Research On Selective Laser Melting Of Alsi10Mg Alloy And Subsequent Surface Magnetic Abrisive Finishing Process

Selective laser melting?SLM?technology is a 3D printing technology for metals and alloys with great potential and development prospects.It can achieve free design and rapid manufacturing of complex parts,and it is occupying an increasingly important position in today's manufacturing field.However,compared with forged parts,there is still a certain gap in the structural properties of formed parts using SLM technology.At the same time,due to the staircase effect of layered manufacturing,the surface quality of the formed parts is poor and it is difficult to meet the requirements for use.Therefore,in order to further improve the SLM forming process,improve the structural performance of the formed part,and reduce its surface roughness.This article uses AlSi10Mg alloy powder,through theoretical analysis,experimental research,and numerical modeling,to perform selective laser melting forming tests of multiple AlSi10Mg alloy powders on a laser melting forming equipment(SLM^?125^HL).Analyze and optimize the density,porosity,and hardness of the formed parts;Magnetic abrasives prepared by gas atomization with rapid solidification was used to test the surface of AlSi10Mg parts formed by SLM.The main research contents is as follows:1. Research on SLM test material and forming process.The morphology and chemical composition of AlSi10Mg test powder were analyzed by Scanning Electron Microscope?SEM?and Energy Dispersive Spectrometer?EDS?,and their effects on the performance of SLM formed parts were discussed.The test powder has a particle size range of 20-63?m,high sphericity,few satellite particles,and good purity,which helps the formation of SLM.Analyze the forming process of the SLM.The laser scans the fill contour and border of the formed part clockwise.The inside of the border is manufactured layer by layer using a 67°rotating laser scanning strategy.After the upper surface layer of the formed part is laser remelted,the entire SLM forming process ends.2. Experimental study on parameters optimization of AlSi10Mg alloy prepared by SLM.Through 27 sets of experiments on AlSi10Mg alloy prepared by SLM,the optimal laser energy density range and process parameter combination of SLM AlSi10Mg formed part density and Vickers hardness were analyzed.The reasons for the formation of pores under different laser energy densities are revealed.Investigate the microhardness value of a single molten pool in the vertical and horizontal directions,and analyze the influence of microstructure on it.The optimal laser energy density of SLM AlSi10Mg alloy density is 52.1J/mm³,and the optimal laser energy density of Vickers hardness is 56.7J/mm³.At lower laser energy density,the formed part will have irregular pores,and at higher laser energy density,the formed part will have spherical pores.The internal hardness of the molten pool is significantly higher than the hardness of the boundary.3. Fundamental study on magnetic abrasive finishing?MAF?of spherical composite magnetic abrasives for SLM workpieces.The CNC milling machine was converted into a MAF test platform for testing SLM AlSi10Mg workpieces.By analyzing the preparation process of spherical composite magnetic abrasives prepared by gas atomization with rapid solidification and its grinding processing characteristics,the reason for its good grinding performance is discussed.Its spherical composite magnetic abrasives has the same high micro-cutting edge,high sphericity and stronger cutting performance.Analyze the force of a single magnetic abrasive particle under an external magnetic field,and then analyze the splash phenomenon of the magnetic abrasive particles.Through multiple formulas,parameters can be derived that can improve the effect of MAF.4. Study on magnetic abrasive finishing of SLM AlSi10Mg alloy.In view of the poor surface quality of SLM workpieces,a combination of Grinding and MAF was used to grind and polish SLM AlSi10Mg alloy workpieces.Corrosion polishing of the contour section of the sample,and analysis of the contour forming principle of the SLM workpieces.Three different types of spherical composite magnetic abrasives were used to perform MAF on the Grinding samples,and the influence of MAF on the surface morphology,roughness and hardness of the SLM workpieces was analyzed.The material removal mechanism of spherical composite magnetic abrasives on AlSi10Mg workpieces prepared by SLM was discussed.The surface roughness of the Grinding samples reached about 0.6?m,and then MAF was performed.The surface processed with Si C?W7?magnetic abrasives has the lowest surface roughness,while the surface roughness processed with Al₂O₃?W7?magnetic abrasives has the fastest decrease.This depends on the number of ceramic phase particles adhered to the magnetic abrasives surface and the degree of adhesion of the ceramic phase particles to the ferromagnetic phase.MAF can release the internal energy of the material and reduce the hardness of the surface after Grinding.This study provides experimental data and technical support for the widespread application of selective laser melting?SLM?metals and alloy processes.