Interdiffusion of cerium in Fe-base alloys with Ni or Cr

Abstract

Isothermal interdiffusion studies relevant to lanthanide interactions with cladding alloys in the Integral Fast Reactor program were carried out at 425°C by employing solid-solid diffusion couples assembled with disks of Ce and disks of Fe, Ni, and Fe-10.1Ni, and Fe-20.1Cr, binary alloys (composition in at%). The diffusion structures and intermetallic layers which developed in the various couples during the diffusion anneal were metallographically examined and analyzed by SEM-EDS techniques for concentration profiles. Computer programs were developed to construct profiles of concentrations and to evaluate interdiffusion fluxes and effective interdiffusion coefficients for the individual components over selected regions of the diffusion zones of the various couples. Intrinsic diffusion data were calculated at marker planes in the Ni3Ce7 and Fe2Ce phases developed in the Ni vs Ce and Fe vs Ce couples, respectively. The intermetallic phases and diffusion layers observed in the various couples are discussed in the light of phase diagrams and experimental diffusion paths. © 1993.