Method for predicting thickness of high temperature oxidation layer of titanium alloy at forging temperature

Abstract

The present application relates to a kind of titanium alloy high-temperature oxidation layer thickness prediction method at forging temperature, including the steps of obtaining the high-temperature oxidation weight gain relationship of different high-temperature oxidation conditions and titanium alloy sample;The step of establishing the high-temperature oxidation weight gain relationship of different high-temperature oxidation conditions and titanium alloy sample;The step of obtaining the high-temperature oxidation layer thickness and oxidation weight gain relationship of titanium alloy sample;And, establish the high-temperature oxidation layer thickness and unit area oxidation weight gain model, so as to obtain the prediction value of the high-temperature oxidation layer thickness of titanium alloy sample under different high-temperature oxidation conditions, i.e. Realize the prediction of the high-temperature oxidation layer thickness of the titanium alloy sample under different high-temperature oxidation conditions.The present application conveniently and quickly calculates the oxidation weight gain and high-temperature oxidation layer thickness of titanium alloy by combining heating time and heating temperature two factors, gives theoretical explanation to fitting result, and prediction accuracy is good, helps real-time control high-temperature oxidation layer thickness, improves component quality.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composites, and more particularly to a method for predicting the thickness of high-temperature oxide layers on titanium alloys. Background Technology

[0002] Titanium-based composites possess excellent specific strength, specific stiffness, and high-temperature durability, and are widely considered one of the most promising structural materials for high-temperature applications, with potential for widespread use in aerospace and automotive industries. However, poor resistance to high-temperature oxidation has been a major factor limiting the engineering applications of titanium alloys. High-temperature oxidation forms a high-temperature oxide layer and an oxygen-rich α-phase within the metal. The porous high-temperature oxide layer cannot prevent further oxygen diffusion, and oxygen enrichment in the α-phase significantly affects the material's machinability. An excessively thick high-temperature oxide layer also reduces the material's thermal conductivity, greatly impacting the plasticity and toughness of titanium alloys. Therefore, evaluating the thickness of the high-temperature oxide layer at processing temperatures is essential to reduce mass loss and improve machinability.

[0003] Calculating the thickness of the high-temperature oxide layer requires the use of a high-temperature oxidation kinetic model of titanium alloys under atmospheric conditions. Current research on high-temperature oxidation kinetic models for titanium alloys mainly focuses on the service stage, while there is less discussion on high-temperature oxidation kinetic models at forging temperatures where the high-temperature oxidation process is more rapid. Chinese patent CN112597627A discloses a method for predicting the thickness of the high-temperature oxide layer during the heating process of spring steel, but it only provides a theoretical formula for the relationship between the high-temperature oxide layer thickness and the weight gain per unit area of ​​oxidation, without actual fitting. Chinese patent CN116504342A discloses a method for calculating the inner layer thickness of the high-temperature oxide layer of martensitic heat-resistant steel in a steam environment, but its application is still based on the service state, and its applicability at higher forging temperatures is questionable.

[0004] For titanium alloys reinforced with titanium boride whiskers, high-temperature oxidation under short-term conditions involves not only the transformation of high-temperature oxidation products in the initial stage of high-temperature oxidation, but also the change in quality is related to the reaction of titanium boride at high temperature. There is currently no patent disclosure on this matter. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for predicting the thickness of the high-temperature oxide layer of titanium alloys at forging temperature. This method is based on a high-temperature oxidation kinetic model and uses the heating time and temperature during the hot working process of titanium alloys as input parameters to calculate the thickness of the high-temperature oxide layer conveniently and quickly. This allows for the adjustment of process parameters to control the thickness of the high-temperature oxide layer, thereby improving the surface quality and processing performance of the material.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for predicting the thickness of a high-temperature oxide layer on titanium alloys at forging temperature, comprising the following steps:

[0007] Step 1: After grinding, ultrasonic cleaning, and drying the titanium alloy sample in sequence, high-temperature oxidation is carried out using a discontinuous weighing method under different high-temperature oxidation conditions; thereby obtaining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of the titanium alloy sample; the oxidation temperature T and oxidation time t of the high-temperature oxidation are consistent with the forging temperature and time of the titanium alloy sample.

[0008] Step 2: Combining the Wanger formula for the weight gain from high-temperature oxidation and the relationship formula established from the relationship between different high-temperature oxidation conditions and the weight gain from high-temperature oxidation of the titanium alloy sample described in Step 1, calculate the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction of the titanium alloy sample under different high-temperature oxidation conditions.

[0009] Step 3: Using the titanium alloy sample obtained in Step 1 by the discontinuous weighing method, obtain scanning electron microscope images of the titanium alloy sample with a high-temperature oxide layer metallographic cross section under different high-temperature oxidation conditions, and obtain the relationship between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample.

[0010] Step 4: Combining the Wanger formula for high-temperature oxidation weight gain and the relationship formula established from the relationship between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample described in Step 3, a model for high-temperature oxide layer thickness and oxidation weight gain per unit area is established. Based on the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction of the titanium alloy sample obtained in Step 2, the predicted value of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions is calculated, thus realizing the prediction of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions.

