A method for evaluating stress-cracking resistance of metal 3D printing materials

Abstract

The present application relates to a kind of for evaluating the method of metal 3D printing material stress cracking resistance performance, belong to 3D printing technical field.The present application provides a kind of for evaluating the method of metal 3D printing material stress cracking resistance performance, and the method is applied to design and print the series model of metal 3D printing, the factor of model change is three corresponding stress-sensitive shape factors, respectively, part sharp angle ∠α1, part bottom plane angle ∠α2, sample and the R angle of bottom plane, find the design boundary of the material in printing process by printing series model not cracking, and the same model is used to compare the stress cracking resistance of different materials.

Description

Technical Field

[0001] This invention relates to a method for evaluating the stress cracking resistance of metal 3D printing materials, belonging to the field of 3D printing technology. Background Technology

[0002] In the process of metal laser additive manufacturing, the rapid heating and cooling characteristics of the manufacturing process itself cause the workpiece to be subjected to significant macroscopic stress. This includes multi-layer, multi-stage cyclic heating and cooling of the material, and the constraint of the substrate and the limitation of part deformation under non-uniform temperature gradients, resulting in significant thermal stress. Furthermore, for alloy materials, non-equilibrium solidification, non-equilibrium phase transformation, and microstructure transitions easily generate complex microstructure phase transformation stresses. When these stresses are high, they will lead to macroscopic deformation and cracking tendencies in the parts. Deformation and cracking generally occur at stress concentration points such as sharp corners, bends, and steps. The degree of deformation and cracking changes with the size of the printed product and the material system. On the one hand, the size and characteristic shape of the workpiece (such as the shape and location of sharp corners, bends, and steps) partially determine the magnitude of the stress; on the other hand, the mechanical properties of the workpiece material determine its ability to resist macroscopic deformation and cracking to a certain extent. The combined effect of these two factors ultimately determines the deformation and cracking state of the workpiece.

[0003] Currently, there is a lack of quantitative methods and standards for assessing the risk of stress cracking in materials during metal laser additive manufacturing. It is impossible to accurately determine whether cracks exist in the weak areas of the workpiece under actual printing conditions. Therefore, there is an urgent need in this technical field for a method suitable for assessing the resistance of metal 3D printing materials to macroscopic stress cracking. This method can quantify the design boundary of a certain material or compare and rank the resistance of different materials to macroscopic stress cracking, which is of great significance for material research and development and practical industrial applications. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem of how to obtain a method suitable for evaluating the macroscopic stress cracking resistance of metal 3D printing materials. This method can quantify the design boundary of a material or compare and rank the macroscopic stress cracking resistance of different materials.

[0005] To address the aforementioned problems, the present invention provides a method for evaluating the stress cracking resistance of metal 3D printing materials, comprising the following steps:

[0006] Step 1: Based on N stress-sensitive shape factors, design and print a model with M similar shapes. Each of the M shapes in the model includes N shape factors. The shape factors include sharp corner angles, slope angles, or radius (R) angles at corners. The number of models includes N.

[0007] Step 2: In the M shapes of a model 1, set shape factor 1 to M different quantized values ​​corresponding to the M shapes respectively, while set other shape factors to have the same quantized value; evaluate the M shapes of model 1, obtain the design boundary of shape factor 1 without cracking during printing, and determine the critical cracking value and critical safety value of shape factor 1.

[0008] Step 3: In the subsequent design and printing of Model 2, set the shape factor one from Step 2 as the critical safety value, set another shape factor two as M different quantized values ​​corresponding to M shapes respectively, and set the other shape factors as having the same quantized value; evaluate the M shapes of Model 2, obtain the design boundary of the shape factor two without cracking during the printing process, and determine the critical cracking value and critical safety value of the shape factor two.

[0009] Step 4: Similarly, in subsequent model design and printing, apply the known critical cracking value or critical safety value of the shape factor, set the unknown shape factor X to M different quantized values ​​corresponding to M shapes, and set the other shape factors to have the same quantized value; evaluate each of the M shapes of the subsequent model to obtain the design boundary of the shape factor X without cracking during printing, and determine the critical cracking value and critical safety value of the shape factor X.

