Method for improving hot forming performance of ceramic particle reinforced TiAl matrix composite by hydrogenation and ultrasonic composite treatment and application thereof

Abstract

The application relates to a method for improving the hot forming performance of ceramic particle reinforced TiAl matrix composite materials through hydrogenation and ultrasonic composite treatment and application, and belongs to the technical field of metal matrix composite material processing. In order to solve the technical problem of poor hot forming performance of ceramic particle reinforced TiAl matrix composite materials, the application provides a method for improving the hot forming performance of ceramic particle reinforced TiAl matrix composite materials through hydrogenation and ultrasonic composite treatment, and the steps are as follows: raw materials are put into a crucible, and the raw materials are subjected to overturning smelting under a mixed atmosphere of argon and hydrogen; after the last smelting is completed, ultrasonic treatment is applied in the current reduction stage; and ceramic particle reinforced TiAl matrix composite materials subjected to hydrogenation and ultrasonic composite treatment are obtained. The ceramic particle reinforced TiAl matrix composite material prepared by the application reduces the hot deformation resistance of the metal matrix composite material, improves the hot forming performance, and the method provided by the application has the advantages of low cost, high efficiency and the like.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite material processing technology, specifically relating to a method and application of hydrogenation and ultrasonic composite treatment to improve the thermoforming properties of ceramic particle-reinforced TiAl matrix composites. Background Technology

[0002] TiAl-based composites optimized with ceramic reinforcement particles possess advantages such as low density, high specific strength, strong high-temperature creep resistance, and strong oxidation resistance, and are expected to be applied in structural components such as turbine blades of aero-engines to achieve energy saving and weight reduction. However, the TiAl alloy matrix has high resistance to high-temperature deformation and poor high-temperature plasticity, resulting in poor hot working and forming performance. The introduction of ceramic reinforcement particles makes the hot working and forming of the composite material even more difficult.

[0003] Currently, the main method to improve the hot forming properties of TiAl-based composites is to add elements that stabilize the B2 phase to increase the B2 phase content, thereby improving hot forming performance. However, the B2 phase is a hard and brittle phase at room temperature, leading to a decrease in the mechanical properties of the metal matrix composite. Finding a near-net-shape forming method to improve the hot forming properties of TiAl-based composites without significantly altering the alloy composition, without reducing mechanical properties, is crucial for the widespread application of metal matrix composites and is a problem that urgently needs to be solved. Summary of the Invention

[0004] To address the technical problem of poor thermoforming performance of TiAl-based composite materials, this invention provides a method and application for improving the thermoforming performance of ceramic particle-reinforced TiAl-based composite materials through hydrogenation and ultrasonic composite treatment.

[0005] One objective of this invention is to provide a method for improving the thermoforming properties of ceramic particle-reinforced TiAl-based composite materials through a combination of hydrogenation and ultrasonic treatment, the method comprising the following steps:

[0006] The raw materials are placed in a crucible, and after evacuation, a mixture of argon and hydrogen is introduced. The mixture is then subjected to multiple tumbling melting processes under the mixed atmosphere. After the final melting process, ultrasonic treatment is applied during the current reduction phase. The ultrasonic power and duration are controlled, and the current immediately drops to 0 after the ultrasonic treatment is completed.

[0007] Furthermore, the raw materials are added in the order of increasing melting point, following the order of ceramic materials, intermediate alloys, and elemental materials.

[0008] Further specifying, the ceramic material is TiN, B powder, or BN powder.

[0009] Further specifying, the intermediate alloy is Al-Nb or Al-W.

[0010] Further specifying, the elemental materials include Al particles and sponge Ti.

[0011] Furthermore, the elemental material also includes one or more of Zr, Mo, Ta, and Hf particles.

[0012] Further specified, the gas pressure during the smelting process is kept constant at 0.05 MPa, and the hydrogen volume content in the mixed gas is 5-50%.

[0013] Further specified, the melting current is 550A-700A, and the melting is carried out by flipping 3-8 times.

[0014] Further specified, ultrasonic treatment should be performed when the current is reduced to 300-450A, the ultrasonic power should be 1.8-2kW, and the treatment time should be 0.5-5min.

