Alloy material with wide temperature range and low resistance temperature coefficient and preparation method thereof

Abstract

The invention relates to the technical field of alloy materials, and discloses an alloy material with a wide temperature range and a low resistance temperature coefficient and a preparation method thereof, the alloy material comprises the following components: a composite beta stable element, a rare earth modified element, a neutral regulation element, an alpha stable element, an Hf-B composite doping element, and the balance of Ti and inevitable impurities; by reasonably optimizing the proportion of alloy components, the composite beta stable element, the rare earth modified element, the neutral regulation element, the alpha stable element and the Hf-B composite doping element form a synergistic effect, all the elements are matched with one another on the micro level, the alloy performance is improved from multiple dimensions such as phase structure stabilization, grain refinement, solid solution strengthening and dispersion strengthening, and the alloy performance is improved. And finally, the core target of wide temperature range and low resistance temperature coefficient in macroscopic view is realized. And meanwhile, the optimized preparation process and the component design supplement each other, so that the effects of all the elements are fully exerted, and the alloy structure is uniform and stable.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, specifically to an alloy material with a wide temperature range and a low temperature coefficient of electrical resistance, and its preparation method. Background Technology

[0002] In modern industrial fields such as aerospace, electronics, and precision instruments, increasingly stringent requirements are being placed on the material properties of key structural components and functional parts. Especially in scenarios where the equipment operates over a wide temperature range, materials not only need to possess stable electrical properties but also need to ensure good mechanical strength and structural reliability. Among these requirements, a low temperature coefficient of resistance is one of the core indicators for ensuring the precise operation of equipment.

[0003] Titanium alloys have garnered widespread attention in the aforementioned fields due to their low density, high specific strength, and excellent corrosion resistance. However, traditional titanium alloys have a high temperature coefficient of resistance, meaning their resistance is prone to significant changes in environments with large temperature fluctuations. This can lead to decreased signal transmission accuracy and energy conversion efficiency in equipment, and in severe cases, even component failure. To address this issue, the industry has attempted to modify titanium alloys by adding alloying elements, but existing technologies have many shortcomings and cannot meet the requirements of high-end equipment for alloy materials with a wide temperature range and low temperature coefficient of resistance.

[0004] Therefore, developing a titanium-based alloy material with a reasonable composition design, controllable preparation process, low temperature coefficient of resistance over a wide temperature range, and excellent mechanical properties and high-temperature stability has become an urgent need for the current industry development. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides an alloy material with a wide temperature range and a low temperature coefficient of electrical resistance.

[0006] The technical solution adopted by this invention to solve its technical problem is: a wide-temperature-range, low-resistivity temperature coefficient alloy material, composed of the following components by mass percentage: 18%-35% composite β-stabilizing elements, 0.5%-3% rare earth modifying elements, 5%-12% neutral regulating elements, 0.001%-0.05% α-stabilizing elements, 0.05%-0.2% Hf-B composite doping elements, with the balance being Ti and unavoidable impurities.

[0007] As a further technical solution, the composite β-stabilizing element is a mixture of Nb and Ta, and the mass ratio of Nb to Ta is 3-5:1.

[0008] As a further technical solution, the rare earth modifying element is a mixture of Nd and Dy, and the mass ratio of Nd to Dy is 2-4:1.

[0009] As a further technical solution, the neutral regulating element is a mixture of Zr and Sn, and the mass ratio of Zr to Sn is 1-2:1.

[0010] As a further technical solution, the α-stabilizing element is o.

[0011] As a further technical solution, the mass ratio of Hf to B in the Hf-B composite doping element is 5-8:1.

