High-performance modified Ti2AlNb-based alloy and preparation method thereof

Abstract

The invention discloses a high-performance modified Ti2AlNb-based alloy and a preparation method thereof. The preparation method comprises the steps of modified alloy design and selective laser melting forming. The alloy comprises the following components in percentage by mass: 0.125%-0.25% of Vit105 (Zr 52.5%, Cu 17.9%, Ni 14.6%, Al 10Ti 5%), and the balance of Ti-22Al-25Nb, the yield strength of the high-performance modified alloy provided by the invention is 912-995 MPa, the tensile strength of the high-performance modified alloy is 975-1007 MPa, and the ductility of the high-performance modified alloy is 8-10%; according to the invention, by designing the element components of the modified alloy, multiple strengthening elements such as Zr, Cu and Ni are selectively introduced in a mixed amorphous alloy manner to carry out alloying modification on the Ti2AlNb-based alloy, so that the strengthening elements are promoted to be uniformly distributed in an alloy structure and are synergistically strengthened; compared with an existing modification technology, the modification design has the advantages that the gain of the strong plasticity of the Ti2AlNb-based alloy is particularly remarkable, and good combination is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of Ti 2 AlNb-based alloy materials, and specifically to a high-performance modified Ti 2 AlNb-based alloy and its preparation method. Background Technique

[0002] Ti 2 AlNb-based alloys belong to intermetallic compounds based on the ordered orthorhombic O phase and are suitable for manufacturing hot-end components of aeroengines. The new generation of aircraft manufacturing technology has put forward the design concept of cost reduction and efficiency improvement, which has restricted most traditional processing technologies. Aerospace materials require mechanical properties that take into account both structural load-bearing capacity and processing formability, ensuring high strength while having excellent plasticity. Ti 2 AlNb alloys have excellent load-bearing capacity due to the high strength of the B2 / O phase, but the nature of intermetallic compounds results in insufficient room-temperature plasticity.

[0003] As a kind of additive manufacturing technology, the powder bed-based selective laser melting process uses laser as the heat source and powder as the raw material to form materials by layer-by-layer stacking from point to surface and from surface to volume. Additive manufacturing products with powder as the raw material have high processing accuracy and are closer to the final use state, thus reducing the cost of subsequent fine processing and being more widely used. The selective laser melting forming technology provides a new path for the precise control of the microstructure and the efficient manufacturing of complex components of Ti 2 AlNb-based alloys.

[0004] Zhang Jian et al. studied the modification of Ti 2 AlNb-based alloys by B element melting, and the results showed that it was difficult to balance strength and plasticity by single-element strengthening. Polozov et al. mixed CYB as a modification component into Ti 2 AlNb-based alloys and found that due to the too large temperature gradient, various alloy elements are prone to mutual exclusion and mutual inhibition, and uneven element distribution may lead to further deterioration of performance. Spuller et al. found that zirconium-based amorphous alloys have a relatively low melting point, melt earlier in the selective laser melting process, and have good melt pool wettability, which can promote the dispersion of each element in the tissue and the melting of refractory elements.

[0005] To sum up, it is urgent to study a modified Ti 2 AlNb-based alloy material with excellent mechanical properties and its preparation method to achieve a good combination of high strength and high plasticity of the alloy. Selectively introducing multiple strengthening elements into Ti 2 AlNb-based alloys in the form of mixed amorphous alloys helps to achieve multi-element synergistic strengthening, enabling each element to have an effect on Ti 2The enhancement of strength and plasticity of the AlNb-based alloy is more significant. Summary of the Invention

[0006] The present invention takes the Ti 2 AlNb-based alloy as the research object, and selectively introduces multiple strengthening elements such as Zr, Cu, and Ni in the form of mixing Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) amorphous alloy to alloy-modify the Ti 2 AlNb-based alloy. The selective laser melting technology is used to prepare a new type of high-performance modified Ti 2 AlNb-based alloy with good combination of high strength and high plasticity, breaking through the bottleneck of room temperature performance.

[0007] To achieve the above invention purpose, the present invention is realized through the following technical solutions.

[0008] A high-performance modified Ti 2 AlNb-based alloy, the mass fraction of the powder components is: Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) 0.125% - 0.25%, and the balance is Ti-22Al-25Nb.

