Phase coexistence in mechanicallly alloyed iron–manganese powders

Abstract

Iron-manganese alloys with Mn concentration of 6-30 at.% were prepared by mechanical alloying. Structure and phase composition of the samples were investigated by X-ray diffraction and Mössbauer spectroscopy. Mechanical alloying results in the formation of b.c.c. and f.c.c. solid solutions with high concentration of structure defects and refined grains. A single b.c.c. phase was observed in Fe-Mn alloys a Mn concentration less than ≤ 8 at.% and, for higher Mn contents, a mixture of b.c.c. and f.c.c. phases was observed. The main features of phase composition of as-prepared alloys consisted in significant widening of single phase concentration range.

Study of the evolution of the hyperfine parameters in nanostructured Fe–Mn–Cu system

“…This interaction was previously associated to the HCP-FeMn phase [5], stacking faults in the FCC phase [6], or to a paramagnetic iron rich FCC-Fe 1−y Mn y phase [7]. Moreover, the low δ values ruled out the possible incorporation of Fe into the FCC-Cu lattice [8].…”

Structural and hyperfine evolution of the (Fe79Mn21)1−xCux system under milling time

“…It is worth to mention that attempts to also include a single line as in Ref. [16] do not noticeably improve the fits. Then, the simplest model, i.e., a HMFD with non-vanishing probability at zero field, was adopted to reproduce the present set of spectra.…”

“…Regarding that, it is tempting to associate the contribution at zero fields observed in Fig. 3 to this paramagnetic phase and/or to stacking faults [16]. During the last stage of milling (t m > 9 h), the hyperfine parameters remain without changes indicating that the chemical mixing of the elements was reached.…”