[0015] The second objective of this invention is to provide an application of the above-mentioned method in improving the thermoforming properties of ceramic particle-reinforced TiAl-based composite materials, wherein the Al content in the ceramic particle-reinforced TiAl-based composite material is 42-48 at%.

[0016] The third objective of this invention is to provide a TiAl-based composite material prepared by the above method.

[0017] The fourth objective of this invention is to provide an application of the TiAl-based composite material prepared by the above method in aerospace engine structural components.

[0018] The significant advantages of this invention compared to existing technologies are:

[0019] (1) The present invention performs hydrogenation treatment on TiAl-based composite materials at high temperature during high-temperature melting, so that hydrogen atoms dissolve into the interior of the composite material during high-temperature melting, stimulate dislocation slip during hot working, promote dynamic recrystallization, reduce yield strength during high-temperature deformation, and improve high-temperature plasticity. Hydrogen atoms can be removed by vacuum annealing after hot working and forming, without causing hydrogen embrittlement or other problems that lead to a decrease in mechanical properties.

[0020] (2) Since the solid solution content of hydrogen atoms in TiAl ingots is limited, the high proportion of hydrogen in the melting furnace will increase the preparation cost. Therefore, in the process of cooling TiAl ingot melting, ultrasonic treatment is performed at the bottom of the water-cooled copper crucible. Ultrasonic treatment can not only increase the amount of hydrogen atoms dissolved, but also reduce casting defects and increase the number of high-temperature softened grain boundaries. The synergistic effect of hydrogenation and ultrasonic treatment further reduces the peak stress during high-temperature deformation, thereby greatly improving its hot working and forming performance.

[0021] (3) The TiAl-based composite material prepared in this invention can withstand hot working at a temperature of 1100℃ and a strain rate of 0.01s. -1 Under these conditions, compared to TiAl-based composites treated with single hydrogenation, the deformation resistance decreased from 475 MPa to 351 MPa, achieving the goal of reducing high-temperature deformation resistance while improving hot working and forming performance, and also has the advantages of low cost and high efficiency. Attached Figure Description

[0022] Figure 1 Schematic diagram of the equipment used to prepare TiAl-based composite materials by hydrogenation and ultrasonic composite treatment;

[0023] Figure 2 The TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2 were subjected to a temperature of 1100°C and a curvature of 0.1 s. -1 Comparison of peak rheological stress measurements at strain rates;

[0024] Figure 3 The TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2 were subjected to a temperature of 1100°C and a curvature of 0.01 s. -1 Comparison of peak rheological stress measurements at strain rates;

[0025] Figure 4 The images show the hot deformation microstructures of TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2, where a is Comparative Example 1, b is Comparative Example 2, and c is Example 1. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0028] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used in the following embodiments, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0029] In this invention, "an embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0030] The raw materials used in the following examples are: blocky grade 0 sponge Ti (5 mm in size, 99.7% purity), Al particles (6 mm in diameter, 99.9% purity), Al-Nb master alloy (3 mm in size, with Nb content of 72.65 wt.%), Mo particles (3 mm in size, 99.9% purity), TiN ceramic powder (75 μm in size, 99.9% purity), Zr, Ta and Hf particles (3 mm in size, 99.9% purity), Al-W master alloy (2 mm in size, with W content of 50 wt%), B ceramic powder (3 μm in size, 99.9% purity), BN ceramic powder (5 μm in size, 99.9% purity), hydrogen (99.999% purity), and argon (99.999% purity).

[0031] Example 1: A method for improving the thermoforming properties of Ti2AlN / Ti-46Al-4Nb-1Mo composite materials through hydrogenation and ultrasonic composite treatment is carried out according to the following steps:

[0032] (1) Weigh Al particles, blocky grade 0 sponge Ti and Mo particles, and Al-Nb master alloy according to the atomic percentage of Ti-46Al-4Nb-1Mo alloy, and weigh TiN ceramic powder according to the addition amount of 1.6 at.%. Then, use anhydrous ethanol to ultrasonically clean the above raw materials for 10 min, and dry them for later use.

