A method for producing a NiTiFe alloy with low elastic modulus based on additive manufacturing

Abstract

The present application relates to the technical field of additive manufacturing, and particularly relates to a method for preparing NiTiFe alloy with low elastic modulus based on additive manufacturing. The method is based on the layer-by-layer additive manufacturing principle to perform additive manufacturing on target metal powder, which can not only provide excellent surface quality and geometric precision, but also quickly realize intelligent integrated forming of complex workpieces compared with traditional metallurgical technology; the set raw material ratio can not only meet the critical defect concentration of low elastic modulus in the material, but also Fe atoms can be used as heterogeneous nucleating agents to form unique fine-grained structure in the non-equilibrium solidification process under suitable forming parameters, greatly improving the mechanical properties of the material and achieving the advantages of synergistically considering the material characteristics; the atomic relaxation generated after Fe element is added to NiTi can not only produce point defects required for low elastic modulus, but also produce dislocations and precipitated phases and other multi-dimensional defects at the matrix and grain boundaries.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a method for preparing NiTiFe alloys with low elastic modulus based on additive manufacturing. Background Technology

[0002] Nickel-titanium based shape memory alloys are attracting increasing attention from the aerospace, defense, biomedical, and automotive industries due to their unique functional properties (such as shape memory effect and superelasticity), biocompatibility, and corrosion resistance. However, due to the limitations of their inherent transformation properties, binary nickel-titanium alloys cannot meet the requirements of some special applications. Among the many shape memory alloy materials, NiTiFe alloys, due to their excellent shape memory effect, have broad application prospects in industrial couplings, aerospace cushioning devices, and cryogenic refrigeration.

[0003] However, for industry applications such as flexible robots and aerospace cushioning, NiTiFe alloys struggle to balance strength (i.e., a high yield strength) with flexibility (i.e., a low elastic modulus).

[0004] Therefore, there is an urgent need for a method to prepare NiTiFe alloys with low elastic modulus based on additive manufacturing to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for preparing NiTiFe alloys with low elastic modulus based on additive manufacturing, which can solve the problem of balancing strength and flexibility.

[0006] This invention provides a method for preparing NiTiFe alloy with low elastic modulus based on additive manufacturing, comprising:

[0007] Obtain the target metal powder; wherein the target metal powder includes pure Fe powder and pre-alloyed NiTi powder;

[0008] The target metal powder is subjected to additive manufacturing to obtain a NiTiFe alloy with a low elastic modulus; wherein the low elastic modulus ranges from 13 to 14 GPa, and the yield strength of the NiTiFe alloy is 700 to 800 MPa.

[0009] As can be seen from the above scheme, the method for preparing NiTiFe alloy with low elastic modulus based on additive manufacturing provided by the present invention uses the additive manufacturing principle of layer-by-layer stacking to additively manufacture the target metal powder. Compared with traditional metallurgical technology, it not only provides excellent surface quality and geometric accuracy, but also enables rapid intelligent integrated forming of complex workpieces, while the economic cost is much lower than that of traditional processes, and the production efficiency is significantly improved. Furthermore, by setting the raw material ratio, not only can the critical defect concentration for the low elastic modulus to appear inside the material be met, but Fe atoms can also act as heterogeneous nucleating agents, forming a unique fine-grained structure during non-equilibrium solidification under appropriate forming parameters, greatly improving the mechanical properties of the material and achieving the advantage of synergistic consideration of material properties. The atomic relaxation generated by the addition of Fe to NiTi can not only generate point defects required to generate low elastic modulus, but also generate multidimensional defects such as dislocations and precipitation at the matrix and grain boundaries. Therefore, the above technical solution can achieve precise control of the chemical composition and defect concentration inside the alloy to reach the critical defect concentration for the appearance of low elastic modulus. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic flowchart of a method for preparing NiTiFe alloy with low elastic modulus based on additive manufacturing, provided in an embodiment of the present invention.

[0012] Figure 2 This is a schematic diagram illustrating the characterization of a target metal powder according to an embodiment of the present invention;

[0013] Figure 3 This is an EBSD schematic diagram of the NiTiFe alloy with low elastic modulus prepared according to an embodiment of the present invention;

[0014] Figure 4 TEM microstructure of the NiTiFe alloy with low elastic modulus prepared in an embodiment of the present invention;

[0015] Figure 5 This is a schematic diagram illustrating the principle of low elastic modulus at the atomic level in the NiTiFe alloy with low elastic modulus prepared according to an embodiment of the present invention.

