Laser additive manufacturing device and method for wear-resistant material

Abstract

The invention relates to the field of laser processing additive manufacturing, in particular to the field of laser processing additive manufacturing of wear-resistant materials. The invention provides a laser additive manufacturing device and method for a wear-resistant material. The additive manufacturing device comprises a system controller, a laser, a beam splitter, a phase modulator, a first laser light path and a second laser light path. According to the additive manufacturing device and method, fusion of the additive material and the substrate material can be effectively promoted, the problem that due to the fact that laser is focused on a target area in the laser cladding process, the local temperature of a focus point is too high, the temperature of a surrounding area is too low, and consequently temperature distribution is uneven can be effectively solved, and the laser cladding efficiency is improved. And fusion of the additive powder, the particles and the substrate material can be promoted, and the bonding strength of the additive part and the substrate part is improved.

Description

Technical Field

[0001] This invention relates to the field of laser beam processing, and more specifically to an additive manufacturing apparatus and method for using a laser beam to add materials to wear-resistant equipment. Background Technology

[0002] High-end equipment, especially high-end conveying equipment (such as high-wear-resistant mining or metallurgical material conveying equipment), often requires excellent properties such as strength, wear resistance, and high-temperature resistance. However, wear-resistant materials generally have high hardness. Therefore, during the preparation or use of wear-resistant materials, excessive hardness and brittleness often lead to localized defects in the wear-resistant material, or difficulties in forming a good transition between wear-resistant material blocks, plates, and layers. Once defects form on the wear-resistant material layer or a good transition is not formed at the junction of two wear-resistant material plates or blocks, it will lead to a serious decrease in overall wear resistance.

[0003] With the development of additive manufacturing technology, repairing and strengthening the surface defects of wear-resistant materials through additive manufacturing has become a feasible method. Additive manufacturing methods include stereolithography, laser cladding, electron beam melting, and layered manufacturing. Laser cladding is receiving increasing attention due to its advantages such as high precision, material flexibility, and environmental friendliness.

[0004] However, in the existing laser cladding process for preparing wear-resistant materials, the excessively concentrated laser focus and very limited single cladding area lead to sudden temperature fluctuations, resulting in uneven internal stress during the formation of the wear-resistant material. Some manufacturers have introduced equipment that uses multiple beams to irradiate different areas separately to achieve mobile preheating and slow cooling; however, its optical path is extremely complex, occupies a large space, and places high demands on the component processing technology.

[0005] Furthermore, for cladding processes using particulate materials with high surface tension as part of the substrate, the preheating and slow cooling processes cannot promote the interaction between the molten metal and the particles. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a laser additive manufacturing apparatus that can reduce temperature differences in the target area and promote the fusion of the additive part and the substrate material during laser cladding processes involving particulate materials. This apparatus effectively reduces the uneven temperature distribution caused by excessively high local temperatures at the focal point and low temperatures in surrounding areas during laser cladding, and promotes the fusion of molten material, particulate material, and substrate material in the additive material. It is particularly suitable for applications where the additive part contains particulate materials. This invention is especially suitable for use in medium- and low-intensity laser additive manufacturing processes and for high-precision, fine-grained additive manufacturing.

[0007] Specifically, the present invention provides a laser additive manufacturing apparatus for wear-resistant materials, the additive manufacturing apparatus comprising: System controller, laser, beam splitter, phase modulator, first laser optical path, second laser optical path, The laser is used to emit pulsed laser or continuous laser; The beam splitter is located in front of the laser's output port and is used to split the laser emitted by the laser into a first beam and a second beam. The phase modulator is disposed in the optical path of at least one of the first beam and the second beam, and is used to perform phase modulation on at least one of them. The first beam split by the beam splitter is guided by the first laser optical path and enters the target working area from the first working position; The second beam split by the beam splitter is guided by the second laser optical path and incident on the target working area from the second working position. The first working position and the second working position are adjacent to or coincide with each other. When incident, the first beam and the second beam are parallel to each other or have an angle of less than 10 degrees, preferably less than 5 degrees, between them. The system controller is used to control the timing of the laser and the phase modulator; The phase modulator is used to modulate the phase of one of the first beam and the second beam, such that the phase difference between the first beam and the second beam changes periodically between 0 and 2π.

