A high-performance laser selective melting Cr3C2 / 316L alloy and its preparation method

Abstract

The present invention discloses a high-performance laser selective melting Cr3C2 / 316L alloy and its preparation method, belonging to the field of additive manufacturing technology. The Cr3C2 / 316L alloy of the present invention is composed of a 316L matrix and a Cr3C2 particle reinforcement phase, wherein the Cr3C2 particles account for 10-11% of the total weight of the alloy. The preparation method is as follows: Cr3C2 and 316L powders are mechanically mixed as raw materials to obtain a mixed powder, and then laser selective melting technology is used to optimize the powder particle size and process parameters to obtain the Cr3C2 / 316L alloy. The relative density of the Cr3C2 / 316L alloy is ≥99.7%, the porosity is ≤0.41%, the hardness is ≥327HV0.1, the tensile strength is ≥1032MPa, the yield strength is ≥839MPa, and the wear rate is ≤2.94*10 ‑12 m 3 / (N*m). Compared with 316L alloy, the product of the present invention has a hardness increased by 23%, a tensile strength increased by 44%, a yield strength increased by 21%, and a wear rate reduced by 52%, and has excellent mechanical properties and wear resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and more specifically, relates to a high-performance laser selectively melted Cr3C2 / 316L alloy and a preparation method thereof. Background Art

[0002] As a modern structural material, 316L stainless steel plays a vital role in industrial development and scientific and technological advancement. Due to its excellent corrosion resistance, formability, and weldability, 316L stainless steel has been widely used in industries such as automotive, biomedical, energy, and marine. With the continuous development of modern industry, the requirements for material performance are becoming increasingly stringent. However, 316L's relatively low strength and wear resistance limit its engineering applications. Due to its low carbon content, carbon and other elements are dissolved in the crystal lattice, and no phase transformation occurs during cooling. Therefore, improving the performance of SLM 316L stainless steel parts through quenching is not feasible. To enhance the strength and wear resistance of 316L stainless steel and expand its application, various research approaches are underway, such as material composites and advanced preparation methods. By adding low-density, high-strength, and high-hardness ceramic particles to the matrix as reinforcement, the excellent properties of stainless steel are enhanced while improving its mechanical properties, such as hardness and wear resistance. This approach holds great promise for applications in fields such as machinery and chemical engineering. Existing 316L stainless steel produced using conventional technology typically results in coarse grains and low strength, limiting its application. Furthermore, 316L stainless steel produced using conventional techniques typically requires subsequent processing, which is complex and time-consuming, and makes it difficult to form complex parts. Laser selective melting technology eliminates the need for molds and can rapidly form complex parts in a single step, eliminating the need for subsequent machining. This significantly shortens the production cycle and reduces production costs.

[0003] After searching, the Chinese patent application number is: 202110475931.7, the application date is April 29, 2021, and the name of the invention is: A nano-alumina reinforced 316L stainless steel composite material and its preparation method. The preparation method of this application includes the following process: mixing powder material A is subjected to powder laser forming to obtain a formed body; the formed body is subjected to stress control to obtain a nano-alumina reinforced 316L stainless steel composite material; the mixed powder material A is a mixed powder obtained by ball milling 316L steel powder and pretreated Al2O3 powder; the pretreatment process of Al2O3 powder includes: placing spherical Al2O3 in NH4OH for corrosion treatment, washing and drying after corrosion to obtain pretreated Al2O3 powder. In this application, nano-alumina reinforced 316L stainless steel composite material is prepared by laser melting technology, which has the characteristics of fast processing speed, high efficiency and short process. By uniformly distributing the ceramic material Al2O3 in the 316L stainless steel matrix, the strength of 316L can be improved to a certain extent, but its improvement effect still needs to be further improved. Summary of the Invention

[0004] 1. Problem to be solved

[0005] To address the shortcomings of 316L stainless steel produced using existing selective laser melting (SLM) technology, which suffers from relatively poor mechanical properties such as hardness and wear resistance, as well as high porosity, a high-performance SLM-processed Cr3C2 / 316L alloy and its preparation method are provided. By adding a certain amount of Cr3C2 ceramic particles to 316L stainless steel as a reinforcement phase, the present invention further improves the 316L alloy's forming quality, hardness, yield strength, tensile strength, and porosity, thereby enhancing the alloy's wear resistance and compactness.

