APPLICATION OF METASTABLE TRANSFORMATION OF MECHANICALLY ALLOYED FE-ZN-SI IN EQUILIBRIUM PHASE STUDIES

A series of six Fe-Zn-Si alloys was investigated with Fe content varyi ng through the range 5.60 to 25.37 wt,% and fixed Si content of 0.12 w t.%. These alloys were formed by mechanical alloying of pure elemental powders-specifically by ball milling, After preparation, uniformity o f microstructure was verified by electron microscopy and microprobe an alysis, Annealing progress was followed by DSC and XRD, Differential s canning calorimetry measurements through the range 200 to 600 degrees C were used to locate the temperatures of relaxation phenomenon and th e structural evolution, X-ray diffraction patterns were used to identi fy the phases present at various stages of the evolution. An invariant reaction was found near 423 degrees C and was identified as the perit ectic melting of Zn, Identification of the formation of FeSi in a broa d composition range below 9.1 wt. % Fe and at temperatures through 400 degrees C suggests the existence of phase field change, The formation of this FeSi phase is suggested as a possible cause for the Sandelin effect.