Laser shock peening process optimization method and system based on interface micro-motion regulation and control

Abstract

The invention relates to the technical field of aero-engines, and provides a laser shock peening process optimization method and system based on interface micro-motion regulation, and the method comprises the steps: carrying out laser shock peening treatment on a contact surface of a first component; the first component and the second component which are subjected to strengthening treatment are assembled to form a micro-motion contact pair; performing a fretting fatigue test on the fretting contact pair to obtain displacement field data of the contact area; determining an evolution law of slippage / adhesion characteristics of the contact surface based on displacement field data, evaluating the influence of laser shock peening treatment on the fatigue performance of the micro contact pair, and optimizing parameters of a laser shock peening process; by establishing a closed-loop optimization path among laser shock peening process parameters, interface dynamic behaviors and fretting fatigue performance, it is ensured that the process optimization direction aims at restraining harmful interface slippage, so that adjustment of the process parameters has a basis, and then accurate regulation and reliable improvement of the fretting fatigue performance can be achieved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to an optimization method and system for laser shock peening process based on interface micro-motion control. Background Technology

[0002] In aero-engines, turbine blades are typically connected to the turbine disk via a tenon-and-mortise joint structure. During service, this connection structure is subjected to high temperatures, high-cycle vibrations, and enormous centrifugal loads generated by rotation. The combined effect of these loads inevitably causes micron-level reciprocating relative motion, or fretting, between the contact surfaces of the turbine disk and the blade tenon. Fretting, combined with contact stress at the interface, easily leads to fatigue cracks initiating at the edges of the contact area, ultimately resulting in fretting fatigue failure, becoming one of the key bottlenecks limiting the overall lifespan and reliability of the engine.

[0003] To improve the fatigue performance of critical load-bearing components, laser shock peening (LSP) technology is widely used. This technology utilizes a high-peak-power pulsed laser beam to induce plasma shock waves, introducing a high-amplitude, deep residual compressive stress field into the material surface. This residual compressive stress can effectively inhibit the initiation and propagation of fatigue cracks, thereby significantly improving the fatigue life of the component.

[0004] Traditional laser shock stabilization (LSS) processes have significant limitations in their design and evaluation. Their optimization typically focuses on the macroscopic mechanical properties of individual components after stabilization, such as surface hardness, residual stress magnitude and distribution, and surface roughness. This evaluation method neglects the fact that fretting fatigue is a systematic failure behavior occurring at the interface between two components. While introducing beneficial residual compressive stress, LSS inevitably alters the surface hardness, roughness, and elastoplastic response of the material. These changes will affect the interfacial behavior of the contact pair during the fretting process.

[0005] However, the optimal mechanical properties of a single component may adversely affect the fretting fatigue life of the entire connection structure, and may even reduce its lifespan. Therefore, existing technologies lack an optimization method that can correlate laser shock strengthening with the behavior of the fretting contact interface, resulting in blind process design and an inability to accurately predict fretting fatigue performance. Summary of the Invention

[0006] This invention provides a laser shock strengthening process optimization method and system based on interface micro-motion control, which solves the defect in the prior art that focuses on the mechanical performance indicators of individual components while ignoring the influence of micro-motion behavior at the contact interface when evaluating laser shock strengthening processes, resulting in blind optimization of the process.

[0007] This invention provides an optimization method for laser shock peening processes based on interface micro-motion control, comprising: The contact surface of the first component, made of turbine disk material, is subjected to laser shock peening treatment; The first component, after being subjected to laser shock strengthening treatment, is assembled with a second component made of turbine blade material to form a micro-motion contact pair; A cyclic load was applied to the fretting contact pair to conduct a fretting fatigue test, and displacement field data of the contact area was obtained based on digital image correlation technology; Based on the displacement field data, the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface is determined; Based on the evolution of the slip / adhesion characteristics, the effect of the laser shock strengthening treatment on the fatigue performance of the micro-motion contact pair is evaluated, and the evaluation results are obtained. Based on the evaluation results, the parameters of the laser shock peening process are optimized.

[0008] According to the laser shock strengthening process optimization method based on interface micro-motion control provided by the present invention, before performing laser shock strengthening treatment on the contact surface of the first component, the method further includes: Determine the Schügonne elastic limit of the turbine disk material; Based on the aforementioned Schungunny elastic limit and according to the shock wave peak pressure model, the laser energy density threshold is obtained; Based on the laser energy density threshold, an initial laser energy density for the laser shock enhancement treatment is determined, wherein the initial laser energy density is greater than or equal to the laser energy density threshold.

[0009] According to the present invention, a laser shock peening process optimization method based on interface micro-motion control is provided, wherein obtaining the laser energy density threshold based on the Schungunny elastic limit and according to the shock wave peak pressure model includes: A model was established to determine the relationship between laser-induced impact pressure and laser energy density. The laser energy density threshold is determined by using the constraint condition that the pressure of the laser shock wave is greater than the Schungunny elastic limit, and based on the relationship model.

[0010] According to the present invention, a laser shock strengthening process optimization method based on interface micro-motion control is provided. In the step of performing laser shock strengthening treatment on the contact surface of the first component, an absorption layer and a constraint layer are arranged on the contact surface. The absorption layer is used to absorb energy under the action of laser to form plasma and protect the contact surface from laser ablation. The constraint layer is used to constrain the plasma to form shock wave pressure acting on the contact surface.

