Non-linear composition transition continuous gradient material additive manufacturing method and system

Abstract

The invention relates to a non-linear component transition continuous gradient material additive manufacturing method and system. The problems that a traditional component linear change functionally gradient material is prone to generating a brittle phase in a component sensitive interval and is insufficient in performance can be solved. The method comprises the steps of determining a gradient step size according to the part size, and calculating the component change rate of each layer based on the printing layer thickness and height; the full-component functionally graded material is prepared in a linear transition mode, and a brittle phase generation interval is recognized in combination with a microstructure characterization means; a component nonlinear transition mode is designed for a sensitive interval, element segregation and brittle phase generation are inhibited, and the interface bonding strength and comprehensive performance are optimized. Components of the gradient material prepared through the method are continuously controllable in any direction, component distribution is free of a mutation interface, the strength, the high-temperature oxidation resistance and the thermal fatigue life of the gradient material are remarkably better than those of a traditional linear gradient material, and the gradient material is suitable for aerospace, nuclear energy heat dissipation, biological implantation and other high-performance requirement scenes.

Description

Technical Field

[0001] This application relates to the technical field of gradient material preparation, and more specifically to an additive manufacturing method and system for continuously gradient materials with non-linear component transition. Background Art

[0002] With the upgrading of the demand for materials serving in extreme environments, traditional homogeneous materials are facing severe challenges. In high temperature gradient scenarios (such as the combustion chamber of aeroengines), it is difficult for a single material to meet multiple performance requirements such as high temperature resistance, corrosion resistance, and lightweight at the same time. For example, hot end components need to be heat resistant in high temperature areas and fatigue resistant in low temperature areas. Direct connection of dissimilar materials (such as Ti / steel, Al / Cu) is prone to generate brittle intermetallic compounds (FeTi, Al2Cu), resulting in a sharp drop in mechanical properties; Functionally Graded Materials (FGMs) effectively avoid the abrupt change problem at the interface of dissimilar materials through continuous transition of composition / structure, and are an important solution to meet complex performance requirements.

[0003] However, traditional functional gradient material preparation technologies face double challenges of complex processes and performance defects. For example, physical vapor deposition and plasma spraying have low deposition rates, large pollution, and cannot manufacture complex three-dimensional blocks; powder metallurgy has cumbersome processes, which are prone to cause composition segregation and discontinuous layer interfaces; centrifugal casting has problems of high surface roughness and significant thermal cracking tendency; self-propagating high-temperature synthesis (SHS) is prone to generate pores and metastable phases due to uncontrollable reactions. Generally speaking, traditional methods are difficult to balance continuous composition transition and integrated manufacturing of complex structures, and have problems such as low interfacial bonding strength and poor compatibility of material systems. The emergence of powder bed fusion technology has broken through the above limitations. It realizes structure construction through layer-by-layer stacking and energy beam scanning, has the advantages of highly free three-dimensional structure design ability and precise control of laser energy, and can effectively control the molten pool state and microstructure evolution, thereby optimizing the interfacial bonding characteristics and improving the overall performance of the material.

[0004] During the process of manufacturing functionally gradient materials by powder bed fusion, the first method to appear was the direct connection method. Due to the differences in thermal physical properties of materials (such as thermal expansion coefficient, melting point), the interface is prone to generate residual stress, pores and cracks, and the bonding strength is relatively low; the subsequently developed discrete composition transition method alleviates the problem of interface discontinuity to a certain extent, but its composition changes abruptly and lacks systematic design, and it is still prone to mechanical property degradation due to insufficient diffusion or brittle intermetallic compounds in the composition sensitive area. In contrast, FGMs with continuous gradient composition transition can better coordinate the differences in thermophysical properties in different regions and reduce the formation of interfacial stress concentration.

[0005] However, even in the entire composition range under the continuous gradient mode, there may still be some composition-sensitive intervals. Within these intervals, defects such as element segregation or brittle intermetallic compounds are likely to occur during the forming process of the material. The commonly used linear gradient functions at present do not fully utilize the potential advantages of functionally graded materials and still have difficulty achieving the global optimization of material properties. Summary of the Invention

[0006] The present application provides an additive manufacturing method for continuously graded materials with non-linear composition transition, which can identify the composition-sensitive intervals of the fully compositional functionally graded materials and, within these intervals, redesign the composition distribution using non-linear transition methods such as logarithmic functions, exponential functions, and polynomial functions, so as to solve the problems of easy generation of brittle phases and insufficient performance in the composition-sensitive intervals of traditional functionally graded materials with linearly varying compositions.