[0009] The designed Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) amorphous alloy components are Zr 52.5 at.%, Cu 17.9 at.%, Ni 14.6 at.%, Al 10 at.%, Ti 5 at.%, belonging to zirconium-based amorphous alloy; the Ti-22Al-25Nb alloy components are Al 22.78 at.%, Nb 24.83 at.%, and the rest is Ti, belonging to the Ti 2 AlNb-based alloy.

[0010] A high-performance modified Ti 2 AlNb-based alloy prepared by the present invention has a yield strength of 912 - 995 MPa, a tensile strength of 975 - 1007 MPa, and an elongation of 8 - 10%.

[0011] The present invention provides a preparation method of a high-performance modified Ti 2 AlNb-based alloy, and the steps are as follows.

[0012] Design the composition of the modified alloy, select Zr, Cu, and Ni as strengthening elements, and design the alloy element components in the form of Vit105 (ZrCuNiAlTi) amorphous alloy.

[0013] According to the designed alloy composition, melt and atomize to prepare Vit105 alloy and Ti-22Al-25Nb alloy pre-alloy powders, and weigh and mix according to the designed mass fraction of the composite powder.

[0014] Mix the weighed Vit105 and Ti-22Al-25Nb alloy evenly by stirring to obtain mixed powder with good sphericity.

[0015] Conduct selective laser melting forming on the mixed powder. Before forming, introduce argon gas into the chamber for purging. The forming process parameters are: laser power: 180 - 190 W, scanning speed: 900 - 1000 mm / s, powder layer thickness: 30 μm, scanning spacing: 90 - 100 μm. Control the oxygen content during the forming process within 400 - 600 ppm. During the forming process, the mixed powder rapidly melts and solidifies under the irradiation of the high-energy laser beam and accumulates layer by layer to obtain a modified Ti 2 AlNb-based alloy.

[0016] In the present invention, by designing the elemental composition in Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) alloy, strengthening elements such as Zr, Cu, Ni, etc. can improve the strength and plasticity of the Ti 2 AlNb-based alloy through grain refinement, precipitation strengthening, and solid solution strengthening; selectively alloying the Ti 2 AlNb-based alloy in the alloying manner of zirconium-based amorphous alloy. This method can improve the selective laser melting forming process and prepare a new high-performance modified Ti 2 AlNb-based alloy with good combination of high strength and high plasticity, breaking through the room temperature performance bottleneck. The yield strength of the formed sample is 912 - 995 MPa, the tensile strength is 975 - 1007 MPa, and the elongation is 8 - 10%. It breaks through the room temperature performance bottleneck of intermetallic compounds and realizes a good combination of high strength and high plasticity. The high-performance modified Ti 2 AlNb-based alloy prepared by the present invention can be widely applied in fields such as high-performance materials for aerospace.

[0017] Compared with the prior art, the present invention has the following innovation and beneficial effects:

[0018] 1. By designing the elemental composition in Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) alloy, selectively introducing multiple strengthening elements such as Zr, Cu, Ni in the form of mixed amorphous alloy to alloy-modify the Ti 2 AlNb-based alloy, it provides a pioneering idea for multi-element alloying modification.

[0019] 2. The high-performance modified Ti 2The tensile strength of the AlNb-based alloy can reach up to 1007.2 MPa, with excellent structural load-bearing capacity, meeting the material strength requirements of the vast majority of aerospace structural components; the yield strength is 994.7 MPa, and the elongation is 9.7%. Compared with traditional titanium-aluminum-based intermetallic compounds, it has better room-temperature plasticity, breaking through the room-temperature performance bottleneck while achieving a good combination of strength and plasticity.

[0020] 3. The high-performance modified Ti of the present invention 2 The AlNb-based alloy solves the problems of difficult forming, low efficiency, and high cost in traditional processing methods through selective laser melting forming technology, responding to the technical concept of cost reduction and efficiency increase advocated by new advanced manufacturing technologies. Brief Description of the Drawings

[0021] Figure 1 is the technical roadmap of the present invention.

[0022] Figure 2 is the powder morphology of the high-performance modified Ti 2 AlNb-based alloy in Example 1 of the present invention.

[0023] Figure 3 is the microstructure morphology of the high-performance modified Ti 2 AlNb-based alloy in Example 1 of the present invention.

[0024] Figure 4 is the tensile stress-strain diagram of the high-performance modified Ti 2 AlNb-based alloy in Example 1 of the present invention. Detailed Embodiments

[0025] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer and more specific, the technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. The following listed embodiments are only partial embodiments, and the present invention is not limited thereto.

