COMPARATIVE STUDY BETWEEN TWO DIE CAST METHODS OF PROCESSING BULK METALLIC GLASSES

摘要

In this work, two copper mold casting techniques with similar cooling rates werecompared: the process with suction casting and the process with centrifugai casting.The suction casting technique has an arc-melting fusion mechanism while thecentrifugai casting has an induction heating mechanism. Three samples of threealloys from the Cu-Zr-AI System in a wedge shape were produced by each process.The main characteristics evaluated were the mold-filling ability, the average time percycle, the oxygen contamination and the maximum thickness on which glassy phasewhich is extensively reported in the literature.The used alloys with nominalcompositions were Cu_(53.5)Zr_(42)Al_(4.5), Cu_(48)Zr_(43)AI_9, Cu_(42)Zr_(44)Al_(14) and Cu_(43.5)Zr_(43.5)Al_(13). Thewedge shape was chosen because it allows evaluation of different thicknesses(hence cooling rates) at the same sample. Results revealed that the copper moldcentrifugai casting had a higher contamination by oxygen, whilst the mold-fillingability was similar in both processes. Also, the average time per cycle was higher andthe maximum thickness in which glassy phase could be obtained was lower, for thecentrifugai casting. A brief analysis considering the oxygen contamination on thesealloys is also presented here, revealing the extreme importance of the control of thisparameter.