IMPROVEMENT IN BRITTLENESS OF AMORPHOUS FE-SI-B-C ALLOY RIBBONS BY CONTROLLING CASTING CONDITIONS

Direct measurements of ribbon temperature were performed at a point wh ere the ribbon lifted from off a rotating roll during a conventional s ingle roll process producing amorphous ribbons. A lower ribbon lift-of f temperature resulted ill a less brittle amorphous state, ductile as- quenched amorphous Fe80.5Si6.5B12C1 alloy ribbons in the thickness ran ge of 52-54 mu m were obtained by maintaining the lift-off temperature below 473 K. Thermal analyses indicate that the embrittlement of the ribbons lifted off at temperatures above 473 K may be caused by the st ructural relaxation, such as the formation of iron clusters which are introduced to the ribbons after lift-off from the roll.