[0010] Step 5: Finally, obtain the design boundaries of N shape factors that will not crack during the printing process, and determine the critical cracking value and critical safety value of the N shape factors.

[0011] This invention provides an application of a method for evaluating the stress cracking resistance of metal 3D printing materials.

[0012] Preferably, the application includes using the same model to compare the crack resistance of different materials.

[0013] This invention provides a model constructed according to the aforementioned method for evaluating the stress cracking resistance of metal 3D printing materials. Based on three stress-sensitive shape factors, a model with five similar shapes is designed and printed. The model includes three sub-models: Model A, Model B, and Model C. Each model contains a cylindrical base with a diameter of Φ1 and a height of H1. The upper surface of the cylindrical base is a circular plane with a diameter of Φ1. A pentagon with a height of H2 is provided on the circular plane. The five vertices of the five points of the star on the circular plane are located on the circumference of a circle with a diameter of Φ2, and the five vertices divide the circumference of the circle with a diameter of Φ2 into five equal parts; the center of the five-pointed star coincides with the center of the circles with diameters of Φ1 and Φ2; the shape elements are the apex of the five-pointed star on the circular plane with a diameter of Φ1, the angle ∠α2 between the edge line at the vertex of the apex of the five-pointed star on the circular plane with a diameter of Φ1 and the circular plane, and the chamfered R angle at the intersection of the edge line and the circular plane.

[0014] Preferably, in model A, ∠α2 is 90°, the radius (R) is 0°, and ∠α1 is 30°, 45°, 60°, 75°, and 90° respectively. After printing model A, metallographic observation is performed on the cracking at the five corners to obtain the critical cracking value of ∠α1. 1c and critical safety value ∠α 1k .

[0015] Preferably, in model B, ∠α1 is ∠α 1k The radius (R) is 0°, and the angles ∠α2 are 60°, 65°, 70°, 75°, and 80°. After printing model B, metallographic observation of the cracking at the five corners is performed to obtain the critical cracking value of ∠α2. 2c and critical safety value ∠α 2k .

[0016] Preferably, in model C, ∠α1 is ∠α 1c ∠α2 is ∠α 2c The radius (R) of the model was 0.2, 0.4, 0.6, 0.8, and 1 mm. After printing the model C, metallographic observation was performed on the cracking at the five corners to obtain the critical cracking value R of the radius. c and critical safety value R k .

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention allows for the identification of critical cracking conditions for a material within a given printing size using a series of models, and the assessment of the workpiece's cracking risk. For different materials, models with the same dimensional parameters can be used for printing to obtain critical cracking values, thereby comparing the crack resistance of two or more materials and their sensitivity to different shape factors. Attached Figure Description

[0019] Figure 1 These are labels for three stress-sensitive shape factors within the model: ∠α1, ∠α2, and R angle.

[0020] Figure 2 For model A, its shape factors are the sharp angles of the parts: ∠α1, ∠α2 = 90°, and R = 0.

[0021] Figure 3 For model B, its shape factor is the included angle ∠α2 of the bottom plane of the part, where ∠α1 is a specific angle and R = 0.

[0022] Figure 4 For model C, its shape factor is the R angle between the sample and the bottom plane, where ∠α1 is a specific angle and ∠α2 is a specific angle.

[0023] Figure 5 This is Model A of Example 1.

[0024] Figure 6 This is Model B of Example 1.

[0025] Figure 7 Model C is from Example 1. Detailed Implementation

[0026] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings:

[0027] like Figure 1-7 As shown, the technical solution adopted by the present invention is to provide a method for evaluating the stress cracking resistance of metal 3D printing materials, comprising the following steps:

[0028] Step 1: Based on N stress-sensitive shape factors, design and print a model with M similar shapes. Each of the M shapes in the model includes N shape factors. The shape factors include sharp corner angles, slope angles, or radius (R) angles at corners. The number of models includes N.

[0029] Step 2: In the M shapes of a model 1, set shape factor 1 to M different quantized values ​​corresponding to the M shapes respectively, while set other shape factors to have the same quantized value; evaluate the M shapes of model 1, obtain the design boundary of shape factor 1 without cracking during printing, and determine the critical cracking value and critical safety value of shape factor 1.

