Method and system for calculating thickness of ultra-thin oxide film of titanium alloy by high temperature color

Abstract

The application belongs to the technical field of service performance of titanium alloy parts of an aero-engine, and provides a method and system for calculating the thickness of an ultra-thin oxide film of a titanium alloy by high-temperature color, the method comprising: performing applicability detection on a target surface area of a titanium alloy part after high-temperature service; obtaining a reflectance spectrum of the high-temperature color of the titanium alloy surface by a colorimeter for the titanium alloy part that passes the applicability detection, and outputting a warning signal for the titanium alloy part that fails to pass the applicability detection; extracting a wavelength corresponding to a lowest point of reflectivity from the reflectance spectrum as a strong absorption wavelength; establishing a quantitative relationship between the thickness of the oxide film and the strong absorption wavelength based on optical interaction between the oxide film and a titanium alloy substrate, and calculating the thickness of the oxide film by the quantitative relationship using the strong absorption wavelength. The method of the application realizes rapid and non-contact measurement of the thickness of the oxide film, is suitable for on-site detection of key parts of an aero-engine, and has the advantages of high precision, low cost and easy operation.

Description

Technical Field

[0001] This invention belongs to the technical field of service performance of titanium alloy components for aero-engines, and relates to a method and system for calculating the thickness of ultra-thin oxide films on titanium alloys by high-temperature colorimetry. This method is particularly suitable for rapid, non-contact thickness measurement of oxide films in high-temperature service components such as aero-engine compressors. Background Technology

[0002] Titanium alloys, with their excellent thermal strength and comprehensive properties, are widely used in key components such as compressor blades and bladed disks for aero-engines, and can operate for extended periods below 600°C. During high-temperature service, their surface reacts with oxygen to form a dense oxide film, which is accompanied by a noticeable color change, known as "high-temperature color." This color change is not only related to the heating temperature but also closely related to the heating time, directly reflecting the material's thermal exposure history.

[0003] The American Welding Society's publicly available standard, "AWS D17.1:2001," states that there is a certain correlation between the surface oxide color of titanium alloys and their microstructure and properties. The color can be used to determine the degree of heat-affected zone in the weld area, whether there is overheating or excessive localized oxidation, and thus assess the degradation trend of the material's microstructure and mechanical properties. Therefore, the color of the oxide film on the alloy surface has significant guiding significance for parts manufacturing quality control, in-service condition assessment, and maintenance decisions.

[0004] Color development mechanisms in nature are mainly divided into two categories: chemical color development (such as dyes and pigments) and physical color development (such as thin-film interference, diffraction, and scattering). The high-temperature color of titanium alloys belongs to a typical physical color development process, which is generally considered to be caused by the thin-film interference effect induced by the surface oxide film. Currently, some empirical graphs on the relationship between the high-temperature color of titanium alloys and heat exposure conditions have been accumulated in engineering practice, which are used to qualitatively determine whether parts have undergone abnormal heating. However, these graphs are mostly based on empirical induction and lack in-depth research on physical mechanisms, and a quantitative mapping relationship between color and oxide film thickness has not yet been established.

[0005] Theoretically, the color rendering of thin-film interference is closely related to the film thickness. Traditionally, it is understood that the thickness of a thin film capable of producing distinct interference colors is typically on the order of a quarter of the incident light wavelength, approximately 100-200 nm. However, actual observations have revealed that when titanium alloys exhibit bright and regular color changes, the thickness of their surface oxide film is often much smaller than this range (as low as below 100 nm), significantly lower than the interference threshold of traditional optical thin films. This phenomenon indicates that the formation mechanism of high-temperature colors in titanium alloys is fundamentally different from the interference of multilayer dielectric films on conventional transparent substrates.

[0006] Further research indicates that the high-temperature color of titanium alloys is a unique interference phenomenon originating from a single-layer dielectric Fabry-Perot (FP) optical cavity structure consisting of air, an ultrathin oxide film, and a high-absorption titanium alloy substrate. In this structure, the oxide film, acting as a high-refractive-index medium, is sandwiched between air and a strongly absorbing metal. Light undergoes multiple reflections and destructive interference at the interface, resulting in the selective and strong absorption of specific wavelengths of light, thus forming absorption valleys in the reflection spectrum, manifesting as macroscopically visible color. The key to this color-producing mechanism lies in:

[0007] 1. Color can still be observed even when the oxide film thickness is <100 nm;

[0008] 2. Color rendering is mainly dominated by the phase change of interface reflection (non-trivial phase shift), rather than simply the difference in propagation path;

[0009] 3. The high absorption characteristics of the titanium alloy matrix significantly enhance the absorption intensity at specific wavelengths;

[0010] 4. It is not sensitive to the incident angle and is suitable for inspecting curved workpieces.