[0012] A method for preparing wide-temperature-range, low-resistivity temperature coefficient alloy materials includes the following steps: (1) Raw material pretreatment and smelting: Weigh Ti, Nb, Ta, Nd, Dy, Zr, Sn, Hf and B pure metal raw materials with a purity of not less than 99.95% according to the composition ratio; After mixing Hf and B, ball mill them at a speed of 300-400 r / min for 2-3 hours under argon protection with a purity ≥99.99% to obtain Hf-B composite powder; Place Ti, Nb, Ta, Nd, Dy, Zr, Sn raw materials and Hf-B composite powder in a vacuum consumable arc furnace, first evacuate to a vacuum degree ≤0.005 Pa, then fill with argon to a pressure of 0.05-0.1 MPa, and then smelt three times with a current of 3000-4000 A. Each time during smelting, electromagnetic stirring is performed at a rate of 50-80 r / min to obtain a uniform alloy ingot. (2) Plastic processing: The alloy ingot is kept at 850℃-900℃ for 2-3 hours for homogenization treatment, and then hot forged at a rate of 5-10 mm / s. After forging, it is air-cooled to room temperature. Then the alloy billet after forging is hot rolled at 800℃-850℃ at a rate of 3-5 m / s, and the rolling deformation is controlled to be 60%-70% to obtain alloy plates or bars. (3) Multi-stage heat treatment: solution treatment, segmented aging treatment and low-temperature tempering are performed in sequence; (4) Finished product processing: The alloy material that has undergone multi-stage heat treatment is machined to remove the surface oxide scale and obtain the finished product of the required size.

[0013] As a further technical solution, in step (2), the solution treatment is to keep the temperature at 950℃-1000℃ for 1-2 hours and then quench it with ice water at a cooling rate of ≥150℃ / s.

[0014] As a further technical solution, in step (2), the segmented aging treatment is a first stage of 300℃-350℃ heat preservation for 2-3 hours, and a second stage of 400℃-450℃ heat preservation for 1-2 hours.

[0015] As a further technical solution, in step (2), the low-temperature tempering is performed by holding at 150℃-200℃ for 2-3 hours, followed by cooling with the furnace at a cooling rate of 5-10℃ / h.

[0016] The beneficial effects of this invention are: In this invention, the composite β-stabilizing element is a mixture of Nb and Ta in a mass ratio of 3-5:1. Both Nb and Ta are typical β-stabilizing elements, which can effectively expand the β-phase region of the titanium alloy, suppress α-phase precipitation, optimize the phase structure composition of the alloy at the microscopic level, and reduce the influence of phase transformation on electrical resistance. This lays the foundation for the alloy to obtain stable electrical properties over a wide temperature range. Simultaneously, the stabilization of the β-phase structure also helps to improve the plasticity and toughness of the alloy and enhance the processing performance of the material. The rare earth modifying element is a mixture of Nd and Dy in a mass ratio of 2-4:1. Rare earth elements have a large atomic radius and tend to segregate at grain boundaries in the alloy, effectively refining the grains and reducing grain boundary defects. On the one hand, this reduces the obstruction of electron transport by grain boundaries, reducing electrical resistance loss; on the other hand, the refined grains can significantly improve the mechanical strength and fatigue resistance of the alloy. Neutral regulating elements Zr and Sn are combined in a 1-2:1 ratio. Zr has a similar crystal structure to Ti and can dissolve into the titanium alloy matrix to form solid solution strengthening. Sn can coordinate the chemical potential of various elements in the alloy and optimize the uniformity of element distribution. The synergistic effect of the two can further stabilize the electrical properties of the alloy and improve the corrosion resistance of the material. The content of the α-stabilizing element O is controlled at 0.001%-0.05%. An appropriate amount of O can form a stable oxide with titanium, enhance the structural stability of the alloy matrix, and avoid drastic fluctuations in resistance due to abrupt changes in phase structure during temperature changes. Hf-B composite doping elements are compounded in a 5-8:1 mass ratio. During the preparation process, a dispersed HfB2 strengthening phase can be formed. This strengthening phase has the characteristics of high hardness and high stability. It can not only improve the mechanical strength and wear resistance of the alloy through dispersion strengthening, but also hinder the disordered movement of electrons during temperature changes and suppress the fluctuation of resistance with temperature.