[0030] Step 3: In the subsequent design and printing of Model 2, set the shape factor one from Step 2 as the critical safety value, set another shape factor two as M different quantized values ​​corresponding to M shapes respectively, and set the other shape factors as having the same quantized value; evaluate the M shapes of Model 2, obtain the design boundary of the shape factor two without cracking during the printing process, and determine the critical cracking value and critical safety value of the shape factor two.

[0031] Step 4: Similarly, in subsequent model design and printing, apply the known critical cracking value or critical safety value of the shape factor, set the unknown shape factor X to M different quantized values ​​corresponding to M shapes, and set the other shape factors to have the same quantized value; evaluate each of the M shapes of the subsequent model to obtain the design boundary of the shape factor X without cracking during printing, and determine the critical cracking value and critical safety value of the shape factor X.

[0032] Step 5: Finally, obtain the design boundaries of N shape factors that will not crack during the printing process, and determine the critical cracking value and critical safety value of the N shape factors.

[0033] This invention provides an application of a method for evaluating the stress cracking resistance of metal 3D printing materials.

[0034] The application includes using the same model to compare the crack resistance of different materials.

[0035] This invention provides a model constructed according to the aforementioned method for evaluating the stress cracking resistance of metal 3D printing materials. Based on three stress-sensitive shape factors, a model with five similar shapes (the five points of a pentagram) is designed and printed. The model includes three sub-models: Model A, Model B, and Model C. Each model contains a cylindrical base with a diameter of Φ1 and a height of H1. The upper surface of the cylindrical base is a circular plane with a diameter of Φ1. A pentagram with a height of H2 is provided on the circular plane. A pentagram is a star whose five vertices lie on the circumference of a circle with a diameter of Φ2 on a circular plane, and the five vertices divide the circumference of the circle with a diameter of Φ2 into five equal parts; the center of the pentagram coincides with the centers of both circles with diameters of Φ1 and Φ2; the shape elements are the apex ∠α1 of the pentagram on the circular plane with a diameter of Φ1, the angle ∠α2 between the edge line at the vertex of the apex of the pentagram on the circular plane with a diameter of Φ1 and the circular plane, and the chamfered R-angle at the intersection of the edge line and the circular plane. Figure 1 As shown, Φ1, Φ2, H1, and H2 are other corresponding diameter or height dimensions.

[0036] Model A: The shape factor is the sharp corner ∠α1 of the part. The bottom of the model is a circular base with a diameter of Φ1 and a height of H1. On the circular base, there is a pentagram with ∠α1 of 30°, 45°, 60°, 75°, and 90°, and a height of H2. The five points fall on the five equal circles of diameter Φ2 on the circular base, and the center of the pentagram coincides with the center of the circular base. ∠α2 is 90°. The radius (R) is 0. Figure 2 As shown.

[0037] Model B: The shape factor is the included angle ∠α2 of the part's bottom plane. The bottom of the model is a circular base with diameter Φ1 and height H1. On the circular base, ∠α1 is a pentagram with a specific angle and height H2. The five points of the pentagram fall on the five equal parts of the circular base with diameter Φ2. The center of the pentagram coincides with the center of the circular base. ∠α2 are 60°, 65°, 70°, 75°, and 80° respectively. The radius (R) is 0. Figure 3 As shown.

[0038] Model C: The shape factor is the radius (R) angle between the sample and the bottom plane. The bottom of the model is a circular base with a diameter of Φ1 and a height of H1. On the circular base, ∠α1 and ∠α2 are pentagrams with specific angles and a height of H2. The five points fall on the five equal parts of the circular base with a diameter of Φ2. The center of the pentagram coincides with the center of the circular base. The radius angles are 0.2, 0.4, 0.6, 0.8, and 1 mm respectively. Figure 4 As shown.

[0039] The area of ​​maximum stress concentration for all models is the interface between the apex of the pentagram and the bottom plane. To determine the actual cracking situation, in addition to macroscopic observation by the human eye, it is also necessary to cut out a longitudinal section at this location and confirm the crack situation at each location under a microscope through metallography.

