Fe-rich border of miscibility gap and activation energy of phase decomposition in a Fe-Cr alloy

TL;DR

This study investigates the Fe-rich border of the miscibility gap and measures the activation energy of phase decomposition in Fe-Cr alloys, revealing effects of irradiation and temperature on phase stability.

Contribution

It provides new measurements of Cr concentration, activation energy, and Avrami exponents in Fe-Cr alloys under different conditions, highlighting irradiation effects on phase decomposition.

Findings

Cr concentration in irradiated samples is higher by ~3 at%.

Activation energy decreases by 12 kJ/mol after irradiation.

Avrami exponent shifts from ~0.5 to 1 with irradiation.

Abstract

Concentration of Cr in the Fe-rich alpha-phase, x, resulted from a phase decomposition caused by an isothermal annealing at T = 415 and 450 C of a non-irradiated (NR) Fe-Cr14 EFDA sample and that of a He-ions irradiated (IR) one annealed at 415 C was determined with M\"ossbauer spectroscopy. The x-value in the latter was by ~3 at% higher than the one in the NR-counterpart. The activation energy for the phase decomposition in the NR-sample was 122 kJ/mol. In the IR-sample its value was by 12 kJ/mol lower. Avrami exponents for the NR-samples were close to 0.5, and that for the IR-sample had a value of about 1.