[0006] 2. Technical solution

[0007] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0008] The present invention discloses a high-performance laser selectively melted Cr3C2 / 316L alloy, which consists of a 316L matrix and a Cr3C2 particle reinforcement phase. The Cr3C2 particles account for 10-11% of the total weight of the alloy. By adding Cr3C2 particles to the 316L alloy, the strength of the resulting alloy is significantly increased, the porosity of the alloy is reduced, and the surface density and molding quality of the alloy are improved.

[0009] The preparation process of the Cr3C2 / 316L alloy of the present invention comprises the following steps:

[0010] (1) Cr3C2 and 316L powders are mechanically mixed as raw materials to obtain a mixed powder;

[0011] (2) constructing a three-dimensional solid model using software in a computer and performing layered analysis on the three-dimensional solid model through laser beam scanning path planning;

[0012] (3) Place the substrate in the molding chamber of the laser selective melting molding equipment, load the obtained mixed powder into the powder cylinder, seal the molding chamber, and start the circulating degassing purification system. After evacuating the molding chamber, high-purity argon gas is introduced to ensure that the oxygen content in the molding chamber is below 500ppm, and preheat the substrate;

[0013] (4) New engineering tasks, set the laser selective melting molding process parameters for preparation, and obtain Cr3C2 / 316L alloy. The present invention adopts a laser selective melting manufacturing process, which discretizes the three-dimensional solid component into a series of two-dimensional structures, uses a high-energy laser to scan the powder layer by layer, and finally forms a three-dimensional solid component through the melting-solidification and layer-by-layer stacking of the powder. This process is based on the discrete-stacking molding method and can form components with complex structures. The preparation process is simple to operate, the surface quality of the prepared molded parts is excellent, and the comprehensive mechanical properties of the molded parts can be greatly improved.

[0014] As a further preference of the present invention, in step (1), the particle size of the 316L powder is controlled to be 15-53 μm, and the particle size of the Cr3C2 powder is controlled to be 8-12 μm. By controlling the different particle size distributions of the 316L powder and the Cr3C2 powder, during preparation, the Cr3C2 powder with smaller particles fills the gaps between the 316L powders in liquid form after melting, so that the packing density of the powder is improved, and the spheroidization phenomenon can also be alleviated, which is beneficial to improving the density of the formed part, improving its strength and improving the surface forming quality, so that the prepared alloy product has excellent comprehensive mechanical properties, and good density and wear resistance.

[0015] As a further preferred embodiment of the present invention, the sphericity of the Cr3C2 powder reaches above 95%. Selecting Cr3C2 particles with higher sphericity is conducive to the smooth progress of the powder spreading process, thereby further ensuring the acquisition of dense molded parts.

[0016] As a further preferred embodiment of the present invention, the mass ratio of 316L powder to Cr3C2 powder is (8-9):1.

[0017] As a further preferred embodiment of the present invention, the Cr3C2 powder is composed of two components with different properties, NiCr and Cr3C2, with the mass of Cr3C2 accounting for 75% of the total weight of the Cr3C2 powder. Among the components of the present invention, Cr3C2 is a hard reinforcing phase with a high melting point, hardness, and excellent high-temperature thermal and chemical stability. However, since the wetting angle of Cr3C2 alone in the binder metals Fe and Ni is 0 and its melting point is high, it is difficult to melt and is very brittle. Therefore, NiCr alloy is used as the binder phase to obtain NiCr-coated Cr3C2 powder. NiCr-Cr3C2 powder is currently commercially produced at a low cost. In addition, the grain growth tendency is relatively low during the preparation process using laser selective melting technology, resulting in the alloy having excellent performance. During the alloy preparation process, some unmelted Cr3C2 particles can serve as non-spontaneous nucleation cores, hindering the growth of columnar crystals and making the alloy structure refined and homogenized. Secondly, the carbides generated by the addition of Cr3C2, whether it causes the grains to precipitate along the grain boundaries or to be dispersed in the matrix, will hinder the migration of grain boundaries during grain growth, thereby hindering the growth of grains. The addition of Cr3C2 will increase the number of fluid types in the molten pool during the alloy preparation process, promote structural uniformity, and make the final formed part have excellent organizational properties.