[0016] Figure 6The stress-strain curves of the NiTiFe alloy with low elastic modulus prepared according to the embodiments of the present invention are shown in the figure after 1 to 30 cycles of hyperelasticity.

[0017] Figure 7 The stress-strain curve of the NiTiFe alloy with low elastic modulus prepared according to Example 1 of the present invention;

[0018] Figure 8 The stress-strain curve of the NiTiFe alloy with low elastic modulus prepared according to Comparative Example 1 of the present invention is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 This invention provides a method for preparing a NiTiFe alloy with low elastic modulus based on additive manufacturing, the method comprising:

[0021] Step S1: Obtain the target metal powder; wherein, the target metal powder includes pure Fe powder and pre-alloyed NiTi powder;

[0022] Step S2: Additive manufacturing is performed on the target metal powder to obtain a NiTiFe alloy with a low elastic modulus; wherein the low elastic modulus ranges from 13 to 14 GPa, and the yield strength of the NiTiFe alloy is 700 to 800 MPa.

[0023] In this embodiment, additive manufacturing of the target metal powder is performed based on the layer-by-layer forming principle of additive manufacturing. Compared with traditional metallurgical technology, this not only provides excellent surface quality and geometric accuracy, but also enables rapid intelligent integrated forming of complex workpieces, while the economic cost is far lower than that of traditional processes, significantly improving production efficiency. Furthermore, the set raw material ratio not only meets the critical defect concentration for the low elastic modulus within the material, but Fe atoms can also act as heterogeneous nucleating agents, forming a unique fine-grained structure during non-equilibrium solidification under appropriate forming parameters, greatly improving the material's mechanical properties and achieving the advantage of synergistically considering material characteristics. The atomic relaxation generated by the addition of Fe to NiTi not only produces point defects required for the low elastic modulus, but also generates multidimensional defects such as dislocations and precipitation at the matrix and grain boundaries. Therefore, the above technical solution can achieve precise control of the chemical composition and defect concentration within the alloy to reach the critical defect concentration for the low elastic modulus.

[0024] In one embodiment of the present invention, pure Fe powder accounts for 2 to 4% of the total mass of the target metal powder.

[0025] In one embodiment of the present invention, pure Fe powder accounts for 3% of the total mass of the target metal powder.

[0026] During the experiment, the inventors discovered that when pure Fe powder accounts for 2 to 4% of the total mass of the target metal powder, the critical defect concentration that can meet the requirements for low elastic modulus within the material can be achieved. Furthermore, when pure Fe powder accounts for 3% of the total mass of the target metal powder, this low elastic modulus is even more intuitive and clear.

[0027] In one embodiment of the present invention, the particle size of pure Fe powder is 90-110 nm, and the particle size of NiTi powder is 15-53 μm.

[0028] In one embodiment of the present invention, additive manufacturing of a target metal powder is performed to obtain a NiTiFe alloy with a low elastic modulus, comprising:

[0029] A three-dimensional model of the required part structure is constructed and then input into 3D printing editing software to perform two-dimensional processing on the three-dimensional model and obtain two-dimensional slice data.

[0030] The two-dimensional slice data is input into the metal powder laser melting system;

[0031] Set the processing parameters for the metal powder laser melting system;

[0032] The target metal powder is spread on the base plate of the metal powder laser melting system, and an inert gas is introduced into the metal powder laser melting system;

[0033] A NiTiFe alloy with low elastic modulus was obtained by additive manufacturing of target metal powder on a substrate using a metal powder laser melting system.

[0034] In one embodiment of the present invention, the processing parameters include laser power, scanning speed, scanning spacing, powder layer thickness, spot diameter, and preheating temperature of the base plate.

[0035] In one embodiment of the present invention, the laser power is 80–140 W, the scanning speed is 150–300 mm / s, the scanning spacing is 70–90 μm, the powder layer thickness is 25–35 μm, the spot diameter is 60–80 μm, and the preheating temperature is 90–110 °C. This configuration ensures that the target metal powder with a high melting point can successfully form a liquid phase.

[0036] In this embodiment, the additive manufacturing technology described above possesses a unique non-equilibrium solidification mechanism. During the liquid crystallization and solid precipitation process, the rapid cooling rate causes uneven diffusion of the precipitated solid molecules in the liquid, resulting in uneven concentrations of solid molecules throughout the crystallization. Even when the temperature drops to the solidus line, non-uniform crystallization of the liquid phase still occurs. Therefore, this method ensures that, in addition to point defects, line defects (i.e., dislocations) and surface defects (i.e., precipitates) can be generated internally during the preparation of NiTiFe alloys. This coupling of multiple defects is considered a necessary condition for expanding novel low-elastic-modulus materials.

