On hot isostatic pressing sintering of fused filament fabricated 316L stainless steel – Evaluation of microstructure, porosity, and tensile properties

Abstract

Abstract Fused filament fabrication (FFF), as a low-cost additive manufacturing process to produce metallic components, has drawn significant attention. However, the pore chains that reside in between filament strands significantly deteriorate the mechanical properties and cause significant anisotropy. The purpose of the present research is to investigate the feasibility of using hot isostatic pressing sintering (HIP) to achieve pore closure and enhanced mechanical properties of FFF metal parts. The results show that the application of HIP sintering under 1320 ˚C for 1 hour reduces the porosity to about 0.3 vol.%. It eliminates the pore chains, leading to a high ultimate tensile strength of 540 MPa and significantly alleviated tensile property anisotropy. The microstructure of HIP sintered parts shows equiaxed grain morphology. The present study provides insight into a low-cost metal AM method with excellent mechanical properties comparable with other AM processes.