Microstructural aspects of new grade ODS alloy consolidated by rotary swaging

Abstract

In the present paper, the authors have investigated the microstructural aspects of recrystallization of new ODS alloy (Fe-14Cr-10Al-4Y2O3) consolidated by hot rotary swaging. Microstructural characterization of samples was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). Insight of mechanical properties was performed by Vickers hardness testing and measurement of Young's modulus. A thorough analysis of microstructure concerning grains, oxide particles and dislocations was performed for two states of the material, i.e. in the as-received state after rotary swaging exhibiting the ultra-fine-grained microstructure and in the state after annealing provoking the desirable coarse-grained structure. Different conditions of rotary swaging followed by the same annealing conditions induced different structures, either coarse-grained or bimodal when secondary recrystallization did not happen in the entire sample's volume. The hardness measurements revealed no significant difference between the coarse-grained and the bimodal microstructures, however, the coarse-grained material exhibited systematically higher values of the temperature-dependent Young's modulus in comparison with the bimodal counterpart. Detailed microscopic analysis of the material helped to clarify and discuss the measured properties of the newly developed ODS alloy.