[0037] In one embodiment of the present invention, after introducing an inert gas, the oxygen and water vapor content in the metal powder laser melting system is both below 10 ppm. This setting can prevent the process parts (i.e., NiTiFe alloy) from being oxidized during the forming process, thus affecting the quality of the finished product.

[0038] In one embodiment of the present invention, the target metal powder on the substrate is additively manufactured in the following manner:

[0039] Laser melting, powder sieving, heat treatment, wire cutting, cleaning and polishing.

[0040] It is known that the metal powder laser melting system needs to be cleaned before use to prevent other components from contaminating and affecting product quality. After loading the powder, the work platform is calibrated to prevent errors from affecting product performance. After calibrating the work platform, the process is as follows: argon gas filling → powder spreading → laser pre-melting → powder spreading again → laser melting → powder spreading again → laser remelting → end. The next step is powder sieving. The purpose of sieving is to prevent the removal of small particles. Generally, a sieve with a specified aperture is used to remove small particles to prevent them from affecting the performance of subsequent product processing.

[0041] In some implementations, 2-5 layers are pre-scanned and melted to ensure a strong bond between the molded part and the bottom. Furthermore, the number of subsequent laser-melted powder layers depends on the size of the workpiece; larger workpieces require more powder layers.

[0042] In one embodiment of the present invention, ultrasonic cleaning is used, the cleaning time is 0.5 to 1 hour, and the cleaning medium is anhydrous alcohol.

[0043] In this embodiment, ultrasonic cleaning utilizes the cavitation, acceleration, and direct current effects of ultrasound in liquids to directly and indirectly affect the liquid and contaminants, thereby dispersing, emulsifying, and peeling off the contaminant layer to achieve the cleaning purpose. This results in a more thorough cleaning. Furthermore, the cleaning medium used is anhydrous alcohol, which is easily volatile after cleaning and leaves no residue on the cleaned items.

[0044] The following is combined with Figures 2 to 6 Let me explain.

[0045] Figure 2 These are the relevant characterizations of the mixed powder raw materials in the embodiments of the present invention, wherein: (a) electron micrograph of NiTi powder; (b) electron micrograph of pure Fe powder; (c) electron micrograph of NiTiFe powder; (d) room temperature XRD patterns of NiTi and Fe powders; Figure 2 The powder scanning electron microscope (SEM) images from the Chinese ac database show the specific morphology of the powder raw materials used in the embodiments of this invention: spherical pre-alloyed NiTi powder with a particle size of 15–53 μm, spherical Fe powder with a size of 90–110 nm, and the mixed powder. It can be seen that all powder surfaces are smooth, the Fe powder is uniformly distributed on the NiTi powder surface, and there is no obvious agglomeration. Figure 2 d represents the phase composition of NiTi and Fe powders obtained by X-ray diffraction (XRD) at room temperature. The results show that the primary phase of NiTi powder is B2 phase, and the primary phase of Fe powder is α-Fe phase. No other impurities or secondary phases were detected in the samples.

[0046] Figure 3 This is an EBSD image of the NiTiFe alloy prepared according to an embodiment of the present invention; the image shows that slender columnar grains grow in a stretched and elongated manner along the parallel construction direction. The non-equilibrium solidification process in the LPBF process generates heterogeneous nucleation of Fe elements, leading to grain refinement and greatly improving the mechanical properties of the NiTiFe alloy.

[0047] Figure 4 This is a TEM microstructure of the NiTiFe alloy prepared according to an embodiment of the present invention. The figure clearly shows the non-equilibrium solidification structure generated by the additive manufacturing process, such as dislocations and precipitates, which is a necessary condition for achieving additive manufacturing to prepare NiTiFe with low elastic modulus.

[0048] Figure 5 This is a schematic diagram illustrating the principle of low elastic modulus at the atomic level in the NiTiFe alloy prepared according to an embodiment of the present invention. It can be seen that under the influence of factors such as Fe element, dislocations, and precipitated phases, the process parameters can achieve the generation of low elastic modulus nanodomain structures.