[0007] In a first aspect, the present application provides an additive manufacturing method for continuously graded materials with non-linear composition transition. The method includes: calculating a gradient step according to the height of the target component and the printing layer thickness; identifying the composition-sensitive intervals based on the fully compositional functionally graded materials formed by using a linear composition transition method; within the identified composition-sensitive intervals, redesigning the composition distribution using a non-linear composition transition method with a preset gradient function; and performing an energy beam scan on the powder materials stacked layer by layer according to the redesigned composition distribution to form the target component.

[0008] In an alternative embodiment of the first aspect, the calculation formula for the gradient step is: , where Step is the gradient step, ω(A) is the material A with a mass fraction of 100%, ω(B) is the material B with a mass fraction of 100%, h is the total height of the target component in the deposition direction, and t is the printing layer thickness.

[0009] In an alternative embodiment of the first aspect, when identifying the composition-sensitive intervals, the method includes: performing an energy beam scan on the powder materials stacked layer by layer using a linear composition transition method to form a fully compositional functionally graded material; performing microstructure characterization and performance testing on the fully compositional functionally graded material to identify the composition-sensitive intervals or the performance indicators to be optimized.

[0010] In an alternative embodiment of the first aspect, the microstructure characterization includes scanning electron microscope analysis and energy dispersive X-ray spectroscopy analysis for detecting whether brittle intermetallic compounds / or element segregation occur within the entire composition range.

[0011] In an alternative embodiment of the first aspect, the performance test selects one or more of the tensile property test of stainless steel, the thermal conductivity test of copper alloy, the high-temperature creep property test of superalloy, the fracture toughness test of titanium alloy, the fatigue property test of aluminum alloy, and the corrosion resistance test of tantalum alloy according to the material system and service requirements.

[0012] In an alternative embodiment of the first aspect, the preset gradient function includes one or more of a monotonic linear gradient function, a monotonic exponential gradient function, a monotonic logarithmic gradient function, and a monotonic polynomial gradient function.

[0013] In an alternative embodiment of the first aspect, when redesigning the composition distribution by means of a non-linear composition transition method, the method includes: an exponential function transition to achieve a sharp transition of the composition change within the composition-sensitive interval, suppressing element mutual solubility and the formation of brittle phases; a logarithmic function transition to achieve a slow transition of the composition change within the composition-sensitive interval, promoting element diffusion and uniform grain refinement.

[0014] In an alternative embodiment of the first aspect, when redesigning the composition distribution by means of a non-linear composition transition method, the method includes: combining thermodynamic simulation to predict the phase transformation behavior within the composition-sensitive interval; adjusting the energy beam power, scanning speed, and interlayer cooling rate to control the melting and solidification conditions; determining the composition transition strategy regulation according to the phase transformation behavior and the target optimized performance.

[0015] In an alternative embodiment of the first aspect, when determining the composition transition strategy, the corresponding gradient function is selected according to the diffusion coefficient and interfacial tension characteristics of different elements within the composition-sensitive interval.

[0016] In an alternative embodiment of the first aspect, when adjusting the energy beam, a preset regulation strategy is adopted to implement layer-by-layer energy compensation within the composition-sensitive interval, thereby reducing the thermal stress concentration caused by composition mutation.

[0017] In an alternative embodiment of the first aspect, the preset regulation strategy includes: gradually reducing the energy beam power layer by layer before entering the composition-sensitive interval, maintaining a constant preset energy level power within the target interval, and gradually restoring to the normal power after leaving the occurrence interval; reducing the energy beam scanning speed within the composition-sensitive interval to increase the local heat input, and combining with a preset power energy beam to avoid local overburning or tissue coarsening; introducing intermittent preheating and cooling operations at the upper and lower boundary layers of the composition-sensitive interval to minimize the interlayer temperature difference.

[0018] Second aspect, the present application provides a continuous gradient material additive manufacturing system using non-linear component transition according to the above additive manufacturing method, including: a gradient calculation module for calculating a gradient step according to the height of the target component and the printing layer thickness; an interval identification module for identifying a component sensitive interval according to a full-component functional gradient material formed by a linear component transition method; a transition design module for re-designing the component distribution in the identified component sensitive interval by using a non-linear component transition method of a preset gradient function; and a scanning control module for performing an energy beam scan on the powder material stacked layer by layer according to the re-designed component distribution to form the target component.

[0019] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. Description of the Drawings

[0020] The drawings incorporated herein and forming a part of the specification illustrate one or more embodiments of the present application and, together with the description, are used to explain the principles of the present application and to enable those of ordinary skill in the relevant art to make and use the present application.

[0021] Figure 1 is a schematic diagram of the component transition direction of an exemplary functional gradient material specimen along the Z-axis according to some embodiments of the present application.