[0011] Furthermore, the specific steps for obtaining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of titanium alloy samples in step one are as follows:

[0012] The dried titanium alloy sample was weighed to obtain the original weight of the titanium alloy sample.

[0013] Then, the titanium alloy sample was subjected to high-temperature oxidation under different high-temperature oxidation conditions. After the high-temperature oxidized titanium alloy sample was cooled to room temperature, it was weighed to obtain the weight of the high-temperature oxidized titanium alloy sample.

[0014] The difference between the weight of the titanium alloy sample after high-temperature oxidation and the original weight of the titanium alloy sample is divided by the initial surface area of ​​the sample to obtain the oxidation weight gain per unit area ΔM of the titanium alloy sample. Subsequently, a table of correspondence between oxidation temperature T, oxidation time t and oxidation weight gain per unit area ΔM is established.

[0015] Furthermore, the titanium alloy sample is wire-cut into block-shaped samples of (5-12)×(5-12)×(5-12)mm, polished with sandpaper from 240# to 1500#, ultrasonically cleaned with anhydrous ethanol for 10-30 minutes, dried in a vacuum drying oven at 60-120℃ for 30-120 minutes, and then placed in a high-temperature sintering furnace for high-temperature oxidation.

[0016] The high-temperature oxidation treatment was carried out in a KSL-1200X box-type high-temperature sintering furnace; the oxidation temperature T in the high-temperature sintering furnace was 960-1000℃, and the oxidation time t was 5-30min; and under each high-temperature oxidation condition, at least three titanium alloy samples were prepared to calculate the average value of the oxidation weight gain per unit area ΔM of the titanium alloy samples.

[0017] Furthermore, the dried titanium alloy sample is placed in a corundum crucible that has been calcined to constant weight, and then weighed together with an analytical balance with an accuracy of 0.1 mg. After obtaining the original weight of the titanium alloy sample, it is subjected to high-temperature oxidation treatment.

[0018] Furthermore, step two specifically involves:

[0019] The Wanger formula for the weight gain due to high-temperature oxidation is expressed as formula (1):

[0020] ΔM n =k p (t)·t (1),

[0021] In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k p (t) is the high-temperature oxidation rate constant at a certain time, with units of g. n ·m -2n ·h -1 t represents oxidation time, in minutes.

[0022] In equation (1), k p (t) is:

[0023]

[0024] In the formula: k0 is the frequency factor; Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T represents the oxidation temperature, measured in K.

[0025] Substituting equation (2) into equation (1), we obtain equation (3) relating the weight gain per unit area due to oxidation to the oxidation temperature T and oxidation time t:

[0026]

[0027] Taking the logarithm of both sides of equation (3), we get equation (4):

[0028]

[0029] In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k0 is the frequency factor; Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T is the oxidation temperature in K; t is the oxidation time in min.

[0030] Using lgt as the abscissa and lgΔM as the ordinate, plot the relationship curves between the oxidation weight gain per unit area and oxidation time under different high-temperature oxidation conditions; then, using 1 / T as the abscissa and lgΔM as the ordinate, plot the relationship curves between the oxidation weight gain per unit area and oxidation temperature under different high-temperature oxidation conditions; by linearly fitting these two relationship curves, the relationship curves between lgΔM and lgt and between lgΔM and 1 / T are established, and the lgΔM formula (5) expressed by lgt and 1 / T is obtained, which is the relationship formula between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of the titanium alloy sample mentioned in step two:

[0031]

[0032] In the formula, A, B, and C are constants, and ΔM is the weight gain per unit area due to oxidation, in g·m². -2 T is the oxidation temperature in K; t is the oxidation time in min. Substitute the data from the table of the relationship between oxidation temperature T, oxidation time t and the oxidation weight gain per unit area ΔM into the lgΔM formula to obtain the values ​​of constants A, B, and C in the formula. Then, obtain the values ​​of the high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q through the formula (3).

[0033] Furthermore, the specific method for obtaining scanning electron microscope images of titanium alloy samples with metallographic cross-sections of high-temperature oxide layers under different high-temperature oxidation conditions in step three is as follows:

[0034] Scanning electron microscope images magnified 5000-20000 times are magnified 2-5 times in image analysis software. IPP software can be used for image analysis. The upper and lower boundaries of the high-temperature oxide layer are depicted in the magnified image. For boundaries whose morphology is difficult to determine, they need to be determined in combination with the elemental distribution of titanium alloy. The thickness y of the high-temperature oxide layer of the titanium alloy sample after high-temperature oxidation is measured. Combined with the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of titanium alloy samples obtained in step one, a table of correspondence between the unit area oxidation weight gain ΔM and the high-temperature oxide layer thickness y is obtained.

[0035] In determining the thickness of the oxide layer, at least 20 thickness data points at different locations of the titanium alloy sample are measured in each photograph, and the average value is taken to reduce the thickness measurement error.

[0036] Furthermore, step four specifically involves:

[0037] The Wanger formula for the weight gain due to high-temperature oxidation is expressed as formula (1):

[0038] ΔM n =k p (t)·t (1),

[0039] In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k p (t) is the high-temperature oxidation rate constant at a certain time, with units of g. n ·m -2n ·h -1 t represents oxidation time, in minutes.

