A high-temperature-resistant ternary nickel-based titanium-niobium alloy and a preparation method thereof

Abstract

The application relates to the technical field of alloy materials, and discloses a high-temperature-resistant ternary nickel-based titanium-niobium alloy with a service temperature of 2500 DEG C and a preparation method thereof, which takes nickel, titanium and niobium as core components, and the atomic percentage composition is as follows: 44-46% of nickel, 43-45% of titanium and 9-11% of niobium; and 0.1-0.5% of one or more trace elements of oxygen, aluminum and chromium can be further added. Through optimization of component design, the alloy is thermodynamically stable under an ultrahigh-temperature environment of 2500-2900 DEG C. The preparation method adopts vacuum consumable arc melting or electron beam melting (vacuum degree >= 10 ‑3 Pa), melting, and solves problems such as component segregation and poor machining performance. The alloy is suitable for aerospace and nuclear industry ultrahigh-temperature parts, and the process is stable and easy to mass-produce.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, specifically to a high-temperature resistant ternary nickel-based titanium-niobium alloy with a temperature resistance of 2500℃ and its preparation method. Background Technology

[0002] In high-end fields such as aerospace, nuclear industry, and energy, many key components need to operate stably for extended periods in ultra-high temperature environments exceeding 2500℃, placing extremely high demands on the high-temperature resistance, thermal stability, and mechanical properties of materials. Traditional nickel-based superalloys typically have melting points between 1230-1390℃, which is insufficient for ultra-high temperature applications. Niobium, as a refractory metal, has a melting point as high as 2477℃ and possesses excellent properties such as low density, high plasticity, good corrosion resistance, and low vapor pressure; titanium can improve the strength and density properties of the alloy. Introducing titanium and niobium into nickel-based alloys can significantly improve their melting point and high-temperature stability. However, existing nickel-titanium-niobium alloys still suffer from problems such as compositional segregation, insufficient thermal stability, poor oxidation resistance, and high processing difficulty at ultra-high temperatures, making large-scale industrial production difficult. Therefore, there is an urgent need to develop high-temperature resistant nickel-titanium-niobium alloys with precise composition, stable processing, and excellent performance, capable of withstanding temperatures up to 2500℃. Summary of the Invention

[0003] Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a ternary nickel-based titanium-niobium alloy with a high temperature resistance of 2500℃ and its preparation method, solving problems such as component segregation and insufficient high-temperature performance, and meeting the requirements for use in ultra-high temperature key components.

[0005] Technical solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a ternary nickel-based titanium-niobium alloy resistant to high temperatures up to 2500℃, wherein the atomic percentage composition of the alloy is: nickel 44-46%, titanium 43-45%, and niobium 9-11%; the alloy further contains 0.1-0.5% trace elements; the trace elements are selected from one or more of oxygen, aluminum, and chromium; the alloy is thermodynamically stable in the temperature range of 2500-2900℃, and its coefficient of thermal expansion is -1.3×10⁻⁶. -6 At ℃⁻¹, the compressive strength at 600℃ is ≥1237MPa, and the specific strength at 600℃ is ≥216MPa / (g·cm). -3 );

[0007] Nickel (44-46%, atomic percentage): As a matrix element, it provides structural stability and toughness. When the content is below 44%, the alloy's toughness decreases (elongation after fracture <18%), and when it is above 46%, the melting point decreases (<2450℃), and it cannot withstand ultra-high temperatures of 2500℃.

[0008] Titanium (43-45%, atomic percentage): forms a negative thermal expansion structure in synergy with nickel and niobium, with a thermal expansion coefficient of -1.3 × 10⁻⁶. -6 ℃ -1 To reduce thermal cycling stress, when the content deviates from this range, the negative thermal expansion characteristic disappears.

[0009] Niobium (9-11%, atomic percentage): It can improve the melting point and high-temperature strength of the alloy through solid solution strengthening. When the content is less than 9%, the compressive strength at 600℃ is <1200MPa, and when it is more than 11%, the brittleness of the alloy increases (impact absorption energy <30J).

