Lattice Parameters of metastable Phases in Quenched Fe-Mn Alloys. Part II: Hcp phase

P. MARINELLI; A. BARUJ; M. SADE; A. FERNÁNDEZ GUILLERMET

ZEITSCHRIFT FUR METALLKUNDE

Carl Hanser Verlag

Lugar: Munich; Año: 2001 vol. 92 p. 489 - 493

0044-3093

This paper is the second of a series presenting the results of a systematic experimental study of the lattice parameters (LPs) of the metaestable phases formed by quenching Fe-Mn alloys with up to 30 at. % Mn. In this work the LPs of the hcp (epsilon ) phase are investigated as functions of composition, using an X-ray technique. With the present results, reliable trends in the composition dependence of a and c are established, which are significantly simpler than those suggested by early measurements. In addition, new extrapolations to 0 at. % Mn, are performed, which are compared with other indirect information on the hcp phase of Fe at room temperature and atmospheric pressure. Finally, by combining the present measurements on the hcp phase with those on the fcc phase reported in the first paper of this series, a detailed analysis is made of the changes in the interatomic distances as well as the relative volume change associated with the fcc/ hcp martensitic transformation (MT). According to the present results such volume change is essentially independent of the Mn content, which should be interesting in modelling the energetics of the fcc hcp MT.