[0026] Example 1

[0027] Raw material preparation and mass ratio: The powder raw materials are melted and atomized according to the designed element components. The mass fractions of the designed powder components are: Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) 0.125%, and Ti-22Al-25Nb 99.875%.

[0028] Preparation method:

[0029] (1) Raw material weighing: Weigh and mix the raw materials according to the mass fraction percentages of each component powder raw material.

[0030] (2) Raw material mixing: The weighed Vit105 alloy powder and Ti-22Al-25Nb alloy powder are stirred and mixed evenly by a powder mixing device.

[0031] (3) Additive manufacturing: The mixed powder is subjected to selective laser melting and forming. Argon gas is introduced into the chamber for gas washing before forming. The forming process parameters are: laser power: 180W, scanning speed: 1000mm / s, powder layer thickness: 30μm, scanning spacing: 100μm, and the oxygen content in the forming process is controlled at 400-600ppm. During the forming process, the mixed powder is rapidly melted and solidified under the irradiation of the high-energy laser beam, and is deposited layer by layer to obtain a modified Ti with uniform structure. 2 AlNb based alloy.

[0032] Mechanical properties test: The modified Ti prepared by the method described in this example 2 AlNb-based alloy parts are processed into standard tensile specimens and subjected to tensile tests. The tensile stress-strain curve is shown in Figure 2 As shown, the yield strength of this embodiment is 994.7MPa, the tensile strength is 1007.2MPa, and the elongation is 9.7%. This embodiment is different from other multi-element modified Ti formed by selective laser melting. 2 The mechanical properties of AlNb-based alloys are compared in Table 1. 2 AlNb-based alloys can achieve similar high strength after hot isostatic pressing (far exceeding that of untreated samples), while also possessing excellent plasticity that other modified alloys fail to achieve.

[0033] Table 1 Selected laser melting forming Ti 2 Comparison of Mechanical Properties of AlNb-Based Alloys

[0034]

[0035] Example 2

[0036] Raw material preparation and mass ratio: Powder raw materials are prepared by smelting and atomization according to the designed elemental components. The designed powder component mass fraction is: Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) 0.25%, Ti-22Al-25Nb 99.75%.

[0037] Preparation method:

[0038] (1) Raw material weighing: weigh and mix the raw materials according to the mass percentage of each component powder.

[0039] (2) Raw material mixing: The weighed Vit105 alloy powder and Ti-22Al-25Nb alloy powder are stirred and mixed evenly by a powder mixing device.

[0040] (3) Additive manufacturing forming: Selective laser melting forming is carried out on the mixed powder. Before forming, argon gas is introduced into the chamber for purging. The forming process parameters are: laser power: 180 W, scanning speed: 1000 mm / s, powder layer thickness: 30 μm, scanning spacing: 100 μm. The oxygen content during the forming process is controlled at 400 - 600 ppm. During the forming process, the mixed powder rapidly melts and solidifies under the irradiation of a high-energy laser beam and is stacked layer by layer to obtain a modified Ti 2 AlNb-based alloy.

[0041] Mechanical property testing: The modified Ti 2 AlNb-based alloy parts manufactured by the method described in this embodiment are processed into standard tensile specimens for tensile testing. The yield strength of this embodiment is measured to be 912.0 MPa, the tensile strength is 975.2 MPa, and the elongation is 8.1%.

[0042] Comparative example 1

[0043] Raw material preparation and mass ratio: Powder raw materials are melted and atomized according to the designed element components. The mass fraction of the designed powder components is: Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) 0.125%, Ti-22Al-25Nb 99.875%.

[0044] Preparation method:

[0045] (1) Raw material weighing: Weigh and proportion the raw materials according to the mass fraction percentage of each component powder raw material.

[0046] (2) Raw material mixing: The weighed Vit105 alloy powder and Ti-22Al-25Nb alloy powder are stirred and mixed evenly by a powder mixing device.

[0047] (3) Additive manufacturing forming: Selective laser melting forming is carried out on the mixed powder. Before forming, argon gas is introduced into the chamber for purging. In this comparative example, high volume energy density forming parameters are used for comparison with Example 1. The forming process parameters are: laser power: 190 W, scanning speed: 900 mm / s, powder layer thickness: 30 μm, scanning spacing: 90 μm. The oxygen content during the forming process is controlled at 400 - 600 ppm. During the forming process, the mixed powder rapidly melts and solidifies under the irradiation of a high-energy laser beam and is stacked layer by layer to obtain a modified Ti 2 AlNb-based alloy.