[0008] Furthermore, the emission wavelength of the laser is 1000nm-1500nm, and the frequency of the phase modulation is 5-20Hz.

[0009] Furthermore, the laser is an Nd:YAG laser, a fiber laser, or a carbon dioxide laser.

[0010] Furthermore, the light spots of the first beam and the second beam are circular.

[0011] Furthermore, it also includes a powder spraying mechanism for spraying a mixture of additive material powder and particulate material onto a target area, wherein the additive powder includes one or more of Fe, W, Ni, Mo or Ti, and the particulate material includes one or more of silicon carbide, titanium carbide, and tungsten carbide.

[0012] Furthermore, the additive powder includes one or more of the following: stainless steel powder, high manganese steel powder, cast iron powder, and titanium alloy powder.

[0013] Furthermore, focusing lenses are respectively set in the light-emitting areas of the first and second optical paths to adjust the spot size of the first and second beams.

[0014] On the other hand, the present invention provides a laser additive manufacturing method for wear-resistant materials, the additive manufacturing method comprising: Apply or spray additive material powder and / or granules to the target work area; Using a laser to emit pulsed or continuous laser light; A beam splitter is set in the laser emission direction to split the laser emitted by the laser into a first beam and a second beam. Phase modulation is applied to at least one of the first beam and the second beam to change the phase of the beam; The first beam is guided through the first laser optical path and incident on the target work area from the first work position; The second beam is guided through the second laser optical path and incident on the target working area from the second working position. The first working position and the second working position partially overlap or coincide with each other. The first laser beam and the second laser beam are parallel to each other or have an angle of less than 5 degrees. The timing of the laser and the phase modulator is controlled so that the phase difference between the first beam and the second beam changes periodically between 0-2π or 0-π.

[0015] The method further includes spraying a mixture of additive material powder and particulate material onto the target area, wherein the powder includes one or more of Fe, W, Ni, Mo and Ti, and the particulate material includes one or more of silicon carbide, titanium carbide and tungsten carbide.

[0016] This invention alters the energy distribution between the central spot and the outer coherent ring of the laser coherent beam by adjusting the phase distribution of the coherent light, thereby changing the laser field distribution. This change in light intensity distribution can be achieved without altering the laser power output or adjusting optical components, significantly improving the controllability of light intensity and the uniformity of the additive material layer during additive manufacturing. Furthermore, the applicant discovered that through periodic phase adjustment and a changing laser field distribution, the microscopic thermal field of the target region can be rapidly altered. Additionally, since the laser energy field consists of alternating electric and magnetic fields, with the electric field direction perpendicular to the laser propagation direction (i.e., along the direction of the action surface), the changing laser oscillation field can also promote the fusion of the substrate material and the additive material, forming a transition layer between them. This results in a more robust bond between the additive part and the substrate. (See attached figures for details.) Attached Figure Description

[0017] Figure 1 This is an illustrative flow diagram of the method of the present invention; Figure 2 This is a schematic diagram of the optical path of the additive manufacturing apparatus in Example 1; Figure 3 This is an example of changing the coherent field distribution by adjusting the laser phase; Figure 4 A photograph of an additive material prepared using the method and apparatus of this invention; Figure 5 Microscopic views of additive materials prepared using the method and apparatus of this invention; Figure 6 Microscopic views of products obtained by additive manufacturing using incoherent light under the same light intensity conditions; Figure 7 This is a comparison chart of abrasion resistance test results. Detailed Implementation Example 1

[0018] like Figure 2 In this embodiment, the laser additive manufacturing apparatus includes: a system controller 1, a laser 3, a beam splitter 4, a phase modulator 5, a first laser optical path 6, and a second laser optical path 7. To control the beam size, a first beam adjustment device 9 and a second beam adjustment device 10 are also provided. The beam adjustment device can be configured according to the required beam size, for example, by using a focusing lens, beam expander, flange, etc. During additive manufacturing, irregular silicon carbide particles with a particle size of 0.5-2 mm are used to increase the contact area. The cladding powder uses iron powder containing 1-2.5% carbon, 5-11% chromium, 5-7% nickel, 0.8-1.2% silicon, and less than 0.2% sulfur. The two laser optical paths are composed of mirrors of several conditional optical paths.

