Tensile Behavior of Sintered Stainless Steel Fiber Felts: Effect of Sintering Joints and Fiber Ligaments

To optimize the tensile properties of sintered 316L stainless steel fiber felts (SSFFs) which is important for their practical applications, the influence of sintering conditions on the microstructure (fiber ligament, sintering joint) and in turn, the tensile properties was investigated experimentally. It was shown that the tensile strength and tensile elongation of SSFFs were dominated by the tensile properties of the fiber ligaments and the bonding strength of the sintering joints. With the increase of sintering temperature versus holding time, the tensile strength of the fiber ligaments dropped significantly, while the sintering joints grew, producing a higher bonding strength between the fibers, resulting in more fibers being involved in the tensile process. These changes in sintering joints and fiber ligaments finally led to a relatively static ultimate strength of SSFFs with a significantly increased elongation, thus with a large increase in tensile fracture energy. The increase of size of the sintering joints also helped to considerably raise the tensile fatigue limit of 316L SSFFs. This research provides a basis to improve the mechanical properties of sintered 316L SSFFs in industrial production.