mass percentage.

[0035] Step two: pretreat the smelting equipment, which is a vacuum arc furnace.

[0036] Step three: smelt the alloy mixture formed in step one for multiple times, and get ingot after cooling.

[0037] The specific operation of the pretreatment of the smelting equipment in step two is as follows:

[0038] The vacuum arc furnace includes a tungsten rod and a crucible.

[0039] Tungsten electrode treatment: use 320# sandpaper to taper grind the working end of the tungsten rod, to ensure that the tungsten electrode remains sharp.

[0040] Smelting cavity cleaning: use anhydrous ethanol to wipe the surface of the crucible three times to ensure cleanliness.

[0041] The specific method of step three smelting is as follows:

[0042] The alloy mixture from step one is placed in the melting station of a vacuum arc furnace. Pure zirconium metal particles are placed in the oxygen absorption station of the vacuum arc furnace. Before each melting of the alloy mixture, the pure zirconium metal particles are melted first to absorb oxygen.

[0043] Argon gas is introduced during the melting process, and the induced current is controlled at 320A. After the alloy mixture melts into a liquid state, magnetic stirring is turned on with a current of 10A, and each melting lasts for 3 minutes. Each sample is melted 6 times. During the 2nd to 5th melting, the sample is held upright to ensure that the alloy mixture is completely melted and that all components are mixed evenly.

[0044] Based on the provided titanium alloy mass percentage composition, titanium alloy ingots were prepared by arc melting. The ingots were then ground and polished to prepare metallographic samples. Subsequently, surface scanning analysis was performed using energy dispersive spectroscopy (EDS) with scanning electron microscopy (SEM) to characterize the atomic number distribution of the alloy elements. The analytical results showed that the atomic ratio of titanium, aluminum, and silicon in this titanium alloy was 85:12:3. This titanium alloy was named Ti based on the atomic ratio of each element. 85 Al 12 Si3.

[0045] The smelted titanium alloy sample Ti 85 Al 12 Si3 was subjected to mechanical property testing.

[0046] Figure 1 This refers to the microstructure of the titanium alloy, specifically the Ti alloy prepared in Example 1. 85 Al 12 The Si3 alloy has a uniform microstructure and relatively clear grain boundaries. Figure 2 XRD analysis showed that the titanium alloy was mainly composed of the α-Ti phase.

[0047] After testing, such as Figure 3 As shown, the titanium alloy Ti obtained in Example 1 85 Al 12 Si3 has a tensile strength of 870 MPa and an elongation of 3.5% at room temperature; a tensile strength of 594 MPa and an elongation of 10.5% at 600°C; a tensile strength of 465 MPa and an elongation of 12.6% at 750°C; and a tensile strength of 432 MPa and an elongation of 34% at 800°C.

[0048] like Figure 4 As shown, the alloy has a compressive strength of 1757 MPa and a compressive plasticity of 35%.

[0049] Example 2

[0050] A low-cost high-toughness titanium alloy material, the titanium alloy material phase composition is α single phase, including 5wt.% Al, 4wt.% Si, the balance is Ti.

[0051] The purity of Al, Si, and Ti is not less than 99.9%. The preparation method is the same as that of Example 1.

[0052] Example 3

[0053] A low-cost high-toughness titanium alloy material, the titanium alloy material phase composition is α single phase, including 4wt.% Al, 5wt.% Si, the balance is Ti.

[0054] The purity of Al, Si, and Ti is not less than 99.9%. The preparation method is the same as that of Example 1.

[0055] Example 4

[0056] A low-cost high-toughness titanium alloy material, the titanium alloy material phase composition is α single phase, including 8wt.% Al, 1wt.% Si, the balance is Ti.

[0057] The purity of Al, Si, and Ti is not less than 99.9%. The preparation method is the same as that of Example 1.

[0058] Example 5

[0059] The alloy material Ti 85 Al 12 Si3 (hereinafter referred to as Ti85) and the commercial titanium alloy Ti 48 Al2Cr2Nb (hereinafter referred to as Ti4822) in the prior art were compared in tensile properties.

[0060] Ti4822 is a typical γ-TiAl-based alloy, which realizes solid solution strengthening by adding 2% Cr and Nb, and the addition of Nb element effectively improves the oxidation resistance and high temperature stability of the alloy.

[0061] The comparison indexes of Ti85 and Ti4822 include tensile strength and elongation at room temperature, 600°C, 750°C, and 800°C. The results are shown in Table 1.

[0062] Table 1 Test Results

[0063]

[0064] As shown in Table 1, the mechanical properties of Ti85 and Ti4822 show significant differences at different temperatures. The tensile strength of Ti85 (870 MPa) is much higher than that of Ti4822 (528 MPa) at room temperature, and its elongation is also significantly better than that of Ti4822, showing higher strength and better plasticity.

[0065] As shown in Figure 3 , with the temperature increasing to 600°C, 750°C, 800°C, the strength of the two alloys gradually decreases, while the elongation significantly increases. For example, the strength of Ti85 decreases to 432 MPa at 800°C, and the elongation increases significantly to 34%, showing excellent high-temperature plasticity; while the strength of Ti4822 at the same temperature is comparable, but the elongation is only 7%, indicating that its high-temperature deformation ability is significantly weaker than that of Ti85. The mechanical properties of Ti85 alloy (mainly α-Ti phase) are significantly better than those of Ti4822 (TiAl intermetallic compound) at room temperature and high temperature, which is mainly due to two advantages: first, the α phase has excellent structural stability, which can maintain high strength and good plasticity at room temperature and high temperature, while the intrinsic brittleness of TiAl intermetallic compound seriously restricts its engineering application; second, through careful design of alloying strategy, the combination of Al (strong α stabilizing element) and Si (weak α stabilizing element) not only achieves significant solid solution strengthening effect, but also effectively maintains the deformation ability of the material through component synergistic control. This optimized matching of composition-structure-performance makes Ti85 alloy show more reliable application prospect in the field of aerospace structures.