[0019] Laser 3 is used to emit high-frequency pulsed laser at a predetermined frequency. Those skilled in the art should understand that they can use high-frequency pulsed laser or continuous laser for additive manufacturing.

[0020] Beam splitter 4 is positioned in front of the laser 3's output port to split the laser emitted by the laser 3 into a first beam and a second beam. The beam splitter uses a ratio of 30%:70% to 50%:50% to split the laser emitted by the laser 3. The splitting ratio can be set according to the desired distribution of beam energy between the center and the periphery. In this embodiment, a 50%:50% equal intensity splitting is used.

[0021] A first beam adjustment device 9 is disposed in the first laser optical path 6, and a second beam adjustment device 10 is disposed in the second laser optical path 7. The apertures of the two adjustment devices are identical. In another implementation, the beam expansion ratios of the first beam adjustment device 9 and the second beam adjustment device 10 are different from each other.

[0022] A phase modulator 5 is disposed in the optical path of at least one of the first beam and the second beam, and is located upstream of the corresponding output port, for performing phase modulation on at least one of them. In this embodiment, the phase modulator 5 is disposed in the first laser optical path 6 of the first beam to adjust the phase of the first beam. In this embodiment, the phase modulator is an electro-optic modulator or an acousto-optic modulator.

[0023] The first beam split by beam splitter 4 is guided by the first laser optical path for constraint and phase modulation, and then incident on the target working area from the first working position. Alternatively, it can be described as incident on the target working area from the first incident direction.

[0024] The second beam split by beam splitter 4 is guided by the second laser optical path and incident on the target working area from the second working position, or it can also be described as incident on the target working area from the second incident direction. The first and second working positions coincide or partially coincide with each other, and the first and second laser beams are generally parallel. During equipment debugging, the phase modulator is temporarily not working (i.e., the phase difference between the two beams is determined by the optical path difference and remains fixed), the output power is reduced or an attenuator is set in the laser optical path to reduce the intensity of the laser output light to a sufficiently low level. A sensor is used to receive the laser signal at the target position to observe the interference pattern of the two beams. The optical components in the first laser optical path are fixed so that the incident position and direction of the first beam remain unchanged. The output position and direction of the second beam in the second laser optical path are gradually adjusted so that the output direction is generally parallel to the first beam but with a small tilt angle so that the target area is illuminated from both positions, and the output position gradually moves closer to the first beam until at least partial interference is observed between the two laser beams, or a complete interference pattern with multiple rings is formed, such as... Figure 3 As shown.

[0025] The system controller is used to control the pulse timing of the laser.

[0026] According to the formula for the intensity of coherent light, the intensity of the interference light obtained after parallel coherent light interference can be determined based on the principle of coherence. In this embodiment, since the two beams used have the same frequency, and although the phase difference between them changes periodically, the period of the phase change is much smaller than the laser frequency. Therefore, for any specific calculation time point, the phase difference between the two laser beams is determined, and the intensity of light in the interference region can be calculated according to the following steps.

[0027] Let the electric field amplitudes of the two beams be E1 and E2, and the phase difference be... .

[0028] For two beams of light, their electric fields can be expressed as follows:

[0029] k=2π / λ is the wave number, w is the angular frequency, λ is the wavelength, i is the imaginary unit, and r1 and r2 are the distances from the light source to the target area.

