Simulation and prediction method for cracking and edge warping of laser powder molten aluminum alloy

Abstract

The invention provides a method for simulating and predicting cracking and edge warping of a laser powder molten aluminum alloy. The method aims at solving the machining problems that the aluminum alloy is high in hot cracking tendency, prone to deformation and the like. The simulation and prediction method comprises the following steps: firstly, establishing a finite element physical model of the laser powder molten aluminum alloy, and loading thermal physical properties, a heat source control equation, a temperature field and a mechanical field boundary condition of the aluminum alloy; then thermal-mechanical coupling calculation of aluminum alloy laser powder melting is conducted, experimental results are compared to optimize the model, the temperature field simulation error is smaller than 15%, and the temperature field and mechanical field characteristics in the solidification process can be accurately predicted; and finally, outputting the characteristics such as thermal history, cooling rate and stress in the solidification process through software. And the change rule of the characteristic parameters of the temperature field and the stress field under different process parameters is calculated through the optimization model, so that the cracking and warping degrees of the alloy are predicted and analyzed. According to the method, the forming quality of the laser powder molten aluminum alloy is improved, and the process regulation and control complexity and the trial and error cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of metal molten deposition manufacturing and simulation calculation, and in particular to a simulation prediction method for cracking and edge warping of laser powder melted aluminum alloy. Background Art

[0002] Aluminum alloys have the advantages of low density, good toughness, fast heat dissipation, and low cost, and are widely used in industrial manufacturing fields such as aerospace, weapons and equipment, and transportation. Since the strength of aluminum alloys is lower than that of high-strength alloy materials such as iron-based, nickel-based, and titanium alloys, they are usually used as non-load-bearing lightweight structural parts such as aircraft skins, automobile bodies, heat sinks, and brackets. However, due to the increasingly complex shape requirements of aluminum alloy parts, their traditional processing methods such as forging, extrusion, and cutting are gradually limited, and the processing of some components has problems such as low production efficiency, poor precision, and high overall cost. At present, facing the demand for manufacturing parts with complex structures, laser powder melting technology has shown unique advantages. It uses computers to construct layered and sliced three-dimensional digital models of parts, and controls the movement path of the laser through system software. By melting the powder layer by layer, it realizes the rapid accumulation and forming of complex structural parts. Therefore, the laser powder melting technology for manufacturing aluminum alloy parts has extremely high application value [non-patent literature: P. Philipp, MB Wilms, A. Weisheit, B. Gault, EA Jaegle,D. Raabe. Nature, 20220, 582, 7813, 515].

[0003] However, due to the high thermal conductivity and thermal expansion coefficient, and wide solidification temperature range of aluminum alloys, cracking and edge warping are prone to occur during the rapid melting and cooling process of laser powder melting, significantly reducing the mechanical properties and service life of aluminum alloy components [Non-patent literature: SY Zhou, Y. Su, H. Wang, J. Enz, T. Ebel, M.Yan. Additive Manufacturing, 2020, 36, 101458]. Existing research has mainly aimed to improve cracking and edge warping by manipulating the composition of aluminum alloys and the process parameters of laser powder melting; however, the complex influencing factors lead to complex process verification and high trial-and-error costs.

[0004] With the rapid development of computer technology and simulation methods, simulation of machining processes has been successfully achieved by establishing physical models of the object being machined and performing multi-physics field coupling calculations. Numerous studies have investigated cracking and deformation during machining, demonstrating that these are primarily influenced by residual stresses caused by temperature gradients. By simulating the effects of different process parameters on residual stresses, an optimized machining window is obtained, effectively alleviating cracking and deformation issues [Non-patent literature: YH Li, ZZ Liu, ZY Wei, PF Hu, JW Chen, LJ Liu, GG Shu, JX Xie. Additive Manufacturing, 2024, 94, 104463]. Because the simulated stress evolution and model accuracy are closely related to factors such as the material being machined, the laser machining process, the characteristics of the formed structure, and production conditions, establishing a reasonable physical model is crucial for obtaining scientific and accurate simulation results.