[0040] According to the method provided by the present invention, a series of models for evaluating the crack resistance of materials are designed and printed. The steps of using the model include:

[0041] 1. Print model A. Use metallographic methods to take cross-sections at the five corners and check for cracks. Denote the ∠α1 where the crack appears as ∠α. 1c Records greater than ∠α 1c The preceding angle is the critical cracking angle ∠α 1k Theoretically, the smaller the angle of a sharp angle, the greater the stress, for example, ∠α. 1c =45°, then ∠α 1k =60°.

[0042] 2. Print model B, where ∠α1 is a fixed value, and the value of ∠α is... 1k Metallographic analysis was used to take cross-sections at the five corners of the sample and examine them for cracks. The ∠α2 where the crack appears was denoted as ∠α. 2c Records greater than ∠α 2cThe preceding angle is the critical cracking angle ∠α 2k Theoretically, the smaller the included angle, the greater the stress, for example, ∠α. 2c =70°, then ∠α 2k =75°.

[0043] 3. Print model C, where ∠α1 is a fixed value, and the value of ∠α is... 1c ∠α2 is a fixed value, and the value of ∠α is... 2c Metallographic analysis was used to take cross-sections at five corners and examine them for cracks. The radius (R) at which cracks appeared was denoted as R. C Records greater than R C The previous angle is the critical value R. k Theoretically, the smaller the radius (R), the greater the stress. For example, R... C =0.2, then R k =0.4.

[0044] The diameter and height of the circular base plane, the height of the pentagram, and the diameter of the five-part circle should be consistent for models A, B, and C in the series.

[0045] The diameter Φ1 of the circular base planes of models A, B, and C is 150mm. The height H1 of the circular base planes of models A, B, and C is 20mm. The height H2 of the pentagram shapes on the circular base planes of models A, B, and C is 100mm each. The five points of the pentagram shapes on the circular base planes of models A, B, and C each fall on a five-part circle with a diameter Φ2 of 120mm. Print and verify the models in the order of A, B, and C.

[0046] The advantage of this invention is that it can use a series of models to find the critical cracking conditions of the material within a certain printing size and assess the cracking risk of the workpiece. For example, within the size range of Φ120mm*100mm, the estimated cracking risk of workpieces of different shapes is shown in the table below:

[0047] Φ120mm*100mm <![CDATA[∠α1]]> <![CDATA[∠α2]]> R Estimated degree of cracking Workpiece 1 <![CDATA[∠α1=∠α 1c ]]> <![CDATA[∠α2=∠α 2c ]]> R＝0 cracking Workpiece 2 <![CDATA[∠α1=∠α 1c ]]> <![CDATA[∠α2=∠α 2c ]]> <![CDATA[R=R k ]]> Certain risk of cracking Workpiece 3 <![CDATA[∠α1=∠α 1k ]]> <![CDATA[∠α2=∠α 2k ]]> <![CDATA[R=R k ]]> Extremely low risk of cracking Workpiece 4 <![CDATA[∠α1>∠α 1k ]]> <![CDATA[∠α2>∠α 2k ]]> <![CDATA[R>R k ]]> No risk of cracking

[0048] Example 1

[0049] like Figure 5 , Figure 6 and Figure 7 As shown, this embodiment discloses a series of 3D-printed models for evaluating the crack resistance of AISI420 stainless steel (0.3wt% C-13wt% Cr-0.8wt% Mn-0.8wt% Si). All models are 3D printed from metal. For models A, B, and C, the diameter Φ1 of the circular base is 150mm, the height H1 of the circular base is 20mm, the height H2 of the pentagram on the circular base is 100mm, and the five points of the pentagram on the circular base fall on a five-part circle with a diameter Φ2 of 120mm.

[0050] In this embodiment, a commercially available metal 3D printer is selected, and the metal 3D printing model is completed and the macroscopic cracking critical value within this size range is verified according to the following steps:

[0051] a) Printing of Model A: The bottom surface of Model A must be tightly fitted to the printing substrate to avoid cracking at the contact surface due to thermal stress during the printing process. Select appropriate printing parameters for the material and proceed with the printing. After printing, obtain Model A by wire cutting from the bottom surface of the printing substrate, such as... Figure 5 As shown.