[0030] For simplicity, we will take the example where the amplitudes A1 and A2 of the two beams are approximately equal for calculation.

[0031] According to the superposition principle, the total electric field intensity when two beams of light meet at a target point in space is the sum of the two beams: , Phase difference , but , Light intensity , Will Substitute, get .

[0032] As can be seen from the above formula, the intensity of the coherent light at any point changes periodically with the phase difference between the two beams. This phase difference is determined on the one hand by the distance between the target point and the emission positions of the two coherent beams, and on the other hand by the modulation of one of the laser beams by the phase modulator. For example... Figure 3 The image shown is a light spot image from a low-intensity coherence test conducted in collaboration with a partner organization. In actual cladding tests, the high light intensity makes it difficult to observe and acquire coherent patterns.

[0033] For any point in the target region, the distance from the emanating positions of the two beams is fixed. Through phase modulation, even at the same location, the intensity of the light formed by the two coherent beams at that point can be changed. During laser propagation, the direction of electric field vibration is perpendicular to the beam propagation direction under special circumstances such as non-adjacent interfaces.

[0034] In laser cladding processes involving particulate materials, traditional laser cladding typically melts the metal material using the heat energy generated by the laser, thus achieving cladding. However, due to the surface tension between the particulate material and the molten metal interface, the molten metal struggles to quickly and completely penetrate the gaps at the edges of the particulate material and achieve a good bond. To address this issue, our research has revealed that a changing coherent field can rapidly alter the thermal field distribution in the target region, thereby promoting the diffusion of metal atoms along the thermal gradient direction and achieving better bonding between materials. This leads to the method proposed in this invention. The additive manufacturing method of the present invention will now be described in detail with reference to the additive manufacturing apparatus described above.

[0035] The additive manufacturing method for wear-resistant materials of the present invention is as follows: Figure 1 As shown, it includes the following steps: Step (1): Perform pretreatment such as degreasing and rust removal on the surface of the workpiece to be processed to ensure surface cleanliness. In this embodiment, stainless steel workpieces are used.

[0036] Step (2): Preheat the workpiece to be processed. Preheating can be achieved by electric heating or photothermal equipment. Preferably, an electric heating device is set under the processing platform of the workpiece to be processed for preheating the workpiece.

[0037] Step (3): Place the workpiece to be processed on the processing platform, and apply or spray additive material powder and / or particles to the target working area of ​​the workpiece. In this embodiment, a mixture of iron powder and silicon carbide particles is used. The application of the powder and particle mixture can be synchronized with the subsequent light irradiation, such as spraying through the spray nozzle, or it can be laid and applied in advance before the laser action. This invention does not impose any restrictions.

[0038] The base material is made of stainless steel, and the particles are irregular silicon carbide particles with a particle size of 0.5-2mm to increase the contact area. The cladding powder is made of iron powder containing 2.4% carbon, 6.1% chromium, 5.3% nickel, 1.0% silicon, and less than 0.2% sulfur.

[0039] Step (4): Use a laser to emit pulsed or continuous laser at a predetermined frequency. In this embodiment, a high-energy pulsed laser of Nd:YAG with a wavelength of 1064nm±10nm is used.

[0040] Step (5): Set a beam splitter in the laser output direction to split the laser emitted by the laser into a first beam and a second beam. Preferably, the beam splitter is a polarization beam splitter.

[0041] Step (6): Phase modulation is performed on at least one of the first beam and the second beam to change the phase of the beam.

[0042] Step (7): Guide the first beam through the first laser optical path and incident it on the target working area from the first working position; guide the second beam through the second laser optical path and incident it on the target working area from the second working position. The first working position and the second working position are adjacent to or coincide with each other, and the first laser beam and the second laser beam are parallel to each other.

[0043] Step (8): Control the timing of the laser and the phase modulator so that the phase difference between the first beam and the second beam changes periodically between 0 and 2π, and use the two coherent beams with gradually changing phases to irradiate and clad the target area.