[0011] According to the laser shock strengthening process optimization method based on interface micro-motion control provided by the present invention, before performing laser shock strengthening treatment on the contact surface of the first component, the method further includes: Construct multiple second components with different preset crystal orientations; The optimization of the parameters of the laser shock peening process based on the evaluation results includes: The differences in the evolution of the slip / adhesion characteristics under different crystal orientations are compared to obtain the comparison results; Based on the comparison and evaluation results, the parameters of the laser shock peening process are optimized.

[0012] According to the present invention, a laser shock peening process optimization method based on interface micro-motion control is provided, wherein evaluating the impact of the laser shock peening treatment on the fatigue performance of the micro-motion contact pair based on the evolution law of the slip / adhesion characteristics includes: At least one key evaluation parameter is extracted from the evolution law, including: the initial relative slip amplitude, the number of cycles required to reach the slip steady state, the average relative slip in the steady state, and the distribution ratio of the slip region along the contact surface. The extracted key evaluation parameters are compared with preset corresponding thresholds or benchmark values, and the effect of the laser shock enhancement treatment is quantitatively evaluated based on the comparison results.

[0013] According to the present invention, a method for optimizing laser shock peening process based on interface micro-motion control is provided, wherein optimizing the parameters of the laser shock peening process based on the evaluation results includes: When the evaluation results show that the key evaluation parameters deviate from the preset target range, the process parameters of the laser shock strengthening process are adjusted. The process parameters include at least one of laser energy density, overlap rate, or number of shocks.

[0014] According to the present invention, a laser shock peening process optimization method based on interface micro-motion control is provided, wherein determining the evolution law of the slip / adhesion characteristics based on the displacement field data includes: Based on the displacement field data, the relative motion between the first component and the second component at the contact surface is determined; Based on the relative motion and the measured tangential load, a hysteresis curve is constructed between the relative motion and the tangential load; Based on the hysteresis curve, the relative slip of the contact surfaces is calculated; Based on the variation characteristics of the relative slip amount with the number of cycles, the evolution law of the slip / adhesion feature is obtained.

[0015] According to the present invention, a laser shock strengthening process optimization method based on interface micro-motion control is provided, wherein the first component is a nickel-based powder superalloy and the second component is a nickel-based single crystal superalloy.

[0016] This invention also provides a laser shock strengthening process optimization system based on interface micro-motion control, the system comprising: A laser shock strengthening module is used to perform laser shock strengthening treatment on the contact surface of a first component made of turbine disk material; The fretting fatigue test module is used to assemble the first component, which has undergone the laser shock strengthening treatment, with the second component made of turbine blade material to form a fretting contact pair. The acquisition module is used to apply cyclic loads to the fretting contact pair to conduct fretting fatigue tests, and to acquire displacement field data of the contact area based on digital image correlation technology; The determination module is used to determine the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface based on the displacement field data; The evaluation module is used to evaluate the impact of the laser shock strengthening treatment on the fatigue performance of the micro-motion contact pair based on the evolution law of the slip / adhesion characteristics, and obtain the evaluation results; An optimization module is used to optimize the parameters of the laser shock peening process based on the evaluation results.

[0017] The present invention provides a laser shock strengthening process optimization method based on interface micro-motion control. This method assembles a laser-shock-strengthened first component and a second component into a micro-motion contact pair and conducts fatigue tests. Digital image correlation technology is used to acquire displacement field data of the contact area in real time, thereby determining the evolution law of slip / adhesion characteristics as micro-motion damage, and evaluating the impact of laser shock strengthening on micro-motion fatigue performance. Based on this evaluation result, process parameters are optimized, thus establishing a closed-loop optimization path between laser shock strengthening process parameters, interface dynamic behavior, and micro-motion fatigue performance. This overcomes the shortcomings of existing technologies that rely solely on the mechanical properties of a single component for indirect and blind evaluation, ensuring that process optimization is directed towards suppressing harmful interface slippage. This provides a basis for adjusting process parameters, enabling accurate control of micro-motion fatigue performance. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1This is one of the flowcharts of the laser shock strengthening process optimization method based on interface micro-motion control provided by the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the first component provided by the present invention.

[0021] Figure 3 This is the second flowchart of the laser shock strengthening process optimization method based on interface micro-motion control provided by the present invention.

[0022] Figure 4 This is a schematic diagram of the variation curve of residual compressive stress with depth provided by the present invention.

[0023] Figure 5 This is the vertical displacement field cloud map provided by the present invention when N=1 cycles.

[0024] Figure 6 This is a schematic diagram showing the distribution of vertical displacement along the x-direction at different height positions when N=1 revolutions, provided by the present invention.

[0025] Figure 7 This is the third flowchart of the laser shock strengthening process optimization method based on interface micro-motion control provided by the present invention.

[0026] Figure 8 This is a schematic diagram of the structure of the laser shock strengthening process optimization system based on interface micro-motion control provided by the present invention.

[0027] Figure label: 10. Micro-motion sample; 11. Reinforced surface. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0031] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] The following is combined with Figures 1 to 7 This invention describes a laser shock peening process optimization method and system based on interface micro-motion control.

[0034] An embodiment of the first aspect of the present invention proposes an optimization method for laser shock peening process based on interface micro-motion control, such as... Figure 1 As shown, the method includes the following steps: Step 100: Perform laser shock peening treatment on the contact surface of the first component made of turbine disk material.