[0011] Although some studies have preliminarily recognized the uniqueness of this mechanism, a simple method based on this physical model for rapid on-site inversion of oxide film thickness has not yet been proposed. Existing mainstream measurement techniques, such as elliptic polarization methods (e.g., CN119780045A, CN1789343A) or multi-wavelength interferometry methods (e.g., CN101133300A), are still based on traditional multilayer media models, requiring complex modeling, fixed incident angles, and expensive equipment, which makes it difficult to meet the convenience and real-time requirements of on-site maintenance of aero-engines.

[0012] More importantly, when the oxide film cracks, peels off, or is over-oxidized (appearing dark yellow, gray, or black), the optical measurement results will be severely distorted. Existing technologies generally do not establish a judgment logic of "surface integrity - measurement validity", which can easily lead to misjudgment.

[0013] Therefore, there is an urgent need for a method for evaluating the thickness of ultrathin oxide films on titanium alloys that is based on clear principles, is easy to operate, is applicable to complex curved workpieces on-site, and can automatically identify the effectiveness of the detection. Summary of the Invention

[0014] To address the issues of existing technologies relying on expensive equipment and being unsuitable for on-site implementation, and to improve the prediction accuracy of oxide film thicknesses <100 nm by introducing a complete phase model, this invention discloses a method for calculating the thickness of ultrathin titanium alloy oxide films using high-temperature colorimetry. The method includes the following steps:

[0015] S1. Conduct suitability testing on the surface target areas of titanium alloy components after they have been in service at high temperatures;

[0016] S2. For surface target areas that pass the suitability test, obtain the reflection spectrum of the high-temperature color of the titanium alloy surface using a colorimeter, and output a warning signal for surface target areas that fail the suitability test.

[0017] S3. Extract the wavelength corresponding to the lowest reflectance point from the reflectance spectrum as the strong absorption wavelength;

[0018] S4. Based on the optical interaction between the oxide film and the titanium alloy substrate, establish a quantitative relationship between the oxide film thickness and the strong absorption wavelength, and calculate the oxide film thickness using the quantitative relationship through the strong absorption wavelength.

[0019] Furthermore, in step S1, the suitability test includes either the surface color test requirement or the surface integrity requirement.

[0020] S101. The surface color detection method is as follows: visually inspect the color of the target area on the surface. When the color is any one of golden yellow, magenta, royal blue, and light blue, it is determined that the applicability test has been passed; when the color is dark yellow, gray, brown, or black, it is determined that the applicability test has not been passed.

[0021] S102. The method for judging the surface integrity requirement is as follows: observe whether there are cracks or peeling on the surface using an optical microscope or a portable microscope. If there are no cracks or peeling, the surface integrity test is passed; if there are cracks or peeling, the surface integrity test is not passed.

[0022] Further, in step S4, a quantitative relationship is established between the oxide film thickness and the strong absorption wavelength, including:

[0023] S41. Analyze the formation mechanism of high-temperature color on the surface of titanium alloy and confirm that the formation mechanism originates from the Fabry-Perot optical cavity structure composed of air layer, oxide film layer and titanium alloy matrix.

[0024] S42. Based on the Fabry-Perot optical cavity structure, the total round-trip phase delay of the incident light in the oxide film layer is defined as: ,in, , Let be the real part of the refractive index of the oxide film. For oxide film thickness, For strong absorption wavelengths, The total round-trip phase delay of the incident light in the oxide film, For round-trip propagation phase delay, and These represent the phase changes of interfacial reflections between the oxide film layer and the air layer, and between the oxide film layer and the titanium alloy substrate, respectively.

[0025] S43, when When strong absorption occurs, the wavelength of strong absorption is the point with the lowest reflectance in the reflection spectrum.

[0026] S44. Using the formula for the round-trip propagation phase delay and the measured strong absorption wavelength, the quantitative relationship between oxide film thickness and strong absorption wavelength is calculated by inversion.

[0027] Furthermore, in step S42, and The reflection coefficients were calculated using the oxide film-air layer and oxide film-titanium alloy substrate, respectively. The reflection coefficients are related to the real and imaginary complex refractive indices of the air layer, oxide film, and titanium alloy substrate.

