Inconel 617 / nb / tc4 laminated composite material and preparation method thereof

Abstract

The application relates to an Inconel617 / Nb / TC4 laminated composite material and a preparation method thereof. The preparation method comprises the following steps: performing surface pretreatment on Inconel617 alloy plate, TC4 titanium alloy plate and pure Nb foil; stacking the Inconel617 alloy plate, the pure Nb foil and the TC4 titanium alloy plate in sequence, performing hot pressure sintering, and continuously maintaining external load after heat preservation, so as to obtain a pre-bonding intermediate; and performing multi-pass hot rolling on the pre-bonding intermediate, so as to obtain the Inconel617 / Nb / TC4 laminated composite material. The pure Nb foil is used to reduce the direct contact and mutual diffusion of Ni elements and Ti elements, to inhibit the formation of continuous brittle intermetallic compounds at the interface, and to improve the compactness and bonding strength of the interface through multi-pass hot rolling, so that the obtained laminated composite material has good strength, plasticity and light weight performance, the preparation process is simple, and the laminated composite material is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of layered metal matrix composites, specifically to an Inconel 617 / Nb / TC4 layered composite material and its preparation method. Background Technology

[0002] As aerospace equipment develops towards lightweight design, high thrust-to-weight ratio, and high service temperature, aero-engine combustion chambers, turbine outer rings, thermal protection structures, and other high-temperature load-bearing components not only need to possess high high-temperature strength, creep resistance, and oxidation resistance, but also need to minimize structural mass. Therefore, a single metallic material is usually insufficient to simultaneously meet the combined requirements of lightweight design and high-temperature service resistance.

[0003] Inconel 617 alloy possesses good high-temperature strength, creep resistance, and oxidation resistance, making it suitable for high-temperature service environments. However, its high density means that using Inconel 617 alloy exclusively for load-bearing components would significantly increase their weight. TC4 titanium alloy features low density, high room-temperature specific strength, and good plasticity, but its high-temperature strength and oxidation resistance are limited, making it unsuitable for use alone in components requiring long-term service at high temperatures.

[0004] Layered composite materials made from Inconel 617 alloy and TC4 titanium alloy can utilize the Inconel 617 alloy layer to bear high-temperature protection and loads, while the TC4 titanium alloy layer bears the main structural loads and reduces component mass. However, Inconel 617 alloy and TC4 titanium alloy have significant differences in physical and chemical properties. During high-temperature composite processing, Ni and Ti elements are prone to direct interdiffusion, potentially forming intermetallic compounds such as Ti₂Ni, TiNi, and TiNi₃ at the interface. When these reaction products form a continuous reaction layer, the interfacial plasticity and crack resistance decrease, making interfacial cracking or delamination more likely.

[0005] Existing technologies typically employ vacuum hot pressing to pre-bond dissimilar metals, supplemented by hot rolling to improve interfacial density. However, existing processes are mostly designed for Ti-6Al-4V / Inconel 718, titanium alloy / stainless steel, or Inconel 617 composite materials, with hot pressing temperatures of approximately 850-1150℃, hot rolling temperatures of approximately 760℃, and reduction rates of approximately 20%. Due to the different material systems, these parameters are difficult to balance in terms of coordinated deformation and interfacial reaction control between Inconel 617 and TC4: too low a temperature results in insufficient diffusion and pore closure, while too high a temperature easily promotes Ni-Ti interdiffusion and the formation of brittle intermetallic compounds. Therefore, existing processes are not directly applicable to the preparation of Inconel 617 / TC4 layered composite materials. Summary of the Invention

[0006] The purpose of this invention is to provide an Inconel 617 / Nb / TC4 layered composite material and its preparation method, so as to solve the problems in the prior art that the interface of Inconel 617 alloy and TC4 titanium alloy is prone to forming continuous brittle intermetallic compounds, the interface porosity is difficult to eliminate, and the interface bonding strength is insufficient during the direct composite process.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing an Inconel 617 / Nb / TC4 layered composite material, comprising the following steps: Step 1: Perform surface pretreatment on Inconel 617 alloy sheet, TC4 titanium alloy sheet and pure Nb foil respectively; Step 2: Stack the Inconel 617 alloy sheet, pure Nb foil, and TC4 titanium alloy sheet in sequence to obtain the Inconel 617 / Nb / TC4 laminated blank. Step 3: Place the laminated blanks in a vacuum hot pressing sintering furnace, with a vacuum degree not exceeding 3×10⁻⁶. -2 Under the conditions of Pa, an external load of 20 MPa, and a temperature of 950-1050 ℃, the material is kept at a temperature of 30-120 min; after the holding period, the external load is maintained until the temperature of the laminated blank drops below 150 ℃ to obtain a pre-bonded intermediate. Step 4: Heat the pre-bonded intermediate to 800-1000 ℃ and perform multiple hot rolling passes with a total reduction rate of 40%-60% to obtain the Inconel617 / Nb / TC4 layered composite material.