[0040] In equation (1), k p (t) is:

[0041]

[0042] In the formula: k0 is the frequency factor; Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T represents the oxidation temperature, measured in K.

[0043] Substituting equation (2) into equation (1), we obtain equation (3) relating the weight gain per unit area due to oxidation to the oxidation temperature T and oxidation time t:

[0044]

[0045] Using the high-temperature oxide layer thickness y as the ordinate and the oxidation weight gain per unit area ΔM as the abscissa, a linear fit was performed to obtain the relationship curves between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM under different high-temperature oxidation conditions. Thus, the relationship formula (6) between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM was obtained, which is the relationship formula between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample in step four:

[0046] y=A·ΔM+B (6),

[0047] Where: y is the thickness of the high-temperature oxide layer (10 -6 m); ΔM is the weight gain per unit area due to oxidation, in g·m -2 A and B are constants; at the same time, based on the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high-temperature oxide layer thickness y, the values ​​of constants A and B in the formula are obtained;

[0048] Furthermore, substituting formula (3) into relational formula (6), we obtain the high-temperature oxide layer thickness model (7) of the titanium alloy sample with high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q:

[0049]

[0050] Where: y is the thickness of the high-temperature oxide layer (10 -6 m); Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 T is the oxidation temperature in K; t is the oxidation time in min; R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 A and B are constants;

[0051] Combining the relationship equation (6) and the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high temperature oxide layer thickness y in step three, the values ​​of constants A and B in the formula are obtained. The high temperature oxidation kinetic power exponent n, frequency factor k0, and high temperature oxidation reaction activation energy Q of the titanium alloy sample are obtained using step two, and the high temperature oxide layer thickness of the titanium alloy sample is obtained.

[0052] Furthermore, the titanium alloy is a titanium alloy reinforced with titanium boride whiskers, and the different high-temperature oxidation conditions used are as follows: oxidation temperatures of 960℃, 980℃ and 1000℃, respectively; and oxidation times of 5min, 10min, 20min and 30min, respectively.

[0053] Furthermore, the titanium alloy matrix reinforced with boronized titanium whiskers is Ti55, and the volume fraction of the titanium boronized titanium whisker reinforcement is 3.5%, with the following composition: TiB 3.606 wt.%, Ti 83.54 wt.%, Al 5.263 wt.%, Sn 3.586 wt.%, Zr 1.87 wt.%, Mo 0.961 wt.%, Nd 0.8 wt.%, and Si 0.255 wt.%.

[0054] Take the titanium alloy sample reinforced with boride whiskers, and according to step two, obtain the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q value of the titanium alloy sample as follows:

[0055] n = 1.27, k0 = 1.3 × 10 8 Q = 191455 J·mol -1 Therefore, the equation relating the weight gain per unit area of ​​the titanium alloy sample by oxidation ΔM to the oxidation time t and oxidation temperature T is as follows:

[0056]

[0057] Using the calculation results of A and B in step four, A = 0.6 and B = -0.6 respectively, the formula for the relationship between the thickness y of the high-temperature oxide layer and the weight gain per unit area due to oxidation is:

[0058] y = 0.6ΔM - 0.6,

[0059] The high-temperature oxide layer thickness model is then obtained as follows:

[0060]

[0061] Furthermore, the weight gain per unit area of ​​the titanium alloy sample due to oxidation, ΔM, is the mass of oxygen atoms in the high-temperature oxide layer. The main high-temperature oxidation product of the titanium alloy sample is TiO2, and the minor products are a small amount of Al2O3 and incompletely oxidized titanium oxide Ti6O at high temperature. If the composition of the high-temperature oxide layer is calculated based on TiO2, then the atomic mass ratio of oxygen in the high-temperature oxide layer is 2 / 5; ρ is the density of TiO2, 4.26 g / cm³. 3 The theoretical reference thickness y of the obtained high-temperature oxide layer is:

[0062]

[0063] The beneficial effects of this invention are: This invention proposes the high-temperature oxide layer thickness of titanium alloys under processing conditions, and conveniently and quickly calculates the oxidation weight gain and high-temperature oxide layer thickness of titanium alloys by combining the two factors of heating time and heating temperature. The fitting results are given a theoretical explanation, and the prediction accuracy is good. In actual factory processing, it can be calculated and predicted in real time, which helps to control the high-temperature oxide layer thickness in real time and improve the quality of components.

[0064] Meanwhile, in determining the upper and lower boundaries during the measurement of the high-temperature oxide layer thickness, this application uses SEM images combined with elemental distribution determination, which effectively ensures measurement accuracy. Attached Figure Description

[0065] Figure 1 (a) is the lgΔM-lgt relationship curve, and (b) is the lgΔM-1 / T relationship curve.

[0066] Figure 2 A graph showing the relationship between the weight gain per unit area due to oxidation ΔM and time t and temperature T.

[0067] Figure 3 The equation relating the thickness y of the high-temperature oxide layer to the weight gain per unit area due to oxidation is given.

[0068] Figure 4 This is a schematic diagram of a high-temperature oxidation experiment using the discontinuous weighing method.