[0028] Further, in step S4, the expression for the quantitative relationship is d = 0.1λ - 23.5.

[0029] Furthermore, in step S2, the colorimeter measures the target area on the surface at any incident angle and observation angle.

[0030] Furthermore, in step S3, the point of lowest reflectance is identified after smoothing and filtering the reflectance spectrum, or the point of lowest reflectance is calculated by fitting the reflection valley region of the reflectance spectrum with a polynomial or Gaussian function.

[0031] Furthermore, in step S2, the high-temperature color on the titanium alloy surface is a physical coloring phenomenon produced by the oxide film formed during the service of the titanium alloy parts, and the main component of the oxide film is TiO2.

[0032] This invention also provides a system for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry. The system includes a colorimeter, an extraction module, a quantitative relationship establishment module, and a film thickness calculation module.

[0033] Among them, the colorimeter is used to collect the reflectance spectrum of the surface target area on the titanium alloy parts that has passed the suitability test;

[0034] The extraction module is used to extract the wavelength corresponding to the lowest reflectance point from the reflectance spectrum as the strong absorption wavelength;

[0035] The quantitative relationship establishment module is used to establish a quantitative relationship between oxide film thickness and strong absorption wavelength based on the optical interaction between the oxide film and the titanium alloy substrate.

[0036] The film thickness calculation module is used to calculate the oxide film thickness using the quantitative relationship based on the strong absorption wavelength.

[0037] Furthermore, the system also includes a display module for displaying warning signals for surface target areas that fail the suitability test and displaying the oxide film thickness of surface target areas that pass the suitability test.

[0038] The method of this invention, by revealing the mechanism of "strong absorption of FP optical cavity on thick metal substrate," constructs a quantitative inversion model from high-temperature color to film thickness, realizing rapid, non-destructive, and intelligent assessment of the service status of titanium alloys, filling a gap in existing technology. Compared with the prior art, the beneficial effects that at least one of the above-mentioned technical solutions adopted in the embodiments of this specification can achieve include at least the following:

[0039] 1. Current research on the high-temperature oxidation color of titanium alloys is limited to qualitative characterization of color, and a quantitative relationship between high-temperature color and oxide film thickness has not been established;

[0040] 2. Measurements can be completed with just a portable colorimeter, without the need for precision instruments. It has the advantages of low cost and simple operation, making it suitable for field applications.

[0041] 3. When establishing the quantitative relationship between oxide film thickness and strong absorption wavelength, the accuracy of predicting the thickness of ultrathin oxide films (<100nm) was improved by introducing the phase change of the interface reflection between the oxide film layer and the air layer and the oxide film layer and the titanium alloy substrate.

[0042] 4. Before calculating the oxide film thickness, conduct a suitability test on the target area to avoid misjudgment in damaged or failed areas;

[0043] 5. The colorimeter can work at any incident angle, regardless of the instrument angle and the viewing angle, and is suitable for curved workpieces, making this method superior to the elliptic method, which requires a fixed angle;

[0044] 6. The method of the present invention establishes an optical path physical model starting from the Fabry-Perot optical cavity, and then calibrates a formula for quantitative relationship through a large number of experiments. The calculation process involves few variables, is fast and simple, and has both scientific rigor and practicality. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart of the method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to the present invention;

[0047] Figure 2 This is a schematic diagram illustrating the interference principle of the Fabry-Perot optical cavity structure.

[0048] Figure 3 The complex refractive index curves are for the oxide film and the titanium alloy substrate.

[0049] Figure 4 This is a quantitative relationship between oxide film thickness and strong absorption wavelength.

[0050] Figure 5 This is a system architecture diagram for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry.

[0051] Among them, 501 is the colorimeter; 502 is the extraction module; 503 is the quantitative relationship establishment module; 504 is the film thickness calculation module; and 505 is the display module. Detailed Implementation

[0052] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0053] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] This invention provides a method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry. (See also...) Figure 1 As shown, the method includes the following steps:

[0055] S1. Conduct suitability testing on the surface target areas of titanium alloy components after they have been in service at high temperatures;

[0056] S2. For surface target areas that pass the suitability test, obtain the reflection spectrum of the high-temperature color of the titanium alloy surface using a colorimeter, and output a warning signal for surface target areas that fail the suitability test.

[0057] S3. Extract the wavelength corresponding to the lowest reflectance point from the reflectance spectrum as the strong absorption wavelength;

[0058] S4. Based on the optical interaction between the oxide film and the titanium alloy substrate, establish a quantitative relationship between the oxide film thickness and the strong absorption wavelength, and calculate the oxide film thickness using the quantitative relationship through the strong absorption wavelength.

