MICROSTRUCTURAL ANALYSIS OF RAPIDLY SOLID IFIED FE-SI-B-C RIBBONS CONTAINING AL

Microstructures of thick Fe80.5Si6.5B12C1 amorphous ribbons which were crystallized by the addition of 0.01 mass%Aluminum have been examined . The ribbons with the thickness of 66-74 mu m were cast by using a mu ltiple slotted nozzle in a conventional single roll method. The micros tructures of the as-cast ribbons were as follows: The region near the free surface of the ribbon was fully crystallized, The confirmed phase s were primarily alpha-Fe which forms dendritic structures, Fe2B and o rthorhombic-Fe3B. The roll side of the ribbons was primarily amorphous with alpha-Fe. The middle region in the ribbon thickness direction wa s primarily amorphous with only a trace of alpha-Fe. In the free side surface, it was found that (110) orientation of the dendritic alpha-Fe occurred by the addition of Aluminum and it is considered that the al pha-Fe formed directly from the molten alloy during casting.