Method and system for additive manufacturing of continuous gradient materials with nonlinear composition transition

Abstract

The present application relates to a method and system for additive manufacturing of continuous gradient materials with nonlinear composition transitions, which can solve the problem that traditional functional gradient materials with linear composition changes are prone to brittle phases and insufficient performance in composition-sensitive intervals. The method includes: determining the gradient step size according to the part size, and calculating the composition change rate of each layer based on the printing layer thickness and height; preparing full-composition functional gradient materials by linear transition, and identifying the brittle phase generation interval in combination with microstructure characterization methods; designing a nonlinear composition transition method for sensitive intervals to suppress element segregation and brittle phase generation, and optimize interface bonding strength and comprehensive performance. The composition of the gradient material prepared by this application is continuously controllable in any direction, and there is no sudden interface in the composition distribution. The strength, high-temperature oxidation resistance and thermal fatigue life are significantly better than those of traditional linear gradient materials, and it is suitable for high-performance demand scenarios such as aerospace, nuclear energy heat dissipation and biological implants.

Description

Technical Field

[0001] The present application relates to the technical field of gradient material preparation, and more specifically to a method and system for additive manufacturing of continuous gradient materials with nonlinear composition transition. Background Art

[0002] As demand for materials serving in extreme environments escalates, traditional homogeneous materials face significant challenges. In high-temperature gradient environments (such as aerospace engine combustion chambers), a single material struggles to simultaneously meet multiple performance requirements, including high-temperature resistance, corrosion resistance, and lightweighting. For example, hot-end components must withstand heat in high-temperature zones and resist fatigue in low-temperature zones. Direct bonding of dissimilar materials (such as Ti / steel and Al / Cu) can easily form brittle intermetallic compounds (FeTi and Al2Cu), leading to a sudden drop in mechanical properties. Functionally graded materials (FGMs), through continuous transitions in composition and structure, effectively avoid the problem of sudden changes at the interface between dissimilar materials, offering a crucial solution to addressing complex performance requirements.

[0003] However, traditional functional gradient material preparation technologies face the dual challenges of complex processes and performance defects. For example, vapor deposition and plasma spraying have low deposition rates, high pollution, and are unable to produce complex three-dimensional blocks; powder metallurgy processes are cumbersome and easily lead to composition segregation and discontinuous interfaces between layers; centrifugal casting has problems such as high surface roughness and significant thermal cracking tendency; self-propagating high-temperature synthesis (SHS) is prone to produce pores and metastable phases due to uncontrollable reactions. Overall, traditional methods find it difficult to balance the continuous transition of composition with the integrated manufacturing of complex structures, and suffer from problems such as low interface bonding strength and poor compatibility of material systems. The emergence of powder bed fusion technology has broken through the above limitations. It achieves structure construction through layer-by-layer stacking and energy beam scanning. It has the advantage of highly free three-dimensional structure design capabilities and precise control of laser energy. It can effectively control the molten pool state and microstructure evolution, thereby optimizing interface bonding characteristics and improving the overall performance of the material.

[0004] In the powder bed fusion manufacturing process for functionally graded materials, direct bonding was the first approach to emerge. However, due to differences in the thermophysical properties of the materials (such as thermal expansion coefficient and melting point), residual stress, pores, and cracks are easily generated at the interface, resulting in low bonding strength. The subsequent development of discrete composition transitions, while somewhat alleviating the interface discontinuity issue, suffers from abrupt composition changes and a lack of systematic design. This still makes it susceptible to mechanical property degradation due to insufficient diffusion or the formation of brittle intermetallic compounds in composition-sensitive areas. In contrast, FGMs employing continuous gradient composition transitions can better balance the differences in thermophysical properties between regions and reduce the formation of interfacial stress concentrations.

