Tensile and axial fatigue properties of AISI 316 L stainless steel fabricated by materials extrusion additive manufacturing

Herein, the surface quality, physical, microstructural, tensile and axial fatigue properties of 316 L stainless steel fabricated by materials extrusion additive manufacturing (MEX) are investigated and compared to the wellestablished and similar fabrication process, metal injection moulding (MIM). The results reveal no discernible difference in microstructure, preferential orientation and grain size between MEX and MIM parts, except for voids between deposited paths found in MEX parts, and Si-O inclusions in MIM parts. MEX parts have slightly higher tensile properties than MIM parts due to the higher relative sintered density. However, the endurance limit of MEX parts is lower than MIM. This is attributed to differences in the surface characteristics, in which MEX parts have layer-by-layer characteristics, higher roughness and Al2O3 contamination from the separator. They sensitively act as crack origination sites and result in lower fatigue resistance when compared to MIM.

Automated summary

In this study, the surface quality, physical, microstructural, tensile, and axial fatigue properties of 316L stainless steel fabricated by materials extrusion additive manufacturing (MEX) and metal injection molding (MIM) were investigated. The results showed that there were no significant differences in microstructure, orientation, and grain size between MEX and MIM parts, except for voids in MEX parts and Si-O inclusions in MIM parts. MEX parts had slightly higher tensile properties due to higher sintered density but lower fatigue resistance compared to MIM parts.