[0018] As a further preference of the present invention, in the preparation method of the Cr3C2 particle reinforced 316L alloy formed by laser selective melting, a SYH-2-3-10 three-dimensional motion mixer is used to mix the powder, the mixer speed is 40 to 60 r / min, the Cr3C2 powder is added to the 316L powder three times to prevent the Cr3C2 powder from agglomerating, and the total mixing time is 8 to 10 hours.

[0019] As a further preference of the present invention, before the selective laser melting preparation, the printed sample substrate is preheated, and the preheating temperature is controlled to be 130-160°C, so as to effectively reduce the thermal stress during the SLM processing and ensure that the sample has good mechanical stability.

[0020] It should be noted that the present invention optimizes the design of the laser selective melting process parameters, especially controlling the laser power to 300-400W, the scanning speed to 1800-2200mm / s, the powder layer thickness to 30μm, the scanning spacing to 60μm, the chessboard scanning, and the rotation angle to 67°. Controlling the above process parameters can ensure that the prepared molded parts meet the requirements of the present invention, and can not only ensure that the prepared molded parts have good comprehensive mechanical properties and wear resistance, but also have a tensile strength of ≥1032MPa, a yield strength of ≥839MPa, and a wear rate of ≤2.94*10 -12 m 3 / (N*m), most importantly, the molded parts also have good surface quality, significantly reduced porosity of the molded parts, high density, the relative density of the molded parts ≥99.7%, porosity ≤0.41%, and hardness ≥327HV0.1.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention adopts laser selective melting technology for preparation. Compared with the traditional forging preparation method, the sample prepared by laser selective melting has higher microhardness and tensile strength, the surface quality of the prepared sample is higher, the size is more precise, and it is more conducive to mechanical automation use; compared with surface treatment technologies such as supersonic flame spraying and laser cladding, laser selective melting technology does not perform coating strengthening treatment on the material surface, but directly prepares the sample. It can directly prepare the required sample and produce parts with more complex shapes. When the prepared coating is compared with the sample structure, the grains of the structure prepared by laser selective melting are finer and the performance is optimized. The experimental process of the present invention is simple and easy to operate.

[0023] In addition, by optimizing the composition and process parameters, it helps to maximize the synergistic effect of the components, so that the prepared Cr3C2 / 316L alloy molded parts have significantly reduced porosity, increased relative density, 23% increased hardness, 44% increased tensile strength, 21% increased yield strength, and 52% reduced wear rate compared to conventional 316L alloy molded parts, showing excellent mechanical properties and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a morphology diagram of the alloy powder used in the present invention, wherein:

[0025] Sub-image a) shows the morphology of 316L powder;

[0026] Sub-image b) shows the morphology of Cr3C2 powder;

[0027] Sub-figure c) shows the powder morphology after mixing Cr3C2 and 316L.

[0028] Figure 2 The microstructure pictures of the products obtained in Example 1 and Comparative Example 1 of the present invention are as follows:

[0029] Sub-figure a) is a microstructure image of the 316L alloy prepared in Comparative Example 1;

[0030] Sub-figure b) is a microstructure image of the Cr3C2 / 316L alloy prepared in Example 1.

[0031] Figure 3The sliding wear surface morphology of the products obtained in Example 1 and Comparative Example 1 of the present invention, wherein:

[0032] Sub-figure a) Sliding wear surface morphology of the 316L alloy prepared in Comparative Example 1;

[0033] Sub-figure b) shows the sliding wear surface morphology of the Cr3C2 / 316L alloy prepared in Example 1; DETAILED DESCRIPTION

[0034] The elemental composition of the 316L alloy used in the following examples or comparative examples is shown in Table 1. The particle size of the 316L alloy powder is 15 to 53 μm, and the morphology of the 316L alloy powder is as follows: Figure 1 Neutron diagram a).