[0049] Figure 6 This is a stress-strain curve diagram of the NiTiFe alloy prepared according to the embodiments of the present invention, after 1 to 30 cycles of hyperelasticity. Figure 6 It can be seen that after multiple superelastic cycles, the NiTiFe alloy prepared under these process parameters exhibits extremely large recoverable strain and extremely narrow strain hysteresis.

[0050] Figure 7 This is a stress-strain curve of the NiTiFe alloy prepared in Example 1 of this invention. Figure 7 As can be seen from the stress-strain curve in Example 1, the yield strength of NiTiFe prepared by LPBF is 752 MPa, and the strain required to reach the yield strength is 5.5%. The calculated elastic modulus of the alloy is 13.7 GPa, which is much lower than the elastic modulus of conventional metals such as Al and Cu (70 GPa and 115 GPa).

[0051] Figure 8 This is a stress-strain curve of the NiTiFe alloy prepared in Comparative Example 1 of this invention. Figure 8 As can be seen from the stress-strain curve in Comparative Example 1, the yield strength of NiTiFe prepared by LPBF is 783 MPa, and the strain required to reach the yield strength is 5.3%. The calculated elastic modulus of the alloy is 14.7 GPa, which is much lower than the elastic modulus of conventional metals such as Al and Cu.

[0052] It is known that the extremely low elastic modulus of NiTiFe alloys allows the material to withstand mechanical deformations such as bending and folding during use without losing its function. This means that the NiTiFe alloy in this patent not only has a high yield strength but can also be driven to deform under very low stress. This overcomes the long-standing material challenge of achieving both strength and flexibility. This has great application potential in flexible robotics and aerospace cushioning industries. This high-strength alloy may open the door to the widespread application of emerging technologies such as deformable spacecraft, humanoid robots, and advanced biomedical devices.

[0053] The following describes specific embodiments and comparative examples. Specific Implementation Example 1

[0055] (a) Pure Fe powder and pre-alloyed NiTi powder were used as raw materials. The particle size of the Fe powder was 90-110 nm, the particle size distribution of the NiTi powder was 15-53 μm, the pure Fe powder accounted for 3% of the total mass of the target metal powder, and the remaining components were all NiTi. NiTiFe alloy powder was prepared by mixing powders using a high-energy planetary ball mill.

[0056] (b) Construct a 3D model of the required part structure and input it into the 3D printing editing software. Pre-build a cube with dimensions of 5×5×8mm, and set the long side direction to be parallel to the printing direction. After editing, perform 2D processing to obtain 2D slice data and import it into the metal powder laser melting system;

[0057] (c) Set the processing parameters of the metal powder laser melting system: laser power is 110W, scanning speed is 200mm / s, powder layer thickness is set to 30μm by the system, scanning interval is fixed at 80μm, and base plate preheating temperature is 100℃.

[0058] (d) Spread NiTiFe powder on the base plate of the metal powder laser melting system. Inert gas argon is introduced into the metal powder laser melting system until the oxygen content in the forming chamber is below 10ppm, and additive manufacturing begins.

[0059] (e) After the additive manufacturing process is stopped, the printed workpiece is wire-cut to obtain a sample.

[0060] Comparative Example 1

[0061] Comparative Example 1 is largely the same as Example 1, with the main difference being that the NiTiFe alloy was prepared using process parameters of 70W laser power, 310mm / s scanning speed, 30μm powder layer thickness, and 80μm scanning spacing.

[0062] The prepared NiTiFe alloy exhibited severe incomplete fusion defects and numerous cracks on its surface, making it impossible to achieve complete forming of the NiTiFe alloy, and it did not exhibit low elastic modulus.

[0063] Comparative Example 2

[0064] Comparative Example 2 is largely the same as Example 1, with the main difference being that the NiTiFe alloy was prepared using process parameters of 150W laser power, 140mm / s scanning speed, 30μm powder layer thickness, and 80μm scanning spacing.

[0065] The surface roughness of the prepared NiTiFe alloy decreased significantly and element burn-out occurred, resulting in extremely poor forming quality and no low elastic modulus was observed.

[0066] Comparative Example 3

[0067] Comparative Example 3 is largely the same as Example 1, with the main difference being that the NiTiFe alloy was prepared using process parameters of 150W laser power, 310mm / s scanning speed, 30μm powder layer thickness, and 80μm scanning spacing.

[0068] The surface roughness of the prepared NiTiFe alloy decreased significantly and element burn-out occurred, resulting in extremely poor forming quality and no low elastic modulus was observed.

