Mössbauer and resistometric study of α(bcc) → γ(fcc) phase transformation induced by ion bombardment and intraphase processes in the Fe + 8.25 at % Mn alloy
Abstract
The results of the Mössbauer and resistometric studies of the atom redistribution and peculiarities of the α(bcc) → γ(fcc) structure-phase transformation in the Fe + 8.25 at % Mn alloy under irradiation by Ar+ ions (E = 20 keV, j = 50–100 μA/cm2) and heating by a light beam with a comparable power are presented. The Cowley parameter α1 of short-range atomic order, the number and composition of the α and γ phases formed during α → γ transition are calculated. An alternative character of atom redistribution in the quenched alloy caused by irradiation with ions at 250°C (atomic ordering, α1 < 0) and at 420°C (short-range separation, α1 > 0) is established. Exposure to the light beam does not cause a redistribution of atoms at 250°C (α1 = 0). At a temperature of 420°C, exposure to an ion beam repeatedly (1–2 orders of magnitude) accelerates the short-range atomic separation in the alloy and initiates the subsequent transformation of the enriched (up to ~18 at % Mn) zones into the γ phase.
- Publication:
-
Physics of Metals and Metallography
- Pub Date:
- December 2015
- DOI:
- 10.1134/S0031918X15120054
- Bibcode:
- 2015PMM...116.1234O
- Keywords:
-
- iron-manganese alloy;
- powerful ion and light beams;
- Mössbauer spectroscopy;
- resistometry;
- shortrange ordering;
- short-range separation;
- bcc → fcc phase transformation