[0035] Table 1 Chemical composition of 316L powder used (wt.%)

[0036] Fe Cr Ni Mo Mn Si P S C O bal 16.41 10.58 2.67 0.71 0.25 0.007 0.006 0.013 0.072

[0037] The sphericity of the Cr3C2 powder used is above 95%, and the particle size is 8-12μm. The powder morphology is as follows: Figure 1 As shown in the neutron diagram b), the Cr3C2 powder is composed of two components with different properties, NiCr and Cr3C2, and the mass of Cr3C2 accounts for 75% of the total weight of the Cr3C2 powder.

[0038] The molding equipment used is the HBD-150D selective laser melting metal 3D printer produced by Guangdong Hanbang Laser Technology Co., Ltd. The powder mixing equipment uses the SYH-2-3-10 three-dimensional motion mixer.

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, the present invention is further described below in conjunction with specific embodiments.

[0040] Example 1

[0041] A high-performance laser selective melting Cr3C2 / 316L alloy of this embodiment is prepared as follows:

[0042] (1) NiCr-Cr3C2 and 316L powders were mechanically mixed in a mass ratio of 1:9 without destroying the original characteristics. The process parameters of mechanical mixing were: mixing speed 50r / min, NiCr-Cr3C2 powder was added to 316L powder three times, mixing time 9h, and the morphology after mixing was as follows: Figure 1 Neutron diagram c) shown.

[0043] (2) Using laser selective melting technology, the mixed powder is used as the printing material to prepare Cr3C2 / 316L alloy. The microstructure of the prepared molded part is as follows: Figure 2 Neutron image b) is shown. Specifically, first, a three-dimensional solid model is constructed using computer software, and the three-dimensional solid model is subjected to layered analysis through laser beam scanning path planning. Then, a substrate is placed in the molding chamber of the laser selective melting molding equipment, and the mixed powder is loaded into the powder cylinder. The molding chamber is sealed, and the circulating degassing and purification system is turned on. After evacuating the molding chamber, high-purity argon gas is introduced to ensure that the oxygen content in the molding chamber is below 500ppm. At the same time, the printed sample substrate is preheated at 150°C. Finally, a new engineering task is created and the laser selective melting molding process parameters are set. The laser power is controlled to 350W, the scanning speed is set to 2200mm / s, the scanning pitch is set to 60μm, the powder layer thickness is set to 30μm, the chessboard scanning is performed, and the rotation angle is set to 67°. After preparation, the Cr3C2 / 316L alloy is obtained.

[0044] Observation of the prepared samples revealed that the samples had no obvious defects and had high surface precision.

[0045] Comparative Example 1

[0046] The 316L alloy specimens in this comparative example were prepared using the same process parameters as in Example 1. The difference from Example 1 is that only 316L powder was used to prepare the specimens, without the addition of Cr3C2 powder. Observation of the prepared specimens revealed no obvious defects and high surface precision.

[0047] The microstructures of the sample prepared in Comparative Example 1 and the alloy obtained in Example 1 were observed and compared, and the hardness, tensile properties, and wear properties of the two alloys were tested. The experimental methods and results are as follows.

[0048] 1. Molding quality

[0049] The relative density of the sample obtained in Comparative Example 1 and the sample of the alloy obtained in Example 1 was measured by the drainage method, and the porosity of the two was measured by the metallographic method. The test results are shown in Table 2. By adding Cr3C2 powder and optimizing the preparation process parameters, the prepared embodiment product has a significantly reduced porosity and a greatly improved density compared with Comparative Example 1, and has better molding quality. In addition, the addition of Cr3C2 powder with a smaller particle size and a higher sphericity in the present invention is conducive to the smooth progress of the powder spreading process, further ensuring the acquisition of dense molded parts. The Cr3C2 powder with a smaller particle size can fill the gaps between the 316L powders in a liquid form after melting, so that the bulk density of the powder is increased, the spheroidization phenomenon can be reduced, and it is beneficial to improve the density of the molded parts, improve the alloy strength and improve the surface forming quality.