[0008] Furthermore, the surface pretreatment in step one above includes: using sandpaper to polish the surfaces of the Inconel 617 alloy plate, TC4 titanium alloy plate and pure Nb foil respectively to remove surface oxides and impurities; then using ethanol for ultrasonic cleaning and drying.

[0009] Furthermore, the initial thickness ratio of the aforementioned TC4 titanium alloy sheet, pure Nb foil, and Inconel 617 alloy sheet is 10:1:10.

[0010] Furthermore, in step three above, the vacuum degree is 5 × 10⁻⁶. -3 Pa, hot pressing temperature is 1000 ℃, and holding time is 120 min.

[0011] Furthermore, in step four above, the rolling temperature of the multi-pass hot rolling is 900 ℃, and the total reduction rate is 60%.

[0012] Furthermore, the Inconel617 / Nb / TC4 layered composite material obtained by the above preparation method.

[0013] Furthermore, the Inconel617 / Nb / TC4 layered composite material prepared by the above preparation method includes, along the thickness direction, an Inconel617 alloy layer, a pure Nb foil, and a TC4 titanium alloy layer, wherein a continuous bonding interface is formed between the Inconel617 alloy layer and the pure Nb foil, and between the pure Nb foil and the TC4 titanium alloy layer.

[0014] 1. In this invention, the pure Nb foil serves not only as a physical isolation layer but also to alter the element diffusion path between the Inconel 617 alloy and the TC4 titanium alloy. With the pure Nb foil, the original Inconel 617 / TC4 direct reaction interface is decomposed into an Inconel 617 / Nb interface and a Nb / TC4 interface, preventing direct, large-scale contact between Ni and Ti elements. EDS scanning results show that the direct interdiffusion of Ni and Ti elements is restricted, and Nb elements form a continuous compositional transition region between the two substrates, thereby reducing the tendency for the formation and growth of a continuous Ni-Ti reaction layer.

[0015] 2. The multi-pass hot rolling in this invention is not simply used to reduce the thickness of the sheet metal, but rather in conjunction with the aforementioned vacuum hot pressing pre-bonding. During the vacuum hot pressing stage, preliminary element diffusion occurs at the interfaces on both sides through temperature and holding time control. During the multi-pass hot rolling stage, the effective contact area of ​​each layer of material is further expanded through staged plastic deformation, and a continuous and gentle concentration gradient of interfacial elements is promoted within a limited high-temperature treatment time, avoiding excessive growth of the reaction layer caused by a single long-term high-temperature treatment.

[0016] 3. The preparation process of this invention is simple. It combines conventional processes and optimizes the process parameters. The specific improvements are as follows: The initial thickness ratio of TC4 titanium alloy sheet, pure Nb foil, and Inconel 617 alloy sheet is 10:1:10. This thickness ratio ensures that the pure Nb foil continuously covers the surface to be laminated and provides a stable diffusion transition region for the interfaces on both sides.

[0017] The vacuum hot pressing temperature is 1000 ℃, and the holding time is 120 min. Under these conditions, a continuous element diffusion transition zone can be formed at both interfaces, while avoiding significant thickening of the reaction layer due to excessively high temperature or excessively long holding time.

[0018] The multi-pass hot rolling temperature was 900 ℃, and the total reduction rate was 60%. Under these conditions, the EDS scan showed a relatively continuous change in the interfacial element concentration, and the thickness of the interfacial reaction layer was controlled within 15 μm, indicating that the process parameters are beneficial for balancing interfacial diffusion and reaction layer growth control.

