A Study on Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated by Selective Laser Melting in Different Directions
The microstructure,microhardness,tensile impact properties,and corrosion resistance of 316L stainless steel were investigated in both parallel(XY)and vertical(XZ)laser scanning directions.The results indicate significant differences in the structural morphology between the XY and XZ directions during the forming process due to various factors.In the XY direction,fine equiaxial cellular crystals are formed,whereas in the XZ direction,cylindrical crystals grow along the fusion line due to heat flow and heat dissipation direction.With regard to microhardness,the average value is 307.98HV0.2 for the XY direction and 260.78HV0.2 for the XZ direction;however,this difference is not significant.Tensile testing reveals superior mechanical properties in the XY direction compared to those in the XZ direction.SEM observation demonstrates typical ductile fracture char-acteristics on tensile fractures.The density and integrity of passivation film are enhanced in the XY direction due to small surface crystals and low porosity,resulting in higher corrosion resistance than those observed in the XZ direction.
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