Oxide dispersion strengthened IN718 owing to powder reuse in selective laser melting

Considering the high cost of powder, powder reuse is necessary for economic and sustainable selective laser melting (SLM). Since powder quality is a key factor in determining the mechanical properties of SLMed parts, it is essential to understand the effects of powder reuse on the powder quality and SLMed parts. In this study, we investigated the effects of IN718 powder reuse on SLM-processed microstructures and their mechanical prop-erties. The SLM process was repeated 10 times using the virgin powder supplement method. As the number of powder reuses increased, the average particle size of the reused powder also increased. Additionally, the powder was oxidized by repeated reuse and resulted in oxide spots on the powder surface. The SLMed parts were recrystallized by homogenization heat treatment at 1065 degrees C, and the recrystallization fraction decreased with increasing extent of oxidation, i.e., the number of powder reuses. In the 10th SLM process conducted with powder reuse, the increased oxide fraction contributed to the dispersion hardening effect and simultaneously improved tensile strength and elongation.