[0050] Table 2 Comparison of relative density of the products obtained in Example 1 and Comparative Example 1

[0051] Porosity density Example 1 0.41％ 99.7％ Comparative Example 1 1.27％ 98.3％

[0052] 2. Microstructure observation

[0053] The sample was removed from the substrate by wire cutting. The sample size for microstructure observation was a block sample of 10mm×10mm×7mm. The sample for microstructure observation was then ground, polished, and etched. The etchant used in this experiment was aqua regia (HNO3:HCl=1:3). The prepared sample was observed for its morphology using a HILIP-XL30 scanning electron microscope (SEM). Figure 2 It can be seen that the structure of 316L obtained in Comparative Example 1 is mainly composed of a large number of relatively coarse columnar crystals and cellular crystals, while the structure of the alloy obtained in Example 1 is mainly a network eutectic structure, the number of columnar crystals is greatly reduced, the grain size is significantly smaller, and the structure is significantly refined and uniform.

[0054] 3. Tensile performance test

[0055] The tensile specimens prepared in Example 1 and Comparative Example 1 were cut from the substrate using wire cutting, polished, and subjected to tensile testing using an Instron 5565 dual-column electronic universal testing machine. The Cr3C2 / 316L alloy specimen obtained in Example 1 achieved a tensile strength of 1032 MPa and a yield strength of 840 MPa. Compared to the 316L alloy prepared in the comparative example, which had a tensile strength of 715 MPa and a yield strength of 695 MPa, the tensile strength increased by 44% and the yield strength increased by 21%. The grain refinement in the examples results in the presence of numerous grain boundaries, which hinder dislocation motion. Dislocations accumulate at the grain boundaries, resulting in grain boundary strengthening and improving the alloy's strength.

[0056] 4. Hardness and wear resistance test

[0057] The microhardness of the block sample surface was measured multiple times using a HMV-2T micro Vickers hardness tester on the samples prepared in Example 1 and Comparative Example 1. The arithmetic mean was taken as the final hardness value. The test load was 0.1 kg and the loading time was 10 seconds. The microhardness of the Cr3C2 / 316L alloy obtained in Example 1 reached 327 HV 0.1 , compared with the microhardness of 316L in Comparative Example 1 (265HV 0.1 ) increased by 23%.

[0058] The wear resistance was measured using a UMT TriboLab friction and wear tester. Before testing, the samples prepared in Example 1 and Comparative Example 1 were ground and polished on sandpaper. The test load was set, the test time was 30 minutes, the speed was 200 rpm, the rotation diameter was 3 mm, the grinding ball was a Φ6.35 mm Si3N4 ceramic ball, and the load was set to 10 N, 20 N, and 30 N. The average wear rate of the Cr3C2 / 316L alloy prepared in Example 1 was 2.94*10 -12 m 3 / (N*m), the average wear rate of 316L stainless steel prepared in Comparative Example 1 is 6.23*10 -12 m 3 / (N*m), the wear rate of Example 1 was reduced by 52%. Figure 3 a) and Figure 3 Figures b) show the sliding wear surface morphologies of the two alloys obtained in Comparative Example 1 and Example 1, respectively. As can be seen, the 316L alloy obtained in Comparative Example 1 exhibits severe delamination and wear, while the Cr3C2 / 316L alloy obtained in Example 1 exhibits a relatively smooth wear surface and significantly improved wear resistance. The alloying elements decomposed from the added Cr3C2 powder in the Cr3C2 / 316L alloy obtained in Example 1 provide solid solution strengthening, improving the wear resistance of the Cr3C2 / 316L alloy.

[0059] Comparative Example 2

[0060] The Cr3C2 / 316L alloy specimens in this comparative example were prepared using the same method as in Example 1, differing from Example 1 in that the laser power was set to 160W during the selective laser melting process. Observation of the prepared specimens revealed surface depressions and low surface precision. Testing of the specimens obtained in this comparative example using the testing method described in Example 1 revealed high porosity, low density, and poor molding quality.