[0017] In the preparation process of the technical solution of this invention, Hf and B are first ball-milled under argon protection to ensure that they are fully mixed and uniform, forming a stable composite powder, which provides a guarantee for the uniform precipitation of HfB2 strengthening phase during the subsequent melting process. The three-stage melting in a vacuum self-consuming electric arc furnace combined with electromagnetic stirring effectively eliminates the component segregation of the alloy ingot, ensuring that each element is uniformly distributed in the matrix and avoiding performance defects caused by local component inhomogeneity. The homogenization treatment can eliminate the internal stress inside the ingot, providing good microstructure conditions for subsequent plastic processing. The synergistic effect of hot forging and hot rolling with specific parameters further refines the grains, increases the density of the alloy, and improves the mechanical properties and electrical conductivity of the material. In the multi-stage heat treatment process, the solution treatment obtains a supersaturated solid solution through rapid cooling, preparing for the precipitation of strengthening phase during aging. The segmented aging treatment causes the precipitation of uniform and fine strengthening phase in the alloy, which not only improves the mechanical strength but also optimizes the stability of electrical properties. Low-temperature tempering effectively eliminates the internal stress generated during aging, further stabilizing the microstructure and properties of the alloy. Each process step is interconnected. From raw material mixing to finished product processing, each step provides support for the realization of the final performance, ensuring the consistency and reliability of the overall performance of the alloy material.

[0018] This invention achieves a synergistic effect among composite β-stabilizing elements, rare earth modifying elements, neutral regulating elements, α-stabilizing elements, and Hf-B composite doping elements by rationally optimizing the alloy composition ratio. These elements work together at the microscopic level to improve alloy performance from multiple dimensions, including phase structure stabilization, grain refinement, solid solution strengthening, and dispersion strengthening, ultimately achieving the core objective of a wide-temperature-range, low-resistivity temperature coefficient. Simultaneously, the optimized preparation process and composition design complement each other, ensuring the full utilization of the effects of each element and the uniformity and stability of the alloy microstructure. This results in a material that not only possesses excellent electrical properties but also high yield strength, high tensile strength, good plasticity, and excellent high-temperature stability. Attached Figure Description

[0019] Figure 1 This is a process flow diagram for the preparation of an alloy material with a wide temperature range and low temperature coefficient of electrical resistance. Figure 2 This is a comparison chart of the elongation after fracture of an example and a comparative example of an alloy material with a wide temperature range and low resistance temperature coefficient. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0021] This invention provides a wide-temperature-range, low-resistivity temperature coefficient alloy material and its preparation method. The alloy material is composed of components with a specific mass percentage. The preparation method includes raw material pretreatment and melting, plastic processing, multi-stage heat treatment, and finished product processing steps, which can obtain a wide-temperature-range, low-resistivity temperature coefficient alloy material with excellent performance.

[0022] The alloy material of the present invention is composed of the following components by mass percentage: 18%-35% composite β-stabilizing element, 0.5%-3% rare earth modifying element, 5%-12% neutral regulating element, 0.001%-0.05% α-stabilizing element, 0.05%-0.2% Hf-B composite doping element, and the balance being Ti and unavoidable impurities.

[0023] In this invention, the composite β-stabilizing element is a mixture of Nb and Ta, and the mass ratio of Nb to Ta is 3-5:1, preferably 4:1. The composite β-stabilizing element can effectively adjust the phase structure of the alloy, improve the structural stability of the alloy over a wide temperature range, and provide a basis for low resistivity temperature coefficient.

[0024] The rare earth modifying element is a mixture of Nd and Dy, with a mass ratio of Nd to Dy of 2-4:1, preferably 3:1. The rare earth modifying element can refine the alloy grains, reduce grain boundary defects, and optimize the electrical and mechanical properties of the alloy.

[0025] The neutral control element is a mixture of Zr and Sn, with a Zr to Sn mass ratio of 1-2:1, preferably 1.5:1. The neutral control element can coordinate the interactions among the elements in the alloy, further improving the stability of the alloy's temperature coefficient of resistance.

[0026] The α-stabilizing element is O, and its mass percentage is controlled between 0.001% and 0.05%. An appropriate amount of O can enhance the structural stability of the alloy and prevent phase transformation during temperature changes that could lead to a sudden change in electrical resistance.

[0027] The mass ratio of Hf to B in the Hf-B composite doping element is 5-8:1, preferably 6:1. The Hf-B composite doping element can form a dispersed strengthening phase, which can improve the mechanical strength of the alloy and suppress the fluctuation of resistivity with temperature.

[0028] This invention does not impose any special restrictions on the source of the raw materials. Commercially available pure metal raw materials known to those skilled in the art can be used, and the purity of each raw material is not less than 99.95% to ensure the composition purity and performance stability of the alloy material.