[0010] Trace elements (0.1-0.5%, atomic percentage): Oxygen enhances yield strength (≥1140MPa) through solid solution strengthening; Aluminum forms a dense alumina film on the surface, reducing oxidation weight gain at 950℃ (≤5mg / cm²); Chromium improves corrosion resistance, making it suitable for nuclear industry environments.

[0011] Furthermore, the microstructure of the alloy consists of nickel-based solid solution (γ phase), titanium-niobium solid solution (β phase) and ternary intermetallic compound phase, wherein the volume fraction of the ternary intermetallic compound phase is 5-10%.

[0012] Furthermore, when the trace element is oxygen, the alloy yield strength is ≥1140MPa and the elongation is ≥20%; when the trace element is aluminum, the oxidation weight gain of the alloy after oxidation at 950℃ for 30 hours is ≤5mg / cm².

[0013] Furthermore, it includes the following steps:

[0014] S1. Raw material preparation: nickel blocks (99.5%), titanium rods (99.9%), niobium powder (99.9%), zirconium oxide (99.99%, oxygen supply), aluminum granules (99.9%), avoiding impurities such as carbon and nitrogen (total impurities ≤0.05%), and proportioned according to the atomic percentages described in claim 1;

[0015] S2. Melting: Add the ingredients from step (1) to the melting equipment and evacuate to a vacuum degree ≥10- 3 Pa, control the melting temperature at 2500-2900℃, and perform 5-8 repeated meltings (the first 1-3 times to eliminate macro segregation, and the 4th-8th times to optimize the micro composition). After each melting, the composition is detected by optical emission spectroscopy and the proportion of the next batch is adjusted. The melting equipment is a vacuum self-consuming electric arc melting furnace or an electron beam melting furnace.

[0016] S3. Hot working: The smelted ingot is hot rolled or hot forged at 800-950℃ (corresponding to the β phase region of the alloy, where the plasticity is best; below 800℃, it is easy to crack, and above 950℃, the grains are coarse). During hot rolling, the single reduction is 10-20%, and during hot forging, the forging ratio is 3-5 (the ratio of the cross-sectional area of ​​the billet before and after deformation). After hot working, it is air-cooled or furnace-cooled to room temperature.

[0017] S4. Cold working: The hot-worked billet is cold-rolled or cold-drawn at room temperature, with a total cold working reduction of 3-15%, and annealed at 600-800℃ after each cold working pass;

[0018] S5. Heat treatment: After cold working, the workpiece is first solution treated at 900-950℃ for 2-4 hours (to fully dissolve the alloying elements), then water cooled (cooling rate ≥100℃ / s) to obtain a supersaturated solid solution; then aged at 600-800℃ for 24-48 hours (to precipitate fine strengthening phases, such as Ni3Ti and NbC), and air cooled to room temperature;

[0019] S6. Surface treatment: The heat-treated workpiece is coated with a protective coating by thermal spraying or vapor deposition, with a coating thickness of 1-10μm;

[0020] Thermal spraying: Plasma spraying of aluminum oxide coating (thickness 5-10μm), spraying power 40-60kW, coating bonding strength ≥50MPa;

[0021] Vapor deposition: Physical vapor deposition of chromium coating (1-3 μm thickness), vacuum degree 10 -4 Pa, deposition temperature 300-400℃, suitable for precision parts.

[0022] Furthermore, in S2, when vacuum self-consuming arc melting is used, the melting current is 1000-5000A and the arc voltage is 20-40V, and electromagnetic stirring is used during the melting process; when electron beam melting is used, the melting power is 300-3000kW, the electron beam scanning mode is uniform scanning, and the cooling bed and electron gun are preheated and baked for 1-2 hours before melting.

[0023] Furthermore, in S3, the rolling speed during hot rolling is 300-400 mm / min.

[0024] Furthermore, in step S4, the annealing time is 1-2 hours.

[0025] Furthermore, in S6, the thermal spraying adopts plasma spraying or supersonic flame spraying, and the spraying material is alumina, zirconium oxide or chromate; the vapor deposition adopts physical vapor deposition or chemical vapor deposition, and the bonding strength between the coating and the substrate is ≥50MPa.