[0005] However, even within the full composition range of a continuous gradient, certain compositionally sensitive regions may still exist, where defects such as element segregation or brittle intermetallic compounds are more likely to occur during the forming process. Currently, the commonly used linear gradient function does not fully exploit the potential advantages of functionally graded materials and still struggles to achieve global optimization of material properties. Summary of the Invention

[0006] The present application provides a method for additive manufacturing of continuous gradient materials with nonlinear composition transition, which can identify the composition-sensitive range of full-composition functional gradient materials and redesign the composition distribution within the composition-sensitive range using nonlinear transition methods such as logarithmic functions, exponential functions, and polynomial functions, thereby solving the problem that traditional functional gradient materials with linear composition changes are prone to brittle phases and insufficient performance in the composition-sensitive range.

[0007] In the first aspect, the present application provides a method for additive manufacturing of continuous gradient materials with nonlinear composition transition, the method comprising: calculating the gradient step size based on the height of the target component and the printing layer thickness; identifying the composition sensitive interval based on the full-composition functional gradient material formed by a linear composition transition method; redesigning the composition distribution within the identified composition sensitive interval using a nonlinear composition transition method with a preset gradient function; and performing energy beam scanning on the powder materials stacked layer by layer according to the redesigned composition distribution to form the target component.

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

[0009] In an optional scheme of the first aspect, when identifying the component-sensitive interval, the method includes: using a linear component transition method to perform energy beam scanning on the powder materials stacked layer by layer to form a full-component functional gradient material; performing microstructural characterization and performance testing on the full-component functional gradient material to identify the component-sensitive interval or the performance indicator to be optimized.

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

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

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

[0013] In an optional scheme of the first aspect, when redesigning the composition distribution using a nonlinear composition transition method, the method includes: an exponential function transition to achieve a sharp transition of composition changes within the composition-sensitive range, thereby suppressing element mutual dissolution and brittle phase formation; a logarithmic function transition to achieve a slow transition of composition changes within the composition-sensitive range, thereby promoting element diffusion and uniform grain refinement.

[0014] In an optional scheme of the first aspect, when redesigning the composition distribution using a nonlinear composition transition method, the method includes: combining thermodynamic simulation to predict the phase change behavior within the composition sensitive range; adjusting the energy beam power, scanning speed and interlayer cooling rate to control the melting conditions; and determining the composition transition strategy control based on the phase transformation behavior and target optimization performance.

[0015] In an optional solution of the first aspect, when determining the composition transition strategy, a corresponding gradient function is selected according to the diffusion coefficients and interfacial tension characteristics of different elements in the composition sensitive range.

[0016] In an optional solution of the first aspect, when adjusting the energy beam, a preset control strategy is adopted to implement layer-by-layer energy compensation within the component-sensitive range, thereby reducing thermal stress concentration caused by sudden changes in composition.

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

[0018] In the second aspect, the present application provides a continuous gradient material additive manufacturing system using nonlinear component transition according to the above-mentioned additive manufacturing method, including: a gradient calculation module for calculating the gradient step size based on the height of the target component and the printing layer thickness; an interval identification module for identifying the component-sensitive interval based on the full-component functional gradient material formed using a linear component transition method; a transition design module for redesigning the component distribution within the identified component-sensitive interval using a nonlinear component transition method with a preset gradient function; and a scanning control module for performing energy beam scanning on the powder materials stacked layer by layer according to the redesigned component distribution to form the target component.

[0019] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0022] Figure 2 This is a schematic diagram of the transition direction of the composition of an exemplary functional gradient material sample 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 It is a flow chart 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 slowly transitioning polynomial gradient function distribution diagram according to some embodiments of the present application.

[0027] Figure 7 This is a flowchart of an exemplary nonlinear component transition parameter optimization method according to some embodiments of the present application.

[0028] Figure 8This is a module schematic diagram of an exemplary continuous gradient material additive manufacturing system according to some embodiments of the present application.

[0029] Figure 9 This is a connection diagram of an exemplary electronic device according to some embodiments of the present application. DETAILED DESCRIPTION

[0030] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of 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 comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of this application.