[0069] Figure 5 The image shows a scanning electron microscope image of the thickness and elemental distribution of the high-temperature oxide layer of the titanium alloy according to the present invention. Detailed Implementation

[0070] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0071] To achieve the above objectives, the present invention provides the following specific embodiments:

[0072] Example 1: A method for predicting the thickness of a high-temperature oxide layer on titanium alloys at forging temperatures, comprising the following steps:

[0073] Step 1: After grinding, ultrasonic cleaning and drying the titanium alloy sample in sequence, high-temperature oxidation is carried out using the discontinuous weighing method under different high-temperature oxidation conditions.

[0074] Specifically, the titanium alloy sample is wire-cut into (5-12)×(5-12)×(5-12)mm block samples, polished with sandpaper from 240# to 1500#, ultrasonically cleaned with anhydrous ethanol for 10-30 minutes, and dried in a vacuum drying oven at 60-120℃ for 30-120 minutes. The dried titanium alloy sample is then placed in a corundum crucible calcined to constant weight, and weighed together with an analytical balance with an accuracy of 0.1mg. After obtaining the original weight of the titanium alloy sample, it is placed in a high-temperature sintering furnace for high-temperature oxidation treatment.

[0075] The high-temperature oxidation treatment was carried out in a KSL-1200X box-type high-temperature sintering furnace; the oxidation temperature T in the high-temperature sintering furnace was 960-1000℃, and the oxidation time t was 5-30 min; and under each high-temperature oxidation condition, at least three titanium alloy samples were prepared to calculate the average value of the oxidation weight gain per unit area ΔM of the titanium alloy samples. The oxidation temperature T and oxidation time t of the high-temperature oxidation were consistent with the forging temperature and time of the titanium alloy samples;

[0076] The relationship between different high-temperature oxidation conditions and the weight gain of titanium alloy samples during high-temperature oxidation was obtained, specifically:

[0077] The dried titanium alloy sample was weighed to obtain the original weight of the titanium alloy sample.

[0078] Then, the titanium alloy sample was subjected to high-temperature oxidation under different high-temperature oxidation conditions. After the high-temperature oxidized titanium alloy sample was cooled to room temperature, it was weighed to obtain the weight of the high-temperature oxidized titanium alloy sample.

[0079] The difference between the weight of the titanium alloy sample after high-temperature oxidation and the original weight of the titanium alloy sample is divided by the initial surface area of ​​the sample to obtain the oxidation weight gain per unit area ΔM of the titanium alloy sample. Subsequently, a table of correspondence between oxidation temperature T, oxidation time t and oxidation weight gain per unit area ΔM is established.

[0080] Step 2: Combining the Wanger formula for the weight gain during high-temperature oxidation and the relationship formula established from the relationship between different high-temperature oxidation conditions and the weight gain during high-temperature oxidation of the titanium alloy sample described in Step 1, calculate the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction for the titanium alloy sample under different high-temperature oxidation conditions; specifically:

[0081] The Wanger formula for the weight gain due to high-temperature oxidation is expressed as formula (1):

[0082] ΔM n =k p (t)·t (1),

[0083] In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k p (t) is the high-temperature oxidation rate constant at a certain time, with units of g. n ·m -2n ·h -1 t represents oxidation time, in minutes.

[0084] In equation (1), k p (t) is:

[0085]

[0086] In the formula: k0 is the frequency factor; Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T represents the oxidation temperature, measured in K.

[0087] Substituting equation (2) into equation (1), we obtain equation (3) relating the weight gain per unit area due to oxidation to the oxidation temperature T and oxidation time t:

[0088]

[0089] Taking the logarithm of both sides of equation (3), we get equation (4):

[0090]

[0091] In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k0 is the frequency factor; Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T is the oxidation temperature in K; t is the oxidation time in min.

[0092] Using lgt as the abscissa and lgΔM as the ordinate, plot the relationship curves between the oxidation weight gain per unit area and oxidation time under different high-temperature oxidation conditions; then, using 1 / T as the abscissa and lgΔM as the ordinate, plot the relationship curves between the oxidation weight gain per unit area and oxidation temperature under different high-temperature oxidation conditions; by linearly fitting these two relationship curves, the relationship curves between lgΔM and lgt and between lgΔM and 1 / T are established, and the lgΔM formula (5) expressed by lgt and 1 / T is obtained, which is the relationship formula between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of the titanium alloy sample mentioned in step two:

[0093]

[0094] In the formula, A, B, and C are constants, and ΔM is the weight gain per unit area due to oxidation, in g·m². -2 T is the oxidation temperature in K; t is the oxidation time in min. Substitute the data from the table of the relationship between oxidation temperature T, oxidation time t and the oxidation weight gain per unit area ΔM into the lgΔM formula to obtain the values ​​of constants A, B, and C in the formula. Then, obtain the values ​​of the high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q through the formula (3).

[0095] Step 3: Using the titanium alloy sample obtained in Step 1 using the discontinuous weighing method, obtain scanning electron microscope (SEM) images of the titanium alloy sample with a high-temperature oxide layer metallographic cross-section under different high-temperature oxidation conditions. Specifically, the SEM images magnified 5000-20000 times are magnified 2-5 times in IPP software. The upper and lower boundaries of the high-temperature oxide layer are depicted in the magnified image. For boundaries whose morphology is difficult to determine, they need to be determined in conjunction with the elemental distribution of the titanium alloy. Thus, the thickness y of the high-temperature oxide layer of the titanium alloy sample after high-temperature oxidation is measured. Combining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of the titanium alloy sample obtained in Step 1, a table of the correspondence between the unit area oxidation weight gain value ΔM and the high-temperature oxide layer thickness y is obtained.

