MOSSBAUER-EFFECT STUDY OF MECHANICALLY ALLOYED GAMMA AND GAMMA(1) FE-ZN INTERMEDIATE PHASES

The Mossbauer effect measurements of as-ball-milled mechanically alloy ed Fe-Zn intermediate phases of Gamma (Fe3Zn10) and Gamma(1) (Fe5Zn21) compositions exhibit-characteristic spectra consisting of triplets. E ach is characterized with an Fe site with unusually large quadrupole s plittings measuring 0.940 mm/s in the cubic Fe-Zn phases and, in addit ion, three other doublets. In-the aged state, both compositions show s pectra free of the Fe site with quadrupole splitting of 0.940 mm/s, de signated as(MS Gamma)Fe(1) and Fe-MS Gamma 1(1), respectively. This su ggests that the metastable states are similar, while their separate tr ansformation paths to stable equilibrium lead to distinct crystal stru ctures. The parameters for the aged states are compared with those rep orted in the literature for both phases.