Iron self diffusion in liquid pure iron and iron-carbon alloys

With incoherent quasielastic neutron scattering self-diffusion coefficients D-s in pure iron, and iron-carbon alloys containing 8.7 at% and 16.9 at% carbon have been measured. At the melting point D-s in liquid iron is 2.8(1) x 10(-9) m(2) s(-1). For the close-to-eutectic Fe83.1C16.9 composition D-s = 1.33(12) x 10(-9) m(2) s(-1) at T-liq = 1432 K. Contradicting conclusions drawn from literature values of tracer diffusion experiments the addition of carbon has only a minor effect on the iron mobility: at a given temperature the self-diffusion coefficient in Fe83.1C16.9 is only 10% larger than in liquid iron, although mixing has a drastic effect on liquidus temperature and phase behavior.