Hard and brittle ceramic matrix composite micro-hole energy field auxiliary machining method

Abstract

The invention discloses a hard brittle ceramic matrix composite material micro-hole energy field auxiliary processing method, which is characterized in that micro bottom holes are rapidly processed through laser ablation, the material removal allowance of subsequent hole processing is reduced, and the problems of low cutter rigidity and easiness in breaking in the hard brittle ceramic matrix composite material micro-hole processing process can be solved. And meanwhile, after the laser bottom hole is machined, ultrasonic-assisted drilling is selected for fine machining of the micro hole, and the quality of the micro hole is guaranteed. The method is based on laser ablation finite element simulation, ultrasonic knife handle modal simulation and ultrasonic-assisted micro-hole drilling simulation, verification and correction are carried out through a small number of groups of tests, the test workload in previous drilling research is greatly reduced, the dependence of selection of technological parameters on engineering technical experience is reduced, and the working efficiency is improved. And data and rules with a wider process parameter range can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of hard-brittle composite material processing, and in particular relates to a micro-pore energy field assisted processing method of a hard-brittle ceramic-based composite material. Background Art

[0002] Hard-brittle ceramic matrix composites are a type of ceramic matrix composites that have been developed in recent years and are reinforced by hard fibers. While retaining the characteristics of ceramic materials such as high temperature resistance, oxidation resistance, wear resistance, and low density, the presence of hard reinforcing fibers enhances the toughness of the material and significantly improves its impact load resistance. Advanced hard-brittle ceramic matrix composites can operate at temperatures of 1200°C to 1500°C without the use of air film hole cooling and thermal barrier coatings, and their density is only 1 / 3 of that of high-temperature alloys, making them extremely promising for application in industries such as aerospace, automobile manufacturing, and transportation.

[0003] With the continuous development and progress of the preparation process of ceramic matrix composites, the densification degree of materials has been significantly improved. For example, ceramic matrix composites prepared by reactive / non-reactive melt infiltration (RMI / MI) have higher density and lower porosity than those prepared by chemical vapor infiltration (CVI) and polymer impregnation pyrolysis (PIP). Correspondingly, RMI / MI ceramic matrix composites have slightly higher density, better wear resistance, and worse machinability. Ceramic matrix composites have excellent high temperature resistance and great application prospects in the aerospace field. They are one of the ideal materials for key parts in the high temperature section of aerospace.

[0004] Air film hole processing, especially micro-hole processing with a diameter less than Φ1.0mm, is the main task of processing and manufacturing high-temperature parts in aerospace. However, due to the high hardness of ceramic-based composite materials, which is higher than the hardness of commonly used cutting tools and the strong wear resistance of the material, ceramic-based composite materials face a series of difficulties when processing micro-holes, such as: poor material machinability, severe tool wear, and even difficulty in cutting materials; the drill bit is prone to slipping and breaking when drilling into the surface of the ceramic-based composite material, and it is not easy to drill into micro-holes; the ceramic-based composite material prepared by the CVI / PIP process has a high porosity and an uneven distribution inside the material. The drill bit is subjected to uneven force during the drilling process and is prone to breaking and getting stuck during the drilling process; the micro-hole has a small diameter (Φ0.7mm, Φ0.5mm), a large aspect ratio, and a low stiffness of the drilling tool; current research is mainly based on trial and error, with a large amount of experiments, and parameter matching and optimization are still one of the current difficulties in the processing of ceramic-based composite materials.