[0048] Mechanical property test: The modified Ti 2 AlNb-based alloy parts are processed into standard tensile specimens for tensile tests. The yield strength of this example is measured to be 575.7 MPa, the tensile strength is 760.5 MPa, and the elongation is 2.0%. Combining Example 1 and Comparative Example 1, it can be seen that the alloy of the present invention can achieve a good combination of high strength and high plasticity at a relatively low volume energy density.

Claims

1. A high performance modified Ti2AlNb based alloy, characterized in that: The modified alloy powder components are calculated by mass fraction as follows: Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) 0.125% to 0.25%, and the balance is Ti-22Al-25Nb; the alloy has a yield strength of 912 to 995 MPa, a tensile strength of 975 to 1007 MPa, and an elongation of 8 to 10%.

2. The high performance modified Ti2AlNb-based alloy according to claim 1, characterized in that: The composition of Vit105 alloy is Zr52.5at.%, Cu 17.9at.%, Ni 14.6at.%, Al 10at.%, Ti 5at.%, which is a zirconium-based amorphous alloy; the composition of Ti-22Al-25Nb alloy is Al 22.78at.%, Nb 24.83at.%, and the rest is Ti, which is a Ti2AlNb-based alloy.

3. The high performance modified Ti2AlNb-based alloy according to claim 1, characterized in that: The following steps are involved: Design modified alloy composition, select Zr, Cu, and Ni as strengthening elements, and design the composition of each alloy element in the form of Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) amorphous alloy; According to the designed alloy composition, Vit105 alloy and Ti-22Al-25Nb alloy pre-alloyed powders are prepared by melting and atomization, and the ingredients are weighed and proportioned according to the designed composite powder mass fraction; The weighed Vit105 and Ti-22Al-25Nb alloy are mixed uniformly by stirring to obtain a mixed powder with good sphericity; The mixed powder is subjected to selective laser melting forming. Argon gas is introduced into the chamber for gas washing before forming. During the forming process, the mixed powder is rapidly melted and solidified under the irradiation of a high-energy laser beam, and is deposited layer by layer to obtain a modified Ti2AlNb-based alloy with uniform structure.

4. The high performance modified Ti2AlNb-based alloy according to claim 3, characterized in that: The process parameters of the selective laser melting forming are as follows: laser power: 180-190 W, scanning speed: 900-1000 mm / s, powder layer thickness: 30 μm, scanning spacing: 90-100 μm, oxygen content in the forming process is controlled at 400-600 ppm, and finally a modified Ti2AlNb-based alloy is obtained.

5. A method for preparing a high-performance modified Ti2AlNb-based alloy, characterized in that: The method comprises: designing modified alloy composition, selecting Zr, Cu and Ni as strengthening elements, and designing each alloy element component in the form of Vit105 (Zr52.5Cu17.9Ni14.6Al10Ti5) amorphous alloy; According to the designed alloy composition, Vit105 alloy and Ti-22Al-25Nb alloy pre-alloyed powders are prepared by melting and atomization, and the ingredients are weighed and proportioned according to the designed composite powder mass fraction; The weighed Vit105 and Ti-22Al-25Nb alloy are mixed uniformly by stirring to obtain a mixed powder with good sphericity; The mixed powder is subjected to selective laser melting forming. Argon gas is introduced into the chamber for gas washing before forming. During the forming process, the mixed powder is rapidly melted and solidified under the irradiation of a high-energy laser beam, and is deposited layer by layer to obtain a modified Ti2AlNb-based alloy with uniform structure.

6. The preparation method according to claim 5, characterized in that: The process parameters of the selective laser melting forming are as follows: laser power: 180-190 W, scanning speed: 900-1000 mm / s, powder layer thickness: 30 μm, scanning spacing: 90-100 μm, oxygen content in the forming process is controlled at 400-600 ppm, and finally a modified Ti2AlNb-based alloy is obtained.

7. The preparation method according to claim 5, characterized in that: The composition of Vit105 alloy is Zr 52.5at.%, Cu 17.9at.%, Ni 14.6at.%, Al 10at.%, Ti 5at.%, which is a zirconium-based amorphous alloy; the composition of Ti-22Al-25Nb alloy is Al 22.78at.%, Nb 24.83at.%, and the rest is Ti, which is a Ti2AlNb-based alloy.

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