A method and system for calculating and evaluating the degree of anisotropy of an additive manufacturing material

Abstract

The application relates to a kind of additive manufacturing material anisotropy degree calculation evaluation method and system, comprising: preparing original sample based on the object to be evaluated;Select part of sample in original sample to be irradiated, obtain irradiated sample;Nanoindentation test is carried out to unirradiated sample and irradiated sample, and the relationship curve of indentation depth and nano-hardness is obtained;Extract characteristic nano-hardness value;According to the characteristic nano-hardness value, the relative irradiation hardening rate of different orientation surfaces and the relative irradiation hardening rate of different deposition surfaces are obtained;According to the relative irradiation hardening rate of different orientation surfaces and the relative irradiation hardening rate of different deposition surfaces, the anisotropy degree factor of hardening effect is obtained;The anisotropy degree of the object to be evaluated is evaluated based on the anisotropy degree factor.The application is more suitable for SLM additive manufacturing of small batch materials or workpieces, and the anisotropy can be quantitatively evaluated, which helps to guide and optimize related material additive process technology.

Description

Technical Field

[0001] The present invention relates to the technical field related to metal additive manufacturing, and more specifically, to a method and system for calculating and evaluating the degree of anisotropy of additively manufactured materials. Background Art

[0002] Additive Manufacturing (AM) is a metal or alloy preparation process that accumulates materials layer by layer. It has the advantages of high design freedom, high material utilization, and convenient and efficient production. Selective Laser Melting (SLM) is one of the more mature processes in metal AM. It uses high-precision laser scanning and energy control to quickly form components, achieving better material properties than traditional manufacturing. It is currently widely used in industrial fields such as aerospace, transportation, and precision medicine.

[0003] As a critical energy industry, nuclear power places strict emphasis on the safety of the materials used. The development and application of metal additive manufacturing in this sector is currently in its infancy, with applications limited to frequently replaced, non-critical components such as circuit filters and fuel assembly base frames. Research on additively manufactured metal materials and components primarily focuses on forming processes and basic performance evaluation. Due to the unique forming method, compared to traditional forging, the microstructure of the material inevitably exhibits a degree of anisotropy. Anisotropy, broadly defined, refers to the dimensional variations in a material's properties, primarily due to its microstructure, such as the columnar structure of as-cast metals or that produced by additive manufacturing. Most alloys produced by SLM (Solid Laser Molding) exhibit a specific columnar structure due to the temperature gradient parallel to the printing direction generated by the melt pool's temperature field. This columnar structure is closely related to the printing material and process. Research often characterizes the anisotropy of additively manufactured materials through mechanical tensile properties, comparing the mechanical properties in the vertical (printing direction) and transverse directions. However, different research results show that the anisotropy of the same material after printing varies under different equipment and process parameters, and there is currently no quantitative evaluation method to characterize the anisotropy of additive materials. Using mechanical tensile property parameter comparison requires a larger sample size, which is difficult to achieve for additive manufacturing of small batches of products. For nickel-based alloys commonly used in industry (such as 718 alloy), due to their excellent high-temperature performance, the columnar crystals obtained by SLM molding are relatively small. The anisotropic effect brought by the columnar crystals will be masked by the performance changes caused by the process defects in SLM molding, making it more difficult to obtain the anisotropy of the columnar crystal structure in macroscopic mechanical tests. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for calculating and evaluating the degree of anisotropy of additive manufacturing materials in response to the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is to construct a method for calculating and evaluating the degree of anisotropy of additive manufacturing materials, comprising the following steps:

[0006] Prepare an original sample based on an object to be evaluated; the object to be evaluated is an additively manufactured nickel-based 718 alloy;

[0007] selecting a portion of the original sample for irradiation to obtain an irradiated sample;

[0008] Performing nanoindentation testing on unirradiated samples and irradiated samples to obtain a relationship curve between indentation depth and nanohardness; the unirradiated samples are samples of the original samples that have not been irradiated;

[0009] Extracting characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values;

[0010] Calculating based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of surfaces with different orientations;

[0011] Calculating based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of different deposition surfaces;

[0012] Calculating the anisotropy degree factor of the hardening effect according to the relative radiation hardening rates of the different orientation surfaces and the relative radiation hardening rates of the different deposition surfaces;

[0013] The anisotropy degree of the object to be evaluated is evaluated based on the anisotropy degree factor.

[0014] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, preparing an original sample based on the object to be evaluated includes:

[0015] Performing wire cutting on the object to be evaluated according to different orientation surfaces and deposition surfaces to obtain square sheet samples;

[0016] The surface of the square plate sample is ground and polished to obtain the original sample.