[0005] Chinese patent application CN111002483A discloses a method for processing holes on ceramic-based composite components and a punching mechanism, which is used to make holes in the preform of the ceramic-based composite component before the CVI process, with a hole diameter range of 1.2mm to 40mm. The preform has a lower hardness than the material after the CVI process, is easy to process, and has a large hole diameter and low processing difficulty. Chinese patent application CN115848616A discloses a ceramic-based composite rudder shaft connection structure and its hole making tooling and riveting hole making method, wherein the diameter of the ceramic-based composite drilling hole is much larger than the size of the micro-hole (D≤Φ1.0mm). However, there is no relevant report on the processing of micro-holes (D≤Φ1.0mm) of ceramic-based composite materials with higher density prepared by RMI / MI process. The tool stiffness is low and easy to break during the processing of micro-holes of hard and brittle ceramic-based composite materials, the test volume is large, and the selection of processing parameters depends more on engineering and technical experience, which cannot achieve efficient and high-quality processing of micro-holes of ceramic-based composite materials. Summary of the invention

[0006] In view of this, in order to overcome the problems of poor tool stiffness and easy breakage during the processing of micro-holes in ceramic-based composite materials, especially denser ceramic-based composite materials prepared by RMI / MI process, large amount of process exploration experiments, low target orientation, etc., the present invention provides a method for energy field-assisted processing of micro-holes in hard and brittle ceramic-based composite materials, the method comprising:

[0007] Step 1): constructing a finite element model for millisecond laser ablation simulation of ceramic matrix composites;

[0008] Step 2): According to the ablation diameter D and the peak laser energy density F pk The relationship function, formula (1), calculates the required peak laser energy density F corresponding to different laser processing hole diameters. pk :

[0009]

[0010] Step 3): Calculate the peak laser energy density F corresponding to different laser processing hole diameters pk As the initial reference value, with the help of the finite element model constructed in step 1), the laser ablation simulation analysis of ceramic matrix composites is carried out to obtain the generalized inward heat flux H, as shown in formula (2):

[0011] H=η(x-x0)*P*λ(t) (2)

[0012] Where η is the Gaussian distribution function, which is used to simulate the laser energy density distribution; P is the laser energy density, which is calculated as follows: P = P_total / (pi*r 2*k), P_total is the total laser power, r is the spot radius, k is the laser frequency; λ is a sawtooth wave function used to simulate the energy change of pulsed laser over time;

[0013] Step 4): Conduct laser ablation tests on a small number of ceramic matrix composites and compare and verify the laser ablation simulation results;

[0014] Step 5): According to the test results of step 4), the finite element simulation analysis of step 3) is reasonably corrected, and step 3) is repeated to comprehensively consider the processing efficiency of laser processing of the material to obtain the corresponding relationship between the corrected laser processing hole diameter and the laser processing parameters;

[0015] Step 6): constructing a finite element simulation model of ultrasonic-assisted drilling of ceramic matrix composites;

[0016] Step 7): Based on the finite element simulation model constructed in step 6), a modal simulation analysis is performed on the ultrasonic tool holder and the drilling tool to obtain a suitable tool clamping overhang and ultrasonic vibration parameter range;

[0017] Step 8): With the help of the finite element simulation model of step 6), the tool clamping overhang and ultrasonic vibration parameter range of step 7, and the laser processing hole diameter of step 5), carry out finite element simulation of ultrasonic assisted drilling of ceramic matrix composite materials;

[0018] Step 9): With the help of a neural network algorithm, a mapping relationship between the laser processing hole diameter, ultrasonic assisted drilling process parameters and the micro-hole diameter is constructed;

[0019] Step 10): Conduct ultrasonic assisted drilling tests on a small number of ceramic matrix composite materials to verify the mapping relationship obtained in step 9), and modify the model in step 9) according to the test results;

[0020] Step 11): Based on the modified mapping model obtained in step 10) and the target aperture size of the micro-hole, the diameter of the laser-processed hole and the ultrasonic-assisted drilling process parameters of the ceramic-based composite material are determined;

[0021] Step 12): Determine laser processing parameters according to the laser processing hole diameter determined in step 11) and the corresponding relationship between the laser processing hole diameter and the laser processing parameters in step 5);

[0022] Step 13): According to the laser processing parameters and ultrasonic-assisted drilling process parameters determined in step 11) and step 12), micro-hole processing of the ceramic-based composite material is performed.

[0023] Furthermore, in step 1), a millisecond laser ablation simulation finite element model of SiC / SiC ceramic matrix composites prepared by RMI process is constructed in Comsol Multiphysics 5.0 multi-physics field finite element simulation software.