[0005] It can be seen that exploring simulation and prediction methods for laser powder melting aluminum alloy forming problems such as cracking and edge warping is of great significance for guiding the actual processing process. Summary of the Invention

[0006] The purpose of the present invention is to provide a simulation prediction method for cracking and edge warping of laser powder melted aluminum alloy, which can be used to improve the forming quality of aluminum alloy and reduce the difficulty of process control and trial and error costs.

[0007] According to one aspect of the present invention, a method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy is provided, comprising the following steps:

[0008] Step 1: Establish a finite element simulation physical model for laser powder melting to prepare aluminum alloy;

[0009] Step 2: Load the aluminum alloy thermophysical properties, heat source control equations, heat transfer and mechanical field boundary conditions into the finite element simulation physical model obtained in step 1;

[0010] Step 3: After loading the aluminum alloy's thermophysical properties, heat source control equations, heat transfer, and mechanical field boundary conditions into the finite element simulation physical model, a thermal-mechanical coupling calculation of the laser powder melted aluminum alloy is performed to obtain the temperature distribution characteristics;

[0011] Step 4: Determine the width and depth of the simulated molten pool based on the temperature distribution. Obtain the simulation error by comparing it with the actual verified width and depth of the laser powder molten aluminum alloy molten pool. Perform model calculation adjustment and optimization based on the error.

[0012] Step 5: Calculate the temperature field and mechanical field characteristics under different process parameters based on the optimized model, and determine the cracking and warping deformation locations through stress distribution and strength values.

[0013] Preferably, the model building software in step 1 includes one or more of ANSYS, COMSOL, and ABAQUS, and the physical model elements include a powder bed and a substrate.

[0014] Preferably, the aluminum alloy in step 2 includes any one of aluminum-copper alloy, aluminum-manganese alloy, aluminum-silicon alloy, and aluminum-magnesium alloy; the thermal properties include density (g / cm 3 ), thermal conductivity (W / m·K), specific heat capacity (J / K·g), Young's modulus (GPa), Poisson's ratio, yield strength (MPa), thermal expansion coefficient (1 / K); the numerical changes of thermal properties with temperature are calculated by one or more software such as Jmatpro and Thermocalc.

[0015] Preferably, the heat source control equation in step 2 is:

[0016] (1)

[0017] In formula (1), P is the laser power (W), A is the laser absorptivity, R is the laser spot radius (m), the coordinates are (x0, y0), and r is the distance between the laser moving to the model space position (x, y) and the starting point (x0, y0) in time t (s). The heat transfer boundary conditions include the initial preheating temperature T0 (K), heat conduction k (W / m·K), heat convection (heat convection coefficient), and heat radiation (W / m 2 ), latent heat of phase change (J / kg); mechanical field boundary conditions include external load (N).

[0018] Preferably, the heat transfer process of the thermal-mechanical coupling calculation in step 3 obeys the transient heat transfer control equation:

[0019] (2)

[0020] k in formula (2) x (T), k y (T) and k z (T) is the thermal conductivity k (W / m·K) of the aluminum alloy in the three-dimensional directions x, y, and z as a function of temperature T (K), respectively. Q, ρ, and C represent the heat generated per unit volume, density, and specific heat capacity of the aluminum alloy, respectively. The mechanical field obeys the Von Mise yield criterion, and the equivalent stress expression is:

[0021] (3)

[0022] In formula (3), 、 、 are the principal stresses in three mutually perpendicular directions; the expression for the equivalent strain is:

[0023] (4)

[0024] In formula (4), 、 、 are the principal strains in three mutually perpendicular directions; μ is the Poisson's ratio of the aluminum alloy.

