Microstructural and mechanical properties of oxide dispersion strengthened iron aluminides produced by mechanical milling and hot extrusion

Yttria dispersed Fe3Al alloy with a nominal composition of Fe–13Al–5Cr-0.18Ti-0.35 Y2O3 was produced by high energy ball milling followed by hot extrusion. The extruded and heat treated ODS Fe3Al exhibited both elongated and fine equi-axed grain structure in longitudinal direction, whereas, equi-axed grain structure was observed in transverse direction. Even though, both prealloyed as well as milled powder showed only FeAl phase, D03 structured Fe3Al along with Y3Al5O12 and TiO phases existed in ODS Fe3Al. Presence of fine (7–25 nm corresponding to Y3Al5O12) and coarse (>25 nm, TiO) particles were observed in ODS Fe3Al. The material exhibited yield and ultimate tensile strengths of 1104 and 1308 MPa with 8% elongation. The improved strength and elongation are due to the presence of dispersoids and fine grained structure. The present work is aimed at improving the tensile strength end elongation of Fe3Al intermetallic compound by alloying as well as incorporating fine grained structure by dispersing nano-sized oxide particles in Fe3Al. The highlights of the study about the effect of dispersion of oxide particles on evolution of microstructure and the resultant mechanical properties of ODS Fe3Al at room temperature are given below:•Yttria dispersed Fe3Al alloy with a nominal composition of Fe–13Al–5Cr-0.18Ti-0.35 Y2O3 was produced by high energy ball milling followed by hot extrusion.•The average grain size of ODS Fe3Al was about 1 μm. Dispersoids of two distinct sizes and compositions were observed.•The fine spherical (7–25 nm) particles were of Y3Al5O12 and the coarser spherical particles (>25 nm) were of TiO type.•The yield and tensile strengths of ODS Fe3Al were 1104 and 1308 MPa respectively with an elongation of 8% at RT. The observed strength and elongation are much higher than the reported values of conventionally manufactured Fe3Al.•The fracture surface indicated that fracture occurred by quasi-cleavage unlike brittle cleavage fracture usually observed in Fe3Al.