Influence of the microstructure on the tensile and impact properties of a 14Cr ODS steel bar

A Fe-14Cr-1W-0.4Ti-0.3Y203 ferritic steel bar was characterised by different microstructural techniques in order to evaluate the link between its microstructure and the mechanical properties achieved. This bar was produced by mechanical alloying of a pre-alloyed gas atomised powder with yttria particles, followed by hot extrusion and subsequently annealing. The knowledge of the microstructure of this 14Cr oxide dispersion strengthened (ODS) steel allows for the explanation of the mechanical properties observed, such as the decrease of the ductility found in the transverse orientation of the bar, the existence of zig-zag crack paths in the broken specimens after the impact tests at low temperatures and the appearance of delaminations when the temperature is increased.