[0019] 4. This invention reduces the direct contact and interdiffusion between Ni and Ti elements using pure Nb foil, inhibiting the formation of continuous brittle intermetallic compounds at the interface. Multi-pass hot rolling further enhances the density and bonding strength of the interface, resulting in a layered composite material with good strength, plasticity, and lightweight properties. Interfacial reaction layer thickness tests show that, using a pure Nb interlayer combined with vacuum hot pressing and multi-pass hot rolling, the reaction layer thickness at the Inconel 617 / Nb interface is 15 μm, and at the Nb / TC4 interface, it is 26.2 μm. In the comparative composite plate without a pure Nb interlayer, the lack of interlayer direct contact led to the formation of a large amount of brittle metallic compounds at the interface, causing the composite plate to crack directly after rolling. Compared to the comparative composite plate, this invention transforms a single, relatively thick Ni-Ti direct reaction layer into two diffusion transition layers with controlled thickness, demonstrating that pure Nb foil and the staged composite process can synergistically alter element diffusion behavior and limit the excessive growth of the interfacial reaction layer. Attached Figure Description

[0020] Figure 1 Microscopic images of the intermediate obtained in Comparative Example 1; Figure 2 This is a flowchart of the preparation method of the present invention; Figure 3 The images shown are scanning microstructure diagrams and stress-strain curves of Example 1 of the present invention. (a) is a scanning microstructure diagram of the Inconel 617 / pure Nb foil interface in the nickel-titanium layered composite material of Example 1. (b) is a scanning microstructure diagram of the pure Nb foil / TC4 interface in the nickel-titanium layered composite material of Example 1. (c) is a stress-strain curve. Figure 4 The following are scanning microstructure diagrams and stress-strain curves of Example 2 of the present invention: (a) is a scanning microstructure diagram of the Inconel 617 / pure Nb foil interface in the nickel-titanium layered composite material of Example 2; (b) is a scanning microstructure diagram of the pure Nb foil / TC4 interface in the nickel-titanium layered composite material of Example 2; and (c) is a stress-strain curve. Figure 5 The following are scanning microstructure diagrams and stress-strain curves of Example 3 of the present invention: (a) is a scanning microstructure diagram of the Inconel617 / pure Nb foil interface in the nickel-titanium layered composite material of Example 3; (b) is a scanning microstructure diagram of the pure Nb foil / TC4 interface in the nickel-titanium layered composite material of Example 3; and (c) is a stress-strain curve. Figure 6The following are scanning microstructure diagrams and stress-strain curves of Comparative Example 2 of the present invention: (a) is a scanning microstructure diagram of the Inconel 617 / pure Nb foil interface in the nickel-titanium layered composite material of Comparative Example 2; (b) is a scanning microstructure diagram of the pure Nb foil / TC4 interface in the nickel-titanium layered composite material of Comparative Example 2; and (c) is a stress-strain curve. Detailed Implementation

[0021] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.

[0022] This invention provides a method for preparing Inconel617 / Nb / TC4 layered composite material, which combines interface control with vacuum hot pressing-multi-pass hot rolling staged composite method using pure Nb foil, and optimizes specific process parameters to prepare Inconel617 / Nb / TC4 composite layered material.

[0023] The mass content of each component in the TC4 alloy used in this invention is as follows: Al: 5.5-6.75%, V: 3.5-4.5%, Fe: 0.12-0.30%, C: 0.08%, N: 0.05%≤0.025%, Ti balance; the mass content of each component in the Inconel 617 alloy is as follows: C: 0.05-0.15%, Al: 0.80-1.50%, Si≤1.00%, Cr: 20.00-24.00%, Ti: ≤0.60%, P: ≤0.015%, Co: 10.00-15.0%, Ni: ≥44.5%, B: ≤0.0060%, Mn: ≤1.00%.

[0024] Example 1, see Figure 2 A method for preparing an Inconel 617 / Nb / TC4 layered composite material includes the following steps: Step 1: Surface pretreatment Plate cutting: TC4 titanium alloy plate and Inconel 617 alloy plate are respectively processed into circular plates with a diameter of 45 mm and a thickness of 3 mm, and pure Nb foil is processed into circular foil with a diameter of 45 mm and a thickness of 0.3 mm.

[0025] The surfaces of TC4 titanium alloy sheet, Inconel 617 alloy sheet, and pure Nb foil were polished with 400# wet sandpaper to remove the surface oxide layer and impurities. The polished sheets and pure Nb foil were then ultrasonically cleaned in ethanol for 10 minutes. After cleaning, they were dried to obtain pretreated TC4 titanium alloy sheet, Inconel 617 alloy sheet, and pure Nb foil.

[0026] The aforementioned TC4 titanium alloy sheet is in the annealed state, while the Inconel 617 alloy sheet is in the solution-treated state.