[0059] Research has revealed that during high-temperature service, titanium alloy components for aero-engines develop a high-temperature color on their surfaces. This color is related to the state and thickness of the oxide film. As the heating temperature and time increase, the oxide film undergoes two stages. The first stage is a dense oxide film stage, where the oxide film composition includes Ti and a small amount of alloying element oxides. The oxide film structure is dense, and its thickness increases with oxidation time and temperature. The high-temperature color changes in this stage from golden yellow to purplish-red to royal blue to light blue. This stage produces a vibrant color that satisfies the Fabry-Perot cavity interference condition, exhibiting strong absorption wavelengths. The second stage is the oxide film cracking and peeling stage. After the high-temperature color turns light blue, if the heating temperature continues to rise or the time continues to extend, the high-temperature color will turn dark yellow, gray, brown, or black, eventually leading to cracking and even peeling.

[0060] Therefore, oxide film thickness detection is based on suitability testing, which can be determined by surface color or by observing the surface integrity, specifically including the following two methods:

[0061] S101. The surface color detection method is as follows: visually inspect the color of the target area on the surface. When the color is any one of golden yellow, magenta, royal blue, and light blue, it is determined that the applicability test has been passed; when the color is dark yellow, gray, brown, or black, it is determined that the applicability test has not been passed.

[0062] S102. The method for judging the surface integrity requirement is as follows: observe whether there are cracks or peeling on the surface using an optical microscope or a portable microscope. If there are no cracks or peeling, the surface integrity test is passed; if there are cracks or peeling, the surface integrity test is not passed.

[0063] In one embodiment, in step S2, the colorimeter measures the target area of ​​the surface at any incident angle and observation angle.

[0064] In one embodiment, in step S2, the high-temperature color on the titanium alloy surface is a physical coloring phenomenon produced by the oxide film formed during the service of the titanium alloy parts. The main component of the oxide film is TiO2. For example, an oxide film is formed during service, and the thickness of the oxide film gradually increases with the extension of service time and the increase of temperature, thereby showing different colors.

[0065] In one embodiment, in step S3, the point of lowest reflectance is identified after smoothing and filtering the reflectance spectrum, or the point of lowest reflectance is calculated by fitting the reflection valley region of the reflectance spectrum with a polynomial or Gaussian function.

[0066] In one embodiment, see Figure 2 and Figure 4 As shown, in step S4, establishing a quantitative relationship between oxide film thickness and strong absorption wavelength includes:

[0067] S41. Analyze the formation mechanism of high-temperature color on the surface of titanium alloy and confirm that the formation mechanism originates from the Fabry-Perot optical cavity structure composed of air layer, oxide film layer and titanium alloy matrix.

[0068] S42. Based on the Fabry-Perot optical cavity structure, the total round-trip phase delay of the incident light in the oxide film layer is defined as: ,in, , Let be the real part of the refractive index of the oxide film. For oxide film thickness, For strong absorption wavelengths, The total round-trip phase delay of the incident light in the oxide film, For round-trip propagation phase delay, and These represent the phase changes of interfacial reflections between the oxide film layer and the air layer, and between the oxide film layer and the titanium alloy substrate, respectively.

[0069] S43, when When strong absorption occurs, the wavelength of strong absorption is the point with the lowest reflectance in the reflection spectrum.

[0070] S44. Using the formula for the round-trip propagation phase delay and the measured strong absorption wavelength, the quantitative relationship between oxide film thickness and strong absorption wavelength is calculated by inversion.

[0071] Furthermore, in step S42, and The reflectance r of the oxide film layer-air layer and oxide film layer-titanium alloy substrate are respectively obtained. 01 and r 12 Calculate the reflection coefficient r 01 and r 12 The complex refractive index is related to the real and imaginary parts of the air layer, oxide film layer, and titanium alloy substrate. The real part of the complex refractive index of air is n=1, and the imaginary part is k=0. The relationship between the real and imaginary parts n and k of the complex refractive index of the oxide film and titanium alloy substrate and the wavelength is as follows: Figure 3 As shown, Figure 3 The horizontal axis represents wavelength, and the vertical axis represents complex refractive index.

[0072] Further, in step S4, the expression for the quantitative relationship is d = 0.1λ - 23.5.

