Development of microstructure and properties within oxide dispersion strengthened steel directly consolidated by hot rotary swaging

Abstract

Steels strengthened with fine oxides maintain favourable mechanical properties at high temperatures. This unique study evaluates the effects of direct consolidation of mechanically alloyed powders of ferritic steel and Y2O3 nanooxides by hot rotary swaging (multiple swaging ratios) on microstrutcures and mechancial properties of final rods. Direct consolidation of the steel powder by the proposed method was successful at the swaging ratio 1.0. However, the quality of consolidation improved with increasing the swaging ratio to 1.4, and finally to 1.8 (no visible pores). The microstructure of the rod processed with swaging ratio 1.8 exhibited homogeneous dispersion of oxide particles and featured ultra-fine (UF) grains, its average Vickers microhardness exceeded 700 HV1.