Distribution of Mn atoms in a substitutional bcc-FeMn solid solution

M. MIZRAHI; A. F. CABRERA; S. M. COTES; S. J. STEWART; R. C. MERCADER; J. DESIMONI

Oman

Congreso; International Conference on Mössbabuer Effect (ICAME' 2003); 2003

ICAME

8 <!-- @page { size: 21.59cm 27.94cm; margin: 2cm } P { margin-bottom: 0.21cm } --> In previous works, some of us showed how the distributions of C and N atoms in an interstitial solid solution of fcc-Fe can be successfully determined by a method, which involves Monte Carlo simulations linked to Mössbauer spectroscopy measurements. It is interesting to expand the method to the study of Fe-based binary systems. In this work, focused on the study of the bcc phase of the Fe-Mn system, we present a comparison between the relative occupation fractions of the different sites extracted from Mössbauer spectra and those obtained after Monte Carlo simulations. The interactions between Fe-Fe, Fe-Mn and Mn-Mn atoms have been modeled using an Ising-type Hamiltonian with periodic boundary conditions. The simulations were performed using a Metropolis algorithm to define the jump probability of Mn atoms. Several Fe-Mn alloys with Mn percentages smaller than 30 wt. % were prepared by arc melting. Mössbauer measurements were taken to samples of fine particle powders ground in a horizontal vibratory mill. The samples exhibit not only the bcc but also the fcc and hcp phases in relative proportions that vary with the Mn content.