[0096] In determining the thickness of the oxide layer, at least 20 thickness data points at different locations of the titanium alloy sample are measured in each photograph, and the average value is taken to reduce the thickness measurement error.

[0097] Finally, the relationship between the high-temperature oxide layer thickness and the oxidation weight gain of the titanium alloy sample was obtained.

[0098] Step 4: Combining the Wanger formula for high-temperature oxidation weight gain and the relationship formula established in Step 3 regarding the relationship between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample, a model for high-temperature oxide layer thickness and oxidation weight gain per unit area is established. Based on the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction obtained in Step 2, the predicted value of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions is calculated. This achieves the prediction of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions. Specifically:

[0099] Still based on the Wanger formula (1) for the high-temperature oxidation weight gain, and the formula (2) obtained through formula (1) and the relationship between the oxidation weight gain per unit area ΔM and the oxidation temperature T and oxidation time t (3), with the high-temperature oxide layer thickness y as the vertical axis and the oxidation weight gain per unit area ΔM as the horizontal axis, a linear fit is performed to obtain the relationship curve between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM under different high-temperature oxidation conditions. Then, the relationship formula (6) between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM is obtained, which is the relationship formula between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample in step four:

[0100] y=A·ΔM+B (6),

[0101] Where: y is the thickness of the high-temperature oxide layer (10 -6 m); ΔM is the weight gain per unit area due to oxidation, in g·m -2 A and B are constants; at the same time, based on the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high-temperature oxide layer thickness y, the values ​​of constants A and B in the formula are obtained;

[0102] Furthermore, substituting formula (3) into relational formula (6), we obtain the high-temperature oxide layer thickness model (7) of the titanium alloy sample with high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q:

[0103]

[0104] Where: y is the thickness of the high-temperature oxide layer (10 -6 m); Q is the activation energy of the high-temperature oxidation reaction, in J·mol⁻¹. -1 T is the oxidation temperature in K; t is the oxidation time in min; R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 A and B are constants;

[0105] Combining the relationship equation (6) and the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high temperature oxide layer thickness y in step three, the values ​​of constants A and B in the formula are obtained. The high temperature oxidation kinetic power exponent n, frequency factor k0, and high temperature oxidation reaction activation energy Q of the titanium alloy sample are obtained using step two, and the high temperature oxide layer thickness of the titanium alloy sample is obtained.

[0106] Example 2: Same as Example 1, except that the titanium alloy is a titanium alloy reinforced with titanium boride whiskers, and the different high-temperature oxidation conditions used are as follows: oxidation temperatures of 960℃, 980℃ and 1000℃, respectively; oxidation times of 5min, 10min, 20min and 30min, respectively.

[0107] The titanium alloy matrix reinforced with boronized titanium whiskers is Ti55, and the volume fraction of the titanium boronized titanium whisker reinforcement is 3.5%. Its composition is as follows: TiB 3.606 wt.%, Ti 83.54 wt.%, Al 5.263 wt.%, Sn 3.586 wt.%, Zr 1.87 wt.%, Mo 0.961 wt.%, Nd 0.8 wt.%, and Si 0.255 wt.%, as shown in Table 1.

[0108] Take the titanium alloy sample reinforced with boride whiskers, and according to step two, obtain the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q value of the titanium alloy sample as follows:

[0109] n = 1.27, k0 = 1.3 × 10 8 Q = 191455 J·mol -1 Therefore, the equation relating the weight gain per unit area of ​​the titanium alloy sample by oxidation ΔM to the oxidation time t and oxidation temperature T is as follows:

[0110]

[0111] Using the calculation results of A and B in step four, A = 0.6 and B = -0.6 respectively, the formula for the relationship between the thickness y of the high-temperature oxide layer and the weight gain per unit area due to oxidation is:

[0112] y = 0.6ΔM - 0.6,

[0113] The high-temperature oxide layer thickness model is then obtained as follows:

[0114]

[0115] The weight gain per unit area of ​​the titanium alloy sample due to oxidation, ΔM, represents the mass of oxygen atoms in the high-temperature oxide layer. The main high-temperature oxidation product of the titanium alloy sample is TiO2, with minor products including a small amount of Al2O3 and incompletely oxidized titanium oxide Ti6O at high temperatures. If the composition of the high-temperature oxide layer is calculated based on TiO2, then the atomic mass ratio of oxygen in the high-temperature oxide layer is 2 / 5; ρ represents the density of TiO2, which is 4.26 g / cm³. 3 The theoretical reference thickness y of the obtained high-temperature oxide layer is:

[0116]

[0117] To further and better explain the present invention, the following specific experimental examples are provided:

[0118] A Ti55 titanium alloy matrix was used, with 3.5% titanium boride whisker reinforcement added. The composition is shown in Table 1.