[0035] It is understandable that laser shock strengthening treatment is applied to the contact surface of the first component made of turbine disk material (such as GH4169 powder superalloy). The strengthening treatment is to introduce a residual compressive stress field with a depth of millimeters and an amplitude of hundreds of megapascals into the surface material of the first component by plasma shock wave induced by a high-energy pulsed laser beam, thereby improving the fatigue resistance of the first component matrix and providing a mechanical basis for suppressing the initiation of fretting fatigue cracks from the material level.

[0036] Step 200: Assemble the first component, which has undergone laser shock strengthening treatment, with the second component made of turbine blade material to form a micro-motion contact pair.

[0037] It is understandable that assembling the first component, which has undergone laser shock strengthening, with the second component, which is made of turbine blade material (such as PWA1383 nickel-based single crystal high-temperature alloy), to form a micro-motion contact pair can realistically simulate the assembly state and contact relationship between the turbine disk and the blade tenon in an aero-engine, ensuring that the test conditions are consistent with the actual service environment.

[0038] Step 300: Apply cyclic load to the fretting contact pair to conduct a fretting fatigue test, and obtain displacement field data of the contact area based on digital image correlation technology.

[0039] Understandably, applying cyclic loads to the fretting contact pair to conduct fretting fatigue tests and acquiring displacement field data of the contact area in real time based on digital image correlation (DIC) technology can accurately capture the dynamic displacement distribution of the entire contact interface during the fretting process, providing raw data for analyzing the mechanical behavior of the interface.

[0040] Step 400: Based on displacement field data, determine the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface.

[0041] Understandably, based on the acquired displacement field data, the evolution law of the slip / adhesion characteristics of the first and second components at the contact surface can be determined. By transforming the macroscopic displacement field data into the microscopic behavior of the interface, the dynamic process of the contact surface changing from the overall slip state in the early stage of the cycle to the partial slip state in the later stage can be revealed, thereby quantifying the state evolution of the contact interface within the fatigue life cycle.

[0042] Step 500: Based on the evolution of slip / adhesion characteristics, evaluate the effect of laser shock strengthening treatment on the fatigue performance of fretting contact pairs and obtain the evaluation results.

[0043] Understandably, based on the obtained evolution law of slip / adhesion characteristics, the actual impact of laser shock peening treatment on the fatigue performance of fretting contact pairs is evaluated, and the evaluation results are obtained. Among them, the increase in the relative slip of the contact surface after strengthening is the key reason for the change in fretting performance. Therefore, by directly evaluating the slip behavior, the comprehensive effect of the laser shock peening process can be judged more accurately, avoiding the blindness caused by evaluating based solely on indirect indicators such as residual stress.

[0044] Step 600: Based on the evaluation results, optimize the parameters of the laser shock peening process.

[0045] Understandably, based on the evaluation results, feedback optimization of parameters in the laser shock peening process (such as energy density and overlap rate) allows the adjustment of process parameters to move beyond blind trial and error and instead have a clear physical objective: controlling the sliding behavior of the interface. Thus, through optimization based on feedback of interface fretting behavior, the optimal process parameters can be determined that both ensure the fatigue performance of the component itself and effectively control fretting damage at the contact surface, thereby effectively improving the fretting fatigue life of the assembled structure.

[0046] The present invention provides a laser shock stabilization process optimization method based on interface micro-motion control. This method assembles a laser-shock-strengthened first component (simulated turbine disk) and a second component (simulated blade) into a micro-motion contact pair and conducts fatigue tests. Digital image correlation technology is used to acquire displacement field data of the contact area in real time, thereby determining the evolution law of slip / adhesion characteristics as micro-motion damage, and evaluating the impact of laser shock stabilization on micro-motion fatigue performance. Based on this evaluation result, process parameters are optimized, thus establishing a closed-loop optimization path between laser shock stabilization process parameters, interface dynamic behavior, and micro-motion fatigue performance. This overcomes the shortcomings of existing technologies that rely solely on the mechanical properties of a single component for indirect and blind evaluation, ensuring that process optimization targets the suppression of harmful interface slip. This provides a basis for adjusting process parameters, enabling accurate control and reliable improvement of micro-motion fatigue performance.

[0047] In one embodiment of the invention, the first component used to simulate the turbine disk is made of nickel-based powder superalloy and is referred to as the micro-motion specimen in the experiment; the second component used to simulate the turbine blade is made of nickel-based single-crystal superalloy and is referred to as the micro-motion pad in the experiment. The two components work together to form a micro-motion contact pair to reproduce the interface contact state in an actual tenon joint.

[0048] In this embodiment, as Figure 2As shown, the fretting specimen 10 has a plate-like structure, including a test section in the middle and clamping sections connected to both ends of the test section along its length. The test section and clamping sections are smoothly connected by an arc-shaped section to reduce stress concentration. The width of the test section is smaller than the width of the clamping sections, while their thickness is consistent. The length of the fretting pad is less than the length of the test section, and it adheres to and acts on the test section area in the middle of the fretting specimen, ensuring that the fretting contact surface is confined within the test section.