[0031] Functionally graded materials (FGMs) are a new class of materials characterized by a spatially continuously varying composition or microstructure, resulting in a spatially graded distribution of properties. FGMs were first proposed in the 1980s to meet the needs of thermal protection structures in aerospace and are now widely used in extreme operating environments such as aerospace, nuclear energy, marine engineering, biomedicine, and automotive manufacturing. They differ fundamentally from traditional composite materials: traditional composites are often composed of multiple materials with distinct interface transitions. FGMs, on the other hand, overcome the mechanical and thermal performance issues inherent in traditional composite materials by eliminating distinct interface transitions.

[0032] Continuous gradient composition transition refers to the way the material composition of a FGM changes along a specific direction in the form of a continuous function, without distinct interfaces, ensuring a smooth transition in performance. Powder Bed Fusion (PBF) technology achieves precise and continuous composition transition by controlling the laser energy and powder ratio layer by layer, making it particularly suitable for the integrated manufacturing of complex FGM structures.

[0033] Powder Bed Fusion (PBF) is an additive manufacturing technology driven by energy beams such as lasers or electron beams. It selectively melts metal or polymer powders layer by layer to create three-dimensional solid parts with complex geometries. PBF technology is particularly suitable for producing high-density, high-precision, and complex metal components, and is widely used in fields with extremely high performance requirements, such as aerospace, biomedicine, and energy and power.

[0034] Currently, PBF is primarily categorized into several types, depending on the energy source used: laser powder bed fusion (L-PBF), electron beam melting (EBM), and selective laser sintering (SLS). The PBF process typically involves powder spreading, energy beam scanning and melting, layer-by-layer lifting, and post-processing. Specifically, a powder spreading mechanism deposits a layer of powder material tens to hundreds of microns thick on a build platform to form a uniform powder bed. Based on the slice data of the 3D component model, a laser or electron beam selectively scans the powder layer along a pre-set path, melting it, and solidifying it to form a solid cross-section. After scanning one layer, the build platform descends one unit of layer thickness to deposit the next layer of powder. This process is repeated layer by layer until the entire 3D component is complete. The component is then removed 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 influenced by multiple parameters, including energy beam power, scanning speed, scanning pitch, layer thickness, scanning strategy, and powder properties.

[0035] At present, powder bed fusion manufactures functional gradient 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 thermophysical properties. However, in the full composition range, there may still be certain composition-sensitive ranges that are prone to brittle defects during the forming process, and the linear composition transition method has not fully explored the advantages of this functional gradient material.

[0036] refer to Figure 1 and Figure 2 As shown, in the process of using the additive manufacturing method with continuous controllable gradient change, the thickness of the printed layer is kept constant and the gradient of the composition change of each layer is changed. For example, from the material A of the first layer to the material B of the nth layer, if it is a linear transition, the change amount of the composition of each layer is , thereby achieving controllable changes in the overall composition of the sample.

[0037] Specific linear component transition method reference Figure 3 As shown, the transition from material A to material B is performed, wherein the transition from components A1 to B1 is also performed in this manner, and the corresponding printing layer height is Z1.

[0038] Therefore, in order to solve the problem of existing powder bed fusion manufacturing of functionally graded materials, reference Figure 4 As shown, Figure 4 A schematic diagram of a process flow of an exemplary continuous gradient material additive manufacturing method according to some embodiments of the present application is shown. The present application provides a continuous gradient material additive manufacturing method with nonlinear component transition, the method comprising:

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

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

[0041] S2: Identify the composition sensitive range based on the full composition functional gradient material formed by linear composition transition.

[0042] Specifically, before printing the target component, a linear composition transition method is used to form a full-composition functional gradient material, and then the full-composition functional gradient material is subjected to microstructure characterization and performance testing to identify the composition sensitive range or performance indicators to be optimized.

