Die forging titanium alloy blade disc double-structure distribution optimization method combined with finite element technology

Abstract

The invention discloses a die forging titanium alloy blade disc double-structure distribution optimization method combined with a finite element technology. The method comprises the following steps that a thermal simulation compression experiment is conducted on a titanium alloy basket structure through an isothermal constant-strain-rate thermal simulation compression testing machine; carrying out microstructure detection on the sample subjected to thermal simulation compression, and quantitatively characterizing the dynamic spheroidizing volume fraction; establishing a dynamic spheroidizing volume fraction mathematical model based on actually measured dynamic spheroidizing volume fraction data; introducing the dynamic spheroidizing volume fraction mathematical model into finite element numerical simulation software through secondary development; finite element numerical simulation optimization is carried out on spheroidizing volume fractions of a wheel disc part, a blade part and a connecting part of the wheel disc part and the blade part in the controllable strain isothermal die forging process of the titanium alloy blade disc by utilizing finite element software subjected to secondary development; and finally, shape / property integrated regulation and control of shape control of a finite element of the controllable strain isothermal die forging titanium alloy blade disc and shape / property integrated regulation and control of double-structure distribution and double-structure distribution are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy materials, and in particular to a method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk in combination with finite element technology. Background Art

[0002] The aviation titanium alloy blade disk is one of the key hot end components of the aircraft engine, including blades and disks. The working conditions of the blade disk are extremely special. The blades of the blade disk are in contact with high-temperature gas and are subjected to high-frequency vibrations. They need to have good high-temperature creep resistance and fatigue crack growth resistance. On the contrary, the disk has a relatively low operating temperature, but is subjected to very high stress levels. It needs to have high tensile strength and fracture toughness. Therefore, the actual working conditions of the blade disk require that it should have a dual performance distribution of blades and disks.

[0003] When a gradient dual-structure distribution of equiaxial structure in the disc part, basket structure in the blade part and gradual transition structure along the diameter direction is formed on the titanium alloy integral turbine disk through controlled strain isothermal forging, not only can the turbine disk have a dual-performance distribution of high strength and toughness in the disc part and excellent resistance to high-temperature creep and fatigue crack propagation in the blade part, but also a gradient performance connection between the blade and the disc can be obtained.

[0004] The development and production are mainly carried out based on experience and repeated trial production, which has a long R&D cycle, high cost and poor reliability. At present, the shape and size changes of titanium alloy controlled strain isothermal die forging compressor blades and the internal forming parameters of the blades can be made "visual" and "controllable" by using computer simulation technology. By introducing the secondary development based on the dynamic spheroidization volume fraction mathematical model into the finite element numerical simulation software, it can not only simulate the controlled strain isothermal die forging forming process of the compressor blade, but also simulate and predict the function of the evolution of the internal spheroidization volume fraction of each part of the blade. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems existing in the prior art and provide a method for optimizing the dual-structure distribution of a die-forged titanium alloy blade disk by combining finite element technology.

[0006] To achieve the above object, the technical solution provided by the present invention is: the present invention provides a method for optimizing the dual-structure distribution of a die-forged titanium alloy blade disk combined with finite element technology, the method comprising the following steps:

[0007] Step 1: Perform a thermal simulation compression test on the titanium alloy basket structure using an isothermal constant strain rate thermal simulation compression testing machine to obtain a sample;

[0008] Step 2: Conduct microstructure testing on the sample after the thermal simulation compression test to quantitatively characterize the dynamic spheroidization volume fraction;

[0009] Step 3: Based on the measured dynamic spheroidization volume fraction data, a dynamic spheroidization volume fraction mathematical model is established;

[0010] Step 4: Introduce the dynamic spheroidization volume fraction mathematical model in step 3 into the finite element numerical simulation software through secondary development;

[0011] Step 5. Use the finite element numerical simulation software after secondary development to perform finite element numerical simulation optimization on the spheroidization volume fraction distribution of the disk, blade and connection parts during the controlled strain isothermal forging process of the titanium alloy blade.

[0012] Preferably, the thermal deformation temperature range of the thermal simulation compression test in step 1 is 700-880°C, and the strain rate range is 0.001-1s -1 , the strain range is 10% to 70%. After thermal deformation, the sample is immediately water quenched to retain its high-temperature deformation structure; the sample is cooled by water after thermal deformation.

[0013] Preferably, in step 2, the dynamic spheroidization area fraction is used to represent the dynamic spheroidization volume fraction, and the dynamic spheroidization volume fraction is measured 5 times, and the arithmetic mean is taken.

[0014] Preferably, the dynamic spheroidization volume fraction mathematical model in step 3 adopts the Avrami equation:

[0015]

[0016] Where X is the dynamic spheroidization volume fraction, k and n are material parameters; ε c is the critical strain of dynamic spheroidization, ε 0.5 is the strain when the spheroidization fraction reaches 50%.