[0049] Two fretting pads are positioned opposite each other on both sides of the test section along the width of the fretting specimen. Each fretting pad includes two contact feet distributed along the length of the fretting specimen. The contact feet are in surface contact with the test section, forming a stable fretting contact area. The two fretting pads have a total of four contact feet, thus establishing four planar contact forms of fretting contact. The fatigue testing machine applies a cyclic load along the length of the fretting specimen, thereby establishing a planar-to-planar fretting contact between the fretting specimen and the fretting pads. A recessed area is formed between the two contact feet of each fretting pad. A stress measuring element (such as a strain gauge) is attached to the recessed area, i.e., the stress measuring element is located between the two contact feet, and is used to directly measure the tangential load generated at the contact interface between the fretting specimen and the fretting pad.

[0050] The fretting specimen and two fretting pads are assembled using a contact pressure loading mechanism. The contact pressure loading mechanism acts on the side of the two fretting pads away from the fretting specimen to apply and maintain a preset contact pressure (Fn), ensuring that the contact state is controllable during the test. At the same time, a stress measuring element is integrated between the two contact feet of each fretting pad to collect the tangential load (Ft) between the contact interface between the fretting specimen and the fretting pad in real time, providing data for subsequent slip state analysis and fretting fatigue performance evaluation.

[0051] like Figure 2 As shown, the side surface of the test section in the middle of the micro-motion specimen is the contact surface that contacts the micro-motion pad, which is also the surface treated by laser shock peening (strengthened surface 11). In this embodiment, the thickness of the micro-motion specimen is 4 mm, the length of the test section is 20 mm, and the area of ​​laser shock peening treatment on each side of the micro-motion specimen is 20 mm × 4 mm.

[0052] In one embodiment of the present invention, before performing step 100, the method further includes the following steps: Step 700: Determine the initial laser energy density for laser shock peening treatment.

[0053] It is understandable that laser shock strengthening induces plastic deformation on the surface of a material through high-amplitude shock waves. The minimum laser energy threshold that can ensure effective plastic deformation can be estimated based on the dynamic yield strength of the material, thereby setting the initial process parameters and avoiding ineffective strengthening due to insufficient energy or surface damage caused by excessive energy.

[0054] Optionally, such as Figure 3 As shown, step 700 may include the following steps: Step 710: Determine the Schügonne elastic limit of the turbine disk material.

[0055] Step 720: Based on the Schungunny elastic limit and the shock wave peak pressure model, obtain the laser energy density threshold.

[0056] Step 730: Based on the laser energy density threshold, determine the initial laser energy density for laser shock strengthening treatment. The initial laser energy density is greater than or equal to the laser energy density threshold.

[0057] Understandably, the Schungner elastic limit is calculated based on the mechanical property parameters of the turbine disk material; according to the model between the peak pressure of the shock wave and the laser energy density during laser shock, the Schungner elastic limit is substituted as the target pressure, and the minimum laser energy density required to ensure plastic deformation is induced on the surface of the material is solved, i.e., the laser energy density threshold; the initial laser energy density used for actual processing is set to be greater than or equal to this threshold, thereby ensuring the effectiveness of the strengthening effect at the beginning of the process.

[0058] For example, the condition under which turbine disk materials undergo plastic deformation under laser shock is closely related to their Schungunny elastic limit. When the laser-induced shock wave pressure exceeds this limit, the material surface will yield and undergo plastic deformation; Schungunny elastic limit It can be determined by the material's Poisson's ratio and dynamic yield strength, based on formula (1): (1) in, The Poisson's ratio represents the material of the turbine disk. This represents the dynamic compressive yield strength of the turbine disk material, which is the mechanical property of the material under impact at a high strain rate.

[0059] Determined based on formula (2): (2) in, This represents the static compressive yield strength, which can be replaced by the static tensile yield strength.

[0060] In this embodiment, the micro-motion sample is prepared using nickel-based powder high-temperature alloy GH4169, with a Poisson's ratio of 0.3 and a static yield strength of 1200.34 MPa. According to the above formulas (1) and (2), the Schönürg elastic limit of the turbine disk material (GH4169 alloy) is 2.916 Gpa.

[0061] Optionally, step 720, based on the Schungunny elastic limit and according to the shock wave peak pressure model, obtains the laser energy density threshold, specifically including the following: A model was established to determine the relationship between laser-induced impact pressure and laser energy density. Using the pressure of the laser shock wave exceeding the Schungunny elastic limit as a constraint, and based on a relational model, the laser energy density threshold is determined.

[0062] It is understandable that establishing a model relating laser-induced impact pressure to laser energy density is a mathematical expression describing the correspondence between laser process parameters (energy density) and the resulting mechanical effects (shock wave pressure). The necessary condition for ensuring material yielding, namely, the pressure of the laser shock wave being greater than the material's Schungeuver elastic limit, is substituted as a physical constraint. Finally, the minimum laser energy density value that can satisfy the plastic deformation requirements is calculated, and this value is the laser energy density threshold set for subsequent processes.

[0063] For example, the relationship between laser-induced impact pressure and laser energy density is modeled as shown in equation (3): (3) in, This indicates the laser-induced impact pressure, expressed in GPa. This represents the energy conversion efficiency coefficient. Take 0.2; This represents the reduced impedance, with a value of 0.926 g⋅cm. -2 ⋅s -1 ; This indicates the laser energy density.

[0064] The Schungonne elastic limit is used as the laser-induced impact pressure. The laser energy density calculated based on formula (3) is used as the laser energy density threshold. Based on this, the initial laser energy density is designed to be greater than or equal to the laser energy density threshold.