[0025] Preferably, in step 4, during the actual laser powder bed melting verification, the aluminum alloy powder particle size D50 = 34 ± 5.0 μm, the aluminum alloy powder is laid on the surface of the substrate with a powder thickness of 25-45 μm, and the preheating temperature range of the substrate is 140-200 ° C; the laser powder bed melting process parameters are: laser power range of 200-500 W, scanning speed range of 200-500 mm / s, overlap rate of 40%-70%, and scanning deflection angle of 30-90 °.

[0026] Preferably, in step 4, the melting width and depth of the molten pool are determined by the molten pool temperature field distribution obtained in step 3, and then compared with the molten pool size obtained in actual verification to obtain the error of the thermal-mechanical coupling simulation, and the simulation calculation process is regulated according to the error to perform model optimization.

[0027] Preferably, in step 5, the key temperature field characteristic parameters include one or more of temperature gradient, cooling rate and solidification rate; the key stress field characteristic parameters include one or more of stress intensity, stress distribution position and strain.

[0028] Preferably, the process parameters in step 5 include one or more of laser power (W), scanning speed (mm / s), overlap rate (μm), powder thickness (μm), scanning path, scanning direction, and boundary load (N).

[0029] According to another aspect of the present invention, the present invention provides a simulation prediction method obtained according to any one of the above technical solutions. After the simulation model is optimized, the comparison error between the actual and simulated molten pool widths and depths of the laser powder melted aluminum alloy is less than 15%. At this time, the evolution law of the temperature field and stress field of the laser powder melted aluminum alloy is accurately predicted, and the cracking and warping positions are judged according to the maximum stress distribution area; at the same time, according to the above rules, laser powder bed melting process parameters with uniform stress distribution and low intensity can be screened.

[0030] Through the above technical solutions, the present invention can achieve the following technical effects.

[0031] 1) Obtain accurate predictions of cracking and edge warping in laser powder melted aluminum alloys;

[0032] 2) Obtaining the processing window range of laser powder melting to improve cracking and edge warping of aluminum alloys;

[0033] 3) Obtaining aluminum alloy with good forming quality without significant cracks and thermal deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the present invention for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy;

[0035] Figure 2 3D physical model (a) and scanning trajectory (b) of laser powder melting of Al-Cu-Mg-Si alloy in Example 1;

[0036] Figure 3 The simulated melt pool (a) and experimental melt pool results (b) of laser powder melting of Al-Cu-Mg-Si alloy in Example 1;

[0037] Figure 4 Comparison results of simulated and actual molten pool width (a) and depth (b) of laser powder melting of Al-Cu-Mg-Si alloy at different scanning speeds in Example 1;

[0038] Figure 5 The simulated temperature field characteristic curve (a) and residual stress (b) of the laser powder melted Al-Cu-Mg-Si alloy in Example 1;

[0039] Figure 6 Comparison of simulated and actual residual stresses of laser powder melted Al-Cu-Mg-Si alloy at different laser powers (a) and scanning speeds (b) in Example 1;

[0040] Figure 7 It is a cracked, edge-warped and well-formed laser powder melted Al-Cu-Mg-Si alloy block. DETAILED DESCRIPTION

[0041] The present invention is further described in detail with reference to the following examples, but is not limited to the following examples.

[0042] The present invention provides a simulation prediction method for cracking and edge warping of laser powder molten aluminum alloy, comprising the following steps: Figure 1 ):

[0043] Step 1: Establish a finite element simulation physical model for laser powder melting to prepare aluminum alloy;

[0044] In a preferred embodiment, the modeling software in step 1 includes one or more of ANSYS, COMSOL, and ABAQUS, and the physical model elements include a powder bed and a substrate.