[0033] (2) Wrap TiN ceramic powder with aluminum foil and place it at the bottom of the crucible (water-cooled copper crucible), then add Al-Nb intermediate alloy and Mo particles, and finally place Al particles and blocky grade 0 sponge Ti.

[0034] (3) The vacuum non-consumable arc melting furnace was evacuated, then purged with 0.01 MPa high-purity hydrogen gas. This purging process was repeated twice. Subsequently, the molecular pump was turned on to evacuate the furnace to a vacuum level of 5 × 10⁻⁶ MPa. -3 Pa;

[0035] (4) A mixture of argon and hydrogen gas was introduced and smelted in the mixed atmosphere. During the gas introduction, hydrogen gas was first introduced until the furnace pressure reached 0.01 MPa, and then argon gas was introduced until the furnace pressure reached 0.05 MPa (hydrogen partial pressure was 20%). Smelting was carried out at a constant pressure of 0.05 MPa and 550 A. The smelting was repeated 6 times. After the last smelting, ultrasonic treatment was applied with the current reduced to 450 A. The ultrasonic power and treatment time were controlled. The ultrasonic power was 2 kW and the treatment time was 60 s. After the ultrasonic treatment, the current was immediately reduced to 0 to obtain the Ti2AlN / Ti-46Al-4Nb-1Mo composite material.

[0036] Example 2

[0037] The difference between this embodiment and Embodiment 1 is that the volume percentage of hydrogen in the mixed gas is 40%, while the remaining steps are the same as in Embodiment 1.

[0038] Example 3

[0039] The difference between this embodiment and Embodiment 1 is that the volume percentage of hydrogen in the mixed gas is 50%, while the remaining steps are the same as in Embodiment 1.

[0040] Example 4

[0041] The difference between this embodiment and Embodiment 1 is that the ceramic powder in the raw material of the ceramic particle-reinforced TiAl-based composite material is B powder; otherwise, it is the same as in Embodiment 1. The resulting ceramic particle-reinforced TiAl-based composite material is TiB. w / Ti-46Al-4Nb-1Mo.

[0042] Example 5

[0043] The difference between this embodiment and Embodiment 1 is that the ceramic powder in the raw material of the ceramic particle-reinforced TiAl-based composite material is BN powder; otherwise, it is the same as in Embodiment 1. The resulting ceramic particle-reinforced TiAl-based composite material is (Ti2AlN+TiB) w ) / Ti-46Al-4Nb-1Mo.

[0044] Example 6

[0045] The difference between this embodiment and Embodiment 1 is that the alloy in the ceramic particle reinforced TiAl-based composite material is replaced with Ti-43Al-2Zr-1Hf-1Ta-0.5W, where W is added in the form of an Al-W master alloy, the high melting point element is , and Zr, Ta and Hf are added in the form of elemental particles, and the rest is the same as in Embodiment 1.

[0046] Example 7

[0047] The difference between this embodiment and Embodiment 1 is that the current applied during ultrasonic treatment is different. In this embodiment, ultrasonic treatment is performed when the current drops to 350A. Otherwise, it is the same as Embodiment 1.

[0048] Example 8

[0049] The difference between this embodiment and Embodiment 1 is that the power applied during ultrasonic treatment is different. The ultrasonic power in this embodiment is 1.8kW, while the rest is the same as in Embodiment 1.

[0050] Example 9

[0051] The difference between this embodiment and Embodiment 1 is that the duration of ultrasonic treatment is different. In this embodiment, the ultrasonic treatment time is 2 minutes, while the rest is the same as in Embodiment 1.

[0052] Comparative Example 1

[0053] The difference between this embodiment and Embodiment 1 is that high-purity argon gas is used to flush the closed melting furnace, and constant pressure melting is carried out under the condition of high-purity argon gas as a protective gas. Ultrasonic treatment is not performed. The remaining steps are the same as in Embodiment 1, and TiAl-based composite material without hydrogenation and ultrasonic treatment is obtained.