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

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

[0045] For example, taking CuCrZr / 316L material as an example, before scanning and forming the target CuCrZr / 316L material component, a linear component transition method is first used to construct a functional gradient material sample with a height of 40 mm and a layer thickness of 0.1 mm. 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, transition from 100% 316L of the sample to 100% CuCrZr, forming a continuously changing bimetallic gradient material. After printing is completed, you can choose to use scanning electron microscopy (SEM-EBSD) analysis or energy dispersive X-ray spectroscopy analysis (EDS) analysis, or you can choose to use scanning electron microscopy (SEM-EBSD) analysis and energy dispersive X-ray spectroscopy analysis (EDS) analysis. Then, according to the material properties and application requirements of CuCrZr and 316L stainless steel, different areas of the sample are tested as follows: tensile properties test in the 316L area, thermal conductivity test in the CuCrZr-dominant area, and microhardness measurement and fracture toughness test in the intermediate transition area. In this way, the area where the microstructure and properties of the target CuCrZr / 316L material component show abnormal fluctuations is identified and this area is used as the composition-sensitive range.

[0046] S3: Within the identified component-sensitive range, the component distribution is redesigned using a nonlinear component transition method with a preset gradient function.

[0047] Specifically, when redesigning the composition distribution using a nonlinear composition transition method, one or more of the exponential function transition and the logarithmic function transition can be selected. The exponential function transition achieves a sharp transition of composition changes within the composition-sensitive range, inhibiting element mutual dissolution and brittle phase formation; the logarithmic function transition achieves a slow transition of composition changes within the composition-sensitive range, 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 monotone linear gradient function, a monotone exponential gradient function, a monotone logarithmic gradient function, and a monotone polynomial gradient function.

[0049] Among them, the monotonic linear gradient function is suitable for bimetallic systems or alloy systems with good composition compatibility and strong element solubility. This function realizes uniform changes in composition with height and can obtain a relatively stable organizational structure. The formula of the monotonic linear gradient function is: , ,in is the mass fraction of a component at the height x position of the component, is the initial mass fraction at the starting position; k is the linear variation coefficient, ; is the total height of the component.

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

[0051] , ,in is the exponential amplitude coefficient that controls the total amplitude of component changes, The exponential growth rate that controls the speed of composition change. For example, in the CuCrZr / 316L system, to suppress the precipitation of Cu-Fe brittle phase in the middle section, α>0 can be set to make the Cu content transition quickly.

[0052] Among them, the monotonic logarithmic gradient function is suitable for areas where slow transition, component diffusion promotion, and grain refinement are required. It is also suitable for heterogeneous metal transition designs with hot cracking tendency or high interface strength requirements. The formula of the monotonic logarithmic gradient function is: , ,in In order to control the maximum variation of composition, For example, in the AlSi10Mg / TC4 system, a small β value is used to reduce the tendency of hot cracking and achieve uniform microstructure control in the transition zone.

[0053] Among them, the monotone polynomial gradient function provides the greatest degree of control freedom and can accurately fit the ideal composition evolution trajectory of the actual composition-sensitive section. It is suitable for handling complex composition transition requirements, such as asymmetric bimetallic and multi-component alloys. The function has strong expressive power and can match any complex target curve. The formula of the monotone polynomial gradient function is:

[0054] , ,in is the coefficient of the polynomial of order i, and n is the order of the polynomial, usually 2–4.

[0055] In actual implementation, the above functions can be used individually or combined to form a composite gradient function, for example: ,in, ,satisfy , which can realize the flexible superposition of multiple gradient control effects; is a monotonic linear gradient function, is a monotonic exponential gradient function, is the monotonic logarithmic gradient function, is a monotone polynomial gradient function. In actual applications, a weighted combination of two functions, a weighted combination of three functions, or a weighted combination of all functions can be used. The specific setting is determined by the operator according to actual needs.

[0056] Specific reference Figure 5 and Figure 6 As shown, Figure 5 An exemplary polynomial gradient function method of a sharp transition in some embodiments of the present application is shown, transitioning from material A to material B, wherein the transition from component A1 to component B1 is also selected in this manner, and the corresponding printing layer height is Z2. Figure 6 An exemplary slow transition polynomial gradient function method of some embodiments of the present application is shown, transitioning from material A to material B, wherein the transition from component A1 to component B1 is also selected in this manner, and the corresponding printing layer height is Z3.