[0061] Comparative Example 3

[0062] The Cr3C2 / 316L alloy specimens in this comparative example were prepared using the same method as in Example 1, differing from Example 1 in that the scanning speed was set to 1000 mm / s during the selective laser melting process. Observation of the prepared specimens revealed no obvious surface defects, but low surface accuracy. Testing of the specimens obtained in this comparative example using the testing method described in Example 1 revealed high porosity, low density, and poor molding quality.

[0063] Compared with Example 1, in order to make the prepared molded parts meet the use requirements of the present invention, especially when using laser selective melting technology for preparation, on the basis of ensuring that the molded parts have excellent mechanical properties and wear resistance, the porosity of the molded parts is further reduced and the density is improved. It is necessary to strictly control the laser selective melting molding process parameters and cooperate with the components and ratio design of the present invention to finally obtain the product of the present invention.

[0064] Example 2

[0065] A high-performance laser selective melting Cr3C2 / 316L alloy of this embodiment is prepared as follows:

[0066] (1) NiCr-Cr3C2 and 316L powders were mechanically mixed at a mass ratio of 1:8.5 without destroying their original characteristics. The process parameters for mechanical mixing were: mixing speed of 50 r / min, NiCr-Cr3C2 powder was added to 316L powder in three batches, and mixing time was 10 h.

[0067] (2) Using laser selective melting technology, the uniformly mixed powder is used as the printing material to prepare Cr3C2 / 316L alloy. Specifically, first, a three-dimensional solid model is constructed using software on a computer, and the three-dimensional solid model is layered and analyzed by laser beam scanning path planning. Then, a substrate is placed in the molding chamber of the laser selective melting molding equipment, and the mixed powder is loaded into the powder cylinder. The molding chamber is sealed, and the circulating degassing purification system is turned on. After the molding chamber is evacuated, high-purity argon gas is introduced to ensure that the oxygen content in the molding chamber is below 500ppm. At the same time, the printed sample substrate is preheated at 140℃. Finally, a new engineering task is created and the laser selective melting molding process parameters are set. The laser power is controlled to 300W, the scanning speed is 2200mm / s, the scanning spacing is 60μm, the powder layer thickness is 30μm, the chessboard scanning is performed, and the rotation angle is 67°. After the preparation is completed, the Cr3C2 / 316L alloy is obtained.

[0068] The prepared sample was observed to have no obvious defects and high surface precision. The sample obtained in this example was tested using the testing method described in Example 1, and the results were basically the same as those in Example 1.

[0069] Example 3

[0070] A high-performance laser selective melting Cr3C2 / 316L alloy of this embodiment is prepared as follows:

[0071] (1) NiCr-Cr3C2 and 316L powders were mechanically mixed in a mass ratio of 1:9 without destroying their original characteristics. The process parameters for mechanical mixing were: mixing speed of 60 r / min, NiCr-Cr3C2 powder was added to 316L powder in three batches, and mixing time was 8 h.

[0072] (2) Using laser selective melting technology, the uniformly mixed powder is used as the printing material to prepare Cr3C2 / 316L alloy. Specifically, first, a three-dimensional solid model is constructed using software on a computer, and the three-dimensional solid model is layered and analyzed by laser beam scanning path planning. Then, a substrate is placed in the molding chamber of the laser selective melting molding equipment, and the mixed powder is loaded into the powder cylinder. The molding chamber is sealed, and the circulating degassing purification system is turned on. After vacuuming the molding chamber, high-purity argon gas is introduced to ensure that the oxygen content in the molding chamber is below 500ppm. At the same time, the printed sample substrate is preheated at 130℃. Finally, a new engineering task is created and the laser selective melting molding process parameters are set. The laser power is controlled to 400W, the scanning speed is 1800mm / s, the scanning pitch is 60μm, the powder layer thickness is 30μm, the chessboard scanning is performed, and the rotation angle is 67°. After the preparation is completed, the Cr3C2 / 316L alloy is obtained.

[0073] The prepared sample was observed to have no obvious defects and high surface precision. The sample obtained in this example was tested using the testing method described in Example 1, and the results were basically the same as those in Example 1.