[0024] Further, in step 2), the hot melt ablation F of the ceramic matrix composite material th Take 0.30J / cm 2 .

[0025] Furthermore, in step 4) and step 10), the small number of groups is 2 or 3 groups.

[0026] Furthermore, in step 4) and step 10), the small number of groups is 2 groups.

[0027] Furthermore, in step 7), the tool clamping overhang is 20 to 30 mm, and the ultrasonic frequency range is 20 kHz to 40 kHz.

[0028] Further, in step 9), the mapping relationship between the laser processing hole diameter, ultrasonic assisted drilling process parameters and micro-hole diameter;

[0029] D=0.4802·d 0.03026 ·n 0.0088 ·f -0.00366 (3)

[0030] Where D is the micro-hole diameter, d is the laser processed hole diameter, n is the spindle speed, and f is the feed speed.

[0031] Further, in step 12), the millisecond laser processing parameters are: peak power 1000W, scanning speed 1mm / s, repetition frequency 144Hz, pulse width 0.5ms, blowing pressure 0.8MPa, scanning times 6 times, the first 3 processing diameters are Φ0.14mm, the defocus is 0mm, the last 3 processing diameters are Φ0.16mm, the defocus is -1.5mm, and the laser processing bottom hole diameter is Φ0.30mm.

[0032] Furthermore, in step 13), the ultrasonic assisted drilling parameters are: spindle speed 13100 r / min, feed speed 6 mm / min, vibration frequency 29.6 kHz, amplitude 2.1 μm.

[0033] The beneficial effects of the present invention are as follows:

[0034] 1. The method of the present invention uses laser ablation to quickly process tiny bottom holes, reducing the amount of material removed in subsequent hole processing, and can solve the problems of low tool stiffness and easy breakage in the process of tiny hole processing of hard and brittle ceramic-based composite materials; at the same time, after laser bottom hole processing, ultrasonic assisted drilling is used to perform fine processing of the tiny holes to ensure the quality of the tiny holes.

[0035] 2. The method of the present invention is based on laser ablation finite element simulation, ultrasonic tool holder modal simulation, and ultrasonic-assisted micro-hole drilling simulation, and is verified and corrected through a small number of test groups. It greatly reduces the experimental workload in previous drilling research, reduces the dependence of process parameter selection on engineering technical experience, and can obtain data and rules with a wider range of process parameters, which is impossible to achieve in actual processing test research. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the technical route of the micro-pore energy field assisted processing method of the hard and brittle ceramic-based composite material of the present invention.

[0037] Figure 2 This is a comparison chart of the porosity / density of CVI ceramic-based composites and RMI ceramic-based composites.

[0038] Figure 3 It is a schematic diagram of the correlation between the ablation area and the laser energy density.

[0039] Figure 4 It is a finite element simulation diagram of laser ablation simulation of ceramic matrix composite materials.

[0040] Figure 5 is the Gaussian distribution function.

[0041] Figure 6 is a sawtooth wave function.

[0042] Figure 7 It is a finite element simulation model of ultrasonic assisted drilling.

[0043] Figure 8 It is a schematic diagram of the structure of ultrasonic assisted drilling tool.

[0044] Fig. 9 It is the modal finite element analysis diagram of ultrasonic assisted drilling tool holder.

[0045] Fig.10 This is the finite element analysis diagram of laser ablation of ceramic matrix composites.

[0046] Fig.11 It is a diagram of ultrasonic assisted drilling of ceramic matrix composites.

[0047] Fig.12 This is a picture of tiny holes in a ceramic-based composite material obtained by processing in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings of the specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] The present invention provides a method for energy field-assisted processing of micro-holes in hard and brittle ceramic-based composite materials. The method is based on laser ablation finite element simulation, ultrasonic toolholder modal simulation, and ultrasonic-assisted micro-hole drilling simulation, and is verified and corrected through a small number of test groups, which greatly reduces the experimental workload in previous drilling research, reduces the dependence of process parameter selection on engineering technical experience, and can obtain data and rules with a wider range of process parameters. Figure 1 The schematic diagram of the technical route of the micro-pore energy field assisted processing method of the hard and brittle ceramic matrix composite material of the present invention is shown in FIG. Figure 2 The pore / density comparison of CVI ceramic matrix composites and RMI ceramic matrix composites is shown schematically in Figure 3 middle.