[0022] Figure 2 is a schematic diagram of the component transition direction of an exemplary functional gradient material specimen along the X-axis according to some embodiments of the present application.

[0023] Figure 3 is an exemplary linear gradient function distribution diagram according to some embodiments of the present application.

[0024] Figure 4 is a schematic flow diagram of an exemplary continuous gradient material additive manufacturing method according to some embodiments of the present application.

[0025] Figure 5 is an exemplary sharp-transition polynomial gradient function distribution diagram according to some embodiments of the present application.

[0026] Figure 6 is an exemplary slow-transition polynomial gradient function distribution diagram according to some embodiments of the present application.

[0027] Figure 7 is a schematic flow diagram of an exemplary non-linear component transition parameter optimization method according to some embodiments of the present application.

[0028] Figure 8It is a schematic diagram of modules of an exemplary additive manufacturing system for continuously graded materials according to some embodiments of the present application.

[0029] Figure 9 It is a schematic diagram of connections of an exemplary electronic device according to some embodiments of the present application. Detailed implementation manners

[0030] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and comprehensive, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of this application.

[0031] Functionally graded materials (FGMs) are a new type of materials with spatially continuously varying compositions or microstructures, thus achieving a gradually varying distribution of properties in space. FGMs were initially proposed in the 1980s to meet the requirements of thermal protection structures in aerospace and have now been widely applied in extreme working conditions such as aerospace, nuclear energy, ocean engineering, biomedicine, and automotive manufacturing. Their essential difference from traditional composite materials is that traditional composite materials are mostly composed of a mixture of multiple materials with obvious interface mutations; while FGMs overcome the mechanical and thermal performance problems between traditional multiple materials through a way of no obvious interface transition.

[0032] Continuous gradient composition transition refers to the change of material composition in FGMs along a certain direction in the form of a continuous function without obvious interfaces, ensuring smooth performance transition. The powder bed fusion (PBF) technology realizes precise continuous composition transition by layer-by-layer controlling the laser energy and powder ratio, and is particularly suitable for the integrated manufacturing of complex structures of FGMs.

[0033] Powder bed fusion (PBF) is an additive manufacturing technology driven by energy beams such as laser beams or electron beams. By selectively melting metal or polymer powder materials layer by layer, three-dimensional solid parts with complex geometric structures are manufactured. The PBF technology is particularly suitable for preparing metal components with high density, high precision, and complex structures, and is widely used in fields with extremely high performance requirements such as aerospace, biomedicine, and energy power.

[0034] At present, according to the different energy sources used, PBF is mainly divided into several types such as laser powder bed fusion (L-PBF), electron beam melting (EBM), and selective laser sintering (SLS). The process flow of PBF usually includes powder spreading, energy beam scanning and melting, interlayer lifting, and post-processing, etc. The specific process is as follows: Use a powder spreading mechanism to lay a layer of powder material with a thickness of dozens to hundreds of micrometers on the forming platform to form a uniform powder bed. Then, according to the slice data of the three-dimensional component model, a laser beam or an electron beam selectively scans, melts, and solidifies the current powder layer along a preset path to form a solid cross-section. After scanning one layer, the forming platform descends by a layer thickness unit, and the next layer of powder is laid. Repeat the above steps to achieve layer-by-layer construction until the entire three-dimensional component is completed. After the component is completed, it is taken out and undergoes post-processing steps such as heat treatment, support removal, and surface treatment to obtain the final product. The performance and quality of PBF are affected by various parameters such as energy beam power, scanning speed, scanning spacing, layer thickness, scanning strategy, and powder characteristics.

[0035] At present, powder bed fusion manufactures functionally graded materials through continuous gradient design. Compared with the discrete composition transition method, it has the advantage of significantly reducing defects caused by excessive differences in thermal physical properties. However, in the entire composition range, there may still be some composition-sensitive intervals that are prone to defects such as brittle phases during the forming process, and the current linear composition transition method has not fully explored the advantages of this functionally graded material.

[0036] Reference Figure 1 and Figure 2 As shown, during the process of using an additive manufacturing method with continuously controllable gradient changes, while ensuring that the printing layer thickness remains unchanged, the composition change gradient of each layer is changed. For example, when transitioning from material A in the first layer to material B in the nth layer, if it is a linear transition, the composition change amount of each layer is , thereby realizing the controllability of the overall composition change of the specimen.

[0037] For the specific linear composition transition method, refer to Figure 3 As shown, when transitioning from material A to material B, among them, the composition from A1 to B1 is also transitioned in this way, and the corresponding printing layer height is Z1.