[0074] Example 4

[0075] A high-performance laser selective melting Cr3C2 / 316L alloy of this embodiment is prepared as follows:

[0076] (1) NiCr-Cr3C2 and 316L powders were mechanically mixed in a mass ratio of 1:9 without destroying their original characteristics. The process parameters for mechanical mixing were: mixing speed of 40 r / min, NiCr-Cr3C2 powder was added to 316L powder in three batches, and mixing time was 9 h.

[0077] (2) Using laser selective melting technology, the uniformly mixed powder is used as the printing material to prepare Cr3C2 / 316L alloy. Specifically, first, a three-dimensional solid model is constructed using software on a computer, and the three-dimensional solid model is layered and analyzed by laser beam scanning path planning. Then, a substrate is placed in the molding chamber of the laser selective melting molding equipment, and the mixed powder is loaded into the powder cylinder. The molding chamber is sealed, and the circulating degassing purification system is turned on. After the molding chamber is evacuated, high-purity argon gas is introduced to ensure that the oxygen content in the molding chamber is below 500ppm. At the same time, the printed sample substrate is preheated at 160℃. Finally, a new engineering task is created and the laser selective melting molding process parameters are set. The laser power is controlled to 360W, the scanning speed is 2000mm / s, the scanning spacing is 60μm, the powder layer thickness is 30μm, the chessboard scanning is performed, and the rotation angle is 67°. After the preparation is completed, the Cr3C2 / 316L alloy is obtained.

[0078] The prepared sample was observed to have no obvious defects and high surface precision. The sample obtained in this example was tested using the testing method described in Example 1, and the results were basically the same as those in Example 1.

[0079] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-performance laser selective melting Cr3C2 / 316L alloy, characterized by: It consists of a 316L matrix and a Cr3C2 particle reinforcement phase, wherein the Cr3C2 particles account for 10-11% of the total weight of the alloy; The relative density of Cr3C2 / 316L alloy is ≥99.7%, the porosity is ≤0.41%, and the hardness is ≥327HV0.1; The Cr3C2 particles are composed of two components with different properties, NiCr and Cr3C2, and the mass of Cr3C2 accounts for 75% of the total weight of the Cr3C2 particles.

2. The high-performance laser selectively melted Cr3C2 / 316L alloy according to claim 1, characterized in that: Its tensile strength is ≥1032 MPa, yield strength is ≥839 MPa, and wear rate is ≤2.94*10 -12 m 3 / (N*m).

3. A method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to any one of claims 1-2, characterized in that: The steps include: (1) Cr3C2 and 316L powders are mechanically mixed as raw materials to obtain mixed powder; (2) Use software to construct a three-dimensional solid model in a computer, and perform layered analysis on the three-dimensional solid model through laser beam scanning path planning; (3) The mixed powder obtained in step (1) is loaded into a powder tank and the substrate is preheated; (4) Create a new engineering task, set the laser selective melting molding process parameters for preparation, and obtain Cr3C2 / 316L alloy.

4. The method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to claim 3, characterized in that: The particle size of the 316L powder is 15-53 μm, and the particle size of the Cr3C2 powder is 8-12 μm.

5. The method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to claim 3, characterized in that: The sphericity of the Cr3C2 powder reaches more than 95%.

6. The method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to claim 3, characterized in that: In the mixed powder, the mass ratio of 316L powder to Cr3C2 powder is (8~9):

1.

7. A method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to any one of claims 3 to 6, characterized in that: In step (1), the process parameters of mechanical powder mixing are: powder mixing speed 40~60r / min, Cr3C2 powder is added to 316L powder three times, and the powder mixing time is 8~10h.

8. A method for preparing a high-performance Cr3C2 / 316L alloy by selective laser melting according to any one of claims 3 to 6, characterized in that: In step (3), the preheating temperature of the printed sample substrate is 130~160℃; in step (4), the laser power is 300~400W, the scanning speed is 1800~2200mm / s, the powder layer thickness is 30μm, the scanning spacing is 60μm, the chessboard scanning is performed, and the rotation angle is 67°.

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