[0045] Step 2: Load the aluminum alloy thermophysical properties, heat source control equations, heat transfer and mechanical field boundary conditions into the finite element simulation physical model obtained in step 1;

[0046] In a preferred embodiment, the aluminum alloy in step 2 includes any one of an aluminum-copper alloy, an aluminum-manganese alloy, an aluminum-silicon alloy, and an aluminum-magnesium alloy; the thermal properties include density (g / cm3), thermal conductivity (W / m·K), specific heat capacity (J / K·g), Young's modulus (GPa), Poisson's ratio, yield strength (MPa), and thermal expansion coefficient (1 / K); and the numerical changes of the thermal properties with temperature are calculated by one or more software such as Jmatpro and Thermo calc.

[0047] In a preferred embodiment, the heat source control equation in step 2 is:

[0048] (1)

[0049] In formula (1), P is the laser power (W), A is the laser absorptivity, R is the laser spot radius (m), the coordinates are (x0, y0), and r is the distance between the laser moving to the model space position (x, y) and the starting point (x0, y0) in time t (s). The heat transfer boundary conditions include the initial preheating temperature T0 (K), heat conduction k (W / m·K), heat convection (heat convection coefficient), and heat radiation (W / m 2 ), latent heat of phase change (J / kg); mechanical field boundary conditions include external load (N).

[0050] Step 3: After loading the aluminum alloy's thermophysical properties, heat source control equations, heat transfer, and mechanical field boundary conditions into the finite element simulation physical model, a thermal-mechanical coupling calculation of the laser powder melted aluminum alloy is performed to obtain the temperature distribution characteristics;

[0051] In a preferred embodiment,

[0052] The heat transfer process of the thermal-mechanical coupling calculation in step 3 obeys the transient heat transfer governing equation:

[0053] (2)

[0054] k in formula (2) x (T), k y (T) and k z(T) is the thermal conductivity k (W / m·K) of the aluminum alloy in the three-dimensional directions x, y, and z as a function of temperature T (K), respectively. Q, ρ, and C represent the heat generated per unit volume, density, and specific heat capacity of the aluminum alloy, respectively. The mechanical field obeys the Von Mise yield criterion, and the equivalent stress expression is:

[0055] (3)

[0056] In formula (3), 、 、 are the principal stresses in three mutually perpendicular directions; the expression for the equivalent strain is:

[0057] (4)

[0058] In formula (4), 、 、 are the principal strains in three mutually perpendicular directions; μ is the Poisson's ratio of the aluminum alloy.

[0059] Step 4: Determine the width and depth of the simulated molten pool based on the temperature distribution. Obtain the simulation error by comparing it with the actual verified width and depth of the laser powder melted aluminum alloy molten pool. Adjust and optimize the model calculation process based on the error.

[0060] In a preferred embodiment, in step 4, during the actual laser powder bed melting verification, the aluminum alloy powder particle size D50 = 34 ± 5.0 μm, the aluminum alloy powder is laid on the surface of the substrate with a powder thickness of 25-45 μm, and the preheating temperature range of the substrate is 140-200 °C; the laser powder bed melting process parameters are: laser power range of 200-500 W, scanning speed range of 200-500 mm / s, overlap rate of 40%-70%, and scanning deflection angle of 30-90 °.

[0061] In a preferred embodiment, in step 4, the melting width and depth of the molten pool are determined by the molten pool temperature field distribution obtained in step 3, and then compared with the molten pool size obtained in actual verification to obtain the error of the thermal-mechanical coupling simulation, and the simulation calculation process is regulated according to the error to perform model optimization.

[0062] Step 5: Calculate the temperature field and mechanical field characteristics under different process parameters based on the optimized model, and determine the cracking and warping deformation locations through stress distribution and strength values;

[0063] In a preferred embodiment, the key temperature field characteristic parameters in step 5 include one or more of temperature gradient, cooling rate and solidification rate; the key stress field characteristic parameters include one or more of stress intensity, stress distribution position and strain.

[0064] In a preferred embodiment, the process parameters in step 5 include one or more of laser power (W), scanning speed (mm / s), overlap rate (μm), powder thickness (μm), scanning path, scanning direction, and boundary load (N).