[0065] In this embodiment, the laser energy density is 4.8 GW⋅cm. -2 At that time, the pressure of the laser shock wave (laser-induced impact pressure) was 5.9 GPa, which is far higher than the Schungonne elastic limit, ensuring that plastic deformation can be produced.

[0066] Furthermore, the laser energy density depends on the laser's parameter settings, as shown in equation (4): (4) Where E represents laser energy, τ represents pulse width, S represents laser spot area, and D represents spot diameter.

[0067] Based on the above formula (4), the laser energy density can be controlled by adjusting at least one of the parameters, namely laser energy E, pulse width τ, or spot diameter D.

[0068] In this embodiment, the specific process parameters used for laser shock peening are as follows: a laser with neodymium-doped yttrium aluminum garnet (Nd:YAG) as the working substance is used, the output laser wavelength is 1064 nm, the pulse width is set to 8 nanoseconds (ns), and the energy of each laser pulse is 3 joules (J); the laser energy density is 4.8 GW⋅cm². -2 The laser spot diameter is 2 mm, and the overlap rate between adjacent spots is set to 50%.

[0069] In one embodiment of the present invention, in step 100, an absorption layer and a confinement layer are arranged on the contact surface; wherein, the absorption layer is used to absorb energy under the action of laser to form plasma and protect the contact surface from laser ablation; the confinement layer is used to confine the plasma to form a shock wave pressure acting on the contact surface.

[0070] For example, in laser shock peening, a 0.13 mm thick black tape is selected as the absorption layer, and water is used as the confinement layer. The main function of the absorption layer is to efficiently convert laser energy into plasma and protect the surface of the first component; the water layer covering it is used to confine the expansion of the plasma, thereby enhancing the shock wave pressure generated.

[0071] In one embodiment of the present invention, the fretting fatigue test is performed using a hydraulic servo fatigue testing machine. The test is performed using load control, with alternating cyclic load being tension loading (stress ratio R = 0), waveform being a sine wave, load cycle frequency being 40Hz, peak cyclic load being 640MPa, and contact pressure being 100MPa.

[0072] In one embodiment of the present invention, after laser shock strengthening treatment is performed on the contact surface of the first component made of turbine disk material, the residual stress distribution is measured by X-ray diffraction.

[0073] Understandably, to obtain the distribution law of residual stress introduced by laser shock strengthening along the material depth direction, it is necessary to measure the stress state at different depths layer by layer. Therefore, in this embodiment, after completing the surface stress measurement, electrolytic polishing technology is used to remove the material surface layer by layer: a Proto-8818V3 electrolytic polishing machine is used with a saturated sodium chloride aqueous solution as the electrolyte, and controlled peeling is performed under conditions of 15V voltage and 2A current; after each polishing cycle, the thickness of the removed material is accurately measured using a micrometer, and then the residual stress on the exposed new surface is measured again using X-ray diffraction, thereby characterizing the curve of residual stress variation with depth.

[0074] like Figure 4 As shown, laser shock peening alters the near-surface stress state of the material, introducing a residual stress field dominated by compressive stress within a certain depth of the surface. Specifically, the residual compressive stress measured at the original surface (i.e., at zero depth) is -235 MPa; as it extends into the material, the amplitude of the residual compressive stress gradually increases, reaching a peak of -383 MPa at a depth of approximately 50 micrometers from the surface. This peak occurs in the subsurface layer rather than the outermost layer, primarily because the absorbing layer fails to completely isolate the laser-induced thermal effects, leading to heating and stress relaxation in the outermost material. Continuing to extend into the material from the peak depth, the residual compressive stress exhibits a monotonically slow decay trend, decreasing to almost zero at a depth of approximately 1200 micrometers from the surface.

[0075] In one embodiment of the present invention, step 300 may specifically include the following: A fretting fatigue test was conducted by applying cyclic loads to the fretting contact pair. The displacement field of the fretting contact area was measured in the whole field using digital image correlation (DIC) technology to obtain the displacement field distribution.

[0076] It should be noted that, in order to ensure the accuracy of subsequent speckle image analysis, a spraying method was used to spray the surface of the fretting sample and the two fretting pads before the fretting fatigue test to form a randomly distributed speckle pattern, thereby meeting the surface texture requirements of digital image correlation (DIC) analysis.

[0077] Understandably, cyclic loads are applied using a testing machine to simulate the fretting contact state; simultaneously, a camera is used to synchronously acquire speckle images of the fretting contact area at different loading moments. For example... Figure 5As shown, the acquired image of the micro-motion contact area contains three relatively moving objects: the micro-motion sample in the middle and the micro-motion pads on both sides. Due to the presence of the contact surface, if all three are placed in the same computational region for digital image correlation analysis, the speckle pattern near the contact surface will become blurred or overlapped due to the relative displacement of the two objects (the micro-motion sample and the micro-motion pads). It is impossible to determine whether the speckle near the contact surface belongs to the micro-motion sample or the micro-motion pads, leading to image matching difficulties and introducing significant computational errors. To solve this problem, this embodiment adopts a partitioned computational strategy, dividing the entire field of view into three independent computational regions with the left and right contact surfaces in the field of view as boundaries, labeled sequentially as the left micro-motion pad, the middle micro-motion sample, and the right micro-motion pad. This effectively isolates different moving bodies and improves the accuracy of displacement field calculation.