[0027] Step 2: Following the top-to-bottom order, place graphite sheets, TC4 titanium alloy plates, pure Nb foil, Inconel 617 alloy plates, and graphite sheets in sequence to obtain an Inconel 617 / Nb / TC4 laminated blank. Place the laminated blank into a hot press mold.

[0028] Step 3: Vacuum hot pressing pre-bonding: The hot pressing mold is placed in a vacuum hot pressing sintering furnace, and the vacuum degree inside the furnace is controlled at 3×10. -3 An external load of 20 MPa was applied, and the laminated billet was heated to 1000 °C and held for 120 min. After holding, the external load of 20 MPa was maintained until the temperature of the laminated billet dropped below 150 °C. Then, the load was unloaded and cooled in the furnace to obtain the pre-bonded intermediate.

[0029] Step 4: Multi-pass hot rolling: The pre-bonded intermediate was heated to 800 °C and held for 30 min, followed by multi-pass hot rolling with a gradient reduction. The initial reduction was 30% of the billet thickness, the next reduction was 20%, and the final reduction was reduced to 10% of the thickness per pass. Each pass was held for 5 min, and the billet was cooled to room temperature in air after the last pass. The rolling speed was 2.5 m / min, and all passes were rolled in the same direction, with a cumulative total reduction of 50%.

[0030] Example 2, see Figure 2 A method for preparing an Inconel 617 / Nb / TC4 layered composite material includes the following steps: Steps one and two are the same as in Example 1; Step 3, the difference from Example 1, is that the vacuum degree in the hot pressing sintering is 5 × 10⁻⁶. -2 Pa; Step 4: The difference from Example 1 is that the rolling temperature during the multi-pass hot rolling is 900°C.

[0031] Example 3, see Figure 2A method for preparing an Inconel 617 / Nb / TC4 layered composite material includes the following steps: Steps one through three are the same as in Example 2; Step 4: The difference from Example 2 is that the rolling temperature during the multi-pass hot rolling is 900°C, and the cumulative total reduction rate is 60%.

[0032] Comparative Example 1: No Nb intermediate layer was set, and the steps were the same as in Example 1.

[0033] Comparative Example 2: See Figure 2 A method for preparing an Inconel 617 / Nb / TC4 layered composite material includes the following steps: Steps one through three are the same as in Example 2; Step 4: The difference from Example 2 is that the rolling temperature during the multi-pass hot rolling is 1000℃.

[0034] The properties of the Inconel 617 / Nb / TC4 layered composite materials prepared in Examples 1-3 and Comparative Example 2 were tested below, and the results are as follows: Figure 3 (a) is a scanning electron micrograph of the interface between the Inconel 617 alloy layer and the Nb intermediate layer in Example 1. Figure 3 (b) is a scanning electron micrograph of the interface between the Nb intermediate layer and the TC4 titanium alloy layer. Figure 3 (a) and Figure 3 (b) It is evident that the outlines of both interfaces are clear and continuous overall, with a transition layer of a certain thickness forming at each interface. Among these, Figure 3 (a) The interface is relatively flat, and no obvious defects are observed in any part; Figure 3 (b) The interface is slightly undulating, and the adjacent interface area exhibits a strip-like or lamellar structure. No through cracks or large unbonded areas extending along the interface were found on either side, indicating that the overall bonding of the interface is good. Figure 3 (c) shows that the tensile strength of the layered composite material obtained in Example 1 is 1061.64 MPa and the tensile strain is 13.57%.

[0035] Figure 4 (a) is a scanning electron micrograph of the interface between the Inconel 617 alloy layer and the Nb intermediate layer in Example 2. Figure 4 (b) is a scanning electron micrograph of the interface between the Nb intermediate layer and the TC4 titanium alloy layer. Figure 4 (a) and Figure 4(b) It can be seen that after rolling at 900 ℃ and 50%, continuous and relatively complete bonding areas are formed on both sides of the interface, with clear interface contours and only slight undulations in some areas. No obvious through cracks or large-sized unbonded defects were observed near the interface, indicating that the overall bonding quality of the interface is good under this process condition. Figure 4 (c) shows that the tensile strength of the layered composite material obtained in Example 2 is 1052.11 MPa and the tensile strain is 12.09%.

