Effects of Fe11+ Ions Irradiation on the Microstructure and Performance of Selective Laser Melted 316L Austenitic Stainless Steels

Abstract

The effect of irradiation temperature on the microstructure, hardness, and corrosion resistance of 316L stainless steels (SS) fabricated by the selective laser melting (SLM) process was investigated to further understand the radiation degradation of the additive manufactured steels. The Transmission Electron Microscopy (TEM) results confirmed the cellular sub-grains and the high-density dislocation networks present in the SLM formed 316L SS. After exposing samples to Fe11+ ions irradiation till 1 dpa at room temperature, the ultra-fine sub-grain structure maintains its configuration, but the dislocations were observed expanding from the vicinity of the sub-grain boundaries into the grains. In contrast, the expanding phenomenon of dislocations was insignificant in samples irradiated at 450 °C. The average size of dislocation loops increased from 6 to 8.5 nm when the irradiation temperature increased, with the number density decreased from 2.7 × 1022/m3 to 1.3 × 1022/m3. This study reveals that the reduced dislocation loop density and distribution region caused by the improved temperature will suppress the radiation hardening and corrosion of SLM 316L SSs.