CHANGEMENTS DE PHASES ET MICROSTRUCTURES
J. Phys. IV France 04 (1994) C3-285-C3-290
Mössbauer effect evidence for disordering induced by mechanical alloying in the Fe-Si systemM. ABDELLAOUI1, E. GAFFET1, C. DJEGA-MARIADASSOU2 and T. BARRADI3
1 ISITEM-CNRS, Groupe "Elaboration et Transitions de Phase loin de l'Equilibre" La Chantrerie, Rue C. Pauc, CP. 3023, 44087 Nantes cedex 03, France
2 Laboratoire de Structure des Matériaux Métalliques, Bât. 413-414, Université Pans-Sud, 91405 Orsay cedex, France
3 Supelec, 91192 Gif-sur-Yvette cedex, France
Based on X - ray diffraction (XRD) patterns, differential scanning calorimetry (DSC) investigations, the phase transitions induced by mechanical alloying (MA) on the Fe rich side of the Fe - Si system has been studied. Starting from a mixture of Fe and Si powders, MA leads to an expansion (up to 27.5 at. % Si) of the A2 crystalline disordered solid solution phase domain. In this composition field, an amorphous phase is also detected. The expansion of the disordered A2 phase domain up to 27.5 at.% Si has been confirmed by Mössbauer spectroscopy investigations. An annealing of the mechanically alloyed powders at 800°C for 48 hours leads exactly to the thermodynamically stable structures consistent with the sample stoechiometry. A high coercive force value of 17.2 kA/m at 1 kHz frequency and 0.15 T magnetic induction was reported for the 9.5 at. % Si.
© EDP Sciences 1994