[0069] Comparative Example 4

[0070] Comparative Example 4 is largely the same as Example 1, with the main difference being that the NiTiFe alloy was prepared using process parameters of 70W laser power, 140mm / s scanning speed, 30μm powder layer thickness, and 80μm scanning spacing.

[0071] The prepared NiTiFe alloy has good surface quality, but low elastic modulus is still not observed. Specific Implementation Example 2

[0073] (a) Using pure Fe powder and pre-alloyed NiTi powder as raw materials. The particle size of Fe powder is 90-110 nm, the particle size distribution of NiTi powder is 15-53 μm, pure Fe powder accounts for 2% of the total mass of the target metal powder, and the remaining components are all NiTi. NiTiFe alloy powder is prepared by mixing powder using a high-energy planetary ball mill.

[0074] (b) Construct a 3D model of the required part structure and input it into the 3D printing editing software. Pre-build a cube with dimensions of 5×5×8mm, and set the long side direction to be parallel to the printing direction. After editing, perform 2D processing to obtain 2D slice data and import it into the metal powder laser melting system;

[0075] (c) Set the processing parameters of the metal powder laser melting system: laser power is 120W, scanning speed is 220mm / s, powder layer thickness is set to 30μm by the system, scanning spacing is fixed at 80μm, and base plate preheating temperature is 100℃.

[0076] (d) Spread NiTiFe powder on the base plate of the metal powder laser melting system. Inert gas argon is introduced into the metal powder laser melting system until the oxygen content in the forming chamber is below 10ppm, and additive manufacturing begins.

[0077] (e) After the additive manufacturing process is stopped, the printed workpiece is wire-cut to obtain a sample. Specific Implementation Example 3

[0079] (a) Using pure Fe powder and pre-alloyed NiTi powder as raw materials. The particle size of Fe powder is 90-110 nm, the particle size distribution of NiTi powder is 15-53 μm, pure Fe powder accounts for 2% of the total mass of the target metal powder, and the remaining components are all NiTi. NiTiFe alloy powder is prepared by mixing powder using a high-energy planetary ball mill.

[0080] (b) Construct a 3D model of the required part structure and input it into the 3D printing editing software. Pre-build a cube with dimensions of 5×5×8mm, and set the long side direction to be parallel to the printing direction. After editing, perform 2D processing to obtain 2D slice data and import it into the metal powder laser melting system;

[0081] (c) Set the processing parameters of the metal powder laser melting system: laser power is 110W, scanning speed is 180mm / s, powder layer thickness is set to 30μm by the system, scanning interval is fixed at 80μm, and base plate preheating temperature is 100℃.

[0082] (d) Spread NiTiFe powder on the base plate of the metal powder laser melting system. Inert gas argon is introduced into the metal powder laser melting system until the oxygen content in the forming chamber is below 10ppm, and additive manufacturing begins.

[0083] (e) After the additive manufacturing process is stopped, the printed workpiece is wire-cut to obtain a sample. Specific Implementation Example 4

[0085] (a) Pure Fe powder and pre-alloyed NiTi powder were used as raw materials. The particle size of the Fe powder was 90-110 nm, the particle size distribution of the NiTi powder was 15-53 μm, the pure Fe powder accounted for 4% of the total mass of the target metal powder, and the remaining components were all NiTi. NiTiFe alloy powder was prepared by mixing powders using a high-energy planetary ball mill.

[0086] (b) Construct a 3D model of the required part structure and input it into the 3D printing editing software. Pre-build a cube with dimensions of 5×5×8mm, and set the long side direction to be parallel to the printing direction. After editing, perform 2D processing to obtain 2D slice data and import it into the metal powder laser melting system;

[0087] (c) Set the processing parameters of the metal powder laser melting system: laser power is 100W, scanning speed is 220mm / s, powder layer thickness is set to 30μm by the system, scanning interval is fixed at 80μm, and base plate preheating temperature is 100℃.

[0088] (d) Spread NiTiFe powder on the base plate of the metal powder laser melting system. Inert gas argon is introduced into the metal powder laser melting system until the oxygen content in the forming chamber is below 10ppm, and additive manufacturing begins.

[0089] (e) After the additive manufacturing process is stopped, the printed workpiece is wire-cut to obtain a sample. Specific Implementation Example 5

[0091] (a) Pure Fe powder and pre-alloyed NiTi powder were used as raw materials. The particle size of the Fe powder was 90-110 nm, the particle size distribution of the NiTi powder was 15-53 μm, the pure Fe powder accounted for 4% of the total mass of the target metal powder, and the remaining components were all NiTi. NiTiFe alloy powder was prepared by mixing powders using a high-energy planetary ball mill.