[0057] For compositionally sensitive regions (compositional regions prone to the generation of undesirable phases), a sharp transition method effectively suppresses crack initiation and brittle phase precipitation in these regions by inhibiting elemental miscibility, optimizing melt pool morphology, and refining the microstructure. A slow transition method promotes epitaxial grain growth and uniform grain refinement. Continuous gradient materials with a slow transition maintain a single-phase austenite structure, with grain size varying with composition, resulting in a smooth transition in melt pool morphology. For example, the TiB / Ti6Al4V gradient material achieves continuous grain size control from submicron to micron through a slow transition, improving mechanical isotropy.

[0058] S4: Energy beam scanning is performed on the powder materials stacked layer by layer according to the redesigned component distribution to form a target component.

[0059] In some embodiments of this application, reference Figure 7 As shown, Figure 7 A flow chart of an exemplary nonlinear component transition parameter optimization method according to some embodiments of the present application is shown. When redesigning the component distribution using a nonlinear component transition method, the parameters of the nonlinear component transition method are optimized by the following steps:

[0060] S31: Combined with thermodynamic simulation to predict phase transition behavior in the composition-sensitive range.

[0061] Specifically, phase change behavior is predicted through thermodynamic simulation and composition-sensitive intervals are identified. The specific process includes: based on thermodynamic software such as Thermo-Calc or Pandat, the elemental composition of the target functional gradient material is imported to construct a multivariate phase diagram database; then the composition scanning path is set and the composition-sensitive interval is identified, thereby extracting the phase change starting temperature and phase content variation curve with composition, providing boundary constraints for the subsequent composition transition function setting.

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

[0063] Specifically, the energy beam power range, scanning speed and interlayer cooling rate are set, and then finite element simulation tools (such as ANSYS Additive and Simufact Additive) are used to simulate the temperature field and cooling rate under different parameter combinations. This is to analyze whether the molten pool solidification process will lead to element segregation, non-equilibrium structure or grain coarsening in the sensitive area, and then control the molten pool size and cooling rate in the sensitive area within a reasonable range to avoid intermetallic compound enrichment or thermal crack formation.

[0064] S33: Determine the composition transition strategy based on phase transition behavior and target optimization performance.

[0065] Specifically, when determining the composition transition strategy, a preset gradient function is set 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 uniformity of the transition zone structure.

[0066] For example, taking 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, the elemental composition of CuCrZr and 316L was imported to construct a multivariate phase diagram database (Cu-Fe-Cr-Ni system). A scanning path of 0–100 wt.% was set for the Cu→Fe content change range, and the phase composition at different Cu contents was extracted. Then, the 20–60 wt.% Cu region was analyzed, where Fe-rich or Cu-rich brittle intermetallic compounds (such as FeCr, CuFe2, etc.) were easily generated, and this region was identified as a composition-sensitive range.

[0068] Then, the laser beam power range (e.g., 150–300 W), scanning speed (200–600 mm / s), interlayer cooling time (2–10 s) are set, and the molten pool size in the sensitive area is controlled within the range of aspect ratio of 1.2–1.8, and the cooling rate is maintained within the range of 103–105 K / s.

[0069] An exponential gradient function is used in the identified sensitive range (e.g. 30–50wt.%Cu) The brittle zone can be quickly avoided and a slow transition can be achieved in the high Cu or high Fe stable section using a logarithmic or polynomial function to improve the uniformity of the transition zone structure. The exponential growth rate α is set to 0.3~0.7, 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 component-sensitive range, we query the literature and thermophysics database to obtain the typical diffusion parameters and interfacial tension values of the main elements in the sensitive range at the corresponding temperature, and then select the corresponding gradient function based on the diffusion parameters and interfacial tension values.