[0050] The following is an explanation using SiC / SiC ceramic matrix composite material as an example.

[0051] This embodiment provides a method for micro-pore energy field assisted processing of hard and brittle ceramic matrix composite materials, comprising:

[0052] Step 1): constructing a millisecond laser ablation simulation finite element model of SiC / SiC ceramic matrix composites prepared by RMI process in Comsol Multiphysics 5.0 multi-physics field finite element simulation software; Figure 4 The finite element simulation diagram of laser ablation of ceramic matrix composite materials is shown in the figure, and the main parameters of the finite element simulation model are shown in Table 1 below;

[0053] Table 1 Main parameters of finite element simulation model

[0054]

[0055] Step 2): According to the ablation diameter D and the peak laser energy density F pk The relationship function, formula (1), calculates the required peak laser energy density F corresponding to different laser processing hole diameters. pk Among them, the hot melt ablation of SiC / SiC ceramic matrix composites th Take 0.30J / cm 2(Zhang Fusheng. Femtosecond laser processing mechanism and experimental study of silicon carbide composites[D]. Liaoning: Liaoning University of Engineering and Technology, 2023.)

[0056]

[0057] Step 3): Calculate the peak laser energy density F corresponding to different laser processing hole diameters pk As the initial reference value, with the help of the finite element model constructed in step 1), the laser ablation simulation analysis of SiC / SiC ceramic matrix composites is carried out to obtain the generalized inward heat flux H, as shown in formula (2). By adjusting the parameters to fit the material removal efficiency of the laser processing material removal process in the experiment, the actual laser prefabricated hole preparation experiment is guided;

[0058] H=η(x-x0)*P*λ(t) (2)

[0059] Where η is the Gaussian distribution function, which is used to simulate the laser energy density distribution; P is the laser energy density, which is calculated as follows: P = P_total / (pi*r 2 *k), P_total is the total laser power, r is the spot radius, k is the laser frequency; λ is a sawtooth wave function used to simulate the energy change of pulsed laser over time; Figure 5 and Figure 6 The Gaussian distribution function and the sawtooth wave function are shown in FIG.

[0060] Step 4): Conduct two groups of RMI process SiC / SiC ceramic matrix composite laser ablation tests and compare and verify with the laser ablation simulation results;

[0061] Step 5): According to the test results of step 4), the finite element simulation analysis of step 3) is reasonably corrected, and step 3) is repeated to comprehensively consider the processing efficiency of laser processing of the material, and obtain the corresponding relationship between the corrected laser processing aperture and the laser processing parameters;

[0062] Step 6): Construct a finite element simulation model of ultrasonic-assisted drilling of SiC / SiC ceramic matrix composites in RMI process. Figure 7 A finite element simulation model of ultrasonic assisted drilling is shown;

[0063] Step 7): Based on the finite element simulation model constructed in step 6), a modal simulation analysis is performed on the ultrasonic tool holder and the drilling tool to obtain a suitable tool clamping overhang and ultrasonic vibration parameter range. The tool clamping overhang is 20 to 30 mm, and the ultrasonic frequency range is 20 kHz to 40 kHz. Figure 8 The structure of the ultrasonic assisted drilling tool is schematically shown in FIG. Fig. 9 This is the modal finite element analysis diagram of the ultrasonic assisted drilling tool holder.