[0078] like Figure 5 The figure shows the vertical displacement field distribution obtained by digital image correlation technology during the first cycle. The central area corresponds to the fretting specimen, and the two side areas correspond to the fretting pads; the two contact interfaces are clearly identifiable. The displacement field of the fretting specimen exhibits a strip-shaped distribution characteristic that varies along the y-axis, and the displacement amplitude at the lower position of the contact interface increases accordingly with the increase of the y-coordinate value (i.e., along the specimen height direction). It is worth noting that at the same height (same y-coordinate), the displacement change amplitude of the two fretting pads is much smaller than that of the central fretting specimen, reflecting that the deformation during fretting is mainly concentrated on the specimen bearing the main cyclic load.

[0079] Because the computational strategy of digital image correlation (DIC) divides the entire observation area into three independent sub-computation regions (central sample region and two side pad regions) with the contact interface as the boundary, displacement data within approximately half the width of the sub-computation region outside its boundary of each sub-region cannot be directly obtained. Therefore, a data gap appears near the contact interface in the image. To accurately analyze the vertical displacement difference between the fretting pads and the fretting sample on both sides of the contact interface, such as... Figure 6 As shown, the distribution curves of vertical displacement along the x-direction (i.e., perpendicular to the contact interface) are plotted. The figure shows the displacement distribution of the fretting sample in the center and the displacement distribution of the fretting pads on both sides, with distribution curves given for different y-coordinate heights (representing different positions along the contact surface). To characterize the distribution of relative motion along the entire contact surface (y-direction), three representative height positions (y = 0.5 mm, 1.5 mm, 2.5 mm) were selected, and the displacement field and relative motion at these positions were calculated and analyzed.

[0080] Depend on Figure 6It can be seen that although direct measurement data is lacking at the contact interface, the displacement data of both the fretting sample and the fretting pad exhibit a good linear trend near the interface. Therefore, a linear extrapolation fitting method can be used to extend the data on both the fretting sample side and the fretting pad side, thereby calculating the displacement values ​​of both at the contact interface. The displacement fields on both sides of the interface can be obtained, thus calculating the relative motion between the objects on both sides of the contact interface, i.e., obtaining the displacement field data of the contact area.

[0081] In one embodiment of the present invention, step 300 further includes: obtaining the tangential load.

[0082] Understandably, during the fretting fatigue test, tangential loads are measured in real time using stress measuring devices when cyclic loads are applied to the fretting contact pair.

[0083] In one embodiment of the present invention, such as Figure 7 As shown, step 400 may specifically include the following steps: Step 410: Based on the displacement field data, determine the relative motion between the first component and the second component at the contact surface.

[0084] Step 420: Based on the relative motion and the measured tangential load, construct the hysteresis curve between the relative motion and the tangential load.

[0085] Step 430: Calculate the relative slip of the contact surfaces based on the hysteresis curve.

[0086] Step 440: Based on the variation characteristics of relative slip with the number of cycles, the evolution law of slip / adhesion characteristics is obtained.

[0087] Understandably, based on the acquired displacement field data, the relative motion between the first and second components at the contact surface is determined. Based on this relative motion and the tangential load measured by the stress measuring device, a hysteresis curve is constructed between the relative motion and the tangential load. The hysteresis curve, as a key characterization parameter, can intuitively reveal the mechanical response during the fretting process. The shape of the curve directly reflects the state transition of the contact surface from overall sliding to partial slip, and the area enclosed by the curve represents the energy dissipated due to friction in each cycle, providing a basis for judging the degree of fretting damage. Based on the constructed hysteresis curve, the core parameter that plays a decisive role in the initiation of fretting fatigue cracks, namely the relative slip, is extracted, enabling direct comparison and quantitative evaluation of the interface damage potential under different processes and different cycle counts. Finally, based on the variation characteristics of the relative slip with the number of cycle counts, the evolution law of slip / adhesion characteristics is obtained. This evolution law describes the entire life cycle behavior of the fretting contact surface from initial operation to stabilization and even final failure.

[0088] In this embodiment, by observing the process of the slip amount rapidly decreasing from a high value at the beginning of the cycle and eventually reaching a stable value, the abrupt change and stabilization of the interface state can be clearly identified, thereby revealing how the laser shock peening process affects the entire process of slip / adhesion feature evolution, and providing an evaluation basis for process optimization.

[0089] In one embodiment of the present invention, step 500, based on the evolution of slip / adhesion characteristics, evaluates the impact of laser shock peening treatment on the fatigue performance of the micro-motion contact pair, which may specifically include the following: At least one key evaluation parameter is extracted from the evolutionary pattern. The key evaluation parameters include: the initial relative slip amplitude, the number of cycles required to reach the slip steady state, the average relative slip in the steady state, and the distribution ratio of the slip zone along the contact surface.

[0090] The extracted key evaluation parameters are compared with the preset corresponding thresholds or benchmark values, and the effect of laser shock peening treatment is quantitatively evaluated based on the comparison results.

