A novel additive manufactured reduced activation ferritic/martensitic steel enhanced by in-situ nanoparticles benefiting from oxygen addition

Abstract

Reduced activation ferritic/martensitic (RAFM) steel emerging as the promising structural material of fusion reactors, has attracted considerable attention to improve its high-temperature performance. In the present study, a new-type RAFM steel (Fe-8.9Cr-0.82W-0.23Mn-0.086Si-0.27Ti-0.075C-0.032O) enhanced by in-situ nanoparticle constituents containing high-density and dispersed TiC, TiO and TiO@TiC (with core (TiO)-shell (TiC) structure) was manufactured using selective laser melting (SLM) with imposed oxygen atmosphere in the printing chamber. The novel TiO@TiC with core-shell structure is reported for the first time in RAFM steels. In addition, the high-temperature mechanical properties achieved in the present study are superior to those of other additive manufactured RAFM or oxide dispersion strengthened RAFM (ODS-RAFM) steels, which is attributed to the high-density and dispersed nanoparticles introduced by additional oxygen addition during SLM. The proposed idea for taking the reactive atmosphere into consideration for alloy design in this study could be extended to other alloys.