[0017] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials according to the present invention, selecting a portion of the original sample for irradiation to obtain the irradiated sample includes:

[0018] Selecting some samples from the original sample;

[0019] The polished surfaces of the part of the samples are subjected to ion irradiation to obtain the irradiated samples.

[0020] In the method for calculating and evaluating the degree of anisotropy of additive manufacturing materials described in the present invention, the maximum depth of ion irradiation damage of the irradiated sample is 1 μm to 1.5 μm, the irradiation operation amount is 1.0 dpa, and the irradiation temperature is room temperature.

[0021] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, performing nanoindentation testing on non-irradiated samples and irradiated samples to obtain a relationship curve between indentation depth and nanohardness includes:

[0022] A nanoindentation test in a continuous stiffness mode is performed on the non-irradiated sample and the irradiated sample to obtain a relationship curve between the indentation depth and nanohardness.

[0023] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, the test conditions of the nanoindentation test are: Poisson's ratio is 0.3, the indentation depth is 2 μm, and the number of test points for each sample is no more than or equal to 10.

[0024] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, extracting a characteristic nanohardness value based on the relationship curve between the indentation depth and the nanohardness to obtain the characteristic nanohardness value includes:

[0025] Based on the relationship curve between the indentation depth and the nanohardness, a relationship curve of the segmented slope is obtained;

[0026] Determine the first selected area;

[0027] Performing linear fitting on the relationship curve of the segmented slopes based on the first selected area to obtain a first fitting straight line;

[0028] Calculating the arithmetic square root of the intercept of the first fitting straight line to obtain the hardness of the substrate;

[0029] Determine the second selection area;

[0030] Performing linear fitting on the relationship curve of the segmented slopes based on the second selected area to obtain a second fitting straight line;

[0031] Calculating the arithmetic square root of the intercept of the second fitting straight line to obtain the hardness of the surface;

[0032] The hardness of the substrate and the hardness of the surface are the characteristic nanohardness values.

[0033] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, the characteristic nanohardness values ​​include: the hardness of the substrate and the hardness of the surface;

[0034] The hardness of the substrate includes: the substrate hardness of the scanning surface A series of unirradiated samples, the substrate hardness of the scanning surface A system irradiated samples, the substrate hardness of the deposition surface B series of unirradiated samples and the substrate hardness of the deposition surface B system irradiated samples;

[0035] The surface hardness includes: the surface hardness of the unirradiated samples of the scanning surface A series, the surface hardness of the irradiated samples of the scanning surface A system, the surface hardness of the unirradiated samples of the deposition surface B series, and the surface hardness of the irradiated samples of the deposition surface B system.

[0036] In the method for calculating and evaluating the degree of anisotropy of additively manufactured materials described in the present invention, the calculation based on the characteristic nanohardness value to obtain the relative radiation hardening rate of different orientation surfaces includes:

[0037] Calculating based on the surface hardness of the unirradiated samples of the scanning surface A series and the matrix hardness of the unirradiated samples of the scanning surface A series to obtain a hardness difference rate between the surface and the matrix of the unirradiated samples of the scanning surface A series;

[0038] Calculating the hardness difference between the surface and substrate of the series of irradiated samples on the scanning surface A according to the surface hardness and the substrate hardness of the series of irradiated samples on the scanning surface A;

[0039] The relative radiation hardening rate of the scanning surface series A is obtained by calculating the hardness difference rate between the surface of the unirradiated sample and the substrate and the hardness difference rate between the surface of the irradiated sample and the substrate of the scanning surface series A; the relative radiation hardening rate of the scanning surface series A is the relative radiation hardening rate of the surfaces with different orientations;

[0040] The calculation based on the characteristic nanohardness value to obtain the relative radiation hardening rate of different deposition surfaces includes:

[0041] Calculating based on the surface hardness of the unirradiated samples of the deposition surface B series and the base hardness of the unirradiated samples of the deposition surface B series to obtain the hardness difference rate between the surface and base of the unirradiated samples of the deposition surface B series;

[0042] Calculating according to the surface hardness of the deposition surface B series irradiated samples and the base hardness of the deposition surface B series irradiated samples to obtain the hardness difference rate between the surface and the base of the deposition surface B series irradiated samples;

[0043] The relative irradiation hardening rate of the deposition surface series B is obtained by calculating the hardness difference rate between the surface and the substrate of the non-irradiated samples of the deposition surface series B and the hardness difference rate between the surface and the substrate of the irradiated samples of the deposition surface series B;

[0044] The relative radiation hardening rates of the deposition surface series B are the relative radiation hardening rates of the different deposition surfaces.