[0064] Step 8): With the help of the finite element simulation model of step 6), the tool clamping overhang and ultrasonic vibration parameter range of step 7, and the laser processing hole diameter of step 5), the finite element simulation of ultrasonic assisted drilling of SiC / SiC ceramic matrix composites in RMI process is carried out. Fig.10 The finite element analysis diagram of laser ablation of ceramic matrix composites is shown in;

[0065] Step 9): With the help of a neural network algorithm, a mapping relationship between the laser processing hole diameter, ultrasonic assisted drilling process parameters and the micro-hole diameter is constructed;

[0066] D=0.4802·d 0.03026 ·n 0.0088 ·f -0.00366 (3)

[0067] Where D is the micro-hole diameter, d is the laser processed hole diameter, n is the spindle speed, and f is the feed speed.

[0068] Step 10): Conduct two groups of ultrasonic-assisted drilling tests on ceramic matrix composite materials to verify the mapping relationship obtained in step 9), and modify the model in step 9) according to the test results. Fig.11 Figure 2 shows an ultrasonic-assisted drilling diagram of a ceramic matrix composite material;

[0069] Step 11): Based on the modified mapping model obtained in step 10) and the target aperture size of the micro-hole (Φ0.5 mm), the diameter of the laser-processed hole and the ultrasonic-assisted drilling process parameters of the SiC / SiC ceramic matrix composite material in the RMI process are determined;

[0070] Step 12): Determine the laser processing parameters according to the correspondence between the laser processing hole diameter determined in step 11) and the laser processing hole diameter in step 5) and the laser processing parameters; the millisecond laser processing parameters are: peak power 1000W, scanning speed 1mm / s, repetition frequency 144Hz, pulse width 0.5ms, blowing pressure 0.8MPa, scanning times 6 times, the first 3 times processing diameter Φ0.14mm, defocus 0mm, the last 3 times processing diameter Φ0.16mm, defocus -1.5mm, laser processing bottom hole diameter Φ0.30mm.

[0071] Step 13): According to the laser processing parameters and ultrasonic assisted drilling process parameters determined in step 11) and step 12), RMI process SiC / SiC ceramic matrix composite micro-hole processing is performed. The ultrasonic assisted drilling parameters are: spindle speed 13100r / min, feed speed 6mm / min, vibration frequency 29.6kHz, amplitude 2.1μm, cooling.

[0072] The target diameter of the micro-holes in the SiC / SiC ceramic matrix composite material produced by the RMI process is Φ0.5mm, and the diameters of the micro-holes processed in the embodiments are 0.502mm, 0.503mm, and 0.507mm respectively. Fig.12 FIG. 2 shows a diagram of micropores in a ceramic matrix composite material obtained by processing in an embodiment of the present invention.

[0073] It can be seen that the embodiment of the present invention uses laser ablation to quickly process tiny bottom holes, reduces the material removal allowance in subsequent hole processing, and can solve the problems of low tool stiffness and easy breakage in the process of processing tiny holes in hard and brittle ceramic-based composite materials; at the same time, after laser bottom hole processing, ultrasonic assisted drilling is used to carry out fine processing of the tiny holes, so that the processed tiny holes of the ceramic-based composite material are of good quality; and through a small number of test verifications and corrections, the test workload in previous drilling research has been greatly reduced, the selection of process parameters has been reduced. The dependence on engineering technical experience, and data and laws with a wider range of process parameters can be obtained, which is impossible to achieve in actual processing test research.