[0029] The method for preparing the wide-temperature-range, low-resistivity temperature coefficient alloy material of the present invention includes the following steps: (1) Raw material pretreatment and smelting: Weigh out pure metal raw materials of Ti, Nb, Ta, Nd, Dy, Zr, Sn, Hf, and B with a purity of not less than 99.95% according to the above component ratio; after mixing Hf and B, ball mill them at a speed of 300-400 r / min for 2-3 hours under argon protection with a purity ≥99.99% to obtain Hf-B composite powder. Argon protection during ball milling can prevent oxidation of raw materials, and specific ball milling speed and time can ensure that Hf and B are fully and uniformly mixed to form a stable composite powder; then weigh out Ti, Nb, Ta... Raw materials of Nd, Dy, Zr, and Sn, along with Hf-B composite powder, are placed in a vacuum consumable arc furnace. First, a vacuum of ≤0.005 Pa is drawn to remove air and impurities from the furnace. Then, argon gas is introduced to a pressure of 0.05-0.1 MPa to form a protective atmosphere. The furnace is then smelted three times with a current of 3000-4000 A. During each smelting, electromagnetic stirring is performed at a rate of 50-80 r / min. Multiple smeltings and electromagnetic stirring ensure a uniform distribution of alloy composition, resulting in a uniform alloy ingot.

[0030] (2) Plastic processing: The alloy ingot is homogenized by holding it at 850℃-900℃ for 2-3 hours to eliminate compositional segregation and internal stress. Then, it is hot-forged at a rate of 5-10 mm / s and air-cooled to room temperature. Hot forging improves the microstructure of the ingot and enhances the plasticity of the material. The alloy billet after forging is then hot-rolled at 800℃-850℃ at a rate of 3-5 m / s, with the rolling deformation controlled at 60%-70%, to obtain alloy plates or bars. Specific hot rolling temperature, rate and deformation can further refine the grains and improve the overall performance of the alloy.

[0031] (3) Multi-stage heat treatment: The alloy undergoes solution treatment, segmented aging treatment, and low-temperature tempering in sequence. Solution treatment involves holding at 950℃-1000℃ for 1-2 hours, followed by ice-water quenching at a cooling rate of ≥150℃ / s. Rapid cooling yields a supersaturated solid solution, preparing for subsequent aging treatment. Segmented aging treatment consists of a first stage holding at 300℃-350℃ for 2-3 hours, and a second stage holding at 400℃-450℃ for 1-2 hours. Segmented aging induces the precipitation of uniform and fine strengthening phases in the alloy, improving its mechanical strength and electrical stability. Low-temperature tempering involves holding at 150℃-200℃ for 2-3 hours, followed by furnace cooling at a rate of 5-10℃ / h. Low-temperature tempering eliminates internal stresses generated after aging treatment, further stabilizing the alloy's microstructure and properties.

[0032] (4) Finished product processing: The alloy material that has undergone multi-stage heat treatment is machined to remove the surface oxide scale and obtain the finished product of the required size. The machining method can be conventional processing methods in this field, such as turning and grinding.

[0033] The alloy material provided by this invention achieves synergistic effects between elements by rationally matching the proportions of each component and combining them with a specific preparation process. This results in an alloy material with a low temperature coefficient of resistance over a wide temperature range, as well as good mechanical properties and structural stability. The preparation method has a clear process flow and controllable process parameters, making it suitable for industrial production.

[0034] To further illustrate the present invention, the following detailed description is provided through the examples and comparative examples.

[0035] Example 1: (1) Raw material pretreatment and smelting: Weigh the following raw materials by mass percentage: 18% composite β-stabilizing element (Nb to Ta mass ratio 3:1), 0.5% rare earth modifying element (Nd to Dy mass ratio 2:1), 5% neutral regulating element (Zr to Sn mass ratio 1:1), 0.001% α-stabilizing element, 0.05% Hf-B composite doping element (Hf to B mass ratio 5:1), with the balance being Ti and unavoidable impurities; the purity of all raw materials is not less than 99.95%. After mixing Hf and B in proportion, ball mill them at 300 r / min for 2 h under argon protection with a purity ≥99.99% to obtain Hf-B composite powder. Ti, Nb, Ta, Nd, Dy, Zr, Sn raw materials and Hf-B composite powder were placed in a vacuum consumable arc furnace. First, the vacuum was evacuated to a vacuum degree ≤0.005 Pa, and then argon gas was introduced to a pressure of 0.05 MPa. Then, the furnace was melted three times with a current of 3000 A. During each melting, the furnace was electromagnetically stirred at a rate of 50 r / min to obtain an alloy ingot with uniform composition.

