MICROSTRUCTURE VS CASTING PROCESSES IN THE FE-SI-CA-AL SYSTEM

A quaternary phase isostructural with alpha-Fe1-xSi2 and named ''caals ifer'' for its chemical constitution was earlier detected in industria l ferrosilicon alloys (Margarido and Figueiredo, 1988). With the aim o f ascertaining the possible domain for such a non-equilibrium compound and contributing to the understanding of microstructure and phase sol idification in casting processes of ferrosilicon alloys, a systematic study of phase formation within the quaternary Fe-Si-Al-Ca system was undertaken. Results are presented of laboratory experiments using both are and induction fusion furnavces with water-cooled copper crucibles , and compositions close to that assumed for cadsifer. The obtained ma terials were chemically and compositionally characterized through scan ning electron microscopy and X-ray diffraction. A relation is tentativ ely established between microstructure plus phase assemblage on the on e hand, and cooling rate on the other.