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

[0073] By searching the literature and thermophysics database, we can find the typical diffusion parameters and interfacial tension values of the main elements in this sensitive range at the corresponding temperature (e.g. 1200K) as follows: Diffusion coefficient of Fe in Cu: ~1.1×10 -15 m² / s, Cu diffusion coefficient in Fe: ~8.5×10 -16 m² / s, the Cu / Fe interfacial tension is about 1.75N / m, which is higher than the Cr / Fe or Ni / Fe interfacial tension. It can be seen that the elements in this range diffuse slowly and the interfacial tension is large. If a linear transition is used, it is easy to cause discontinuous tissue and fragile bonding. Therefore, in order to improve the tissue transition characteristics in this sensitive range and avoid the rapid formation of brittle phase, an exponential gradient function is selected in this embodiment. The brittle zone can be quickly avoided and a slow transition is achieved in the high Cu or high Fe stable section by using a logarithmic gradient function to improve the uniformity of the transition zone structure. Based on the application of this nonlinear component distribution, the energy beam parameters are adjusted to optimize the melting conditions: the energy beam power is smoothly increased from 180W in the Cu zone to 230W, the scanning speed is slowly reduced from 800mm / s to 500mm / s, and the interlayer cooling time is appropriately extended to 5s in the sensitive zone to reduce heat accumulation.

[0074] In some examples of the present application, when adjusting the energy beam, a preset control strategy is used to implement layer-by-layer energy compensation within the component-sensitive range, so as to reduce the thermal stress concentration caused by the sudden change of the composition.

[0075] Specifically, the preset control strategy includes:

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

[0077] At the same time, the energy beam scanning speed is adjusted, and the scanning speed is moderately reduced after entering the composition-sensitive range (for example, from 800 mm / s to 500 mm / s), thereby increasing the heat input per unit volume and forming a more uniform and stable molten pool in combination with the low-power setting. This method can extend the high-temperature residence time, promote the full diffusion of alloying elements, inhibit the formation of brittle phases, improve grain morphology, and avoid local overburning or microstructure coarsening by combining the energy beam.

[0078] In addition, 1 to 3 transition layers are set at the upper and lower boundaries of the identified component-sensitive range, and intermittent preheating and cooling operations are introduced in these boundary layers. For example, the printing area is preheated for a short time by intermittently switching the hot air flow, the thermal radiation source or the low-power auxiliary scanning method of the multi-energy head, so that the temperature difference between layers is maintained within the minimum range (such as controlled within 15°C). At the same time, a certain time (such as 2 to 10 seconds) is paused after each boundary layer is printed, allowing natural or active cooling to release heat accumulation, alleviate stress mutations caused by thermal gradients, and minimize the temperature difference between layers.

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

[0080] Therefore, reference Figure 8 As shown, Figure 8 A schematic diagram of a module of an exemplary continuous gradient material additive manufacturing system according to some embodiments of the present application is shown. The present application also relates to a continuous gradient material additive manufacturing system 2 with nonlinear composition transition using the above-mentioned additive manufacturing method, comprising:

[0081] The gradient calculation module 201 is used to calculate the gradient step size based on the height of the target component and the printing layer thickness; the interval identification module 202 is used to identify the component-sensitive interval based on the full-component functional gradient material formed by the linear component transition method; the transition design module 203 is used to redesign the component distribution within the identified component-sensitive interval by using the nonlinear component transition method of the preset gradient function; the scanning control module 204 is used to perform energy beam scanning on the powder materials stacked layer by layer according to the redesigned component distribution to form the target component.

[0082] In the actual implementation process, the above-mentioned additive manufacturing method of this application is applicable to at least one of the following material systems: CuCrZr / 316L, TC4 / Inconel718, AlSi10Mg / TC4, CuCrZr / Inconel718, 316L / Ta, AlSi10Mg / 316L; specifically, the operator can adapt more material systems according to actual needs.

[0083] In some embodiments, reference Figure 9 As shown, Figure 9 A schematic diagram of the connections of an electronic device used to implement an embodiment of the present application is shown. The electronic device 3 includes a memory 301 and a processor 302. The memory 301 stores a computer program executable by the processor 302. When the processor 302 executes the computer program, the method of the above embodiment 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] The communication interface 303 is used to communicate with external devices and perform data exchange 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 may be connected to each other via a bus and communicate with each other.