[0017]

[0018] Where A1 and A2 are constants, ε is the strain rate, Q is the activation energy, R is the gas constant, whose value is about 8.314 J / (mol·K), and T is the deformation temperature.

[0019]

[0020] In the formula, B1, B 2、 Q1 is a constant.

[0021] Preferably, the material parameters k and n in equation (1) are solved as follows: Taking the natural logarithm of both sides of equation (1), we can get Then take ln[-ln(1-X)] as the ordinate, ln[(ε-ε c ) / ε 0.5] as the horizontal axis, plot ln[-ln(1-X)] and ln[(ε-ε c ) / ε 0.5 ] relationship curve, and perform linear fitting. The n value can be used as the slope of the fitting line, and the lnk value is the intercept of the line, so the k value can be obtained.

[0022] Preferably, the finite element numerical simulation software in step 4 is DEFORM 3D 6.1.

[0023] Preferably, the isothermal forging die for the controlled strain isothermal forging of the titanium alloy blade disk in step 5 includes two forming dies and two punches, and the two forming dies and two punches are buckled together to form a forming cavity for placing the preform and controlling the shape of the blade part of the blade disk.

[0024] Preferably, the controllable strain isothermal forging parameters in step 5 are: the forging temperature range is 700-880°C, and the punch pressing rate range is 0.05-0.4 mm / min.

[0025] Beneficial effects of the present invention:

[0026] The present invention optimizes the controllable strain isothermal forging process and its parameters from the perspective of forming a dual-tissue distribution inside the blade disk through the synergy of finite element technology and deformation induced basket tissue spheroidization, thereby realizing the integrated shape / property regulation of the controlled strain isothermal forging titanium alloy blade disk by finite element "shape control" and dual-tissue distribution "property control". BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 Schematic diagram of controlled strain isothermal forging of titanium alloy turbine disk;

[0029] Figure 2 Schematic diagram for comparing turbine disk preforms with different initial heights;

[0030] Figure 3 The finite element numerical simulation comparison results of the spheroidization fraction distribution of turbine disks after controlled strain die forging of preforms with different initial heights;

[0031] Figure 4 The finite element numerical simulation comparison results of the spheroidization fraction distribution of turbine discs after controlled strain die forging at different die forging temperatures;

[0032] Figure 5 The finite element numerical simulation comparison results of the spheroidization fraction distribution of turbine disk after controlled strain forging at different punch reduction rates. DETAILED DESCRIPTION

[0033] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0034] Reference Figure 1-Figure 5 The preferred embodiment of the present invention is a method for optimizing the dual-organization distribution of a forged titanium alloy blade disk in combination with finite element technology, wherein the method performs a thermal simulation compression experiment on a titanium alloy basket structure by using an isothermal constant strain rate thermal simulation compression testing machine; performs microstructure detection on the sample after thermal simulation compression to quantitatively characterize the dynamic spheroidization volume fraction; establishes a dynamic spheroidization volume fraction mathematical model based on the measured dynamic spheroidization volume fraction data; introduces the above-mentioned dynamic spheroidization volume fraction mathematical model into the finite element numerical simulation software through secondary development; uses the finite element software after secondary development to perform finite element numerical simulation optimization on the spheroidization volume fraction of the wheel disc, blade part and its connection part during the controlled strain isothermal forging of the titanium alloy blade disk, and finally realizes the shape / property integrated regulation of the finite element "shape control" and the dual-organization distribution "property control" of the controlled strain isothermal forging titanium alloy blade disk.

[0035] The specific steps of the method are as follows:

[0036] Step 1: Perform a thermal simulation compression test on the titanium alloy basket structure using an isothermal constant strain rate thermal simulation compression testing machine to obtain a sample;

[0037] Step 2: Conduct microstructure testing on the sample after the thermal simulation compression test to quantitatively characterize the dynamic spheroidization volume fraction;

[0038] Step 3: Based on the measured dynamic spheroidization volume fraction data, a dynamic spheroidization volume fraction mathematical model is established;

[0039] Step 4: Introduce the dynamic spheroidization volume fraction mathematical model in step 3 into the finite element numerical simulation software through secondary development;

[0040] Step 5. Use the finite element numerical simulation software after secondary development to perform finite element numerical simulation optimization on the spheroidization volume fraction distribution of the disk, blade and connection parts during the controlled strain isothermal forging process of the titanium alloy blade.

[0041] Furthermore, the thermal deformation temperature range of the thermal simulation compression experiment in step 1 is 700-880°C, and the strain rate range is 0.001-1s -1 , the strain range is 10% to 70%. After thermal deformation, the sample is immediately water quenched to retain its high-temperature deformation structure; the sample is cooled by water after thermal deformation.