[0036] Figure 5 (a) is a scanning electron micrograph of the interface between the Inconel 617 alloy layer and the Nb intermediate layer in Example 3. Figure 5 (b) is a scanning electron micrograph of the interface between the Nb intermediate layer and the TC4 titanium alloy layer. Figure 5 (a) and Figure 5 (b) It can be seen that after rolling at 900 ℃-60%, both sides of the interface are continuous and relatively dense, and the interface outline is clear. Figure 5 (a) The interface shows slight undulations in some areas. Figure 5 (b) The interfaces were relatively flat, and no obvious through cracks, large pores or macroscopic unbonded areas were observed, indicating that the interface bonding quality was good under the process conditions. Figure 5 (c) shows that the tensile strength of the layered composite material obtained in Example 3 is 1068.67 MPa and the tensile strain is 14.94%.

[0037] Figure 6 (a) is a scanning electron micrograph of the interface between the Inconel 617 alloy layer and the Nb intermediate layer in Comparative Example 2. Figure 6 (b) is a scanning electron micrograph of the interface between the Nb intermediate layer and the TC4 titanium alloy layer. Figure 6 (a) and Figure 6 (b) It can be seen that after rolling at 1000 ℃-50%, the interfaces on both sides remain continuous and the overall bonding is relatively complete. Figure 6 (a) The interface shows slight undulations in some areas. Figure 6 (b) The interface is relatively flat, and a transition area of ​​a certain width is visible near the interface. Figure 6 The stress-strain curve shown in (c) indicates that the tensile strength of the layered composite material obtained in Comparative Example 2 is 915.66 MPa, and the tensile strain is 12.87%. Compared with Examples 1, 2, and 4, the tensile strength of Comparative Example 2 is lower, indicating that under the experimental conditions, increasing the hot rolling temperature to 1000 °C is not conducive to obtaining higher tensile strength.

[0038] In the above embodiments, the layered composite material obtained in Example 3 has higher tensile strength and tensile strain, therefore Example 3 is a preferred embodiment.

[0039] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing an Inconel 617 / Nb / TC4 layered composite material, characterized in that: Includes the following steps: Step 1: Perform surface pretreatment on Inconel 617 alloy sheet, TC4 titanium alloy sheet and pure Nb foil respectively; Step 2: Stack the Inconel 617 alloy sheet, pure Nb foil, and TC4 titanium alloy sheet in sequence to obtain the Inconel 617 / Nb / TC4 laminated blank. Step 3: Place the laminated blanks in a vacuum hot pressing sintering furnace, with a vacuum degree not exceeding 3×10⁻⁶. -2 Under the conditions of Pa, an external load of 20 MPa, and a temperature of 950-1050 ℃, the material is kept at a temperature of 30-120 min; after the holding period, the external load is maintained until the temperature of the laminated blank drops below 150 ℃ to obtain a pre-bonded intermediate. Step 4: Heat the pre-bonded intermediate to 800-900 ℃ and perform multiple hot rolling passes with a total reduction rate of 40%-60% to obtain the Inconel617 / Nb / TC4 layered composite material.

2. The method for preparing an Inconel 617 / Nb / TC4 layered composite material according to claim 1, characterized in that: The surface pretreatment in step one includes: polishing the surfaces of the Inconel 617 alloy plate, TC4 titanium alloy plate and pure Nb foil with sandpaper to remove surface oxides and impurities; then ultrasonically cleaning with ethanol and drying.

3. The method for preparing an Inconel 617 / Nb / TC4 layered composite material according to claim 1 or 2, characterized in that: The initial thickness ratio of the TC4 titanium alloy sheet, pure Nb foil, and Inconel 617 alloy sheet is 10:1:

10.

4. The method for preparing an Inconel 617 / Nb / TC4 layered composite material according to claim 3, characterized in that: In step three, the vacuum level is 5 × 10⁻⁶. -3 Pa, hot pressing temperature is 1000 ℃, and holding time is 120 min.

5. The method for preparing an Inconel 617 / Nb / TC4 layered composite material according to claim 4, characterized in that: In step four, the rolling temperature of the multi-pass hot rolling is 900 ℃, and the total reduction rate is 60%.

6. An Inconel 617 / Nb / TC4 layered composite material obtained by the preparation method according to claim 1.

7. The Inconel 617 / Nb / TC4 layered composite material according to claim 6, characterized in that: The structure comprises, sequentially along its thickness, an Inconel 617 alloy layer, a pure Nb foil, and a TC4 titanium alloy layer, with continuous bonding interfaces formed between the Inconel 617 alloy layer and the pure Nb foil, as well as between the pure Nb foil and the TC4 titanium alloy layer.

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