[0026] Beneficial technical effects

[0027] The alloy of this invention is thermodynamically stable at 2500℃ and has a negative coefficient of thermal expansion of -1.3×10⁻⁶. -6 ℃ -1 With a compressive strength of ≥1237MPa at 600℃, it solves the problem of insufficient high-temperature performance of traditional alloys; it adopts multi-pass vacuum melting (5-8 times) and electromagnetic stirring to eliminate component segregation, and the microstructure is controlled by the synergistic regulation of hot working and heat treatment, with a component uniformity deviation of ≤±0.2%, meeting the requirements for mass production quality stability; by adding trace elements such as oxygen, aluminum, and chromium, it can respectively achieve strength improvement, oxidation resistance modification or corrosion resistance optimization, adapting to different application scenarios; it adopts mature vacuum self-melting (melting energy consumption is 15% lower than existing processes), which is conducive to mass production. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Vacuum self-consuming electric arc melting furnace (50-500kg capacity); electron beam melting furnace (300-3000kW).

[0030] Quality Inspection

[0031] Chemical composition: rapid screening by X-ray fluorescence spectrometry, and accurate verification by inductively coupled plasma atomic emission spectrometry (error ≤ ±0.01%).

[0032] Mechanical properties: High-temperature tensile testing machine was used to test the compressive strength and yield strength at 600℃, and impact testing machine was used to test the impact absorption energy at room temperature;

[0033] Defect detection: Ultrasonic testing (frequency 2-5MHz) to check for internal cracks, and X-ray testing (tube voltage 200-400kV) to detect pores;

[0034] Microstructure: Grain size (≤50μm) was observed using metallographic microscopy, and phase distribution was analyzed using scanning electron microscopy (SEM).

[0035] Example 1

[0036] Preparation of basic high-temperature resistant ternary nickel-based titanium-niobium alloy (2500℃)

[0037] Raw material preparation: Weigh 44 kg of 99.5% nickel blocks, 45 kg of 99.9% titanium rods, and 11 kg of 99.9% niobium powder (convert atomic percentages to mass ratios), and mix them evenly;

[0038] Melting: Add the mixture to a 200kg vacuum consumable arc furnace and evacuate to 100°C. -3 Pa, current set at 3000A, voltage at 30V, melting temperature at 2600℃, composition was tested after each melting, a total of 6 meltings were performed, and the final ingot composition deviation was ≤±0.1%;

[0039] Hot working: The ingot is heated to 850℃ and hot rolled into a 20mm thick plate at a rolling speed of 350mm / min, with a single reduction of 15% and a total deformation of 70%. After forging, it is air-cooled.

[0040] Cold working: Cold rolled at room temperature to 18 mm thickness (reduction 10%), followed by annealing at 700°C for 1.5 hours;

[0041] Heat treatment: Solution treatment at 920℃ for 3 hours, followed by water cooling; Aging treatment at 700℃ for 24 hours, followed by air cooling;

[0042] Quality inspection: Chemical composition conforms to Ni 44%, Ti 45%, Nb 11%; compressive strength at 600℃ is 1250MPa, elongation is 22%; no internal defects, grain size is 35μm.

[0043] Example 2

[0044] Preparation of oxygen-containing high-temperature resistant ternary nickel-based titanium-niobium alloys (2500℃)

[0045] Raw material preparation: Weigh 45 kg of 99.6% nickel powder, 44 kg of 99.9% titanium rod, 10 kg of 99.9% niobium powder, and 0.3 kg of 99.99% zirconium oxide, and mix them evenly;

[0046] Melting: Add to a 300kW electron beam melting furnace and evacuate to 10°C. -3 Pa, preheat the furnace for 1.5 hours, set the power to 1500kW, use uniform electron beam scanning (15Hz), melt at 2700℃, and melt a total of 7 times;

[0047] Hot working: The ingot is heated to 900℃ and hot forged (forging ratio 4) into Φ50mm bars, and then air-cooled.