[0073] In this invention, the principle and detailed process of establishing quantitative relationships are as follows:

[0074] In the first stage, the color change process from golden yellow to purplish red to royal blue to pale blue, according to the Fabry-Perot interference principle, such as Figure 2 As shown, the complex refractive indices of the air layer, oxide film layer, and titanium alloy metal substrate are defined as n, respectively. 0+ n1 and n2, with an oxide film thickness of d, a beam of light is incident at an angle θ to the interface between the air layer and the oxide film layer, and part of it is reflected at the interface (r 01 Of the light entering the oxide film, some is refracted and enters the oxide film layer. Part of the light entering the oxide film layer is reflected at the oxide film layer-air layer interface (r...). 12 The light continuously reflects at the interfaces between the air layer and the oxide film layer, and between the oxide film layer and the titanium alloy substrate, accompanied by absorption attenuation. This induces interference. When light moves between the two interfaces, they produce constructive or destructive interference, selectively filtering out certain wavelengths, resulting in strong absorption wavelengths. Under these conditions, the oxide film thickness, the strong absorption wavelength, and the complex refractive index of the oxide film and the titanium alloy substrate exhibit the relationship described in step S42 above.

[0075] Based on the same inventive concept, this invention also provides a system for calculating the thickness of ultrathin titanium alloy oxide films using high-temperature colorimetry, as described in the following embodiments. Since the principle behind a system for calculating the thickness of ultrathin titanium alloy oxide films using high-temperature colorimetry is similar to the method described above, implementation of such a system can refer to the implementation of another system for calculating the thickness of ultrathin titanium alloy oxide films using high-temperature colorimetry; repeated details will not be elaborated further. The terms "unit" or "module" used below refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0076] like Figure 5 The diagram shown is a structural block diagram of a system for calculating the thickness of an ultrathin oxide film on titanium alloys using high-temperature colorimetry, according to an embodiment of the present invention. Figure 5 As shown, the system includes a colorimeter 501, an extraction module 502, a quantitative relationship establishment module 503, and a film thickness calculation module 504.

[0077] Among them, the colorimeter 501 is used to collect the reflectance spectrum of the surface target area on the titanium alloy parts that has passed the suitability test;

[0078] Extraction module 502 is used to extract the wavelength corresponding to the lowest reflectance point from the reflectance spectrum as the strong absorption wavelength;

[0079] The quantitative relationship establishment module 503 is used to establish a quantitative relationship between oxide film thickness and strong absorption wavelength based on the optical interaction between oxide film and titanium alloy substrate;

[0080] The film thickness calculation module 504 is used to calculate the oxide film thickness using the quantitative relationship through a strong absorption wavelength.

[0081] Further, see Figure 5 As shown, the system also includes a display module 505, which is used to display warning signals for surface target areas that fail the suitability test and to display the oxide film thickness of surface target areas that pass the suitability test.

[0082] The method and system of this invention, by revealing the mechanism of "strong absorption of FP optical cavity on thick metal substrate," constructs a quantitative inversion model from high-temperature color to film thickness, realizing rapid, non-destructive, and intelligent assessment of the service status of titanium alloys, filling a gap in existing technology. Compared with the prior art, the beneficial effects that at least one of the above-mentioned technical solutions adopted in the embodiments of this specification can achieve include at least the following:

[0083] 1. Current research on the high-temperature oxidation color of titanium alloys is limited to qualitative characterization of color, and a quantitative relationship between high-temperature color and oxide film thickness has not been established;

[0084] 2. Measurements can be completed with just a portable colorimeter, without the need for precision instruments. It has the advantages of low cost and simple operation, making it suitable for field applications.

[0085] 3. When establishing the quantitative relationship between oxide film thickness and strong absorption wavelength, the accuracy of predicting the thickness of ultrathin oxide films (<100 nm) was improved by introducing the phase change of the interface reflection between the oxide film layer and the air layer and the oxide film layer and the titanium alloy substrate.

[0086] 4. Before calculating the oxide film thickness, conduct a suitability test on the target area to avoid misjudgment in damaged or failed areas;

[0087] 5. The colorimeter can work at any incident angle, regardless of the instrument angle and the viewing angle, and is suitable for curved workpieces, making this method superior to the elliptic method, which requires a fixed angle;

[0088] 6. The method of the present invention establishes an optical path physical model starting from the Fabry-Perot optical cavity, and then calibrates a formula for quantitative relationship through a large number of experiments. The calculation process involves few variables, is fast and simple, and has both scientific rigor and practicality.