[0042] Furthermore, in step 2, the dynamic spheroidization area fraction is used to represent the dynamic spheroidization volume fraction, and the dynamic spheroidization volume fraction is measured 5 times, and the arithmetic mean is taken.

[0043] Furthermore, the mathematical model of the dynamic spheroidization volume fraction in step 3 adopts the Avrami equation:

[0044]

[0045] Where X is the dynamic spheroidization volume fraction, k and n are material parameters; ε c is the critical strain of dynamic spheroidization, ε 0.5 is the strain when the spheroidization fraction reaches 50%.

[0046]

[0047] In the formula, A1 and A2 are constants, is the strain rate, Q is the activation energy, R is the gas constant, which is about 8.314 J / (mol·K), and T is the deformation temperature.

[0048]

[0049] In the formula, B1, B 2、 Q1 is a constant.

[0050] Furthermore, the material parameters k and n in equation (1) can be solved as follows: Taking the natural logarithm of both sides of equation (1), we can get Then take ln[-ln(1-X)] as the ordinate, ln[(ε-ε c ) / ε 0.5 ] as the horizontal axis, plot ln[-ln(1-X)] and ln[(ε-ε c ) / ε 0.5 ] relationship curve, and perform linear fitting. The n value can be used as the slope of the fitting line, and the lnk value is the intercept of the line, so the k value can be obtained.

[0051] Furthermore, the finite element numerical simulation software in step 4 is DEFORM 3D 6.1.

[0052] Furthermore, the isothermal forging die for the controlled strain isothermal forging of the titanium alloy blade disk in step 5 includes two forming dies and two punches, and the two forming dies and two punches are buckled together to form a forming cavity for placing the preform and controlling the shape of the blade part of the blade disk.

[0053] Specifically, Figure 1As shown, the two punches have the same shape and size, and the end of the punch is provided with a gradient width, which corresponds to the gradient width of the blade disk connection part after the final forming, and is used to control the shape of the blade disk wheel part and the connection part. The two punches are extruded toward the preform at the same rate until the blade disk wheel part reaches the preset thickness, and finally the blade disk product is obtained.

[0054] Furthermore, the controllable strain isothermal forging parameters in step five are as follows: the forging temperature range is 700-880° C., and the punch pressing rate range is 0.05-0.4 mm / min.

[0055] Example 1

[0056] Preferably, the titanium alloy blade disk is a TC18 titanium alloy blade disk.

[0057] 1) The isothermal constant strain rate thermal simulation compression test was carried out on the basketweave TC18 titanium alloy using a Gleeble-3800 thermal simulation compression testing machine. The deformation temperatures were 700℃, 720℃, 740℃, 760℃, 780℃, 800℃, 820℃, 840℃, 860℃, and 880℃, with a temperature interval of 20℃; the strain rate was 0.001s -1 、0.01s -1 , 0.1s -1 , 1s -1 ; The deformation amount is 10%, 20%, 30%, 40%, 50%, 60%, 70%, and the deformation interval is 10%.

[0058] 2) The microstructure of the samples after thermal simulation compression was tested. The dynamic spheroidization area fraction was used to represent the dynamic spheroidization volume fraction. The dynamic spheroidization volume fraction was quantitatively measured. The dynamic spheroidization volume fraction was measured 5 times and the arithmetic mean was taken.

[0059] 3) Based on the measured dynamic spheroidization volume fraction data, according to the Avrami equation Fitting material parameters k and n, and establishing a mathematical model of dynamic spheroidization volume fraction:

[0060]

[0061] ε is the dynamic spheroidization strain, ε c is the critical strain of dynamic spheroidization, ε 0.5 is the strain when the spheroidization fraction reaches 50%, is the strain rate, Q is the activation energy, R is the gas constant, which is about 8.314 J / (mol·K), and T is the deformation temperature.

[0062] 4) The established dynamic spheroidization volume fraction mathematical model was introduced into the DEFORM 3D6.1 finite element numerical simulation software through secondary development;

[0063] 5) The finite element software after secondary development was used to perform finite element numerical simulation optimization on the spheroidized volume fraction of the wheel disc, blade and connection parts during the controlled strain isothermal forging process of the titanium alloy blade. The controlled strain isothermal forging parameters are as follows: the forging temperature range is 700-880℃, and the punch pressing rate range is 0.05-0.4mm / min. The schematic diagram of controlled strain isothermal forging is shown in the figure. Figure 1 As shown in the figure, a series of turbine disk preforms with different initial heights at the wheel disk part are set, and then the preforms are subjected to controlled strain isothermal die forging. In this way, the influence of the initial height of the wheel disk part on the distribution of the spheroidization fraction of the turbine disk forged by controlled strain isothermal die forging can be predicted and optimized by finite element numerical simulation. Figure 3 Given an initial height of 400 mm ( Figure 3 (a)) and the initial height is 600 mm ( Figure 3 (b) Comparison results of finite element numerical simulation of the spheroidization fraction distribution of turbine disk after controlled strain die forging of preform.