[0054] Comparative Example 2

[0055] The difference between this embodiment and Embodiment 1 is that no ultrasonic treatment was applied in this embodiment. Otherwise, it is the same as Embodiment 1, and a TiAl-based composite material without ultrasonic treatment is obtained.

[0056] The preparation apparatus of Example 1 is as follows Figure 1 As shown, it consists of three parts: a melting control system, a hydrogen-argon mixing system, and an ultrasonic generation system. During the melting process, a tungsten inert gas torch is used for melting, and a water-cooled copper crucible is used for cooling. The hydrogen-argon mixed atmosphere is monitored and proportionally controlled by a pressure gauge. The ultrasonic generator is located at the bottom of the water-cooled copper crucible, and ultrasonic treatment is performed by indirectly introducing ultrasonic waves.

[0057] The TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2 were subjected to deformation at a temperature of 1100℃ and a strain rate of 0.1 s⁻¹. -1 Peak stress at time Figure 2 As shown, the peak stress of TiAl-based composite materials after single hydrogenation treatment is significantly reduced from 695 MPa to 605 MPa, while the peak stress of TiAl-based composite materials after hydrogenation and ultrasonic combined treatment is further reduced to 561 MPa.

[0058] The TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2 were subjected to deformation at a temperature of 1100℃ and a strain rate of 0.01 s⁻¹. -1 Peak stress at time Figure 3 As shown, the peak stress of TiAl-based composites after single hydrogenation treatment is significantly reduced from 475 MPa to 403 MPa, while the peak stress of TiAl-based composites after hydrogenation and ultrasonic combined treatment is further reduced to 351 MPa.

[0059] The above conclusions demonstrate that the synergistic effect of hydrogenation and ultrasonic composite treatment can improve the thermoforming properties of TiAl-based composite materials.

[0060] The high-temperature compression microstructures of the TiAl-based composite materials prepared in Example 1 and Comparative Examples 1-2 are as follows: Figure 4 As shown, Figure 4 (a) indicates that the deformation amplitude of α2 / γ lamellar clusters in TiAl-based composites without hydrogenation and ultrasonic treatment is small; Figure 4 (b) indicates that the α2 / γ lamellar clusters of the TiAl-based composite material treated with single hydrogenation exhibit significant lateral elongation, with a larger and more uniform deformation amplitude; Figure 4 (cd) indicates that the α2 / γ lamellar clusters of the TiAl-based composite material treated by hydrogenation and ultrasound exhibit obvious transverse elongation, and a large number of equiaxed recrystallized grains appear at the lamellar cluster grain boundaries, proving that the TiAl-based composite material has a good thermal deformation structure.

[0061] The contents not described in detail in this specification are well-known to those skilled in the art. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for improving the thermoforming properties of ceramic particle-reinforced TiAl-based composite materials through a combination of hydrogenation and ultrasonic treatment, characterized in that, Includes the following steps: The raw materials are placed in a crucible, and after evacuation, a mixture of argon and hydrogen is introduced. The mixture is then subjected to multiple tumbling and melting processes under the mixed atmosphere. After the final melting process, ultrasonic treatment is applied during the current reduction phase. The ultrasonic power and duration are controlled. After the ultrasonic treatment is completed, the current immediately drops to 0. The raw materials are added in the order of increasing melting point, following the order of ceramic material, master alloy, and elemental material. The ceramic material is TiN, B powder, or BN powder; the master alloy is Al-Nb or Al-W; the elemental material is one or more of Zr, Mo, Ta, and Hf particles, as well as Al particles and sponge Ti. The Al content in the ceramic particle-reinforced TiAl-based composite material is 42-48 at%. When the current is reduced to 300-450A, ultrasonic treatment is performed with an ultrasonic power of 1.8-2kW and an action time of 0.5-5min. The gas pressure is kept constant at 0.05 MPa during the smelting process, and the hydrogen volume content in the mixed gas is 5-50%.

2. The method according to claim 1, characterized in that, The melting current is 550A-700A, and the melting is carried out by flipping the furnace 3-8 times.

3. The TiAl-based composite material obtained by the method of claim 1 or 2.

4. The application of the TiAl-based composite material prepared by the method of claim 1 or 2 in aerospace engine structural components.

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