Effect of composition and heat treatment on the fracture of melt-spun Fe-Al-Cr intermetallic alloys

Abstract

Fe-Al-Cr alloys in the composition range 50–78 at% Fe, 0–20 at.% Cr and 15–50 at.% Al were rapidly solidified using chill-block melt spinning. Observations of tensile fracture surfaces of as-spun and subsequently heat-treated ribbons revealed transitions from ductile to cleavage to intergranular failure with increasing Al-content. These transitions are related to hardness and to dislocation-antiphase-boundary interactions. Rapid solidification improved ductility only at compositions where there is a significant suppression of ordering and/or formation of thermal antiphase domains. Implications for ductility improvement are discussed in the light of these results.