[0052] b) Verify the cracking of model A: Divide model A along ∠α1 and perform a line cut. Perform metallographic observation at the junction of the pentagram and the circular base plane, examining the cracking under different ∠α1 values. Obtain ∠α... 1c =60°, ∠α 1k =75°. Given that within the dimensions of Φ120mm*100mm, with R=0 and ∠α2=90°, when ∠α1≥75°, the workpiece is less prone to macroscopic cracking. The critical value for model A is ∠α. 1k =75°.

[0053] c) Printing and Verification of Model B: Model B is designed with ∠α1 = 75° and R = 0. Its printed bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are used. After printing, Model B is obtained by wire cutting along the printed bottom surface against the printing substrate. Model B is then wire-cut along the midpoint of ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α2 values. ∠α2 is then obtained. 2c =65°, ∠α 2k =70°. It is known that within the size range of Φ120mm*100mm, when R=0 and ∠α1≥75°, and ∠α2≥70°, the workpiece is less prone to macroscopic cracking. The critical value of Model B is ∠α. 2k =70°.

[0054] d) Printing and Verification of Model C: Model C has ∠α1 = 60° and ∠α2 = 65°. Its printing bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are selected. After printing, model C is obtained by wire cutting along the printing bottom surface against the printing substrate. Model C is then wire-cut along the midpoint of ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α1 values. R is obtained. C =0.2, R k=0.4. It is known that within the size range of Φ120mm*100mm, when ∠α1≥60° and ∠α2≥65°, when R≥0.4, the workpiece is not prone to macroscopic cracking. The critical value of model B is R=0.4.

[0055] e) Obtain the critical value for no macroscopic cracking during the printing process of this material: within the size range of Φ120mm*100mm, the workpiece shape characteristic values ​​∠α1≥75°, ∠α2≥70°, R≥0.4mm, there is no risk of cracking.

[0056] Example 2

[0057] This embodiment discloses an evaluation method for 18Ni300:

[0058] A series of 3D-printed crack-resistant models made of (18wt% Ni-9wt% Co-5wt% Mo-0.7wt% Ti-0.1wt% Al) material. All models are 3D printed from metal. For models A, B, and C, the diameter Φ1 of the circular base is 150mm, the height H1 of the circular base is 20mm, the height H2 of the pentagram on the circular base is 100mm, and the five points of the pentagram on the circular base fall on a five-part circle with a diameter Φ2 of 120mm.

[0059] In this embodiment, a commercially available metal 3D printer is selected, and the metal 3D printing model is completed and the macroscopic cracking critical value within this size range is verified according to the following steps:

[0060] a) Printing of Model A: The bottom surface of Model A must be tightly fitted to the printing substrate to avoid cracking of the contact surface due to thermal stress during the printing process. Select appropriate printing parameters for the material and print. After printing, obtain Model A by wire cutting from the bottom surface of the printing substrate.

[0061] b) Verify the cracking of model A: Divide model A along ∠α1 and perform a line cut. Perform metallographic observation at the junction of the pentagram and the circular base plane, examining the cracking under different ∠α1 values. Obtain ∠α... 1c =30°, ∠α 1k =45°. Given that within the dimensions of Φ120mm*100mm, with R=0 and ∠α2=90°, when ∠α1≥45°, the workpiece is less prone to macroscopic cracking. The critical value for model A is ∠α. 1k =45°.

[0062] c) Printing and Verification of Model B: Model B is designed with ∠α1 = 45° and R = 0. Its printing bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are used. After printing, Model B is obtained by wire cutting along the printing bottom surface against the printing substrate. Model B is then wire-cut along the midpoint of ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α2 values. ∠α2 is then obtained. 2c =60°, ∠α 1k =65°. It is known that within the size range of Φ120mm*100mm, when R=0 and ∠α1≥45°, macroscopic cracking is less likely to occur in the workpiece when ∠α1≥65°. The critical value of Model B is ∠α. 2k =65°.