[0045] The present invention also provides a system for calculating and evaluating the degree of anisotropy of additive manufacturing materials, comprising:

[0046] A sample preparation unit, configured to prepare an original sample based on an object to be evaluated; the object to be evaluated is a sample of additively manufactured nickel-based 718 alloy;

[0047] an irradiation unit, configured to select a portion of the original sample for irradiation to obtain an irradiated sample;

[0048] A nanoindentation testing unit, used to perform nanoindentation testing on non-irradiated samples and irradiated samples to obtain a relationship curve between indentation depth and nanohardness; the non-irradiated samples are samples of the original samples that have not been irradiated;

[0049] A characteristic value extraction unit is used to extract characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values;

[0050] A first hardening rate calculation unit is used to calculate according to the characteristic nanohardness value to obtain relative radiation hardening rates of surfaces with different orientations;

[0051] a second hardening rate calculation unit, configured to calculate, based on the characteristic nanohardness value, relative radiation hardening rates of different deposition surfaces;

[0052] an anisotropy degree factor calculation unit, configured to calculate the anisotropy degree factor of the hardening effect according to the relative radiation hardening rates of the different orientation surfaces and the relative radiation hardening rates of the different deposition surfaces;

[0053] An anisotropy program evaluation unit is used to evaluate the anisotropy degree of the object to be evaluated based on the anisotropy degree factor.

[0054] The method and system for calculating and evaluating the degree of anisotropy of additively manufactured materials of the present invention have the following beneficial effects: comprising: preparing an original sample based on the object to be evaluated; selecting a portion of the original sample for irradiation to obtain an irradiated sample; performing nanoindentation testing on the unirradiated sample and the irradiated sample to obtain a curve showing the relationship between indentation depth and nanohardness; extracting characteristic nanohardness values; calculating based on the characteristic nanohardness values ​​to obtain the relative irradiation hardening rates of different oriented surfaces and the relative irradiation hardening rates of different deposition surfaces; calculating based on the relative irradiation hardening rates of different oriented surfaces and the relative irradiation hardening rates of different deposition surfaces to obtain an anisotropy degree factor of the hardening effect; and evaluating the degree of anisotropy of the object to be evaluated based on the anisotropy degree factor. The present invention is more suitable for small batches of materials or workpieces formed by SLM additive manufacturing, and can quantitatively evaluate anisotropy, which helps guide and optimize related material additive process technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0056] Figure 1 1 is a flow chart of a method for calculating and evaluating the degree of anisotropy of additive manufacturing materials provided by the present invention;

[0057] Figure 2 This is a principle block diagram of the system for calculating and evaluating the degree of anisotropy of additive manufacturing materials provided by the present invention;

[0058] Figure 3 This is a dH relationship diagram before and after ion irradiation of different orientation surfaces provided by the present invention;

[0059] Figure 4 The 1 / dH before and after ion irradiation of different orientation surfaces provided by the present invention 2 Relationship diagram. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0061] refer to Figure 1 , Figure 1 Schematic diagram of the process for calculating and evaluating the degree of anisotropy of additively manufactured materials provided by the present invention.

[0062] Specifically, such as Figure 1 As shown, the method for calculating and evaluating the anisotropy degree of additive manufacturing materials includes the following steps:

[0063] Step S101: preparing an original sample based on an object to be evaluated.

[0064] Among them, the object to be evaluated is the additively manufactured nickel-based 718 alloy.

[0065] In an embodiment of the present invention, preparing an original sample based on the object to be evaluated includes: performing wire cutting processing on the object to be evaluated according to different orientation surfaces and deposition surfaces to obtain a square sheet sample; and grinding and polishing the surface of the square sheet sample to obtain an original sample.

[0066] Specifically, a certain additively manufactured nickel-based 718 material was processed into square sheet samples with a thickness of 1 mm and a side length of 5 to 10 mm by wire cutting according to different orientation surfaces (i.e., scanning surface (A series)) and deposition surface (B series). The sample surface was polished using 400 to 2000# metallographic sandpaper and then polished to a mirror finish.

[0067] Step S102: Select a portion of the original sample for irradiation to obtain an irradiated sample.

[0068] In an embodiment of the present invention, selecting a portion of the original sample for irradiation to obtain the irradiated sample includes: selecting the portion of the original sample; and ion irradiating the polished surface of the portion of the sample to obtain the irradiated sample. The maximum depth of ion damage to the irradiated sample is 1 μm to 1.5 μm, the irradiation dose is 1.0 dPa, and the irradiation temperature is room temperature.

[0069] Optionally, in an embodiment of the present invention, the number of original samples can be selected and determined according to actual needs. For example, two original samples can be prepared, and correspondingly, some of the samples can be any one of the original samples, that is, the irradiated sample is one, and accordingly, the remaining sample in the original sample is one, which is the subsequent non-irradiated sample.