[0038] Therefore, to solve the problems of the existing powder bed fusion for manufacturing functionally graded materials, refer to Figure 4 As shown, Figure 4 shows a schematic flow chart of an exemplary additive manufacturing method for continuously graded materials according to some embodiments of the present application. The present application designs a non-linear composition transition additive manufacturing method for continuously graded materials, and this method includes:

[0039] S1: Calculate the gradient step size according to the height of the target component and the printing layer thickness.

[0040] Specifically, the calculation formula for the gradient step size is: , where Step is the gradient step size, ω(A) is the A material with a mass fraction of 100%, ω(B) is the B material with a mass fraction of 100%, h is the total height of the target component in the deposition direction, and t is the printing layer thickness; among them, the A material can be a single-component material or a composite-component material; the B material can be a single-component material or a composite-component material.

[0041] S2: Identify the composition-sensitive interval according to the fully-composition functional gradient material formed by the linear composition transition method.

[0042] Specifically, before printing the target component, first form the fully-composition functional gradient material by the linear composition transition method, and then perform microstructure characterization and performance testing on the fully-composition functional gradient material to identify the composition-sensitive interval or the performance indicators to be optimized.

[0043] Among them, the microstructure characterization includes scanning electron microscopy (SEM-EBSD) analysis and energy-dispersive X-ray spectroscopy analysis (EDS), etc., which are used to detect whether brittle intermetallic compounds / or element segregation appears in the fully-composition interval.

[0044] Among them, the performance testing selects at least one of the following testing types according to the material system and service requirements: tensile property testing of stainless steel, thermal conductivity testing of copper alloy, high-temperature creep property testing of superalloy, fracture toughness testing of titanium alloy, fatigue property testing of aluminum alloy, and corrosion resistance testing of tantalum alloy.

[0045] Exemplarily, taking the CuCrZr / 316L material as an example, before scanning and forming the target CuCrZr / 316L material component, a functionally graded material sample with a height of 40 mm and a layer thickness of 0.1 mm is first constructed by means of linear composition transition. During the printing process, the powder feeding ratio is adjusted layer by layer to make the CuCrZr and 316L stainless steel linearly transition along the height direction in the deposition direction, that is, transitioning from 100% 316L of the sample to 100% CuCrZr, forming a continuously varying bimetallic gradient material. After printing, it can be selected to analyze by scanning electron microscopy (SEM-EBSD) or by energy dispersive X-ray spectroscopy analysis (EDS), and it can also be selected to analyze by scanning electron microscopy (SEM-EBSD) and by energy dispersive X-ray spectroscopy analysis (EDS); then, according to the material properties and application requirements of CuCrZr and 316L stainless steel, the following tests are carried out on different regions of the specimen: tensile property test in the 316L region, thermal conductivity test in the CuCrZr-dominated region, and microhardness measurement and fracture toughness test on samples taken from the intermediate transition region; thus, the regions where the microstructure and properties of the target CuCrZr / 316L material component show abnormal fluctuations are identified and this region is used as the composition-sensitive interval.

[0046] S3: Within the identified composition-sensitive interval, redesign the composition distribution by means of a non-linear composition transition manner with a preset gradient function.

[0047] Specifically, when redesigning the composition distribution by means of a non-linear composition transition manner, one or more of exponential function transition and logarithmic function transition can be selected. Among them, the exponential function transition realizes a sharp transition of the composition change within the composition-sensitive interval, suppressing element mutual dissolution and the formation of brittle phases; the logarithmic function transition realizes a slow transition of the composition change within the composition-sensitive interval, promoting element diffusion and uniform grain refinement.

[0048] In some examples of the present application, the preset gradient function includes one or more of a monotonic linear gradient function, a monotonic exponential gradient function, a monotonic logarithmic gradient function, and a monotonic polynomial gradient function.

[0049] Among them, the monotonic linear gradient function is applicable to a bimetallic system or alloy system with good composition compatibility and strong element mutual solubility. This function realizes a uniform change of the composition with height and can obtain a relatively stable organizational structure; the formula of the monotonic linear gradient function is: , , where is the mass fraction of a certain component at the height x position of the component, is the initial mass fraction at the starting position; k is the linear change coefficient, ; is the total height of the component.