[0089] Obviously, those skilled in the art should understand that the modules or steps of the above-described embodiments of the present invention can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the embodiments of the present invention are not limited to any particular hardware and software combination.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of calculating the thickness of an ultra-thin oxide film on a titanium alloy by high temperature colorimetry, characterized in that, include: The suitability testing of the surface target area of ​​titanium alloy parts after high-temperature service includes either surface color testing or surface integrity testing. The surface color testing method is as follows: visually inspect the color of the surface target area. If the color is any one of golden yellow, purplish red, royal blue, and light blue, the suitability test is considered passed; if the color is dark yellow, gray, brown, or black, the suitability test is considered failed. The surface integrity testing method is as follows: observe the surface for cracks or peeling using an optical microscope. If no cracks or peeling are found, the surface integrity test is considered passed; if cracks or peeling are found, the surface integrity test is considered failed. For surface target areas that pass the suitability test, the reflectance spectrum of the high-temperature color of the titanium alloy surface is obtained by a colorimeter; for surface target areas that fail the suitability test, a warning signal is output. The wavelength corresponding to the lowest reflectance point is extracted from the reflectance spectrum as the strong absorption wavelength; Based on the optical interaction between the oxide film and the titanium alloy substrate, a quantitative relationship between the oxide film thickness and the strong absorption wavelength is established, and the oxide film thickness is calculated using the strong absorption wavelength and the quantitative relationship.

2. The method of calculating the thickness of an ultra-thin oxide film of a titanium alloy by high temperature color according to claim 1, characterized in that, Establish a quantitative relationship between oxide film thickness and strong absorption wavelength, including: The formation mechanism of high-temperature color on the surface of titanium alloy was analyzed, and it was confirmed that the formation mechanism originates from the Fabry-Perot optical cavity structure composed of the air layer, oxide film layer and titanium alloy matrix. Based on the Fabry-Perot optical cavity structure, the total round-trip phase delay of the incident light in the oxide film layer is defined as , wherein, , is the real part of the refractive index of the oxide film, is the thickness of the oxide film, is the strong absorption wavelength, is the round-trip propagation phase delay, and are the interface reflection phase changes of the oxide film layer-air layer and the oxide film layer-titanium alloy substrate, respectively. When occurs, the minimum point of reflectance in the reflection spectrum corresponds to the strong absorption wavelength. The quantitative relationship between oxide film thickness and strong absorption wavelength was calculated by using the formula for round-trip propagation phase delay and the measured strong absorption wavelength.

3. The method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to claim 2, characterized in that, and The reflectance of the oxide film layer-air layer and the oxide film layer-titanium alloy substrate was calculated, respectively, and the reflectance was related to the real and imaginary complex refractive indexes of the air layer, the oxide film layer, and the titanium alloy substrate.

4. The method of calculating the thickness of an ultra-thin oxide film of a titanium alloy by high-temperature color according to claim 2 or 3, characterized in that, The quantitative relationship is expressed as d = 0.1λ - 23.

5.

5. The method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to claim 1, characterized in that, The colorimeter measures the target area on the surface at any incident angle and observation angle.

6. The method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to claim 1, characterized in that, The point of lowest reflectance can be identified by smoothing and filtering the reflectance spectrum, or the point of lowest reflectance can be calculated by fitting the reflectance valley region of the reflectance spectrum with a polynomial or Gaussian function.

7. The method for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to claim 1, characterized in that, The high-temperature color on the surface of the titanium alloy is a physical color phenomenon caused by the oxide film formed on the titanium alloy parts during service. The main component of the oxide film is TiO2.

8. A system for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry, characterized in that, To implement the method as described in any one of claims 1 to 7, comprising: A colorimeter is used to collect the reflectance spectrum of a target surface area on a titanium alloy component that has passed suitability testing. The extraction module is used to extract the wavelength corresponding to the lowest reflectance point from the reflectance spectrum as the strong absorption wavelength; The quantitative relationship establishment module is used to establish a quantitative relationship between oxide film thickness and strong absorption wavelength based on the optical interaction between the oxide film and the titanium alloy substrate. The film thickness calculation module is used to calculate the oxide film thickness using the quantitative relationship based on the strong absorption wavelength.

9. The system for calculating the thickness of ultrathin oxide films on titanium alloys using high-temperature colorimetry according to claim 8, characterized in that, Also includes: The display module is used to display warning signals for surface target areas that fail the suitability test and to display the oxide film thickness of surface target areas that pass the suitability test.

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