[0070] Specifically, a sample was selected from the original samples for ion irradiation experiment, and an irradiation experiment was carried out on its polished surface. The maximum depth of ion irradiation damage was 1μm to 1.5μm, the irradiation operation amount was 1.0dPa, and the irradiation temperature was room temperature.

[0071] Step S103: Perform nanoindentation testing on the unirradiated sample and the irradiated sample to obtain a relationship curve between indentation depth and nanohardness, wherein the unirradiated sample is the original sample that has not been irradiated.

[0072] In an embodiment of the present invention, performing nanoindentation testing on the unirradiated sample and the irradiated sample to obtain a curve showing the relationship between the indentation depth and the nanohardness includes: performing nanoindentation testing on the unirradiated sample and the irradiated sample in a continuous stiffness mode to obtain a curve showing the relationship between the indentation depth and the nanohardness. The nanoindentation testing conditions are: a Poisson's ratio of 0.3, an indentation depth of 2 μm, and no more than 10 test points per sample.

[0073] Specifically, nanoindentation tests in continuous stiffness mode were carried out on unirradiated samples and irradiated samples, with a Poisson's ratio of 0.3 and an indentation depth of 2 μm. No less than 10 test points were selected for each sample, and the average curve of the relationship between "indentation depth (nm), d" and "nanohardness (GPa), H" of the corresponding samples was obtained, that is, the indentation depth and nanohardness relationship curve (dH relationship curve).

[0074] Step S104: extracting characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values.

[0075] In an embodiment of the present invention, characteristic nanohardness value extraction is performed based on the relationship curve between indentation depth and nanohardness, and obtaining characteristic nanohardness value includes: plotting the relationship curve between indentation depth and nanohardness to obtain a relationship curve of segmented slope; determining a first selected area; performing linear fitting on the relationship curve of segmented slope based on the first selected area to obtain a first fitting straight line; calculating the arithmetic square root of the intercept of the first fitting straight line to obtain the hardness of the substrate; determining a second selected area; performing linear fitting on the relationship curve of segmented slope based on the second selected area to obtain a second fitting straight line; calculating the arithmetic square root of the intercept of the second fitting straight line to obtain the hardness of the surface; the hardness of the substrate and the hardness of the surface are characteristic nanohardness values. Wherein, the first selected area is 0μm -1 ≤1 / d≤1μm -1 The second selected area is 4μm -1 ≤1 / d≤10μm -1 area.

[0076] In an embodiment of the present invention, the characteristic nanohardness values ​​include: the hardness of the substrate and the hardness of the surface; the hardness of the substrate includes: the substrate hardness of the unirradiated samples of the scanning surface A series, the substrate hardness of the samples irradiated by the scanning surface A system, the substrate hardness of the unirradiated samples of the deposition surface B series, and the substrate hardness of the samples irradiated by the deposition surface B system; the surface hardness includes: the surface hardness of the unirradiated samples of the scanning surface A series, the surface hardness of the samples irradiated by the scanning surface A system, the surface hardness of the unirradiated samples of the deposition surface B series, and the surface hardness of the samples irradiated by the deposition surface B system.

[0077] Specifically, according to the obtained dH relationship curve, 1 / d(μm-1 ) and H 2 (GPa 2 ) to obtain a segmented slope relationship curve, select 0μm -1 ≤1 / d≤1μm -1 Perform linear fitting on the area of ​​​​the fitted line, calculate the arithmetic square root H0 of the intercept of the fitted line, and obtain the hardness of the substrate; select 4μm -1 ≤1 / d≤10μm -1 Perform a linear fit on the area of ​​​​the surface, calculate the arithmetic square root H1 of the intercept of the fitting line, and obtain the surface hardness. According to this step, the calculation is:

[0078] Scanning surface A series non-irradiated sample matrix hardness: H A0,unirr ;

[0079] Scanning surface A series non-irradiated sample surface hardness: H A1,unirr ;

[0080] Scanning surface A series irradiated sample matrix hardness: H A0,irr ;

[0081] Scanning surface A series irradiated sample surface hardness: H A1,irr ;

[0082] Deposition surface B series non-irradiated sample matrix hardness: H B0,unirr ;

[0083] Surface hardness of unirradiated samples of series B on the deposition surface: H B1,unirr ;

[0084] Deposition surface B series irradiated sample matrix hardness: H B0,irr ;

[0085] Surface hardness of B series irradiated samples on the deposition surface: H B1,irr .

[0086] Step S105: performing calculations based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of surfaces with different orientations.