[0065] According to another aspect of the present invention, the present invention provides a simulation prediction method obtained using any one of the above technical solutions.

[0066] In a preferred embodiment, after the simulation model is optimized, the comparison errors of the actual and simulated molten pool widths and depths of the laser powder melted aluminum alloy are both less than 15%. At this time, the evolution laws of the temperature field and stress field of the laser powder melted aluminum alloy are accurately predicted, and the cracking and warping locations are determined based on the maximum stress distribution area. At the same time, according to the above laws, laser powder bed melting process parameters with uniform stress distribution and low intensity can be selected.

[0067] Example 1

[0068] A simulation prediction method for cracking and edge warping of laser powder melted aluminum alloy, specifically implemented as follows:

[0069] Step 1: Use ANSYS to establish a finite element simulation physical model for laser powder melting of Al-Cu-Mg-Si alloy (its specific composition is Al-5Cu-Mg-Si-Zr-0.3Mn-0.15Ti, wt.%). The model elements include powder bed and substrate ( Figure 2 a). The laser scanning path is multi-layer and multi-track ( Figure 2 b) At the same time, APDL parametric language is used to realize the movement of heat source and the birth and death unit technology is used to simulate the part forming process.

[0070] Meshing was performed based on the physical model: a fine mesh (10μm×10μm×10μm) was created using hexahedral elements in the heat-affected zone of the powder layer, while a coarse mesh was created using tetrahedral elements in the substrate. A fine mesh was also created around the contact area with the scanning region to ensure efficient and accurate calculation results. The final mesh consisted of 12,560 elements and 63,807 nodes. The laser scanned in a unidirectional raster pattern.

[0071] Step 2: Load the density, thermal conductivity, specific heat, Young's modulus, Poisson's ratio, yield strength, and thermal expansion coefficient of the Al-Cu-Mg-Si alloy (the room temperature data of the above thermal properties are obtained by consulting materials or experiments), and calculate their temperature variation using Jmatpro software. Calculated by the following formula:

[0072]

[0073] in, represents the effective thermal conductivity of the solid alloy, and Φ is the porosity of the powder bed. The laser heat source control equation is:

[0074]

[0075] Where P is the laser power (W), A is the laser absorptivity, R is the laser spot radius (m), the starting point coordinates are (x0, y0), and r is the distance between the laser's movement to the model's spatial position (x, y) and the starting point (x0, y0) in time t (s). The powder's laser absorptivity is calculated using the Hagen-Ruben relationship:

[0076]

[0077] Where β is the DC resistivity of the metal and λ is the wavelength of the laser. The resistivity β of Al-Cu-Mg-Si alloy is calculated as follows:

[0078]

[0079] Since the absorptivity of Al-Cu-Mg-Si alloy powder is usually twice as high as that of polished bulk material, an absorptivity value of 2 is chosen. The heat transfer boundary conditions of laser powder melting of Al-Cu-Mg-Si alloy include initial preheating temperature, heat conduction, heat convection, heat radiation and phase change latent heat; the mechanical field boundary conditions are set as free boundaries.

[0080] Step 3: Perform thermal-mechanical coupling calculations on laser powder-melted aluminum alloy. The heat transfer process obeys the transient heat transfer governing equation:

[0081]

[0082] In the formula, k x (T), k y (T) and k z (T) is the thermal conductivity k (W / m·K) of the aluminum alloy in the three-dimensional directions x, y, and z as a function of temperature T (K), respectively. Q, ρ, and C represent the heat generated per unit volume, density, and specific heat capacity of the aluminum alloy, respectively. The mechanical field obeys the Von Mise yield criterion, and the equivalent stress expression is:

[0083]

[0084] in the formula 、 、 are the principal stresses in three mutually perpendicular directions. The expression for equivalent strain is:

[0085]

[0086] in the formula 、 、 are the principal strains in three mutually perpendicular directions; μ is the Poisson's ratio of the material.