[0063] d) Printing and Verification of Model C: Model C has ∠α1 = 30° and ∠α2 = 60°. Its printing bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are selected. After printing, model C is obtained by wire cutting along the printing bottom surface against the printing substrate. Model C is then wire-cut along ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α1 values. R is obtained. C =0.2, R k =0.4. Given a dimension range of Φ120mm*100mm, with ∠α1≥30° and ∠α2≥60°, when R≥0.4, the workpiece is less prone to macroscopic cracking. The critical value for Model B is R. k =0.4.

[0064] e) Obtain the critical value for no macroscopic cracking during the printing process of this material: within the size range of Φ120mm*100mm, the workpiece shape characteristic values ​​∠α1≥45°, ∠α2≥65°, R≥0.4mm, there is no risk of cracking.

[0065] Example 3

[0066] This embodiment discloses a series of models for evaluating and comparing the resistance to macroscopic cracking of two different materials. The two materials are H11 (0.4wt% C-5wt% Cr-1.2wt% Mo-0.4wt% Mn-0.45wt% V-0.8wt% Si) and H13 (0.39wt% C-5.3wt% Cr-1.3wt% Mo-0.4wt% Mn-0.9wt% V-0.8wt% Si). All models in the series are 3D printed from metal. The diameter Φ1 of the circular base plane of models A, B, and C is 150mm, the height H1 of the circular base plane is 20mm, the height H2 of the pentagram on the circular base plane is 100mm, and the five points of the pentagram on the circular base plane fall on a five-part circle with a diameter Φ2 of 120mm.

[0067] In this embodiment, a commercially available metal 3D printer is selected, and the metal 3D printing model is completed and the macroscopic cracking critical value within this size range is verified according to the following steps:

[0068] a) Printing of Model A: The bottom surface of Model A must be tightly fitted to the printing substrate to avoid cracking of the contact surface due to thermal stress during the printing process. Select the appropriate printing parameters for each material and print. After printing, obtain Model A by wire cutting from the bottom surface of the printing substrate. Model A of H11 material is denoted as H11-A, and Model A of H13 material is denoted as H13-A.

[0069] b) Verify the cracking of model A: Divide model A along ∠α1 and perform a line cut. Perform metallographic observation at the junction of the pentagram and the circular base plane to examine the cracking under different ∠α1 values. H11-A obtains ∠α 1c =45°, ∠α 1k =60°, H13-A obtains ∠α 1c =60°, ∠α 1k =75°. It is known that under the same conditions, the critical value of H11-A is ∠α. 1k =60°, the critical value of H13-A is ∠α 1k =75°, for the part with a sharp angle ∠α1 as the shape factor, H11 has better crack resistance than H13.

[0070] c) Printing and Verification of Model B: Model B is designed with ∠α1 = 75° and R = 0. Its printing bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are used. After printing, Model B is obtained by wire cutting along the printing bottom surface against the printing substrate. Model B for H11 material is denoted as H11-B, and Model B for H13 material is denoted as H13-B. Model B is wire-cut along the midpoint of ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α2 values. H11-B yields ∠α... 2c =60°, ∠α 2k =65°, H13-B obtains ∠α 2c =70°, ∠α 2k =75°. It is known that under the same conditions, the critical value of H11-A is ∠α. 2k =65°, the critical value of H13-A is ∠α 2k =75°, for the part with a sharp angle ∠α2 as the shape factor, H11 has better crack resistance than H13.

[0071] d) Printing and Verification of Model C: Model C has ∠α1 = 60° and ∠α2 = 60°. Its printing bottom surface must be in close contact with the printing substrate. Printing parameters consistent with those of Model A are selected. After printing, model C is obtained by wire cutting along the printing bottom surface against the printing substrate. Model C for H11 material is denoted as H11-C, and model C for H13 material is denoted as H13-C. Model C is wire-cut along ∠α1. Metallographic observation is performed at the junction of the pentagram and the rounded bottom plane to examine the cracking under different ∠α1 values. R is obtained from H11-C. K ≤0.2, H13-C obtains R C =0.4, R K =0.6, indicating that under the same conditions, the critical value of H11-C is R. K ≤0.2, the critical value of H13-C is R K =0.6. For the shape factor of the sample's radius (R) relative to the bottom plane, H11's crack resistance is significantly better than H13's.