[0087] In an embodiment of the present invention, calculating based on characteristic nanohardness values ​​to obtain relative radiation hardening rates of surfaces with different orientations includes: calculating based on the surface hardness of unirradiated samples in scanning surface A series and the substrate hardness of unirradiated samples in scanning surface A series to obtain the hardness difference between the surface and substrate of unirradiated samples in scanning surface A series; calculating based on the surface hardness of irradiated samples in scanning surface A series and the substrate hardness of irradiated samples in scanning surface A series to obtain the hardness difference between the surface and substrate of irradiated samples in scanning surface A series; and calculating based on the hardness difference between the surface and substrate of unirradiated samples in scanning surface A series and the hardness difference between the surface and substrate of irradiated samples in scanning surface A series to obtain the relative radiation hardening rates of scanning surface A series. The relative radiation hardening rates of scanning surface A series are the relative radiation hardening rates of surfaces with different orientations.

[0088] Specifically, the hardness difference rate △H between the original unirradiated sample surface and the substrate of the scanning surface A series is calculated by formula (1): A,unirr , calculate the hardness difference rate △H between the surface and substrate of the irradiated sample of scanning surface A series by formula (2) A,irr , calculate the relative radiation hardening rate R of the scanning surface A series by formula (3) A , as follows:

[0089]

[0090] R A =ΔH A,irr -ΔH A,unirr (3).

[0091] Step S106: performing calculations based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of different deposition surfaces.

[0092] In an embodiment of the present invention, calculating based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of different deposition surfaces includes: calculating based on the surface hardness of unirradiated samples in series B of deposition surface and the substrate hardness of the unirradiated samples in series B of deposition surface to obtain the hardness difference rate between the surface and substrate of the unirradiated samples in series B of deposition surface; calculating based on the surface hardness of irradiated samples in series B of deposition surface and the substrate hardness of the irradiated samples in series B of deposition surface to obtain the hardness difference rate between the surface and substrate of the irradiated samples in series B of deposition surface; and calculating based on the hardness difference rate between the surface and substrate of the unirradiated samples in series B of deposition surface and the hardness difference rate between the surface and substrate of the irradiated samples in series B of deposition surface to obtain the relative radiation hardening rate of series B of deposition surface. The relative radiation hardening rate of series B of deposition surface is the relative radiation hardening rate of different deposition surfaces.

[0093] Specifically, the hardness difference △H between the original unirradiated sample surface and the substrate of the deposition surface B series is calculated by formula (1): B,unirrThe hardness difference between the surface and substrate of the B series irradiated sample is calculated by formula (2): B,irr , the relative irradiation hardening rate R of the deposition surface series B is calculated by formula (3) B , as follows:

[0094]

[0095] R B =ΔH B,irr -ΔH B,unirr (6).

[0096] Step S107: Calculate the relative radiation hardening rates of different orientation surfaces and the relative radiation hardening rates of different deposition surfaces to obtain anisotropy degree factors of the hardening effect.

[0097] In the embodiment of the present invention, the R calculated according to formula (3) is A R calculated by formula (6) B , the anisotropy degree factor (X) of the hardening effect can be calculated. The anisotropy degree factor can be calculated using formula (7):

[0098]

[0099] Step S108: Evaluate the anisotropy degree of the object to be evaluated based on the anisotropy degree factor.

[0100] In the embodiments of the present invention, after the anisotropy factor X is calculated, the anisotropy factor X can be evaluated. Specifically, when X ≤ 1, the material has essentially no microscopic anisotropy; when 1 < X ≤ 10, the material has a low microscopic anisotropy; and when X > 10, the material has a high microscopic anisotropy.

[0101] It is understandable that in the embodiment of the present invention, by repeating steps S101 to S108, the anisotropic effects of different additive materials can be compared, and the anisotropy degree factors of different materials can be calculated for comparison. The larger the anisotropy degree factor, the higher the anisotropy degree of the additive material.

[0102] refer to Figure 2 , Figure 2 This is a principle block diagram of the system for calculating and evaluating the degree of anisotropy of additive manufacturing materials provided by the present invention.

[0103] Specifically, such as Figure 2 As shown, the anisotropy degree calculation and evaluation system for additive manufacturing materials includes:

[0104] The sample preparation unit 201 is used to prepare an original sample based on the object to be evaluated; the object to be evaluated is a sample of additively manufactured nickel-based 718 alloy.

[0105] The irradiation unit 202 is used to select a portion of the original sample for irradiation to obtain an irradiated sample.

[0106] The nanoindentation testing unit 203 is used to perform nanoindentation testing on non-irradiated samples and irradiated samples to obtain a relationship curve between indentation depth and nanohardness; the non-irradiated samples are samples in the original samples that have not been irradiated.

[0107] The characteristic value extraction unit 204 is used to extract characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values.

