Experimental investigation on process parameters induced mechanical and microstructural properties for laser powder bed fusion additive manufacturing of SS316L

Abstract

The effect of energy density on different mechanical, microstructural and surface properties was examined for laser powder bed fusion of additively manufactured stainless steel 316L (AM SS316L). The energy density was varied by changing laser power from 80 to 180 W to print AM SS316L samples. The investigations include various mechanical tests and microstructural characterizations such as tensile strength, hardness, density, roughness, wear and residual stresses. At an energy density of 84 J/mm³, maximum tensile strength, hardness and density were obtained as 640 MPa, 246 HV and 99.47%, respectively. However, a minimum wear rate of 1.9 (mm³/(N*m))*10⁻⁵ was achieved at an energy density of 84 J/mm³. Residual stresses were tensile on the top surface and varied with the energy density. The corrosion performance of SS316L was measured in Ringer's solution for bio-implant applications with the potentiodynamic polarization test. The minimum corrosion rate was obtained at an energy density of 37 J/mm³. The microstructure behavior with respect to different characterizations was examined. The non-homogenous grain growth was observed with the cellular and columnar grains. This study would help to find optimum parameters for desired mechanical and surface properties.