[0044] Step (9): Switch the target area and perform laser cladding on the next area. Cool the original cladding area or turn off the laser and cool the target area.

[0045] Preferably, in the first laser optical path and the second laser optical path, the size of the focusing lens beam is adjusted according to the size of the target area and the required laser light intensity.

[0046] Preferably, a powder supply device is used to deliver additive powder material to the target area. Of course, those skilled in the art should understand that for areas that only require a single layer of additive manufacturing, the additive powder can be pre-coated onto the target area, thus eliminating the need for a powder supply device.

[0047] The protective gas delivery mechanism includes a gas storage tank and a delivery pipeline. One end of the gas storage tank is connected to the delivery pipeline, and the other end of the delivery pipeline is equipped with a gas supply nozzle that extends into the target work area to deliver protective gas to the target work area.

[0048] In a preferred implementation, instead of using a single laser for beam splitting, two laser sources, a first laser source and a second laser source, are used for irradiation, each emitting laser light of the same frequency. The first and second laser sources emit coherent light with the same wavelength. In one implementation, the first and second laser sources are 1064nm fiber lasers or Nd:YAG lasers of the same frequency, triggered by a synchronization pulse to ensure their coherence. Alternatively, the first and second laser sources can be obtained by splitting the laser emitted from the same laser to form two highly coherent laser beams. An optical path assembly includes a first optical path and a second optical path. The first optical path guides the laser emitted from the first laser source from a first position to the target area, and the second optical path guides the laser emitted from the first laser source from a second position to the target area. The first and second positions are adjacent to each other, and the output directions of the first and second optical paths are generally parallel, with one path slightly tilted so that they can be focused at approximately the same position. A phase modulator (such as an acousto-optic modulator) is provided in at least one of the first and second optical paths to change the phase of at least one of the laser beams.

[0049] Example 1 like Figure 4-5 The image shows a cross-sectional view and a microscopic view of a particle-doped laser cladding material prepared using the method of the present invention.

[0050] The specific equipment used in this example is as follows: The system controller 1 is an IPC industrial computer, the laser 3 is an Nd:YAG pulsed light source with a laser power of 0.5-2kW. The beam splitter 4 is a polarization beam splitter, and the phase modulator 5 is an electro-optic phase modulator.

[0051] Beam splitter 4 is located in front of the output port of laser 3 and is used to split the laser emitted by laser 3 into a first beam and a second beam. The beam splitter uses a 50%:50% beam splitter to split the laser emitted by laser 3 into two pulsed lasers of roughly equal intensity.

[0052] The first laser beam path 6 and the second laser beam path 7 are guided by multiple total reflection mirrors to determine the laser incident direction. Two laser beams exit from the two beam paths, via the first beam adjustment device 9 and the second beam adjustment device 10, and are emitted towards the target area. A flange is provided to better control the beam's exit shape and can be closed to stop emission when necessary. The first laser beam path is slightly tilted relative to the second laser beam path; that is, the optical axis of the first beam has a slight angle relative to the second optical axis. This allows two beams emitted from different positions to be focused on the same area, forming interference. The phase adjustment frequency is 5-10Hz, and the phase difference adjustment range is 0-2π.

[0053] The cladding material is a mixture of iron powder and silicon carbide particles containing 2.4% carbon, 6.1% chromium, 5.3% nickel, 1.0% silicon and less than 0.2% sulfur, with a mass ratio of approximately 4:1.

[0054] like Figure 4 The figure shows a planar view of the particle fusion structure obtained by the preparation method of the present invention. As can be seen from the figure, the particles of the particle fusion structure prepared by the method of the present invention are well bonded to the encapsulating material, and there is no obvious boundary between them.

[0055] like Figure 5 The image shows a microscopic view of the particle-embedded structure obtained using the method of this invention. As can be seen under a 50x microscope, the particles are well-fused and tightly bonded, with a clear transition structure between the particles and the matrix. This demonstrates that the method of this invention can promote the bonding between the substrate and the particles.