[0108] The first hardening rate calculation unit 205 is used to calculate according to the characteristic nanohardness value to obtain the relative radiation hardening rates of the surfaces with different orientations.

[0109] The second hardening rate calculation unit 206 is used to calculate the relative radiation hardening rates of different deposition surfaces according to the characteristic nanohardness values.

[0110] The anisotropy degree factor calculation unit 207 is used to calculate the anisotropy degree factor of the hardening effect according to the relative radiation hardening rates of different orientation surfaces and the relative radiation hardening rates of different deposition surfaces.

[0111] The anisotropy program evaluation unit 208 is used to evaluate the anisotropy degree of the object to be evaluated based on the anisotropy degree factor.

[0112] Specifically, the specific coordination operation process between the various units in the additive manufacturing material anisotropy degree calculation and evaluation system can refer to the above-mentioned additive manufacturing material anisotropy degree calculation and evaluation method, which will not be repeated here.

[0113] This method utilizes the differences in the degree of ion irradiation hardening in different directions of additively manufactured metal materials (a characteristic of columnar crystal structures) to quantitatively evaluate anisotropy by observing the variation in hardness properties at the microscopic grain scale. The advantages of this method are that, compared to conventional mechanical tensile methods for evaluating macroscopic mechanical properties such as yield strength, tensile strength, and elongation, it requires smaller samples, making it more suitable for small batches of materials or workpieces produced by SLM additive manufacturing. It also provides relatively quantitative anisotropy evaluation indicators for evaluating additive manufacturing technologies and helping to guide and optimize related additive manufacturing processes.

[0114] The following is an explanation using a specific embodiment.

[0115] Specifically, the anisotropy degree of a nickel-based 718 alloy specimen manufactured by selective laser melting (SLM) additive manufacturing was calculated and evaluated.

[0116] 1) Sample preparation and processing: According to different orientation surfaces (scanning surface samples (series A) and deposition surface (series B)), square samples with a thickness of 1 mm and a side length of 8 mm were processed by wire cutting. The sample surface was polished to a mirror surface using 400-2000# metallographic sandpaper.

[0117] 2) Ion irradiation: The polished surface of the sample in 1) was subjected to 540keV He 2+ In the ion irradiation experiment, the maximum depth of ion irradiation damage is 1 μm, and the irradiation damage amount is 1.0 dPa (the actual injection amount is 4.6×10 16 ions / cm 2 ), and the irradiation temperature was room temperature.

[0118] 3) Nanoindentation test: Nanoindentation test in continuous stiffness mode was carried out on non-irradiated and irradiated samples, with Poisson's ratio of 0.3, indentation depth of 2 μm, and 10 test points per sample. The average curve of the relationship between "indentation depth (nm, d)" and "nanohardness (GPa, H)" of the corresponding samples was obtained, as shown in Figure 3. Figure 3 shown.

[0119] 4) Characteristic nanohardness value extraction: According to the obtained dH relationship curve, 1 / d (μm -1 ) and H 2 (GPa 2 ) relationship diagram, such as Figure 4 As shown, a segmented slope relationship curve is obtained, and 0μm is selected -1 ≤1 / d≤1μm -1 Perform linear fitting on the area of ​​​​the fitted line, calculate the arithmetic square root H0 of the intercept of the fitted line, and obtain the hardness of the substrate; select 4μm -1 ≤1 / d≤10μm -1 Perform a linear fit on the area of ​​​​the surface, calculate the arithmetic square root H1 of the intercept of the fitting line, and obtain the surface hardness. According to this step, the calculation is:

[0120] Scanning surface A series non-irradiated sample matrix hardness: H A0,unirr =3.653GPa;

[0121] Scanning surface A series non-irradiated sample surface hardness: H A1,unirr =4.583GPa;

[0122] Scanning surface A series irradiated sample matrix hardness: H A0,irr =3.316GPa;

[0123] Scanning surface A series irradiated sample surface hardness: H A1,irr =5.838GPa;

[0124] Deposition surface B series non-irradiated sample matrix hardness: H B0,unirr =3.584GPa;

[0125] Surface hardness of unirradiated samples of series B on the deposition surface: H B1,unirr =4.655GPa;

[0126] Deposition surface B series irradiated sample matrix hardness: H B0,irr =3.534GPa;

[0127] Surface hardness of B series irradiated samples on the deposition surface: H B1,irr =5.841GPa.

[0128] 5) Calculate the hardness difference between the original unirradiated sample surface and the substrate of the scanning surface A series by formula (1): A,unirr , calculate the hardness difference rate △H between the surface and substrate of the irradiated sample of scanning surface A series by formula (2) A,irr , and then calculate the relative radiation hardening rate R of the scanning surface A by formula (3) A .

