Influence of the low interfacial density energy on the coarsening resistivity of the nano-oxide particles in Ti-added ODS material

The ODS materials are composed of very fine (Y, Ti, O) nano-particles. During annealing at 1573 K, the nano-clusters evolve into a fully cubical shape Y2Ti2O7-type particles. This evolution is caused by the elastic interaction energy at the nano-particle/matrix interface. Indeed, the cube-on-cube orientation relationship of the daughter Y2Ti2O7 phase is likely linked to be a coherent configuration of the parent nano-clusters. The elastic driven morphology allows for an estimate of the interfacial energy of these nano-clusters of σ = 290 mJ m−2. This low interfacial energy value could be part of the explanation of the very high resistivity to coarsening of the (Y, Ti, O) coherent nano-cluster system, which is confirmed by observations of particle coarsening when the nano-size particles lose their coherency after recrystallisation or grain growth.