[0092] (b) Construct a 3D model of the required part structure and input it into the 3D printing editing software. Pre-build a cube with dimensions of 5×5×8mm, and set the long side direction to be parallel to the printing direction. After editing, perform 2D processing to obtain 2D slice data and import it into the metal powder laser melting system;

[0093] (c) Set the processing parameters of the metal powder laser melting system: laser power is 140W, scanning speed is 200mm / s, powder layer thickness is set to 30μm by the system, scanning interval is fixed at 80μm, and base plate preheating temperature is 100℃.

[0094] (d) Spread NiTiFe powder on the base plate of the metal powder laser melting system. Inert gas argon is introduced into the metal powder laser melting system until the oxygen content in the forming chamber is below 10ppm, and additive manufacturing begins.

[0095] (e) After the additive manufacturing process is stopped, the printed workpiece is wire-cut to obtain a sample.

[0096] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0097] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. The application of a NiTiFe alloy with low elastic modulus prepared by additive manufacturing in flexible robots, characterized in that, The low elastic modulus ranges from 13 to 14 GPa, the yield strength of the NiTiFe alloy is 700 to 800 MPa, and the preparation method of the NiTiFe alloy includes: Obtain target metal powder; wherein the target metal powder comprises pure Fe powder and pre-alloyed NiTi powder, the pure Fe powder accounts for 2-4% of the total mass of the target metal powder, the particle size of the pure Fe powder is 90-110 nm, and the particle size of the NiTi powder is 15-53 μm; in the target metal powder, the primary phase of the NiTi powder is B2 phase, the Fe powder is α-Fe phase, and no other impurities or secondary phases are detected; Additive manufacturing of the target metal powder yields a NiTiFe alloy with low elastic modulus. The set raw material ratio satisfies the critical defect concentration for low elastic modulus within the material. Fe atoms act as heterogeneous nucleating agents, forming a fine-grained structure during non-equilibrium solidification. The atomic relaxation generated by the addition of Fe to NiTi produces point defects necessary for low elastic modulus, and multidimensional defects (line and surface defects) are generated at the matrix and grain boundaries, constituting a necessary condition for extending the low elastic modulus material. In the EBSD image of the NiTiFe alloy, slender columnar grains grow in a stretched and extended manner along the parallel construction direction. The non-equilibrium solidification process generates heterogeneous nucleation of Fe, leading to grain refinement and improving the mechanical properties of the NiTiFe alloy. In the TEM microstructure image of the NiTiFe alloy, the non-equilibrium solidification structure generated by the additive manufacturing process can be observed. The additive manufacturing process of the target metal powder to obtain a NiTiFe alloy with low elastic modulus includes: A three-dimensional model of the required part structure is constructed, and the three-dimensional model is input into 3D printing editing software to perform two-dimensional processing on the three-dimensional model to obtain two-dimensional slice data. The two-dimensional slice data is input into the metal powder laser melting system; Set the processing parameters of the metal powder laser melting system; The target metal powder is spread on the base plate of the metal powder laser melting system, and an inert gas is introduced into the metal powder laser melting system; The target metal powder on the substrate is additively manufactured using the metal powder laser melting system to obtain a NiTiFe alloy with low elastic modulus. The processing parameters include laser power, scanning speed, scanning spacing, powder layer thickness, spot diameter, and preheating temperature of the base plate; The laser power is 80~140W, the scanning speed is 150~300mm / s, the scanning spacing is 70~90μm, the powder layer thickness is 25~35μm, the spot diameter is 60~80μm, and the preheating temperature is 90~110℃.

2. The application according to claim 1, characterized in that, The pure Fe powder accounts for 3% of the total mass of the target metal powder.

3. The application according to claim 1, characterized in that, After the inert gas is introduced, the oxygen and water vapor content in the metal powder laser melting system is both below 10 ppm.

4. The application according to claim 1, characterized in that, The target metal powder on the substrate is manufactured by additive manufacturing in the following manner: Laser melting, powder sieving, heat treatment, wire cutting, cleaning and polishing.

5. The application according to claim 4, characterized in that, The cleaning process employs ultrasonic cleaning, with a cleaning time of 0.5 to 1 hour, and the cleaning medium is anhydrous alcohol.

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