[0036] (2) Plastic processing: The alloy ingot is homogenized by holding it at 850℃ for 2 hours, and then hot-forged at a rate of 5 mm / s. After forging, it is air-cooled to room temperature. The alloy billet after forging is then hot-rolled at 800℃ at a rate of 3 m / s, and the rolling deformation is controlled to be 60% to obtain alloy sheet.

[0037] (3) Multi-stage heat treatment: First, solution treatment is carried out at 950℃ for 1 hour, followed by ice water quenching at a cooling rate of 150℃ / s; then, segmented aging treatment is carried out, with the first stage at 300℃ for 2 hours and the second stage at 400℃ for 1 hour; finally, low-temperature tempering is carried out, with the furnace being cooled at a cooling rate of 5℃ / h after holding at 150℃ for 2 hours.

[0038] (4) Finished product processing: The alloy plate that has undergone multi-stage heat treatment is machined to remove the surface oxide scale and obtain the finished product of the required size.

[0039] Example 2: (1) Raw material pretreatment and smelting: The following raw materials were weighed by mass percentage: composite β-stabilizing element (Nb to Ta mass ratio 4:1) 26%, rare earth modifying element (Nd to Dy mass ratio 3:1) 1.7%, neutral regulating element (Zr to Sn mass ratio 1.5:1) 8%, α-stabilizing element o 0.025%, Hf-B composite doping element (Hf to B mass ratio 6:1) 0.12%, with the balance being Ti and unavoidable impurities; the purity of all raw materials was not less than 99.95%. After mixing Hf and B in proportion, the mixture was ball-milled at 350 r / min for 2.5 h under argon protection with a purity ≥99.99% to obtain Hf-B composite powder. Ti, Nb, Ta, Nd, Dy, Zr, Sn raw materials and Hf-B composite powder were placed in a vacuum consumable arc furnace. First, the vacuum was evacuated to a vacuum degree ≤0.005Pa, and then argon gas was introduced to a pressure of 0.07MPa. Then, the furnace was melted three times with a current of 3500A. During each melting, the furnace was electromagnetically stirred at a rate of 65r / min to obtain an alloy ingot with uniform composition.

[0040] (2) Plastic processing: The alloy ingot is homogenized by holding it at 875℃ for 2.5h, and then hot-forged at a rate of 7mm / s. After forging, it is air-cooled to room temperature. The alloy billet after forging is then hot-rolled at 825℃ at a rate of 4m / s, and the rolling deformation is controlled to be 65% to obtain alloy bar.

[0041] (3) Multi-stage heat treatment: First, solution treatment is carried out at 975℃ for 1.5h, followed by ice water quenching at a cooling rate of 180℃ / s; then, segmented aging treatment is carried out, with the first stage at 325℃ for 2.5h and the second stage at 425℃ for 1.5h; finally, low-temperature tempering is carried out, with the furnace cooling at a cooling rate of 7℃ / h after holding at 175℃ for 2.5h.

[0042] (4) Finished product processing: The alloy bars that have undergone multi-stage heat treatment are machined to remove the surface oxide scale and obtain the finished product of the required size.

[0043] Example 3: (1) Raw material pretreatment and smelting: Weigh the following raw materials by mass percentage: 35% composite β-stabilizing element (Nb to Ta mass ratio 5:1), 3% rare earth modifying element (Nd to Dy mass ratio 4:1), 12% neutral regulating element (Zr to Sn mass ratio 2:1), 0.05% α-stabilizing element, 0.2% Hf-B composite doping element (Hf to B mass ratio 8:1), with the balance being Ti and unavoidable impurities; the purity of all raw materials is not less than 99.95%. After mixing Hf and B in proportion, ball mill them at 400 r / min for 3 h under argon protection with a purity ≥99.99% to obtain Hf-B composite powder. Ti, Nb, Ta, Nd, Dy, Zr, Sn raw materials and Hf-B composite powder were placed in a vacuum consumable arc furnace. First, the vacuum was evacuated to a vacuum degree ≤0.005Pa, and then argon gas was introduced to a pressure of 0.1MPa. Then, the furnace was melted three times with a current of 4000A. During each melting, the furnace was electromagnetically stirred at a rate of 80r / min to obtain an alloy ingot with uniform composition.