[0056] Comparative Example 1 In this example, the same system as in the above embodiments is used. The system controller 1 is an IPC industrial computer, the laser 3 is an Nd:YAG pulsed light source with a laser power of 0.5-2kW, and the beam splitter 4 is a beam splitting prism instead of a phase modulator.

[0057] Beam splitter 4 is located in front of the output port of laser 3 and is used to split the laser emitted by laser 3 into a first beam and a second beam. The beam splitter uses a 50%:50% beam splitter to split the laser emitted by laser 3 into two pulsed lasers of roughly equal intensity.

[0058] The additive manufacturing method for wear-resistant materials in this example includes the following steps: Step (1): Perform pretreatment such as degreasing and rust removal on the surface of the workpiece to be processed to ensure surface cleanliness. In this embodiment, stainless steel workpieces are used.

[0059] Step (2): Preheat the workpiece to be processed. Preheating can be achieved by electric heating or photothermal equipment. Preferably, an electric heating device is set under the processing platform of the workpiece to be processed for preheating the workpiece.

[0060] Step (3): Place the workpiece to be processed on the processing platform, and apply or spray additive material powder and / or particles to the target working area of ​​the workpiece. In this embodiment, a mixture of iron powder and silicon carbide particles is used. The application of the powder and particle mixture can be synchronized with the subsequent light irradiation, such as spraying through the spray nozzle, or it can be laid and applied in advance before the laser action. This invention does not impose any restrictions.

[0061] The substrate is made of stainless steel, and the particles are irregular silicon carbide particles with a particle size of 0.5-2mm to increase the contact area. The cladding powder is the same as above.

[0062] Step (4): Use a laser to emit pulsed or continuous laser at a predetermined frequency. In this embodiment, a high-energy pulsed laser of Nd:YAG with a wavelength of 1064nm±10nm is used.

[0063] Step (5): Set a beam splitter in the laser output direction to split the laser emitted by the laser into a first beam and a second beam. Preferably, the beam splitter is a polarization beam splitter.

[0064] Step (6): Phase modulation is performed on at least one of the first beam and the second beam to change the phase of the beam.

[0065] Step (7): Guide the first beam through the first laser optical path and incident it on the target working area from the first working position; guide the second beam through the second laser optical path and incident it on the target working area from the second working position. The first working position and the second working position are adjacent to or coincide with each other, and the first laser beam and the second laser beam are parallel to each other.

[0066] Step (8): Control the timing of the laser so that the first beam and the second beam arrive at the target area at approximately the same time for irradiation and cladding.

[0067] Step (9): Switch the target area and perform laser cladding on the next area. Cool the original cladding area or turn off the laser and cool the target area.

[0068] The comparative example uses the same laser and cladding material, but the cladding is performed directly using a pulsed laser without coherence or modulation of the pulsed laser.

[0069] like Figure 6The image shows a microscopic view of the particle fusion structure obtained by the preparation method in this example. As can be seen from the image, under a 50x microscope, the particle fusion is not tightly bonded, and the boundary between the particles and the matrix is ​​distinct with no obvious transition structure.

[0070] Comparative Example 2 In this example, the same system as in the above embodiments is used. The system controller 1 is an IPC industrial computer, the laser 3 is an Nd:YAG pulsed light source with a laser power of 0.5-2kW, and the beam splitter 4 is a beam splitting prism instead of a phase modulator.

[0071] Beam splitter 4 is located in front of the output port of laser 3 and is used to split the laser emitted by laser 3 into a first beam and a second beam. The beam splitter uses a 50%:50% beam splitter to split the laser emitted by laser 3 into two pulsed lasers of roughly equal intensity.

[0072] The additive manufacturing method for wear-resistant materials in this example includes the following steps: Step (1): Perform pretreatment such as degreasing and rust removal on the surface of the workpiece to be processed to ensure surface cleanliness. In this embodiment, stainless steel workpieces are used.

