Nucleation of Y–Si–O Nano-clusters in Multi-microalloyed Nano-structured Ferritic Alloys: a First-principles Study

First-principles energetics analyses were performed to investigate the nucleation of (Y–Si–O) nano-clusters (NCs) in nano-structured ferritic alloys (NFAs). It was predicted that (Y-Si–O) NCs follows same general pathway as previously found for (Y–Ti/Al/Zr–O) NFAs: they all tend begin with (O–O) pairs and grow (O–Y)-cores further larger by attracting Y other solute elements nearby. Nucleation a hexa-atomic –[2Y–Si–3O]– cluster can reduce total energy 4.71 eV. Among various microalloying-induced NCs, preference ordering (Y–Zr–O) > (Y–Ti–O) (Y–Al–O) (Y–Si–O). The number densities chemical compositions multi-microalloyed NFAs would largely depend on availability (O,Y)-cores, well relative abundance atomic diffusivities microalloying