[0044] (2) Plastic processing: The alloy ingot is homogenized by holding it at 900℃ for 3 hours, and then hot-forged at a rate of 10 mm / s. After forging, it is air-cooled to room temperature. The alloy billet after forging is then hot-rolled at 850℃ at a rate of 5 m / s, and the rolling deformation is controlled to be 70% to obtain alloy sheet.

[0045] (3) Multi-stage heat treatment: First, solution treatment is carried out at 1000℃ for 2 hours, followed by ice water quenching at a cooling rate of 200℃ / s; then, segmented aging treatment is carried out, with the first stage at 350℃ for 3 hours and the second stage at 450℃ for 2 hours; finally, low-temperature tempering is carried out, with the furnace being cooled at a cooling rate of 10℃ / h after holding at 200℃ for 3 hours.

[0046] (4) Finished product processing: The alloy plate that has undergone multi-stage heat treatment is machined to remove the surface oxide scale and obtain the finished product of the required size.

[0047] Comparative Example 1: The preparation method of Example 2 is adopted, except that the alloy composition does not contain composite β stabilizing elements. The remaining components and their mass percentages are: rare earth modifying elements (Nd to Dy mass ratio 3:1) 1.7%, neutral regulating elements (Zr to Sn mass ratio 1.5:1) 8%, α stabilizing element o 0.025%, Hf-B composite doping elements (Hf to B mass ratio 6:1) 0.12%, and the balance is Ti and unavoidable impurities.

[0048] Comparative Example 2: The preparation method of Example 2 is adopted, except that the alloy composition does not contain rare earth modifying elements. The remaining components and their mass percentages are: 26% composite β stabilizing element (Nb to Ta mass ratio 4:1), 8% neutral regulating element (Zr to Sn mass ratio 1.5:1), 0.025% α stabilizing element, 0.12% Hf-B composite doping element (Hf to B mass ratio 6:1), and the balance is Ti and unavoidable impurities.

[0049] Comparative Example 3: The preparation method of Example 2 is adopted, except that the alloy composition does not contain Hf-B composite doping elements. The remaining components and mass percentages are: composite β stabilizing elements (Nb to Ta mass ratio 4:1) 26%, rare earth modifying elements (Nd to Dy mass ratio 3:1) 1.7%, neutral regulating elements (Zr to Sn mass ratio 1.5:1) 8%, α stabilizing element O 0.025%, and the balance is Ti and unavoidable impurities.

[0050] Comparative Example 4: The preparation method of Example 2 is adopted, except that: no segmented aging treatment is performed during the preparation process, only solution treatment (after holding at 975℃ for 1.5h, quenching with ice water at a cooling rate of 180℃ / s) and low temperature tempering (after holding at 175℃ for 2.5h, cooling with furnace at a cooling rate of 7℃ / h).

[0051] Tests and experiments; Experiment 1: Wide Temperature Range Temperature Coefficient of Resistance Test Alloy products prepared in Examples 1-3 and Comparative Examples 1-4 were selected and processed into samples with dimensions of 100mm × 10mm × 1mm. A four-probe resistance meter was used to test the resistance values ​​of the samples at -50℃, 25℃, 100℃, 200℃, and 300℃. The temperature coefficient of resistance α was calculated using the formula α=(R2-R1) / (R1(T2-T1)) (where R1 is the resistance value at temperature T1, and R2 is the resistance value at temperature T2). The average value of the temperature coefficient of resistance for each temperature range was taken as the final test result. The ambient humidity was controlled at 50%±5% during the test. Each sample was tested three times, and the average value was taken. The test results are as follows: Table 1

[0052] As can be seen from Table 1, the temperature coefficient of resistance of the alloy materials in Examples 1-3 is all below 13 × 10⁻⁶. -6 / ℃ indicates that the alloy material of the present invention has excellent low temperature coefficient of resistance performance over a wide temperature range.