[0087] Step 4: Comparison of simulated melt pool of laser powder melted aluminum alloy ( Figure 3 a) and experimental melt pool ( Figure 3 b) morphology, thereby optimizing and verifying the model. During the experiment, the Al-Cu-Mg-Si alloy powder particle size D50 = 34 μm was pre-laid on the substrate surface. The substrate preheating temperature was 160°C, and the powder thickness was 30 μm. The laser power was 210 W, the scanning speed was 350 mm / s, the overlap rate was 60%, and the scanning deflection angle was 67°. Extraction simulation ( Figure 4 a) and experimental ( Figure 4 b) The molten pool width and depth under different laser process parameters during the process are compared to verify the accuracy of the simulation.

[0088] Step 5: Extract the key characteristic parameters of the temperature field and stress field of laser powder melted Al-Cu-Mg-Si alloy, including the temperature distribution curve and cooling rate ( Figure 5 a) and residual stress ( Figure 5 b) simulation results; simulation calculation and experimental verification of the stress field distribution law of laser powder melting Al-Cu-Mg-Si alloy under different process parameters in the power range of 180-240 W and scanning speed of 300-350 mm / s ( Figure 6 ), and conduct simulation error statistics, and determine the degree of cracking and warping.

[0089] From the simulation and experimental verification of the embodiment, it can be seen that the morphology of the laser powder melting Al-Cu-Mg-Si alloy molten pool can be seen that the simulation results can accurately demonstrate the actual experimental process. According to the simulation and experimental comparison data of the molten pool width and depth at different scanning speeds, it can be seen that the simulation error of the simulation model is less than 15%, and the temperature field and residual stress distribution can be accurately obtained. According to the temperature distribution curve and stress distribution cloud map obtained by simulation, it can be seen that the maximum stress distribution area is the interface position between the aluminum alloy and the substrate, the laser powder bed melting adjacent aluminum alloy scanning track and the interlayer interface position, which is the key position for cracking and warping. By comparing the simulation and actual residual stress results under different laser powers and scanning speeds, it can be seen that the simulation model can predict the forming situation of the laser powder melting Al-Cu-Mg-Si alloy. By selecting appropriate laser power and scanning speed (e.g. 180 W-210 W and 300-350 mm / s) and further increasing the substrate preheating temperature (e.g. to 180, 200 °C), the cracking and warping phenomena can be effectively improved, thereby obtaining Al-Cu-Mg-Si alloy samples without significant cracks and thermal deformation ( Figure 7 ).

Claims

1. A simulation and prediction method for cracking and edge warping of laser powder melted aluminum alloy, characterized in that: The following steps are involved: Step 1: Establish a finite element simulation physical model for laser powder melting to prepare aluminum alloy; Step 2: Load the aluminum alloy thermophysical properties, heat source control equations, heat transfer and mechanical field boundary conditions into the finite element simulation physical model obtained in step 1; Step 3: After loading the aluminum alloy's thermophysical properties, heat source control equations, heat transfer, and mechanical field boundary conditions into the finite element simulation physical model, a thermal-mechanical coupling calculation of the laser powder melted aluminum alloy is performed to obtain the temperature distribution characteristics; Step 4: Determine the width and depth of the simulated molten pool based on the temperature distribution. Obtain the simulation error by comparing it with the actual verified width and depth of the laser powder melted aluminum alloy molten pool. Adjust and optimize the model calculation process based on the error. Step 5: Calculate the temperature field and mechanical field characteristics under different process parameters based on the optimized model, and determine the cracking and warping deformation locations through stress distribution and strength values.

2. The method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy according to claim 1, characterized in that : The model building software in step 1 includes one or more of ANSYS, COMSOL, and ABAQUS, and the physical model elements include a powder bed and a substrate.