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

[0088] Optionally, in a 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] An embodiment of the present application provides a computer-readable storage medium storing a computer program, which implements the method provided in the embodiment of the present application when the program is executed by the processor 302.

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

[0092] It should be understood that the processor 302 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A 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 RISC Machine (ARM) architecture.

[0093] Furthermore, the 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 (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM) and direct memory bus random access memory (DRRAM).

[0094] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. A 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 device. The computer instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another.

[0095] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for additive manufacturing of continuous gradient materials with nonlinear component transition, characterized in that: The method comprises: Calculate the gradient step size based on the height of the target component and the printing layer thickness; Identify the composition sensitive range based on the full composition functional gradient material formed by linear composition transition; Redesigning the component distribution within the identified component-sensitive interval using a nonlinear component transition method with a preset gradient function; and Performing energy beam scanning on powder materials stacked layer by layer according to a redesigned component distribution to form a target component; When redesigning the component distribution by adopting a nonlinear component transition method, the method includes: The exponential function transition achieves a sharp transition of composition change within the composition-sensitive range, inhibiting element mutual dissolution and brittle phase formation; The logarithmic function transition achieves a slow transition of composition change within the composition-sensitive range, promoting element diffusion and uniform grain refinement; Combined with thermodynamic simulation to predict phase transition behavior in the composition-sensitive range; Adjust the energy beam power, scanning speed and interlayer cooling rate to control the melting conditions; Determine the composition transition strategy based on phase transition behavior and target optimization performance; When determining the composition transition strategy, the corresponding gradient function is selected according to the diffusion coefficients and interfacial tension characteristics of different elements in the composition sensitive range; When adjusting the energy beam, a preset control strategy is adopted to implement layer-by-layer energy compensation within the composition-sensitive range to reduce the thermal stress concentration caused by compositional mutations; The preset control strategy includes: The energy beam power is gradually reduced before entering the component-sensitive range, and is maintained at a constant preset energy level within the target range, and is gradually restored to normal power after leaving the occurrence range; Reduce the energy beam scanning speed in the composition-sensitive range to increase local heat input, and combine it with the preset power energy beam to avoid local overburning or tissue coarsening; Intermittent preheating and cooling operations are introduced in the upper and lower boundary layers of the composition-sensitive range to minimize the temperature difference between the layers.

2. The additive manufacturing method according to claim 1, characterized in that The calculation formula of the gradient step length is: ， Where Step is the gradient step size, ω(A) is the mass fraction of 100% material A, ω(B) is the mass fraction of 100% material B, 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, characterized in that When identifying component-sensitive intervals, the method includes: The powder materials stacked layer by layer are scanned with energy beams using a linear composition transition method to form a full-composition functional gradient material. The microstructure characterization and performance testing of the full-component functional gradient material are performed to identify component-sensitive ranges or performance indicators to be optimized.

4. The additive manufacturing method according to claim 3, characterized in that The microstructural characterization includes scanning electron microscopy analysis and energy dispersive X-ray spectroscopy analysis for detecting the presence of brittle intermetallic compounds and / or element segregation within the full composition range.

5. The additive manufacturing method according to claim 3, characterized in that: The performance test is selected from one or more of the following: tensile performance test of stainless steel, thermal conductivity test of copper alloy, high temperature creep performance test of high temperature alloy, fracture toughness test of titanium alloy, fatigue performance test of aluminum alloy and 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 monotone linear gradient function, a monotone exponential gradient function, a monotone logarithmic gradient function, and a monotone polynomial gradient function.

7. A continuous gradient material additive manufacturing system with nonlinear composition transition using the additive manufacturing method according to any one of claims 1 to 6, characterized in that: include: Gradient calculation module, used to calculate the gradient step size based on the height of the target component and the printing layer thickness; An interval recognition module is used to identify the composition sensitive interval based on the full composition functional gradient material formed by the linear composition transition method; A transition design module is used to redesign the component distribution within the identified component-sensitive range using a nonlinear component transition method with a preset gradient function; The scanning control module is used for performing energy beam scanning on powder materials stacked layer by layer according to the redesigned component distribution to form a target component.

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