[0050] Among them, the monotonic exponential gradient function is applicable to scenarios where rapid transition is required within the composition-sensitive interval to reduce element interdiffusion or avoid the formation of intermetallic compounds. This function helps to avoid the formation of undesirable phases through rapid transition. The formula for the monotonic exponential gradient function is:

[0051] , , where is the exponential amplitude coefficient that controls the total amplitude of composition change, is the exponential growth rate that regulates the speed of composition change. Exemplarily, for example, in the CuCrZr / 316L system, to inhibit the precipitation of the brittle Cu-Fe phase in the middle section, α > 0 can be set to enable a rapid transition of the Cu content;

[0052] Among them, the monotonic logarithmic gradient function is applicable to regions where slow transition needs to be achieved, component diffusion needs to be promoted, and grain refinement is required. It is applicable to the design of heterogeneous metal transition with a tendency of hot cracking or high interface strength requirements. The formula for the monotonic logarithmic gradient function is: , , where controls the maximum amplitude of composition change, is the change rate parameter, and the smaller it is, the slower the change. Exemplarily, for example, in the AlSi10Mg / TC4 system, to reduce the tendency of hot cracking and achieve uniform control of the microstructure in the transition zone, a small β value is used for regulation.

[0053] Among them, the monotonic polynomial gradient function provides the greatest degree of regulation freedom, can accurately fit the ideal composition evolution trajectory of the actual composition-sensitive section, and is applicable to dealing with complex composition transition requirements, such as asymmetric bimetals and multi-component alloys. This function has strong expression ability and can match any complex target curve. The formula for the monotonic polynomial gradient function is:

[0054] , , where is the polynomial coefficient of the i-th order, and n is the order of the polynomial, usually taking 2 - 4 orders.

[0055] In the actual implementation process, the above functions can be used alone or combined through weighting to form a composite gradient function. For example: , where, , satisfying , can achieve flexible superposition of various gradient regulation effects; is the monotonic linear gradient function, is the monotonic exponential gradient function, is the monotonic logarithmic gradient function, is a monotonic polynomial gradient function. In actual applications, two functions can be combined with weights, or three functions can be combined with weights, or all functions can be combined with weights for use, which is specifically set by the operator according to actual needs.

[0056] For specific reference Figure 5 and Figure 6 as shown in Figure 5 shows an exemplary way of a sharp-transition polynomial gradient function in some embodiments of the present application, transitioning from Material A to Material B. Among them, the transition from Component A1 to Component B1 also adopts this method, and the corresponding printing layer height is Z2. Figure 6 shows an exemplary way of a slow-transition polynomial gradient function in some embodiments of the present application, transitioning from Material A to Material B. Among them, the transition from Component A1 to Component B1 also adopts this method, and the corresponding printing layer height is Z3.

[0057] For the composition-sensitive interval (the composition interval where bad phases are likely to occur), the sharp-transition method effectively inhibits the initiation of cracks in the composition-sensitive interval and the precipitation of brittle phases by suppressing element mutual solubility, optimizing the molten pool morphology, and refining the microstructure, etc.; the slow-transition method promotes grain epitaxial growth and uniform refinement. The slow-transition continuous gradient material maintains a single-phase austenite structure, and the grain size changes gradually with the composition, forming a smooth transition of the molten pool morphology. For example, the TiB / Ti6Al4V gradient material realizes continuous regulation of the grain size from sub-micron to micron through slow transition, improving the mechanical isotropy.

[0058] S4: Perform an energy beam scan on the powder material stacked layer by layer according to the redesigned composition distribution to form the target component.

[0059] In some embodiments of the present application, as shown in reference Figure 7 shown Figure 7 shows a schematic flow chart of an exemplary method for optimizing non-linear composition transition parameters in some embodiments of the present application. When redesigning the composition distribution using the non-linear composition transition method, the parameters of the non-linear composition transition method are optimized through the following steps:

[0060] S31: Combine thermodynamic simulations to predict the phase transformation behavior within the composition-sensitive interval.

[0061] Specifically, the phase transformation behavior is predicted through thermodynamic simulations to identify the composition-sensitive interval. The specific process includes: based on thermodynamic software such as Thermo-Calc or Pandat, import the element composition of the target functionally graded material to construct a multi-component phase diagram database; then set the composition scanning path and identify the composition-sensitive interval, and thereby extract the phase transformation start temperature and the curve of phase content changing with the composition, providing boundary constraints for the subsequent setting of the composition transition function.

[0062] S32: Adjust the energy beam power, scanning speed, and interlayer cooling rate to control the melting and solidification conditions.

[0063] Specifically, set the energy beam power range, scanning speed, and interlayer cooling rate. Then, use finite element simulation tools (such as ANSYS Additive, Simufact Additive) to simulate the temperature field and cooling rate under different parameter combinations, and analyze whether the solidification process of the molten pool will cause element segregation, non-equilibrium microstructure, or grain coarsening in the sensitive interval. Furthermore, control the molten pool size and cooling rate within a reasonable range in the sensitive interval to avoid the enrichment of intermetallic compounds or the generation of hot cracks.