[0064] 6) The finite element software after secondary development is used to perform finite element numerical simulation on the distribution of spheroidization fraction of controlled strain isothermal forged turbine disks at different forging temperatures. In this way, the influence of forging temperature on the distribution of spheroidization fraction of controlled strain isothermal forged turbine disks can be predicted and optimized through finite element numerical simulation. Figure 4 The die forging temperature is 700℃( Figure 4 (a)) and die forging temperature is 850℃( Figure 4 (b) Comparison results of finite element numerical simulation of the spheroidization fraction distribution of turbine disk after controlled strain die forging.

[0065] 7) The finite element software after secondary development is used to perform finite element numerical simulation on the distribution of spheroidization fraction of controlled strain isothermal forging turbine disks under different punch reduction rates. In this way, the influence of punch reduction rate on the distribution of spheroidization fraction of controlled strain isothermal forging turbine disks can be predicted and optimized through finite element numerical simulation. Figure 5 The punch pressing rate is given as 0.4 mm / min ( Figure 5 (a)) and the punch pressing rate is 0.1mm / min( Figure 5 (b) Comparison results of finite element numerical simulation of the spheroidization fraction distribution of turbine disk after controlled strain die forging.

[0066] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0067] The above description is only a preferred implementation mode of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means belongs to the protection scope of the present invention.

Claims

1. A method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk in combination with finite element technology, characterized in that: The method comprises the following steps: Step 1: Perform a thermal simulation compression test on the titanium alloy basket structure using an isothermal constant strain rate thermal simulation compression testing machine to obtain a sample; Step 2: Conduct microstructure testing on the sample after the thermal simulation compression test to quantitatively characterize the dynamic spheroidization volume fraction; Step 3: Based on the measured dynamic spheroidization volume fraction data, a dynamic spheroidization volume fraction mathematical model is established; Step 4: Introduce the dynamic spheroidization volume fraction mathematical model in step 3 into the finite element numerical simulation software through secondary development; Step 5. Use the finite element numerical simulation software after secondary development to perform finite element numerical simulation optimization on the spheroidization volume fraction distribution of the disk, blade and connection parts during the controlled strain isothermal forging process of the titanium alloy blade.

2. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk combined with finite element technology according to claim 1, characterized in that: The thermal deformation temperature range of the thermal simulation compression test in step 1 is 700-880°C, and the strain rate range is 0.001-1s -1 , the strain range is 10% to 70%. After thermal deformation, the sample is immediately water quenched to retain its high-temperature deformation structure; the sample is cooled by water after thermal deformation.

3. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk combined with finite element technology according to claim 1, characterized in that: In step 2, the dynamic spheroidization area fraction is used to represent the dynamic spheroidization volume fraction. The dynamic spheroidization volume fraction is measured 5 times and the arithmetic mean is taken.

4. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk combined with finite element technology according to claim 1, characterized in that: The mathematical model of dynamic spheroidization volume fraction in step 3 adopts the Avrami equation: Where X is the dynamic spheroidization volume fraction, k and n are material parameters; ε c is the critical strain of dynamic spheroidization, ε 0.5 is the strain when the spheroidization fraction reaches 50%. In the formula, A1 and A2 are constants, is the strain rate, Q is the activation energy, R is the gas constant, which is about 8.314 J / (mol·K), and T is the deformation temperature. In the formula, B1, B 2、 Q1 is a constant.

5. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk in combination with finite element technology according to claim 4, characterized in that: The material parameters k and n in equation (1) are solved as follows: Taking the natural logarithm of both sides of equation (1), we can get Then take ln[-ln(1-X)] as the ordinate, ln[(ε-ε c ) / ε 0.5 ] as the horizontal axis, plot ln[-ln(1-X)] and ln[(ε-ε c ) / ε 0.5 ] relationship curve, and perform linear fitting. The n value can be used as the slope of the fitting line, and the lnk value is the intercept of the line, so the k value can be obtained.

6. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk combined with finite element technology according to claim 1, characterized in that: The finite element numerical simulation software in step 4 is DEFORM 3D 6.

1.

7. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk in combination with finite element technology according to claim 1, characterized in that: In step 5, the isothermal forging die for the controlled strain isothermal forging of the titanium alloy blade disk includes two forming dies and two punches, and the two forming dies and two punches are buckled together to form a forming cavity for placing the preform and controlling the shape of the blade part of the blade disk.

8. The method for optimizing dual-structure distribution of a die-forged titanium alloy blade disk in combination with finite element technology according to claim 7, characterized in that: The controllable strain isothermal forging parameters in step 5 are as follows: the forging temperature range is 700-880°C, and the punch pressing rate range is 0.05-0.4 mm / min.

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