[0053] Comparative Example 1, lacking a composite β-stabilizing element, suffers from insufficient phase structure stability, resulting in significant resistance fluctuations during temperature changes and a substantial increase in the temperature coefficient of resistance, reaching 35.7 × 10⁻⁶. -6 / ℃; Comparative Example 2 lacks rare earth modifying elements, resulting in coarse alloy grains, numerous grain boundary defects, and increased sensitivity of electrical resistance to temperature changes, with a temperature coefficient of resistance of 28.9 × 10⁻⁶. -6 / ℃; Comparative Example 3, without the addition of Hf-B composite dopant, could not form a dispersed reinforcing phase to suppress resistance fluctuations, and its temperature coefficient of resistance was 24.6 × 10⁻⁶. -6 / ℃; Comparative Example 4 omitted the segmented aging treatment, and no uniform and fine strengthening phase precipitated in the alloy, resulting in insufficient microstructural stability and a temperature coefficient of electrical resistance of 21.4 × 10⁻⁶. -6 / ℃. Therefore, it is evident that the synergistic effect of the composite β-stabilizing element, rare earth modifying element, and Hf-B composite doping element, along with the segmented aging process, are crucial for reducing the temperature coefficient of resistance of the alloy material.

[0054] Experiment 2: Mechanical property testing; The alloy products from Examples 1-3 and Comparative Examples 1-4 were processed into standard tensile specimens and subjected to room temperature tensile tests using a universal testing machine to measure yield strength, tensile strength, and elongation after fracture. The Brinell hardness (HBW) of the specimens was measured using a Brinell hardness tester, with three different locations tested for each specimen, and the average value was taken. The test results are as follows: Table 2

[0055] As can be seen from Table 2, the alloy materials of Examples 1-3 have excellent mechanical properties, with yield strengths all above 820 MPa, tensile strengths exceeding 950 MPa, elongation after fracture greater than 15%, and Brinell hardness higher than 285 HBW.

[0056] Comparative Example 1, lacking a composite β-stabilizing element, suffers from insufficient phase structure strength, resulting in significantly reduced yield strength and tensile strength, at only 650 MPa and 780 MPa, respectively. Elongation after fracture and Brinell hardness also decrease markedly. Comparative Example 2, lacking rare earth modifying elements, exhibits poor grain refinement, limiting mechanical property improvement; yield strength is 720 MPa and tensile strength is 860 MPa. Comparative Example 3, without Hf-B composite doping elements, lacks the effect of dispersed strengthening phases, resulting in poor mechanical properties; yield strength is 690 MPa and tensile strength is 830 MPa. Comparative Example 4, without segmented aging treatment, shows insufficient precipitation of strengthening phases and insufficient microstructural stability; yield strength is 750 MPa and tensile strength is 890 MPa, both lower than the levels of the examples. This demonstrates that the synergistic effect of the components and the optimized preparation process of this invention can effectively improve the mechanical properties of the alloy material.

[0057] Experiment 3: High-temperature stability test; The alloy products from Examples 1-3 and Comparative Examples 1-4 were processed into samples with dimensions of 50mm × 5mm × 5mm and placed in a high-temperature chamber. They were held at 300℃ for 1000 hours, with argon gas of ≥99.99% purity introduced during the holding period to protect the samples and prevent oxidation. After the holding period, the samples were cooled to room temperature, and the temperature coefficient of electrical resistance (test method same as in Experiment 1) and tensile properties (test method same as in Experiment 2) were tested. The results were compared with the properties before the holding period, and the rate of change in properties was calculated. The test results are as follows: Table 3

[0058] As can be seen from Table 3, after the alloy materials of Examples 1-3 were kept at 300℃ for 1000h, the change rate of the temperature coefficient of resistance was less than 6%, and the absolute value of the change rate of tensile strength was less than 2%, indicating that the alloy materials of the present invention have excellent high-temperature stability and small performance fluctuations under long-term high-temperature environment.