[0048] Cold working: cold drawing at room temperature to Φ45mm (reduction 15%), followed by annealing at 650℃ for 1 hour after each drawing pass;

[0049] Heat treatment: Solution treatment at 950℃ for 2 hours, followed by water cooling; Aging treatment at 750℃ for 30 hours, followed by air cooling;

[0050] Quality inspection: Yield strength 1150 MPa, elongation 21%; specific strength at 600℃ 225 MPa / (g·cm) -3 This meets the requirements for aircraft engine components.

[0051] Example 3

[0052] Preparation of aluminum-containing high-temperature resistant ternary nickel-based titanium-niobium alloys (2500℃)

[0053] Raw material preparation: Weigh 46 kg of 99.5% nickel rods, 43 kg of 99.9% titanium rods, 9 kg of 99.9% niobium powder, and 0.5 kg of 99.9% aluminum granules, and mix them evenly;

[0054] Melting: Add to a 200kg vacuum consumable arc furnace and evacuate to 100°C. -3 Pa, current 4000A, voltage 35V, melting temperature 2800℃, melting 5 times in total;

[0055] Hot working: The ingot is heated to 950℃ and hot rolled into a 50mm thick forging billet at a rolling speed of 300mm / min and a single reduction of 20%.

[0056] Cold working: Cold roll to 48mm thickness at room temperature (reduction 4%), anneal at 800℃ for 2 hours;

[0057] Heat treatment: Solution treatment at 900℃ for 4 hours, followed by water cooling; Aging treatment at 600℃ for 36 hours, followed by air cooling;

[0058] Surface treatment: Plasma spraying of aluminum oxide coating (5μm), spraying power 50kW;

[0059] Quality testing: Weight gain of 4.2 mg / cm² after 30 hours of oxidation at 950℃; compressive strength of 1280 MPa at 600℃, suitable for nuclear reactor structural components.

[0060] The analysis of Comparative Examples 1-3 is as follows:

[0061] project Comparative Example 1 (Component Deviation) Comparative Example 2 (Insufficient number of smelting attempts) Comparative Example 3 (without heat treatment) Composition (atomic percentage) Ni 50%, Ti 40%, Nb 10% (Nickel above the upper limit, titanium below the lower limit) Ni 45%, Ti 44%, Nb 10% (same as Example 2) Ni 44%, Ti 45%, Nb 11% (same as Example 1) Smelting process Vacuum consumable arc melting, 5 times, 2600℃ Vacuum consumable arc melting, twice, 2600℃ Vacuum consumable arc melting, 6 times, 2600℃ Heat treatment process Solution treatment at 920℃ for 3 hours + aging at 700℃ for 24 hours Solution treatment at 920℃ for 3 hours + aging at 700℃ for 24 hours none Compressive strength at 600℃ (MPa) 1120 1050 980 Specific strength at 600℃ (MPa / (g·cm⁻³)) 195 182 172 Yield strength (MPa) 950 880 820 Elongation (%) 16 14 12 Coefficient of thermal expansion (°C⁻¹) <![CDATA[+0.8×10 -6 ]]> <![CDATA[-1.0×10 -6 ]]> <![CDATA[-1.1×10 -6 ]]>

[0062] Comparative Example 1 had a nickel content exceeding the upper limit (50%) and a titanium content below the lower limit (40%), resulting in a melting point drop to 2420℃ (unable to withstand 2500℃), the disappearance of negative thermal expansion characteristics, a positive coefficient of thermal expansion, and a significant decrease in mechanical properties. The number of melting cycles affected Comparative Example 2 (compared to Example 2): Comparative Example 2 was only melted twice, resulting in severe component segregation and a lower compressive strength at 600℃ compared to Example 2, indicating that 5-8 melting cycles are crucial for eliminating segregation and ensuring performance. The heat treatment effect affected Comparative Example 3 (compared to Example 1): Comparative Example 3 was not heat-treated, resulting in no precipitation of strengthening phases (Ni3Ti, NbC), a lower yield strength than Example 1, and a decrease in elongation, verifying the performance-regulating effects of solution treatment and aging processes. The advantages of trace elements (Examples 2 and 3): Example 2, with the addition of 0.3% oxygen, showed an improved yield strength compared to Example 1; Example 3, with the addition of 0.5% aluminum and an alumina coating, showed a weight gain of only 4.2 mg / cm² at 950℃, demonstrating superior oxidation resistance compared to the uncoated alloy.