[0066] Example 6

[0067] The Ti 85 Al 12 Si3 alloy provided in Example 1 (hereinafter referred to as Ti85) and the commercial titanium alloy Ti 48 Al l2 Cr2Nb (hereinafter referred to as Ti4822) were compared in compression performance.

[0068] The commercial titanium alloy Ti4822 is a typical titanium-aluminum intermetallic compound alloy, which is known for its excellent high-temperature strength, oxidation resistance and lightweight characteristics. The alloy is mainly composed of titanium (Ti), aluminum (Al), chromium (Cr) and niobium (Nb), among which the addition of aluminum significantly improves the high-temperature stability and oxidation resistance of the alloy, and the addition of chromium and niobium further enhances its mechanical properties and corrosion resistance, and is widely used in the field of aerospace. Although the Ti4822 alloy has excellent performance, its high cost and complex processing process limit its wider application.

[0069] The comparison indicators of Ti85 and Ti4822 include compression strength, compression plasticity and hardness. The results are shown in Table 2.

[0070] Table 2 test results

[0071]

[0072] As can be seen from the performance comparison data in Table 2, the Ti85 alloy is significantly superior to the commercial titanium alloy Ti4822 in multiple key performance indicators.

[0073] In terms of compression strength, as shown in the compression stress-strain curves of the two alloys, Ti85 is much higher than Ti4822, indicating that the alloy of the application has higher load-carrying capacity and structural stability, and is suitable for high-stress environments. Figure 4

[0074] In terms of plasticity, the alloy of the application has better deformation capacity when subjected to external force, can effectively avoid brittle fracture, and is suitable for application scenarios requiring high toughness.

[0075] In terms of hardness, the hardness of Ti85 is significantly enhanced, indicating that the application has better wear resistance and anti-deformation capacity, and is suitable for high-wear environments.

[0076] The alloy Ti85 of the application uses Al and Si as the main alloying elements, which are abundant in resources and low in price, replacing the expensive Cr and Nb in Ti4822, thereby greatly reducing the raw material cost, and in the preparation process of the Ti85 alloy, titanium waste can be fully utilized for recycling, further reducing the production cost.

[0077] The application adopts the above-mentioned low-cost high-strength and tough titanium alloy material and its preparation method to prepare the Ti 85 Al 12 Si3 alloy, which has significant advantages in mechanical properties, cost-effectiveness and process feasibility. In terms of compression performance, the room temperature compression strength of the alloy is as high as 1757 MPa, far exceeding traditional commercial titanium alloys, showing excellent plasticity, which can effectively avoid brittle fracture, and is suitable for application scenarios requiring high stress and high deformation. In terms of tensile performance, the tensile strength at room temperature reaches 870 MPa, at high temperature 600°C, the tensile strength is 594 MPa, and the elongation is 10.5%; at high temperature 750°C, the tensile strength is 465 MPa, and the elongation is 12.6%; at high temperature 800°C, the tensile strength is 432 MPa, and the elongation is 34%.

[0078] By using inexpensive Al and Si as the main alloying elements, replacing expensive chromium (Cr), niobium (Nb) and other elements in traditional titanium alloys, the material cost is reduced; in terms of preparation process, the smelting process is optimized, and the operation steps are simplified, not only reducing energy consumption and production complexity, but also improving production efficiency.

[0079] ​It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the technical solutions of the present application.

Claims

1. A low cost high toughness titanium alloy material, characterized by: The titanium alloy material has an α single phase, and an atomic ratio chemical formula of the titanium alloy material is Ti 85 Al 12 Si3, and the titanium alloy material includes 7.2 wt.% of Al, 1.8 wt.% of Si, and the balance of Ti.

2. The low cost high toughness titanium alloy material of claim 1, wherein: The purity of Al, Si and Ti is not less than 99.9%.

3. The method of claim 1 or 2, wherein the method further comprises the step of: The method comprises the following steps: ​ Step one: uniformly mixing raw materials according to mass percentage; Step two: preprocessing of the smelting equipment, which is a vacuum arc furnace; Step three: the alloy mixture obtained in step one is subjected to multiple melting in a melting device, and a titanium alloy material Ti 85 Al 12 Si3.

4. The method of claim 3, wherein the low-cost high-toughness titanium alloy material is prepared by the following steps of: In step two, the vacuum arc furnace comprises a tungsten rod and a crucible, and the preprocessing comprises taper grinding of the working end of the tungsten rod by using sandpaper and wiping the surface of the crucible by using anhydrous ethanol. ​ 5. The method for preparing a low-cost, high-strength, and tough titanium alloy material according to claim 3, characterized in that, In step three, the specific method of smelting is as follows: The alloy mixture is placed in the smelting station of the vacuum arc furnace, and pure zirconium metal particles are placed in the oxygen absorption station of the vacuum arc furnace. Before smelting the alloy mixture each time, the pure zirconium metal particles are first smelted to absorb oxygen.

6. The method for preparing a low-cost, high-strength, and tough titanium alloy material according to claim 3, characterized in that, In step three, the inductive current is controlled between 300-350 A during smelting. After the alloy mixture is melted into a liquid state, the magnetic stirring is started, and the magnetic stirring current is 10 A. Each smelting lasts for 3-4 minutes, and each sample is smelted for 6 times. During the 2nd-5th smelting, the sample is vertically placed to ensure that the alloy mixture is completely melted and the components are uniformly mixed.

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