Stability of untransformed ferrite in 10Cr ODS steel

The development of generation IV nuclear reactor requires improvements in structural and cladding materials. Oxide dispersion strengthened (ODS) steels are promising candidates because improved creep properties. Two main families ODS known, the first one is martensitic steel with a full reverse ferrite to austenite phase transformation at high temperatures. second ferritic matrix whatever temperature. Previous papers mention existence untransformed (UF) temperature very particular [S. Ukai 2009, M. Yamamoto 2010, T. Yamashiro 2016, A. Durand 2021]. UF unexpected according experimental observation thermodynamic calculations non-strengthened materials (NR) same chemical composition. This particularly interesting way improve resistance grades [H. Sakasegawa 2008, 2021] then conciliates benefits both grades. present study focused on thermal stability 10 wt% Cr. Effects heat treatments holding times temperatures studied by considering fraction evolution microstructural changes. decrease correlated nano-oxides density coupled increase their size. also affected treatments. Those appear as mix equivalent ones.