[0091] It is understood that at least one key evaluation parameter can be extracted from the evolutionary pattern. This key evaluation parameter may include: the initial relative slip amplitude, the number of cycles required to reach a stable slip state, the average relative slip in the stable state, or the distribution ratio of the slip zone along the contact surface. This allows the complex, time-evolving interface slip / adhesion dynamic process to be refined into a set of clear and quantifiable physical indicators. For example, the initial relative slip directly reflects the severity of damage in the early stages of fatigue, while the number of cycles required to reach a stable slip state characterizes the speed at which the interface breaks in and enters the stable damage stage. By extracting these core parameters directly related to the fretting damage mechanism, the complexity and ambiguity of the analysis can be avoided. The extracted key evaluation parameters are compared with preset corresponding thresholds or benchmark values ​​(e.g., parameter values ​​corresponding to untreated contact pairs). Based on the comparison results, the effect of the laser shock stabilization treatment is quantitatively evaluated, thus providing an objective and quantitative basis for evaluating the laser shock stabilization process. By comparing the strengthened slip parameters with the benchmark value, it can be determined whether the current process optimizes or degrades the fretting behavior. For example, strengthening treatments may actually increase relative slip by altering surface properties, negatively impacting fretting fatigue. This embodiment quantifies the extent of this impact, indicating the correct direction for subsequent process optimization and ensuring that the optimization process is based on monitoring the physical behavior of the interface.

[0092] In one embodiment of the present invention, step 600 may specifically include the following: When the evaluation results show that the key evaluation parameters deviate from the preset target range, the process parameters of the laser shock strengthening process are adjusted. The process parameters include at least one of laser energy density, overlap rate, or number of shocks.

[0093] Understandably, when evaluation results show that key evaluation parameters (such as the initial relative slip amplitude) deviate from the preset target range, the process parameters for laser shock peening are adjusted. These process parameters include at least one of laser energy density, overlap rate, or number of impacts. Laser energy density, overlap rate, and number of impacts are process parameters that determine the effect of laser shock peening, directly controlling the energy injected into the material surface, the degree and range of plastic deformation, and ultimately determining the residual stress, hardness, and microstructure of the surface. Therefore, by adjusting these parameters, the properties of the contact interface can be intervened and changed, thereby achieving active control over key evaluation parameters (such as relative slip) and bringing them back within the preset target range. This makes it possible to achieve a balance between ensuring the strengthening effect of the component itself and optimizing the micro-movement behavior of the interface, ultimately obtaining a strengthening process with better overall performance.

[0094] In one embodiment of the present invention, before performing step 100, the method further includes the following steps: Step 800: Construct multiple second components with different preset crystal orientations.

[0095] It is understandable that the second component is made of a nickel-based single-crystal superalloy, whose mechanical properties exhibit significant anisotropy. Even under the same laser shock peening treatment and external load conditions, different contact crystal orientations (such as crystal orientation A and crystal orientation B) will lead to significant differences in the fretting behavior of the contact surface. Specifically, this manifests in differences in the tangential load coefficient, relative slip amplitude, and the speed at which the slip / adhesion state reaches stability. Therefore, this embodiment, by pre-constructing and testing contact pairs with different crystal orientations, enables a more comprehensive subsequent evaluation and optimization process. This avoids deviations in the strengthening process evaluation caused by neglecting the crystal orientation dependence of the single-crystal blade, thereby improving the reliability of the optimization results in practical engineering applications.

[0096] Furthermore, step 600 may specifically include the following: The differences in the evolution patterns of glide / adhesion characteristics under different crystal orientations were compared to obtain comparative results; Based on the comparison and evaluation results, the parameters of the laser shock peening process were optimized.

[0097] Understandably, during the experiments, multiple micro-motion contact pairs were pre-constructed and tested, with the second component in each pair having different, pre-defined crystal orientations. By analyzing experimental data under different crystal orientations, the evolution of slip / adhesion characteristics (e.g., initial relative slip amplitude, number of cycles required for slip stabilization) under the same laser shock peening process was compared to obtain a comparative result. For example, after strengthening, the relative slip and its evolution patterns of the contact surfaces under different crystal orientations showed significant differences. Combining the comparative results regarding the influence of crystal orientation with the obtained evaluation results, the laser shock peening process parameters were jointly optimized. This ensured that the optimized laser shock peening process had better universality, avoiding unexpected early failures in practical applications due to neglecting the anisotropy of single-crystal materials, and making the process optimization more reliable.

[0098] The laser shock strengthening process optimization system based on interface micro-motion control provided by the present invention is described below. The laser shock strengthening process optimization system based on interface micro-motion control described below can be referred to in correspondence with the laser shock strengthening process optimization method based on interface micro-motion control described above.

[0099] A second aspect of the present invention proposes a laser shock peening process optimization system based on interface micro-motion control, such as... Figure 8 As shown, the device includes a laser shock strengthening module 810, a fretting fatigue testing module 820, an acquisition module 830, a determination module 840, an evaluation module 850, and an optimization module 860; wherein: The laser shock strengthening module 810 is used to perform laser shock strengthening treatment on the contact surface of the first component made of turbine disk material.

[0100] The fretting fatigue test module 820 is used to assemble a first component that has undergone laser shock strengthening treatment with a second component made of turbine blade material to form a fretting contact pair.

[0101] The acquisition module 830 is used to apply cyclic loads to the fretting contact pair to conduct fretting fatigue tests and acquire displacement field data of the contact area based on digital image correlation technology.

[0102] The determination module 840 is used to determine the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface based on displacement field data.

[0103] Evaluation module 850 is used to evaluate the impact of laser shock peening treatment on the fatigue performance of fretting contact pairs based on the evolution of slip / adhesion characteristics, and obtain evaluation results.