[0119] Table 1 Chemical composition (wt.%)

[0120]

[0121] The calculation model for the high-temperature oxide layer thickness under atmospheric conditions based on 3.5 vol.% TiBw / Ti55 includes the following steps:

[0122] Step 1: Determine the relationship between oxidation weight gain and time / temperature under high-temperature conditions using a discontinuous weighing method: 3.5 vol.% TiBw / Ti55 titanium alloy wire cut into 10×10×10 mm block samples, polished with sandpaper from 240# to 1500#, ultrasonically cleaned with anhydrous ethanol for 10 min, dried in a vacuum drying oven at 80℃ for 60 min, and then placed in a crucible calcined to constant weight. All samples were weighed using an analytical balance with an accuracy of 0.1 mg and then placed in a high-temperature sintering furnace for high-temperature oxidation. The high-temperature oxidation temperatures were 960℃, 980℃, and 1000℃, with oxidation times of 5 min, 10 min, 20 min, and 30 min, respectively. Figure 4 As shown. After high-temperature oxidation and cooling to room temperature, the samples were weighed. Three samples were prepared for each parameter, and the average weight gain was calculated.

[0123] Step Two: As Figure 1 , Figure 2 As shown, the calculation of weight gain due to oxidation at high temperature is as follows: Figure 1 As shown in (a), to plot the relationship curve between lgΔM and lgt, as follows: Figure 1 As shown in (b), to plot the relationship curve between lgΔM and 1 / T, linear fitting was performed using Origin, and the results are as follows:

[0124] At an oxidation temperature of 960℃, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation over time is as follows:

[0125] 1.04lgΔM=0.596+lgt,

[0126] At an oxidation temperature of 980℃, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation over time is as follows:

[0127] 1.25lgΔM=1.340+lgt,

[0128] At an oxidation temperature of 1000℃, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation over time is as follows:

[0129] 1.38lgΔM=2.404+lgt,

[0130] Plot the curve of lgΔM versus 1 / T, and perform linear fitting using Origin. The results are as follows:

[0131] When the oxidation time is 10 min, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation is as follows with temperature:

[0132]

[0133] When the oxidation time is 20 min, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation is as follows with temperature:

[0134]

[0135] When the oxidation time is 30 min, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation is as follows with temperature:

[0136]

[0137] Since there is a linear relationship between lgΔM and lgt, and also a linear relationship between lgΔM and 1 / T, we obtain the following... Figure 2 The relationship between the oxidative weight gain per unit area ΔM and time T and temperature t shown can be expressed as lgΔM by lgt and 1 / T as formula (5):

[0138]

[0139] Substituting ΔM, T, and t from Table 2 into equation (5), we get A = -7889.7, B = 0.78897, and C = 6.40265.

[0140] Table 2

[0141]

[0142] The relationship between the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 due to oxidation and oxidation temperature and time is as follows:

[0143]

[0144] The above formula is transformed mathematically to obtain formula (8):

[0145]

[0146] Because constructing a high-temperature oxide layer thickness versus oxidation weight gain per unit area model for 3.5 vol.% TiBw / Ti55 requires precise data, high-temperature oxidation parameters with minimal surface peeling and moderate oxide layer thickness were selected to construct the model. The high-temperature oxide layer thickness versus oxidation weight gain per unit area for 3.5 vol.% TiBw / Ti55 under different high-temperature oxidation parameters, as shown in Table 3, was obtained through fitting. Figure 3 Table 3 was also obtained.

[0147] Table 3

[0148]

[0149]

[0150] The fitting result of the relationship between the thickness y of the high-temperature oxide layer and the weight gain per unit area due to oxidation is as follows:

[0151] y = 0.6ΔM - 0.6

[0152] Substituting formula (8) into the above formula, we get formula (9):

[0153]

[0154] When the oxidation temperature is 960℃ and the oxidation time is 30 min, the weight gain per unit area of ​​3.5 vol.% TiBw / Ti55 after oxidation is 8.17 g·m. -2 Substituting into formula (9), the calculated error between the high-temperature oxide layer thickness of 7.37 μm and the actual high-temperature oxide layer thickness of 8.17 μm is 9.8%.

