Tracer Diffusion of Iron in Stainless Steel

Abstract

The tracer diffusion of iron in 18−8 stainless steel has been measured over a wide temperature range by the surface activity decrease method, using radioactive Fe55. The results show that the lattice diffusion coefficients can be described by the equation D=0.58 exp(−67 100/RT) cm2 sec−1. The effect of variations in grain size has been determined, and it has been shown that when the grain size is small, grain boundary diffusion contributes appreciably to the over-all diffusion process, this effect decreasing with increasing temperature.