[0063] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0065] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A high-temperature resistant ternary nickel-based titanium-niobium alloy with a temperature resistance of 2500℃, characterized in that, The alloy has the following atomic percentage composition: nickel 44-46%, titanium 43-45%, and niobium 9-11%; the alloy also contains 0.1-0.5% trace elements; these trace elements are selected from one or more of oxygen, aluminum, and chromium; the alloy is thermodynamically stable in the temperature range of 2500-2900℃, and its coefficient of thermal expansion is -1.3 × 10⁻⁶. -6 At ℃⁻¹, the compressive strength at 600℃ is ≥1237MPa, and the specific strength at 600℃ is ≥216MPa / (g·cm). -3 ).

2. The high-temperature resistant ternary nickel-based titanium-niobium alloy according to claim 1, characterized in that, The microstructure of the alloy consists of a nickel-based solid solution γ phase, a titanium-niobium solid solution β phase, and a ternary intermetallic compound phase, wherein the volume fraction of the ternary intermetallic compound phase is 5-10%.

3. The high-temperature resistant ternary nickel-based titanium-niobium alloy according to claim 1, characterized in that, When the trace element is oxygen, the alloy yield strength is ≥1140MPa and elongation is ≥20%; when the trace element is aluminum, the alloy weight gain after oxidation at 950℃ for 30 hours is ≤5mg / cm².

4. A method for preparing a high-temperature resistant ternary nickel-based titanium-niobium alloy as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Raw material preparation: Select nickel raw materials with a purity ≥99.5%, titanium raw materials with a purity ≥99.9%, niobium raw materials with a purity ≥99.9%, and trace element raw materials with corresponding purity, and formulate them according to the atomic percentages described in claim 1; S2. Melting: Add the ingredients from step (1) to the melting equipment and evacuate to a vacuum degree ≥10. -3 Pa, control the melting temperature at 2500-2900℃, and perform 5-8 repeated meltings. After each melting, use optical emission spectroscopy to detect the composition and adjust the next batching ratio. The melting equipment is a vacuum consumable arc furnace or an electron beam furnace. S3. Hot working: The smelted ingot is hot rolled or hot forged at 800-950℃. The single reduction during hot rolling is 10-20%, and the forging ratio during hot forging is 3-5. After hot working, it is air-cooled or furnace-cooled to room temperature. S4. Cold working: The hot-worked billet is cold-rolled or cold-drawn at room temperature, with a total cold working reduction of 3-15%, and annealed at 600-800℃ after each cold working pass; S5. Heat treatment: The cold-worked workpiece is first solution treated at 900-950℃ for 2-4 hours and then cooled with water; then aged at 600-800℃ for 24-48 hours and air-cooled to room temperature. S6. Surface treatment: The heat-treated workpiece is coated with a protective coating by thermal spraying or vapor deposition, with a coating thickness of 1-10μm.

5. The preparation method of the high-temperature resistant ternary nickel-based titanium-niobium alloy according to claim 4, characterized in that, In S2, when vacuum self-consuming arc melting is used, the melting current is 1000-5000A and the arc voltage is 20-40V. Electromagnetic stirring is used during the melting process. When electron beam melting is used, the melting power is 300-3000kW and the electron beam scanning mode is uniform scanning. The cooling bed and electron gun are preheated and baked for 1-2 hours before melting.

6. The method for preparing the high-temperature resistant ternary nickel-based titanium-niobium alloy of claim 4, characterized in that, In S3, the rolling speed during hot rolling is 300-400 mm / min.

7. The method for preparing the high-temperature resistant ternary nickel-based titanium-niobium alloy of claim 4, characterized in that, In step S4, the annealing time is 1-2 hours.

8. The method for preparing the high-temperature resistant ternary nickel-based titanium-niobium alloy of claim 4, characterized in that, In S6, thermal spraying is performed using plasma spraying or supersonic flame spraying, and the spraying material is alumina, zirconium oxide, or chromate; vapor deposition is performed using physical vapor deposition or chemical vapor deposition, and the bonding strength between the coating and the substrate is ≥50 MPa.