Very High Cycle Fatigue Behavior of Additively Manufactured 316L Stainless Steel

• Main Authors: Boris Voloskov, Stanislav Evlashin, Sarkis Dagesyan, Sergey Abaimov, Iskander Akhatov, Ivan Sergeichev
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Materials
• Subjects: additive manufacturing (AM); laser powder bed fusion (L-PBF); very high cycle fatigue (VHCF); fine granular area (FGA); fracture surface; crack initiation
• Online Access: https://www.mdpi.com/1996-1944/13/15/3293
• ISSN: 1996-1944

The present paper is focused on an experimental study of the damage-to-failure mechanism of additively manufactured 316L stainless steel specimens subjected to very high cycle fatigue (VHCF) loading. Ultrasonic axial tension-compression tests were carried out on specimens for up to 10⁹ cycles, and fracture surface analysis was performed. A fine granular area (FGA) surrounding internal defects was observed and formed a “fish-eye” fracture type. Nonmetallic inclusions and the lack of fusion within the fracture surfaces that were observed with SEM were assumed to be sources of damage initiation and growth of the FGAs. The characteristic diameter of the FGAs was ≈500 mm on the fracture surface and were induced by nonmetallic inclusions; this characteristic diameter was the same as that for the fracture surface induced by a lack of fusion. Fracture surfaces corresponding to the high cycle fatigue (HCF) regime were discussed as well to emphasize damage features related to the VHCF regime.