[0072] e) A comparison of the two materials’ resistance to deformation was obtained: H11’s resistance to macroscopic cracking was superior to H13 in all aspects.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for evaluating the stress cracking resistance of metal 3D printing materials, characterized in that, Includes the following steps: Step 1: Based on N stress-sensitive shape factors, design and print a model with M similar shapes. Each of the M shapes in the model includes N shape factors. The shape factors include sharp corner angles, slope angles, or radius (R) angles at corners. The number of models includes N. Step 2: In the M shapes of a model 1, set shape factor 1 to M different quantized values ​​corresponding to the M shapes respectively, while set other shape factors to have the same quantized value; evaluate the M shapes of model 1, obtain the design boundary of shape factor 1 without cracking during printing, and determine the critical cracking value and critical safety value of shape factor 1. Step 3: In the subsequent design and printing of Model 2, set the shape factor one from Step 2 as the critical safety value, set another shape factor two as M different quantized values ​​corresponding to M shapes respectively, and set the other shape factors as having the same quantized value; evaluate the M shapes of Model 2, obtain the design boundary of the shape factor two without cracking during the printing process, and determine the critical cracking value and critical safety value of the shape factor two. Step 4: Similarly, in subsequent model design and printing, apply the known critical cracking value or critical safety value of the shape factor, set the unknown shape factor X to M different quantized values ​​corresponding to M shapes, and set the other shape factors to have the same quantized value; evaluate each of the M shapes of the subsequent model to obtain the design boundary of the shape factor X without cracking during printing, and determine the critical cracking value and critical safety value of the shape factor X. Step 5: Finally, obtain the design boundaries of N shape factors that will not crack during the printing process, and determine the critical cracking value and critical safety value of the N shape factors.

2. The method for evaluating the stress cracking resistance of metal 3D printing materials according to claim 1, characterized in that, It is used to compare the crack resistance of different materials using the same model.

3. A model construction method for implementing the method of claim 2 for evaluating the stress cracking resistance of metal 3D printing materials, characterized in that, Based on three stress-sensitive shape factors, a model with five similar shapes was designed and printed. The model includes three sub-models: Model A, Model B, and Model C. Each model contains a cylindrical base with a diameter of Φ1 and a height of H1. The upper surface of the cylindrical base is a circular plane with a diameter of Φ1. A pentagram with a height of H2 is placed on the circular plane. The vertices of the five points of the pentagram on the circular plane are located on the circumference of a circle with a diameter of Φ2, and the five vertices divide the circumference of the circle with a diameter of Φ2 into five equal parts. The center of the pentagram coincides with the centers of the circles with diameters of Φ1 and Φ2. The shape factors are the apex of the pentagram on the circular plane with a diameter of Φ1, ∠α1; the angle ∠α2 between the edge line at the vertex of the apex of the pentagram on the circular plane with a diameter of Φ1 and the circular plane; and the chamfered R-angle at the intersection of the edge line and the circular plane.

4. The model construction method according to claim 3, characterized in that, In model A, ∠α2 is 90°, the radius (R) is 0°, and ∠α1 is 30°, 45°, 60°, 75°, and 90°. After printing model A, metallographic observation is performed on the cracking at the five corners to obtain the critical cracking value of ∠α1. 1c and critical safety value ∠α 1k .

5. The model construction method according to claim 4, characterized in that, In model B, ∠α1 is ∠α 1k The radius (R) is 0°, and the angles ∠α2 are 60°, 65°, 70°, 75°, and 80°. After printing model B, metallographic observation of the cracking at the five corners is performed to obtain the critical cracking value of ∠α2. 2c and critical safety value ∠α 2k .

6. The model construction method according to claim 5, characterized in that, In model C, ∠α1 is ∠α 1c ∠α2 is ∠α 2c The radius (R) of the model was 0.2, 0.4, 0.6, 0.8, and 1 mm. After printing the model C, metallographic observation was performed on the cracking at the five corners to obtain the critical cracking value R of the radius. c and critical safety value R k .

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