3. The method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy according to claim 1, characterized in that : The aluminum alloy in step 2 includes any one of aluminum-copper alloy, aluminum-manganese alloy, aluminum-silicon alloy, and aluminum-magnesium alloy; the thermal properties include density, thermal conductivity, specific heat capacity, Young's modulus, Poisson's ratio, yield strength, and thermal expansion coefficient; the numerical changes of the thermal properties with temperature are calculated by one or more software such as Jmatpro and Thermo calc.

4. The method for simulating and predicting cracking and edge warping of laser powder-melted aluminum alloy according to claim 1, characterized in that: The heat source control equation in step 2 is: （1） In formula (1), P is the laser power (unit: W), A is the laser absorptivity, R is the laser spot radius (unit: m), the starting point coordinates are (x0, y0), and r is the distance between the laser moving to the model space position (x, y) and the starting point (x0, y0) at time t (unit: s). Heat transfer boundary conditions include initial preheating temperature T0, unit K, heat conduction k, unit W / m·K, heat convection coefficient, thermal radiation, unit W / m 2 ), latent heat of phase change, unit J / kg; The boundary conditions of the mechanical field include external loads and units of N.

5. The method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy according to claim 1, characterized in that: The heat transfer process of the thermal-mechanical coupling calculation in step 3 obeys the transient heat transfer governing equation: （2） k in formula (2) x (T), k y (T) and k z (T) is the thermal conductivity k (W / m·K) of the aluminum alloy in the three-dimensional directions x, y, and z as a function of temperature T (K), Q, ρ, and C represent the heat generated per unit volume, density, and specific heat capacity of the aluminum alloy, respectively. The mechanical field obeys the Von Mise yield criterion, and the equivalent stress expression is: （3） In formula (3), 、 、 are the principal stresses in three mutually perpendicular directions; the expression for the equivalent strain is: （4） In formula (4), 、 、 are the principal strains in three mutually perpendicular directions; μ is the Poisson's ratio of the aluminum alloy.

6. The method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy according to claim 1, characterized in that: In step 4, during the actual laser powder bed melting verification, the aluminum alloy powder particle size D50 = 34 ± 5.0 μm, the aluminum alloy powder is spread on the substrate surface with a powder thickness of 25-45 μm, and the substrate preheating temperature range is 140-200 °C; the laser powder bed melting process parameters are: laser power range of 200-500 W, scanning speed range of 200-500 mm / s, overlap rate of 40%-70%, and scanning deflection angle of 30-90 °.

7. The method for simulating and predicting cracking and edge warping of laser powder-melted aluminum alloy according to claim 1, characterized in that: In step 4, the melting width and depth of the molten pool are determined based on the molten pool temperature field distribution obtained in step 3, and then compared with the molten pool size obtained in actual verification to obtain the error of the thermal-mechanical coupling simulation. The simulation calculation process is regulated according to the error to optimize the model.

8. The method for simulating and predicting cracking and edge warping of laser powder melted aluminum alloy according to claim 1, characterized in that: In step 5, the key temperature field characteristic parameters include one or more of temperature gradient, cooling rate and solidification rate; the key stress field characteristic parameters include one or more of stress intensity, stress distribution position and strain.

9. The method for simulating and predicting cracking and edge warping of laser powder-melted aluminum alloy according to claim 1, characterized in that: The process parameters in step 5 include one or more of laser power, scanning speed, overlap rate, powder thickness scanning path, scanning direction, and boundary load.

10. A simulation prediction method using the method according to any one of claims 1 to 9, characterized in that: After model optimization, the comparison errors between the actual and simulated molten pool widths and depths of laser powder-melted aluminum alloys were both less than 15%. This allowed accurate prediction of the evolution of the temperature and stress fields of the laser-melted aluminum alloys, and the locations of cracking and warping were determined based on the areas of maximum stress distribution. Furthermore, these rules allowed the selection of laser powder bed melting process parameters with uniform stress distribution and low strength.

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