PROCESSING OF THICK DUCTILE METALLIC-GLASS

The paper reviews the progress made in understanding the effect of pro cessing parameters on ductility of thick cast ribbons of an Fe-B-Si tr ansformer core alloy. The ductile to brittle transition temperature (D BTT) of amorphous ribbons has been studied as a function of their thic kness and quenching conditions. Modeling and simulation indicated that ribbon thickness with a given DBTT could be significantly increased b y increasing the conductivity of the wheel and improving the heat extr action system. Casts made on wheels modified in this manner allowed fo r a substantial increase (> 2 x) in the thickness of amorphous ribbon that is ductile enough to be processed during manufacturing of stacked core transformers. The thicker ribbon also exhibits attractive low co re loss properties. The low coreless properties of the annealed ribbon have been preserved in stacked transformer corelets. (C) 1997 Elsevie r Science S.A.