[0064] S33: Determine the composition transition strategy regulation according to the phase transformation behavior and target optimized performance.

[0065] Specifically, when determining the composition transition strategy, set a preset gradient function in the identified sensitive interval according to S31 and S32 to quickly avoid the brittle interval, and achieve a slow transition in the stable interval to improve the microstructure uniformity of the transition zone.

[0066] Exemplarily, taking the CuCrZr / 316L functionally graded material as an example, the specific process is as follows:

[0067] Based on thermodynamic software such as Thermo-Calc or Pandat, import the element compositions of CuCrZr and 316L, construct a multi-component phase diagram database (Cu-Fe-Cr-Ni system), set a scanning path of 0–100 wt.% for the Cu→Fe content change interval, extract the phase compositions at different Cu contents, and then analyze that in the 20–60 wt.% Cu region, brittle intermetallic compounds rich in Fe or Cu (such as FeCr, CuFe2, etc.) are likely to be generated, and determine it as the composition sensitive interval.

[0068] Then set the laser energy beam power range (such as 150–300 W), scanning speed (200–600 mm / s), interlayer cooling time (2–10 s), control the molten pool size in the sensitive interval within a depth-to-width ratio range of 1.2–1.8, and maintain the cooling rate within the range of 103~105 K / s;

[0069] Adopt an exponential gradient function in the identified sensitive interval (such as 30–50 wt.% Cu) to quickly avoid the brittle interval and adopt a logarithmic or polynomial function to achieve a slow transition in the high Cu or high Fe stable section to improve the microstructure uniformity of the transition zone; where the exponential growth rate α = 0.3~0.7 is set, and the amplitude coefficient A is consistent with the target maximum composition difference.

[0070] In some examples of the present application, when determining the composition transition strategy, a corresponding gradient function is selected according to the diffusion coefficients and interfacial tension characteristics of different elements within the composition-sensitive range.

[0071] Specifically, when identifying the diffusion coefficients and interfacial tension characteristics of different elements within the composition-sensitive range, literature and thermophysical databases are queried to obtain the typical diffusion parameters and interfacial tension values of the main elements in the corresponding temperature of this sensitive range, and then a corresponding gradient function is selected according to the diffusion parameters and interfacial tension values.

[0072] Exemplarily, taking the CuCrZr / 316L functionally graded material as an example, the specific process is as follows:

[0073] Literature and thermophysical databases are queried to obtain the typical diffusion parameters and interfacial tension values of the main elements in the corresponding temperature (such as 1200K) of this sensitive range as follows: the diffusion coefficient of Fe in Cu: ~1.1×10 -15 m² / s, the diffusion coefficient of Cu in Fe: ~8.5×10 -16 m² / s, the interfacial tension of the Cu / Fe interface is about 1.75 N / m, which is higher than the interfacial tension of Cr / Fe or Ni / Fe. It can be seen therefrom that the interdiffusion of elements in this range is slow and the interfacial tension is large. If a linear transition is adopted, it is likely to cause non-continuous structure and weak bonding; thus, to improve the tissue transition characteristics in this sensitive range and avoid the rapid formation of brittle phases, an exponential gradient function is selected in this embodiment to quickly avoid the brittle range and in the stable section of high Cu or high Fe, a logarithmic gradient function is used to achieve a slow transition and improve the tissue uniformity in the transition zone; among them, on the basis of applying this non-linear composition distribution, the energy beam parameters are adjusted accordingly to optimize the melting and solidification conditions: the energy beam power is smoothly increased from 180 W in the Cu area to 230 W, the scanning speed is slowly decreased from 800 mm / s to 500 mm / s, and the interlayer cooling time is appropriately extended to 5 s within the sensitive range to reduce heat accumulation.

[0074] In some examples of the present application, when adjusting the energy beam, a preset regulation strategy is adopted to implement layer-by-layer energy compensation within the composition-sensitive range, thereby reducing the thermal stress concentration caused by composition mutation.

[0075] Specifically, the preset regulation strategy includes:

[0076] Before the scanning path enters the composition-sensitive range, the energy beam power is gradually reduced layer by layer in small increments (taking a decrease range of 1% - 5% as an example) until it reaches the preset stable power level when entering the range, and a constant low power output is maintained within the range to control the molten pool temperature within a stable range and avoid element segregation or grain coarsening caused by excessive energy input. After the scanning path leaves the sensitive range, the power is restored layer by layer in the reverse direction and finally restored to the normal energy beam power.