[0104] The optimization module 860 is used to optimize the parameters of the laser shock peening process based on the evaluation results.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing laser shock peening processes based on interface micro-motion control, characterized in that, include: The contact surface of the first component, made of turbine disk material, is subjected to laser shock peening treatment; The first component, after being subjected to laser shock strengthening treatment, is assembled with a second component made of turbine blade material to form a micro-motion contact pair; A cyclic load was applied to the fretting contact pair to conduct a fretting fatigue test, and displacement field data of the contact area was obtained based on digital image correlation technology; Based on the displacement field data, the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface is determined; Based on the evolution of the slip / adhesion characteristics, the effect of the laser shock strengthening treatment on the fatigue performance of the micro-motion contact pair is evaluated, and the evaluation results are obtained. Based on the evaluation results, the parameters of the laser shock peening process are optimized.

2. The laser shock peening process optimization method based on interface micro-motion control according to claim 1, characterized in that, Before performing laser shock peening on the contact surface of the first component, the method further includes: Determine the Schügonne elastic limit of the turbine disk material; Based on the aforementioned Schungunny elastic limit and according to the shock wave peak pressure model, the laser energy density threshold is obtained; Based on the laser energy density threshold, an initial laser energy density for the laser shock enhancement treatment is determined, wherein the initial laser energy density is greater than or equal to the laser energy density threshold.

3. The laser shock peening process optimization method based on interface micro-motion control according to claim 2, characterized in that, The process of obtaining the laser energy density threshold based on the Schungunny elastic limit and according to the shock wave peak pressure model includes: A model was established to determine the relationship between laser-induced impact pressure and laser energy density. The laser energy density threshold is determined by using the constraint condition that the pressure of the laser shock wave is greater than the Schungunny elastic limit, and based on the relationship model.

4. The laser shock peening process optimization method based on interface micro-motion control according to claim 1, characterized in that, In the step of performing laser shock strengthening treatment on the contact surface of the first component, an absorption layer and a constraint layer are arranged on the contact surface; wherein, the absorption layer is used to absorb energy to form plasma under the action of laser and protect the contact surface from laser ablation; the constraint layer is used to constrain the plasma to form shock wave pressure acting on the contact surface.

5. The laser shock peening process optimization method based on interface micro-motion control according to claim 1, characterized in that, Before performing laser shock peening on the contact surface of the first component, the method further includes: Construct multiple second components with different preset crystal orientations; The optimization of the parameters of the laser shock peening process based on the evaluation results includes: The differences in the evolution of the slip / adhesion characteristics under different crystal orientations are compared to obtain the comparison results; Based on the comparison and evaluation results, the parameters of the laser shock peening process are optimized.

6. The laser shock strengthening process optimization method based on interface micro-motion control according to any one of claims 1 to 5, characterized in that, The evaluation of the impact of laser shock peening treatment on the fatigue performance of the micro-motion contact pair based on the evolution law of the slip / adhesion characteristics includes: At least one key evaluation parameter is extracted from the evolution law, including: the initial relative slip amplitude, the number of cycles required to reach the slip steady state, the average relative slip in the steady state, and the distribution ratio of the slip region along the contact surface. The extracted key evaluation parameters are compared with preset corresponding thresholds or benchmark values, and the effect of the laser shock enhancement treatment is quantitatively evaluated based on the comparison results.

7. The laser shock strengthening process optimization method based on interface micro-motion control according to claim 6, characterized in that, The optimization of the parameters of the laser shock peening process based on the evaluation results includes: When the evaluation results show that the key evaluation parameters deviate from the preset target range, the process parameters of the laser shock strengthening process are adjusted. The process parameters include at least one of laser energy density, overlap rate, or number of shocks.

8. The laser shock strengthening process optimization method based on interface micro-motion control according to any one of claims 1 to 5, characterized in that, The determination of the evolution law of the slip / adhesion characteristics based on the displacement field data includes: Based on the displacement field data, the relative motion between the first component and the second component at the contact surface is determined; Based on the relative motion and the measured tangential load, a hysteresis curve is constructed between the relative motion and the tangential load; Based on the hysteresis curve, the relative slip of the contact surfaces is calculated; Based on the variation characteristics of the relative slip amount with the number of cycles, the evolution law of the slip / adhesion feature is obtained.

9. The laser shock strengthening process optimization method based on interface micro-motion control according to claim 8, wherein the first component is a nickel-based powder superalloy and the second component is a nickel-based single crystal superalloy.

10. A laser shock peening process optimization system based on interface micro-motion control, characterized in that, include: A laser shock strengthening module is used to perform laser shock strengthening treatment on the contact surface of a first component made of turbine disk material; The fretting fatigue test module is used to assemble the first component, which has undergone the laser shock strengthening treatment, with the second component made of turbine blade material to form a fretting contact pair. The acquisition module is used to apply cyclic loads to the fretting contact pair to conduct fretting fatigue tests, and to acquire displacement field data of the contact area based on digital image correlation technology; The determination module is used to determine the evolution law of the slip / adhesion characteristics of the first component and the second component at the contact surface based on the displacement field data; The evaluation module is used to evaluate the impact of the laser shock strengthening treatment on the fatigue performance of the micro-motion contact pair based on the evolution law of the slip / adhesion characteristics, and obtain the evaluation results; An optimization module is used to optimize the parameters of the laser shock peening process based on the evaluation results.

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