SUPERPLASTIC BEHAVIOR OF A KAPPA-CARBIDE MATERIAL (FE3ALCX)

Fine-grained kappa carbide (Fe3AlCx) materials, containing 12.5 and 14 % Al, and 3.5% C, were prepared by powder processing and hipping proce dures. The creep behavior of the kappa materials was shown to be ident ical to that observed in superplastic iron carbide, and was shown to f ollow a grain boundary-diffusion-controlled grain boundary sliding rel ation. The tensile fracture strains in kappa, however, were shown to b e considerably less than in iron carbide with a maximum elongation of 92% noted. This difference is attributed to either a low stress intens ity factor or to contamination of the powder surface in the kappa mate rial. The compression creep strength, at a given strain rate, was show n to be about two times higher than the tension creep strength.