[0155] This invention is the first to study the high-temperature oxide layer thickness of titanium alloys reinforced with boride whiskers under processing conditions. By combining heating time and heating temperature, the oxidation weight gain and high-temperature oxide layer thickness of the titanium alloy can be calculated quickly and conveniently. The fitting results are given a theoretical explanation and the prediction accuracy is good. In actual factory processing, real-time calculation and prediction can be performed, which helps to control the high-temperature oxide layer thickness in real time and improve the quality of components.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit 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 for predicting the thickness of a high-temperature oxide layer on titanium alloys at forging temperatures, characterized in that, Includes the following steps: Step 1: After grinding, ultrasonic cleaning, and drying the titanium alloy sample in sequence, high-temperature oxidation is carried out using a discontinuous weighing method under different high-temperature oxidation conditions; thereby obtaining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of the titanium alloy sample; the oxidation temperature T and oxidation time t of the high-temperature oxidation are consistent with the forging temperature and time of the titanium alloy sample. Step 2: Combining the Wanger formula for the weight gain during high-temperature oxidation and the relationship formula established from the relationship between different high-temperature oxidation conditions and the weight gain of the titanium alloy sample during high-temperature oxidation described in Step 1, calculate the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction for the titanium alloy sample under different high-temperature oxidation conditions. Specifically: The Wanger formula for the weight gain due to high-temperature oxidation is expressed as formula (1): (1)， In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k p (t) is the high-temperature oxidation rate constant at a certain time, with units of g. n ·m -2n ·h -1 t represents oxidation time, in minutes. In equation (1), k p (t) is: (2)， In the formula: k0 is the frequency factor; The activation energy for high-temperature oxidation reactions is expressed in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 · K -1 T represents the oxidation temperature, measured in K. Substituting equation (2) into equation (1), we obtain equation (3) relating the weight gain per unit area due to oxidation to the oxidation temperature T and oxidation time t: (3)， Taking the logarithm of both sides of equation (3), we get equation (4): (4)， In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k0 is the frequency factor; The activation energy for high-temperature oxidation reactions is expressed in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T represents the oxidation temperature, measured in K. t represents the oxidation time, in minutes. Plot the relationship between lgt as the abscissa and lgΔM as the ordinate, and plot the relationship between the weight gain per unit area under different high-temperature oxidation conditions and oxidation time; then plot the relationship between 1 / T as the abscissa and lgΔM as the ordinate, and plot the relationship between the weight gain per unit area under different high-temperature oxidation conditions and oxidation temperature. By linearly fitting these two relationship curves, the relationship curves between lgΔM and lgt and between lgΔM and 1 / T are established. Then, the lgΔM formula (5) expressed in terms of lgt and 1 / T is obtained, which is the formula for the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of titanium alloy samples described in step two: (5)， In the formula, A, B, and C are constants, and ΔM is the weight gain per unit area due to oxidation, in g·m². -2 T represents the oxidation temperature, measured in K. t is the oxidation time in minutes. Substitute the data from the table showing the relationship between oxidation temperature T, oxidation time t, and the oxidation weight gain per unit area ΔM into the lgΔM formula to obtain the values ​​of constants A, B, and C in the formula. Then, obtain the high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy through the formula (3). The value; Step 3: Using the titanium alloy sample obtained in Step 1 by the discontinuous weighing method, obtain scanning electron microscope images of the titanium alloy sample with a high-temperature oxide layer metallographic cross section under different high-temperature oxidation conditions, and obtain the relationship between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample. Step 4: Combining the Wanger formula for high-temperature oxidation weight gain and the relationship formula established from the relationship between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample described in Step 3, a model for high-temperature oxide layer thickness and oxidation weight gain per unit area is established. Based on the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and activation energy Q value of the high-temperature oxidation reaction of the titanium alloy sample obtained in Step 2, the predicted value of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions is calculated, thus realizing the prediction of the high-temperature oxide layer thickness of the titanium alloy sample under different high-temperature oxidation conditions.

2. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 1, characterized in that, The specific steps for obtaining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of titanium alloy samples in step one are as follows: The dried titanium alloy sample was weighed to obtain the original weight of the titanium alloy sample. Then, the titanium alloy sample was subjected to high-temperature oxidation under different high-temperature oxidation conditions. After the high-temperature oxidized titanium alloy sample was cooled to room temperature, it was weighed to obtain the weight of the high-temperature oxidized titanium alloy sample. The difference between the weight of the titanium alloy sample after high-temperature oxidation and the original weight of the titanium alloy sample is divided by the initial surface area of ​​the sample to obtain the oxidation weight gain per unit area ΔM of the titanium alloy sample. Subsequently, a table of correspondence between oxidation temperature T, oxidation time t and oxidation weight gain per unit area ΔM is established.

3. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 1, characterized in that, The titanium alloy sample was wire-cut into (5-12)×(5-12)×(5-12)mm block samples, polished with sandpaper from 240# to 1500#, ultrasonically cleaned with anhydrous ethanol for 10-30 minutes, dried in a vacuum drying oven at 60-120℃ for 30-120 minutes, and then placed in a high-temperature sintering furnace for high-temperature oxidation. The high-temperature oxidation treatment was carried out in a KSL-1200X box-type high-temperature sintering furnace; the oxidation temperature T in the high-temperature sintering furnace was 960-1000℃, and the oxidation time t was 5-30min; and under each high-temperature oxidation condition, at least three titanium alloy samples were prepared to calculate the average value of the oxidation weight gain per unit area ΔM of the titanium alloy samples.

4. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 2, characterized in that, The dried titanium alloy sample was placed in a corundum crucible that had been calcined to constant weight, and then weighed together with an analytical balance with an accuracy of 0.1 mg. After obtaining the original weight of the titanium alloy sample, it was subjected to high-temperature oxidation treatment.

5. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 1, characterized in that, The specific method for obtaining scanning electron microscope images of titanium alloy samples with metallographic cross-sections of high-temperature oxide layers under different high-temperature oxidation conditions in step three is as follows: Scanning electron microscope images magnified 5000-20000 times are magnified 2-5 times in image analysis software. The upper and lower boundaries of the high-temperature oxide layer are depicted in the magnified images. For boundaries whose morphology is difficult to determine, they need to be determined in conjunction with the elemental distribution of titanium alloy. The thickness y of the high-temperature oxide layer of the titanium alloy sample after high-temperature oxidation is measured. Combining the relationship between different high-temperature oxidation conditions and the high-temperature oxidation weight gain of titanium alloy samples obtained in step one, a table of the correspondence between the unit area oxidation weight gain ΔM and the high-temperature oxide layer thickness y is obtained. In determining the thickness of the oxide layer, at least 20 thickness data points at different locations of the titanium alloy sample are measured in each photograph, and the average value is taken to reduce the thickness measurement error.

6. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 1, characterized in that, The fourth step is specifically as follows: The Wanger formula for the weight gain due to high-temperature oxidation is expressed as formula (1): (1)， In the formula: ΔM is the weight gain per unit area due to oxidation, in g·m -2 n is the power exponent of high-temperature oxidation kinetics; k p (t) is the high-temperature oxidation rate constant at a certain time, with units of g. n ·m -2n ·h -1 t represents oxidation time, in minutes. In equation (1), k p (t) is: (2)， In the formula: k0 is the frequency factor; The activation energy for high-temperature oxidation reactions is expressed in J·mol⁻¹. -1 R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 T represents the oxidation temperature, measured in K. Substituting equation (2) into equation (1), we obtain equation (3) relating the weight gain per unit area due to oxidation to the oxidation temperature T and oxidation time t: (3)， Using the high-temperature oxide layer thickness y as the ordinate and the oxidation weight gain per unit area ΔM as the abscissa, a linear fit was performed to obtain the relationship curves between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM under different high-temperature oxidation conditions. Thus, the relationship formula (6) between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM was obtained, which is the relationship formula between the high-temperature oxide layer thickness and oxidation weight gain of the titanium alloy sample in step four: (6)， In the formula: y is the thickness of the high-temperature oxide layer (10 -6 m); ΔM is the weight gain per unit area due to oxidation, in g·m -2 A and B are constants; at the same time, based on the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high-temperature oxide layer thickness y, the values ​​of constants A and B in the formula are obtained; Furthermore, substituting formula (3) into relational formula (6), we obtain the high-temperature oxide layer thickness model (7) of the titanium alloy sample with high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q: (7)， In the formula: y is the thickness of the high-temperature oxide layer (10 -6 m); The activation energy for high-temperature oxidation reactions is expressed in J·mol⁻¹. -1 T represents the oxidation temperature, measured in K. t is the oxidation time in minutes; R is the gas constant, R = 8.3145 J·mol⁻¹ -1 ·K -1 A and B are constants; Combining the relationship formula (6) and the data in the table of correspondence between the unit area oxidation weight gain value ΔM and the high temperature oxide layer thickness y in step three, the values ​​of constants A and B in the formula are obtained. Then, the high temperature oxidation kinetic power exponent n, frequency factor k0, and high temperature oxidation reaction activation energy Q of the titanium alloy sample are obtained using step two, and the high temperature oxide layer thickness of the titanium alloy sample is obtained.

7. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in any one of claims 1-6, characterized in that, The titanium alloy is a titanium alloy reinforced with titanium boride whiskers, and the different high-temperature oxidation conditions used are as follows: oxidation temperatures of 960℃, 980℃ and 1000℃, respectively; and oxidation times of 5min, 10min, 20min and 30min, respectively.

8. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 7, characterized in that, The titanium alloy matrix reinforced with boronized titanium whiskers is Ti55, and the volume fraction of the titanium boronized titanium whisker reinforcement is 3.5%, with the following composition: TiB 3.606 wt.%, Ti 83.54 wt.%, Al 5.263 wt.%, Sn 3.586 wt.%, Zr 1.87 wt.%, Mo 0.961 wt.%, Nd 0.8 wt.%, and Si 0.255 wt.%. Take the titanium alloy sample reinforced with boride whiskers, and according to step two, obtain the corresponding high-temperature oxidation kinetic power exponent n, frequency factor k0, and high-temperature oxidation reaction activation energy Q value of the titanium alloy sample as follows: n=1.27, k0=1.3×10 8 Q = 191455 J·mol -1 Therefore, the equation relating the weight gain per unit area of ​​the titanium alloy sample by oxidation ΔM to the oxidation time t and oxidation temperature T is as follows: ， Using the calculation results of A and B in step four, A=0.6 and B=-0.6 respectively, the formula for the relationship between the high-temperature oxide layer thickness y and the oxidation weight gain per unit area ΔM is: ， The high-temperature oxide layer thickness model is then obtained as follows: 。 9. The method for predicting the thickness of the high-temperature oxide layer of titanium alloy at the forging temperature as described in claim 8, characterized in that, The weight gain per unit area of ​​the titanium alloy sample due to oxidation, ΔM, represents the mass of oxygen atoms in the high-temperature oxide layer. The main high-temperature oxidation product of the titanium alloy sample is TiO2, with minor products including a small amount of Al2O3 and incompletely oxidized titanium oxide Ti6O at high temperatures. If the composition of the high-temperature oxide layer is calculated based on TiO2, then the atomic mass ratio of oxygen in the high-temperature oxide layer is 2 / 5; ρ represents the density of TiO2, which is 4.26 g / cm³. 3 The theoretical reference thickness y of the high-temperature oxide layer is: 。

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