[0074] It should be noted that the above-described embodiments are only preferred embodiments of the present invention. For those skilled in the art, without departing from the principles of the present invention, the present invention may be modified, improved and replaced with equivalents, and these modifications, improvements and equivalents are also considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A method for micro-pore energy field assisted processing of hard and brittle ceramic matrix composite materials, comprising: Step 1): constructing a finite element model for millisecond laser ablation simulation of ceramic matrix composites; Step 2): According to the ablation diameter D and the peak laser energy density F pk The relationship function, formula (1), calculates the required peak laser energy density F corresponding to different laser processing hole diameters. pk : Step 3): Calculate the peak laser energy density F corresponding to different laser processing hole diameters pk As the initial reference value, with the help of the finite element model constructed in step 1), the laser ablation simulation analysis of ceramic matrix composites is carried out to obtain the generalized inward heat flux H, as shown in formula (2): H=η(x-x0)*P*λ(t) (2) Where η is the Gaussian distribution function, which is used to simulate the laser energy density distribution; P is the laser energy density, which is calculated as follows: P = P_total / (pi*r 2 *k), P_total is the total laser power, r is the spot radius, k is the laser frequency; λ is a sawtooth wave function used to simulate the energy change of pulsed laser over time; Step 4): Conduct laser ablation tests on a small number of ceramic matrix composites and compare and verify the laser ablation simulation results; Step 5): According to the test results of step 4), the finite element simulation analysis of step 3) is reasonably corrected, and step 3) is repeated to comprehensively consider the processing efficiency of laser processing of the material to obtain the corresponding relationship between the corrected laser processing hole diameter and the laser processing parameters; Step 6): constructing a finite element simulation model of ultrasonic-assisted drilling of ceramic matrix composites; Step 7): Based on the finite element simulation model constructed in step 6), a modal simulation analysis is performed on the ultrasonic tool holder and the drilling tool to obtain a suitable tool clamping overhang and ultrasonic vibration parameter range; Step 8): With the help of the finite element simulation model of step 6), the tool clamping overhang and ultrasonic vibration parameter range of step 7, and the laser processing hole diameter of step 5), carry out finite element simulation of ultrasonic assisted drilling of ceramic matrix composite materials; Step 9): With the help of a neural network algorithm, a mapping relationship between the laser processing hole diameter, ultrasonic assisted drilling process parameters and the micro-hole diameter is constructed; Step 10): Conduct ultrasonic assisted drilling tests on a small number of ceramic matrix composite materials to verify the mapping relationship obtained in step 9), and modify the model in step 9) according to the test results; Step 11): Based on the modified mapping model obtained in step 10) and the target aperture size of the micro-hole, the diameter of the laser-processed hole and the ultrasonic-assisted drilling process parameters of the ceramic-based composite material are determined; Step 12): Determine laser processing parameters according to the laser processing hole diameter determined in step 11) and the corresponding relationship between the laser processing hole diameter and the laser processing parameters in step 5); Step 13): According to the laser processing parameters and ultrasonic-assisted drilling process parameters determined in step 11) and step 12), micro-hole processing of the ceramic-based composite material is performed.

2. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 1), a millisecond laser ablation simulation finite element model of SiC / SiC ceramic matrix composites prepared by RMI process is constructed in Comsol Multiphysics 5.0 multi-physics field finite element simulation software.

3. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 2), the hot melt ablation of the ceramic matrix composite material F th Take 0.30J / cm 2 .

4. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 4) and step 10), the small number of groups is 2 or 3 groups.

5. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 4) and step 10), the small number of groups is 2 groups.

6. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 7), the tool clamping overhang is 20 to 30 mm, and the ultrasonic frequency range is 20 kHz to 40 kHz.

7. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 9), the mapping relationship between the laser processing hole diameter, ultrasonic assisted drilling process parameters and micro-hole diameter; D=0.4802·d 0.03026 ·n 0.0088 ·f -0.00366 (3) Where D is the micro-hole diameter, d is the laser processed hole diameter, n is the spindle speed, and f is the feed speed.

8. The micropore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1 is characterized in that: In step 12), the millisecond laser processing parameters are: peak power 1000W, scanning speed 1mm / s, repetition frequency 144Hz, pulse width 0.5ms, blowing pressure 0.8MPa, scanning times 6 times, the first 3 processing diameters are Φ0.14mm, the defocus is 0mm, the last 3 processing diameters are Φ0.16mm, the defocus is -1.5mm, and the laser processing bottom hole diameter is Φ0.30mm.

9. The micro-pore energy field assisted processing method of hard and brittle ceramic matrix composite materials according to claim 1, characterized in that: In step 13), the ultrasonic assisted drilling parameters are: spindle speed 13100 r / min, feed speed 6 mm / min, vibration frequency 29.6 kHz, amplitude 2.1 μm.

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