[0077] Meanwhile, adjust the energy beam scanning speed, and moderately reduce the scanning speed after entering the composition-sensitive range (such as slowly decreasing from 800 mm / s to 500 mm / s), so as to increase the heat input per unit volume, cooperate with the low-power setting to form a more uniform and stable molten pool. This method can extend the high-temperature residence time, promote the full diffusion of alloying elements, inhibit the formation of brittle phases, improve the grain morphology, and avoid local overburning or tissue coarsening through the combined energy beam.

[0078] Moreover, set 1 - 3 transition layers at the upper and lower boundaries of the identified composition-sensitive range, and introduce intermittent preheating and cooling operations in these boundary layers. For example, short-term preheat the printing area by intermittently switching on and off the heat-carrying gas flow, heat radiation source, or low-power auxiliary scanning method of multiple energy heads, so that the interlayer temperature difference is maintained within the minimum range (such as controlled within 15 °C). At the same time, pause for a certain period (such as 2 - 10 seconds) after each boundary layer is printed, allowing natural or active cooling to release heat accumulation, relieve the stress mutation caused by the thermal gradient, and minimize the interlayer temperature difference.

[0079] Thus, the continuous gradient material prepared by using the above additive manufacturing method satisfies the following: the conditional composition distribution is consistent with the preset gradient function, and the element analysis detection error is less than 3%; the density gradient changes continuously, without interface delamination or pore aggregation; within the composition-sensitive range, the volume fraction of brittle phases is reduced to less than 1%.

[0080] Thus, referring to Figure 8 as shown, Figure 8 shows a schematic module diagram of an exemplary continuous gradient material additive manufacturing system according to some embodiments of the present application. The present application also relates to a continuous gradient material additive manufacturing system 2 with non-linear composition transition using the above additive manufacturing method, including:

[0081] A gradient calculation module 201 for calculating the gradient step according to the height of the target component and the printing layer thickness; an interval identification module 202 for identifying the composition-sensitive interval according to the full-composition functional gradient material formed by the linear composition transition method; a transition design module 203 for re-designing the composition distribution in the identified composition-sensitive interval by using the non-linear composition transition method of the preset gradient function; a scanning control module 204 for performing energy beam scanning on the powder materials stacked layer by layer according to the re-designed composition distribution to form the target component.

[0082] In the actual implementation process, the above additive manufacturing method of the present application refers to at least one of the following material systems: CuCrZr / 316L, TC4 / Inconel718, AlSi10Mg / TC4, CuCrZr / Inconel718, 316L / Ta, AlSi10Mg / 316L; specifically, operators can adapt and debug more material systems according to actual needs.

[0083] In some embodiments, referring to Figure 9 as shown, Figure 9 Figure 7 shows a schematic connection diagram of an electronic device for implementing the embodiments of the present application. The electronic device 3 includes: a memory 301 and a processor 302. The memory 301 stores a computer program that can run on the processor 302. When the processor 302 executes the computer program, the method in the above embodiments is implemented. The number of the memory 301 and the processor 302 can be one or more.

[0084] The electronic device 3 further includes:

[0085] a communication interface 303, which is used to communicate with external devices and perform data interaction and transmission.

[0086] If the memory 301, the processor 302, and the communication interface 303 are implemented independently, the memory 301, the processor 302, and the communication interface 303 can be interconnected through a bus and communicate with each other.

[0087] This bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 9 only a thick line is shown in Figure 7, but it does not mean that there is only one bus or one type of bus.

[0088] Optionally, in specific implementation, if the memory 301, the processor 302, and the communication interface 303 are integrated on a chip, the memory 301, the processor 302, and the communication interface 303 can communicate with each other through an internal interface.

[0089] The embodiments of the present application provide a computer-readable storage medium that stores a computer program, and when the program is executed by the processor 302, the method provided in the embodiments of the present application is implemented.

[0090] An embodiment of the present application also provides a chip, which includes a processor 302 for calling and running instructions stored in a memory 301 from the memory 301, so that a communication device equipped with the chip executes the method provided by the embodiment of the present application.

[0091] An embodiment of the present application also provides a chip, including: an input interface, an output interface, a processor 302, and a memory 301. The input interface, the output interface, the processor 302, and the memory 301 are connected through an internal connection path. The processor 302 is used to execute the code in the memory 301. When the code is executed, the processor 302 is used to execute the method provided by the embodiment of the application.

[0092] It should be understood that the above-mentioned processor 302 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. It is worth noting that the processor 302 may be a processor that supports the advanced reduced instruction set machine (ARM) architecture.

[0093] Further, the above-mentioned memory 301 may include a read-only memory and a random access memory, and may also include a non-volatile random access memory. The memory 301 may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may include a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may include a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available. For example, static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus random access memory (DRRAM).