[0129] △H A,uirr =(H A1,unirr -H A0,unirr ) / H A0,unirr ×100%=25.5%;

[0130] △H A,irr =(H A1,irr -H A0,irr ) / H A0,irr ×100%=76.1%;

[0131] R A =△H A,irr -△H A,uirr =50.6%.

[0132] 6) Calculate the hardness difference between the original unirradiated sample surface and the substrate of the deposition surface B series by formula (4): B,unirr The hardness difference between the surface and substrate of the B series irradiated sample is calculated by formula (5): B,irr , and then calculate the relative radiation hardening rate R of the deposition surface B by formula (6) B .

[0133] △H B uirr =(H B1,unirr –H B0,unirr) / H B0,unirr ×100%=29.9%;

[0134] △H B,irr =(H B1,irr –H B0,irr ) / H B0,irr ×100%=65.3%;

[0135] R B =△H B,irr -△H B,uirr =35.4%.

[0136] 7) Based on the degree of irradiation hardening, the "anisotropy factor X" of the hardening effect is calculated using Formula 7, and the degree of anisotropy is evaluated.

[0137]

[0138] Since X>10, it indicates that the additively manufactured 718 material has a high degree of microscopic anisotropy.

[0139] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0140] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0141] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0142] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent variations and modifications within the scope of the claims of the present invention are intended to be covered by the claims of the present invention.

Claims

1. A method for calculating and evaluating the degree of anisotropy of additive manufacturing materials, characterized in that: The following steps are involved: Prepare an original sample based on an object to be evaluated; the object to be evaluated is an additively manufactured nickel-based 718 alloy; selecting a portion of the original sample for irradiation to obtain an irradiated sample; Nanoindentation tests were performed on non-irradiated and irradiated samples to obtain the relationship curve between indentation depth and nanohardness. The non-irradiated sample is a sample of the original sample that has not been irradiated; Extracting characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values; The characteristic nanohardness value extraction based on the relationship curve between the indentation depth and the nanohardness to obtain the characteristic nanohardness value includes: plotting the relationship curve between the indentation depth and the nanohardness to obtain a segmented slope relationship curve; determining a first selected area; performing a linear fit on the segmented slope relationship curve based on the first selected area to obtain a first fitted straight line; calculating the arithmetic square root of the intercept of the first fitted straight line to obtain the hardness of the substrate; determining a second selected area; performing a linear fit on the segmented slope relationship curve based on the second selected area to obtain a second fitted straight line; calculating the arithmetic square root of the intercept of the second fitted straight line to obtain the hardness of the surface; the hardness of the substrate and the hardness of the surface are the characteristic nanohardness values; Calculating based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of surfaces with different orientations; Calculating based on the characteristic nanohardness values ​​to obtain relative radiation hardening rates of different deposition surfaces; Calculating the anisotropy degree factor of the hardening effect according to the relative radiation hardening rates of the different orientation surfaces and the relative radiation hardening rates of the different deposition surfaces; The anisotropy degree of the object to be evaluated is evaluated based on the anisotropy degree factor.

2. The method for calculating and evaluating the anisotropy degree of additive manufacturing materials according to claim 1, characterized in that: The preparation of the original sample based on the object to be evaluated includes: Performing wire cutting on the object to be evaluated according to different orientation surfaces and deposition surfaces to obtain square sheet samples; The surface of the square plate sample is ground and polished to obtain the original sample.

3. The method for calculating and evaluating the anisotropy degree of additive manufacturing materials according to claim 1, characterized in that: The selecting a portion of the original sample for irradiation to obtain the irradiated sample comprises: Selecting some samples from the original sample; The polished surfaces of the part of the samples are subjected to ion irradiation to obtain the irradiated samples.

4. The method for calculating and evaluating the degree of anisotropy of additive manufacturing materials according to claim 1, characterized in that: The maximum depth of ion irradiation damage of the irradiated sample is 1 μm to 1.5 μm, the irradiation operation amount is 1.0 dpa, and the irradiation temperature is room temperature.

5. The method for calculating and evaluating the degree of anisotropy of additive manufacturing materials according to claim 1, characterized in that: The nanoindentation test is performed on the non-irradiated sample and the irradiated sample to obtain the relationship curve between the indentation depth and the nanohardness, comprising: A nanoindentation test in a continuous stiffness mode is performed on the non-irradiated sample and the irradiated sample to obtain a relationship curve between the indentation depth and nanohardness.

6. The method for calculating and evaluating the anisotropy degree of additive manufacturing materials according to claim 5, characterized in that: The test conditions of the nanoindentation test are: Poisson's ratio of 0.3, indentation depth of 2 μm, and no more than 10 test points for each sample.