[0073] Step (2): Preheat the workpiece to be processed. Preheating can be achieved by electric heating or photothermal equipment. Preferably, an electric heating device is set under the processing platform of the workpiece to be processed for preheating the workpiece.

[0074] Step (3): Place the workpiece to be processed on the processing platform, and apply or spray additive material powder and / or particles to the target working area of ​​the workpiece. In this embodiment, a mixture of iron powder and silicon carbide particles is used. The application of the powder and particle mixture can be synchronized with the subsequent light irradiation, such as spraying through the spray nozzle, or it can be laid and applied in advance before the laser action. This invention does not impose any restrictions.

[0075] The base material is made of stainless steel, and the particles are irregular silicon carbide particles with a particle size of 0.5-2mm to increase the contact area. Undoped iron powder is used for cladding.

[0076] Step (4): Use a laser to emit pulsed laser or continuous laser at a predetermined frequency. In this embodiment, a high-energy pulsed laser of Nd:YAG with a wavelength of 1064nm±10nm is used. Step (5): Set a beam splitter in the laser output direction to split the laser emitted by the laser into a first beam and a second beam. Preferably, the beam splitter is a polarization beam splitter.

[0077] Step (6): Phase modulation is performed on at least one of the first beam and the second beam to change the phase of the beam; Step (7): Guide the first beam through the first laser optical path and incident it on the target working area from the first working position; guide the second beam through the second laser optical path and incident it on the target working area from the second working position. The first working position and the second working position are adjacent to or coincide with each other, and the first laser beam and the second laser beam are parallel to each other. Step (8): Control the timing of the laser so that the first beam and the second beam arrive at the target area at approximately the same time for irradiation and cladding; Step (9): Switch the target area and perform laser cladding on the next area. Cool the original cladding area or turn off the laser and cool the target area.

[0078] In this embodiment, undoped iron powder was used for laser cladding experiments. The experiments confirmed that even under coherent light, the transition layer between the particles and the substrate was almost unobservable.

[0079] Frequency tuning comparison To determine whether the modulation frequency would affect the interaction between the metal layer, particles, and substrate, the phase modulation frequency was gradually increased from 10 Hz to over 40 Hz, and the thickness of the transition layer was observed at different modulation frequencies.

[0080] Experimental tests showed that once the phase modulation frequency exceeds 30Hz, the bonding between the particles in the prepared particle-embedded structure and the encapsulating material will deteriorate due to the rapid phase change, making it difficult to form a transition layer.

[0081] The statistical results are shown in the table below. Table 1 Transition layer conditions at different modulation frequencies

[0082] Wear performance was assessed according to standard GB / T 12444-2006, "Test Methods for Abrasive Wear of Metallic Materials - Low Stress Scratch Test". During testing, additive manufacturing was performed on a standard mass substrate. The surface was cleaned and dried, and the total weight of the standard block before and after additive manufacturing was measured. The total weight of the additively manufactured substrate was then measured. Weight loss was measured at different time points after the wear test. Tests were conducted at room temperature using an MMS wear tester at a speed of 300 r / min and a load pressure of 20 N. A quartz grinding wheel was used. Test results are as follows: Figure 7 As shown in the figure, although the wear-resistant layer manufactured by additive manufacturing according to the method of the present invention has little difference in initial wear resistance compared with Comparative Example 1, the amount of wear loss is significantly reduced as the wear time increases. Comparative Example 2 also shows significant differences in performance compared with the high-chromium content iron powder used in the method of the present invention due to the inherent difference in wear resistance between pure iron powder and high-chromium iron powder.

[0083] It should be noted that the components in the various embodiments of the present invention can be combined and substituted with each other, and these are all included within the scope of the present invention. Furthermore, it should be noted that the tube body of the present invention can also be irregularly shaped; those skilled in the art only need to make appropriate adjustments based on the principles of the present invention according to the actual situation, and this is also included within the scope of the present invention.