[0059] The alloy materials in Comparative Examples 1-4 exhibited poor high-temperature stability, with the temperature coefficient of resistance changing by more than 18%, and Comparative Example 4 showing the highest rate of change at 24.8%. The absolute values ​​of the tensile strength change rates were all greater than 6%, with Comparative Example 4 showing an 8.4% decrease in tensile strength. Comparative Example 1, lacking a composite β-stabilizing element, was prone to phase structure changes at high temperatures, leading to performance deterioration. Comparative Example 2, lacking rare earth modifying elements, experienced grain growth at high temperatures, affecting performance stability. Comparative Example 3, without the addition of Hf-B composite doping elements, saw its strengthening phase coarsen at high temperatures, losing its strengthening effect. Comparative Example 4, omitting segmented aging treatment, suffered from insufficient stability of the alloy microstructure at high temperatures, resulting in significant performance degradation. Therefore, the alloy composition design and preparation process of this invention can effectively improve the high-temperature stability of the material, ensuring its long-term stable operation over a wide temperature range.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An alloy material with a wide temperature range and low temperature coefficient of electrical resistance, characterized in that, It consists of the following components by mass percentage: 18%-35% composite β-stabilizing elements, 0.5%-3% rare earth modifying elements, 5%-12% neutral regulating elements, 0.001%-0.05% α-stabilizing elements, 0.05%-0.2% Hf-B composite doping elements, with the balance being Ti and unavoidable impurities.

2. The alloy material according to claim 1, characterized in that, The composite β-stabilizing element is a mixture of Nb and Ta, and the mass ratio of Nb to Ta is 3-5:

1.

3. The alloy material according to claim 1, characterized in that, The rare earth modifying element is a mixture of Nd and Dy, and the mass ratio of Nd to Dy is 2-4:

1.

4. The alloy material according to claim 1, characterized in that, The neutral regulating element is a mixture of Zr and Sn, and the mass ratio of Zr to Sn is 1-2:

1.

5. The alloy material according to claim 1, characterized in that, The α-stabilizing element is o.

6. The alloy material according to claim 1, characterized in that, The mass ratio of Hf to B in the Hf-B composite doping element is 5-8:

1.

7. The method for preparing a wide-temperature-range, low-resistivity temperature coefficient alloy material according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Raw material pretreatment and smelting: Weigh Ti, Nb, Ta, Nd, Dy, Zr, Sn, Hf and B pure metal raw materials with a purity of not less than 99.95% according to the composition ratio; After mixing Hf and B, ball mill them at a speed of 300-400 r / min for 2-3 hours under argon protection with a purity ≥99.99% to obtain Hf-B composite powder; Place Ti, Nb, Ta, Nd, Dy, Zr, Sn raw materials and Hf-B composite powder in a vacuum consumable arc furnace, first evacuate to a vacuum degree ≤0.005 Pa, then fill with argon to a pressure of 0.05-0.1 MPa, and then smelt three times with a current of 3000-4000 A. Each time during smelting, electromagnetic stirring is performed at a rate of 50-80 r / min to obtain a uniform alloy ingot. (2) Plastic processing: The alloy ingot is kept at 850℃-900℃ for 2-3 hours for homogenization treatment, and then hot forged at a rate of 5-10 mm / s. After forging, it is air-cooled to room temperature. Then the alloy billet after forging is hot rolled at 800℃-850℃ at a rate of 3-5 m / s, and the rolling deformation is controlled to be 60%-70% to obtain alloy plates or bars. (3) Multi-stage heat treatment: solution treatment, segmented aging treatment and low-temperature tempering are performed in sequence; (4) Finished product processing: The alloy material that has undergone multi-stage heat treatment is machined to remove the surface oxide scale and obtain the finished product of the required size.

8. The preparation method according to claim 7, characterized in that, In step (2), the solution treatment is to keep the temperature at 950℃-1000℃ for 1-2 hours, followed by ice water quenching at a cooling rate of ≥150℃ / s.

9. The preparation method according to claim 7, characterized in that, In step (2), the segmented aging treatment consists of a first stage of heat preservation at 300℃-350℃ for 2-3 hours and a second stage of heat preservation at 400℃-450℃ for 1-2 hours.

10. The preparation method according to claim 7, characterized in that, In step (2), the low-temperature tempering is performed by holding at 150℃-200℃ for 2-3 hours, followed by cooling with the furnace at a cooling rate of 5-10℃ / h.

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