The Microstructure and Tensile Properties of Extruded Melt-Spun Ribbons of Iron-Rich B2 FeAl

Abstract

AbstractThe microstructure of extruded rods of iron-rich FeAl (B2-structure), as characterized by TEM, SEM, optical microscopy and x-ray diffractometry, consisted of elongated grains with a <111> fibre texture containing a high dislocation density. Numerous oxide particles were found, mostly in lines which reflected the matrix flow during extrusion. In addition, some large inclusions were present. Tensile testing of annealed, relatively dislocation-free specimens as a function of increasing temperature found increasing ductility up to 900K, above which a ductility drop occurred accompanied by a change in fracture mode, from transgranular cleavage to intergranular fracture. The yield strength, which was independent of temperature up to 800K (at ∼500MPa), also decreased rapidly as diffusion became more important. The predominant slip vector changed from <111> to <100> around 700K