[0084] Although the principles of the present invention have been described in detail above with reference to preferred embodiments, those skilled in the art should understand that the above embodiments are merely illustrative explanations of the implementation of the present invention and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute a limitation on the scope of the present invention. Any obvious changes, such as equivalent transformations or simple substitutions, based on the technical solutions of the present invention without departing from the spirit and scope of the present invention fall within the protection scope of the present invention.

Claims

1. A laser additive manufacturing apparatus for wear-resistant materials, characterized in that, The laser additive manufacturing apparatus includes: a system controller, a laser, a beam splitter, a phase modulator, a first laser optical path, and a second laser optical path. The laser is used to emit pulsed laser or continuous laser; The beam splitter is positioned in front of the laser's output port and is used to split the laser emitted by the laser into a first beam and a second beam. The phase modulator is disposed in the optical path of at least one of the first beam and the second beam, and is used to perform phase modulation on at least one of them. The first beam split by the beam splitter is guided by the first laser optical path and enters the target working area from the first working position; The second beam split by the beam splitter is guided by the second laser optical path and enters the target working area from the second working position. The first working position and the second working position are adjacent to or coincide with each other. When incident, the first beam and the second beam are parallel to each other or have an angle of less than 5 degrees between them. The system controller is used to control the timing of the laser and the phase modulator; The phase modulator is used to modulate the phase of one of the first beam and the second beam, such that the phase difference between the first beam and the second beam changes periodically between 0 and 2π.

2. The laser additive manufacturing apparatus for wear-resistant materials according to claim 1, characterized in that, The laser emits light at a wavelength of 1000nm-1500nm, and the phase modulation frequency is 5-20Hz.

3. The laser additive manufacturing apparatus for wear-resistant materials according to claim 1, characterized in that, The laser is an Nd:YAG laser, a fiber laser, or a carbon dioxide laser.

4. The laser additive manufacturing apparatus for wear-resistant materials according to claim 1, characterized in that, The light spots of the first beam and the second beam are circular.

5. The laser additive manufacturing apparatus for wear-resistant materials according to claim 1, characterized in that, It also includes a powder spraying mechanism for spraying a mixture of additive material powder and particulate material onto a target area, wherein the powder includes one or more of Fe, W, Ni, Mo or Ti, and the particulate material includes one or more of silicon carbide, titanium carbide, and tungsten carbide.

6. The laser additive manufacturing apparatus for wear-resistant materials according to claim 5, characterized in that, The powder includes one or more of the following: stainless steel powder, high manganese steel powder, cast iron powder, and titanium alloy powder.

7. A laser additive manufacturing method for wear-resistant materials, characterized in that, The additive manufacturing method includes: Apply or spray additive material powder and / or granules to the target work area; Using a laser to emit pulsed or continuous laser light; A beam splitter is installed in the laser's output direction to split the emitted laser light into a first beam and a second beam. Phase modulation is applied to at least one of the first beam and the second beam to change the phase of the beam; The first beam is guided through the first laser optical path and incident on the target work area from the first work position; The second beam is guided through the second laser optical path and incident on the target working area from the second working position. The first working position and the second working position coincide or partially coincide with each other. When incident, the first beam and the second beam are parallel to each other or have an angle of less than 5 degrees. The timing of the laser and the phase modulator is controlled so that the phase difference between the first beam and the second beam changes periodically between 0 and 2π.

8. The laser additive manufacturing method for wear-resistant materials according to claim 7, characterized in that, The method further includes spraying a mixture of additive material powder and particulate material onto the target area, wherein the powder includes one or more of Fe, W, Ni, Mo and Ti, and the particulate material includes one or more of silicon carbide, titanium carbide and tungsten carbide.

9. The laser additive manufacturing method for wear-resistant materials according to claim 7, characterized in that, The frequency of the phase modulation is 5-20Hz.

10. The laser additive manufacturing method for wear-resistant materials according to claim 7, characterized in that, The powder is made of iron powder containing 1-2.5% carbon, 5-11% chromium, 5-7% nickel, 0.8-1.2% silicon, and less than 0.2% sulfur.

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