7. The method for calculating and evaluating the anisotropy degree of additive manufacturing materials according to claim 1, characterized in that: The characteristic nanohardness values ​​include: the hardness of the substrate and the hardness of the surface; The hardness of the substrate includes: the substrate hardness of the scanning surface A series of unirradiated samples, the substrate hardness of the scanning surface A system irradiated samples, the substrate hardness of the deposition surface B series of unirradiated samples and the substrate hardness of the deposition surface B system irradiated samples; The surface hardness includes: the surface hardness of the unirradiated samples of the scanning surface A series, the surface hardness of the irradiated samples of the scanning surface A system, the surface hardness of the unirradiated samples of the deposition surface B series, and the surface hardness of the irradiated samples of the deposition surface B system.

8. The method for calculating and evaluating the degree of anisotropy of additive manufacturing materials according to claim 7, characterized in that: The calculation based on the characteristic nanohardness value to obtain the relative radiation hardening rate of different orientation surfaces includes: Calculating based on the surface hardness of the unirradiated samples of the scanning surface A series and the matrix hardness of the unirradiated samples of the scanning surface A series to obtain a hardness difference rate between the surface and the matrix of the unirradiated samples of the scanning surface A series; Calculating the hardness difference between the surface and substrate of the series of irradiated samples on the scanning surface A according to the surface hardness and the substrate hardness of the series of irradiated samples on the scanning surface A; The relative radiation hardening rate of the scanning surface series A is obtained by calculating the hardness difference rate between the surface of the unirradiated sample and the substrate and the hardness difference rate between the surface of the irradiated sample and the substrate of the scanning surface series A; the relative radiation hardening rate of the scanning surface series A is the relative radiation hardening rate of the surfaces with different orientations; The calculation based on the characteristic nanohardness value to obtain the relative radiation hardening rate of different deposition surfaces includes: Calculating based on the surface hardness of the unirradiated samples of the deposition surface B series and the base hardness of the unirradiated samples of the deposition surface B series to obtain the hardness difference rate between the surface and base of the unirradiated samples of the deposition surface B series; Calculating according to the surface hardness of the deposition surface B series irradiated samples and the base hardness of the deposition surface B series irradiated samples to obtain the hardness difference rate between the surface and the base of the deposition surface B series irradiated samples; The relative irradiation hardening rate of the deposition surface series B is obtained by calculating the hardness difference rate between the surface and the substrate of the non-irradiated samples of the deposition surface series B and the hardness difference rate between the surface and the substrate of the irradiated samples of the deposition surface series B; The relative radiation hardening rates of the deposition surface series B are the relative radiation hardening rates of the different deposition surfaces.

9. A system for calculating and evaluating the degree of anisotropy of additive manufacturing materials, characterized in that: include: A sample preparation unit, used for preparing an original sample based on an object to be evaluated; The object to be evaluated is a sample of additively manufactured nickel-based 718 alloy; an irradiation unit, configured to select a portion of the original sample for irradiation to obtain an irradiated sample; Nanoindentation test unit, used to perform nanoindentation tests on non-irradiated samples and irradiated samples to obtain the relationship curve between indentation depth and nanohardness; The non-irradiated sample is a sample of the original sample that has not been irradiated; A characteristic value extraction unit is used to extract characteristic nanohardness values ​​based on the relationship curve between the indentation depth and the nanohardness to obtain characteristic nanohardness values; The characteristic nanohardness value extraction based on the relationship curve between the indentation depth and the nanohardness to obtain the characteristic nanohardness value includes: plotting the relationship curve between the indentation depth and the nanohardness to obtain a segmented slope relationship curve; determining a first selected area; performing a linear fit on the segmented slope relationship curve based on the first selected area to obtain a first fitted straight line; calculating the arithmetic square root of the intercept of the first fitted straight line to obtain the hardness of the substrate; determining a second selected area; performing a linear fit on the segmented slope relationship curve based on the second selected area to obtain a second fitted straight line; calculating the arithmetic square root of the intercept of the second fitted straight line to obtain the hardness of the surface; the hardness of the substrate and the hardness of the surface are the characteristic nanohardness values; A first hardening rate calculation unit is used to calculate according to the characteristic nanohardness value to obtain relative radiation hardening rates of surfaces with different orientations; a second hardening rate calculation unit, configured to calculate, based on the characteristic nanohardness value, relative radiation hardening rates of different deposition surfaces; an anisotropy degree factor calculation unit, configured to calculate the anisotropy degree factor of the hardening effect according to the relative radiation hardening rates of the different orientation surfaces and the relative radiation hardening rates of the different deposition surfaces; An anisotropy program evaluation unit is used to evaluate the anisotropy degree of the object to be evaluated based on the anisotropy degree factor.

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