[0094] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions according to the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium.

[0095] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for additive manufacturing of a continuous gradient material with a non-linear component transition, characterized in that, The method includes: Calculating a gradient step according to the height of the target component and the printing layer thickness; Identifying a composition-sensitive interval based on a fully compositional functionally graded material formed by a linear composition transition method; Within the identified composition-sensitive interval, redesigning the composition distribution by using a non-linear composition transition method of a preset gradient function; and Performing an energy beam scan on the powder materials stacked layer by layer according to the redesigned composition distribution to form the target component.

2. The additive manufacturing method according to claim 1, characterized in that The calculation formula of the gradient step is: ， Where Step is the gradient step, ω(A) is the material A with a mass fraction of 100%, ω(B) is the material B with a mass fraction of 100%, h is the total height of the target component in the deposition direction, and t is the printing layer thickness.

3. The additive manufacturing method according to claim 1, wherein When identifying the composition-sensitive interval, the method includes: Performing an energy beam scan on the powder materials stacked layer by layer by using a linear composition transition method to form a fully compositional functionally graded material; Performing a microstructure characterization and performance test on the fully compositional functionally graded material to identify the composition-sensitive interval or the performance indicators to be optimized.

4. The additive manufacturing method according to claim 3, wherein The microstructure characterization includes scanning electron microscopy analysis and energy dispersive X-ray spectroscopy analysis for detecting whether brittle intermetallic compounds and / or elemental segregation occur within the full composition range.

5. The additive manufacturing method according to claim 3, characterized in that, The performance test selects one or more of the tensile property test of stainless steel, the thermal conductivity test of copper alloy, the high-temperature creep property test of superalloy, the fracture toughness test of titanium alloy, the fatigue property test of aluminum alloy, and the corrosion resistance test of tantalum alloy according to the material system and service requirements.

6. The additive manufacturing method according to claim 1, wherein, The preset gradient function includes one or more of a monotonic linear gradient function, a monotonic exponential gradient function, a monotonic logarithmic gradient function, and a monotonic polynomial gradient function.

7. The additive manufacturing method according to claim 1, wherein When redesigning the composition distribution by using a non-linear composition transition method, the method includes: The exponential function transition realizes a sharp transition of the composition change within the composition-sensitive interval, suppressing element mutual solubility and the formation of brittle phases; The logarithmic function transition realizes a slow transition of the composition change within the composition-sensitive interval, promoting element diffusion and uniform grain refinement.

8. The additive manufacturing method according to claim 7, wherein When redesigning the composition distribution by using a non-linear composition transition method, the method includes: Combining thermodynamic simulation to predict the phase transformation behavior within the composition-sensitive interval; Adjusting the energy beam power, scanning speed, and interlayer cooling rate to control the melting and solidification conditions; Determining the composition transition strategy regulation according to the phase transformation behavior and the target optimized performance.

9. The additive manufacturing method according to claim 8, wherein When determining the composition transition strategy, select the corresponding gradient function according to the diffusion coefficients and interfacial tension characteristics of different elements within the composition-sensitive interval.

10. The additive manufacturing method according to claim 8, characterized in that, When adjusting the energy beam, adopt a preset regulation strategy to implement layer-by-layer energy compensation within the composition-sensitive interval, thereby reducing the thermal stress concentration caused by composition mutation.

11. The additive manufacturing method according to claim 10, wherein The preset regulation strategy includes: Gradually reducing the energy beam power layer by layer before entering the composition-sensitive interval, maintaining a constant preset energy level power within the target interval, and gradually restoring to the normal power after leaving the occurrence interval; Reducing the energy beam scanning speed within the composition-sensitive interval to increase the local heat input, and combining with a preset power energy beam to avoid local overburning or tissue coarsening; Introducing intermittent preheating and cooling operations at the upper and lower boundary layers of the composition-sensitive interval to minimize the interlayer temperature difference.

12. A continuous gradient material additive manufacturing system using non-linear composition transition of the additive manufacturing method according to any one of claims 1 to 11, characterized in that, Includes: Gradient calculation module, configured to calculate a gradient step length according to the height of the target component and the printing layer thickness; Interval identification module, configured to identify a composition-sensitive interval according to a fully compositional functionally gradient material formed by a linear composition transition method; Transition design module, configured to re-design the composition distribution in the identified composition-sensitive interval by means of a non-linear composition transition method using a preset gradient function; Scanning control module, configured to perform an energy beam scan on the powder materials stacked layer by layer to form a target component according to the re-designed composition distribution.

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