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Indexed by:期刊论文

Date of Publication:2013-11-01

Journal:RARE METAL MATERIALS AND ENGINEERING

Included Journals:SCIE、PKU、ISTIC

Volume:42

Page Number:453-457

ISSN No.:1002-185X

Key Words:metallic glasses; microstructure; pulsated orifice ejection method (POEM); critical cooling rate

Abstract:[(Fe0.5Co0.5)(0.75)B0.2Si0.05](96)Nb-4 metallic glass alloy particles were prepared with narrow size distribution and high sphericity in a mixed inter gas atmosphere 50%Ar +50%He (volume fraction) by pulsated orifice ejection method. The analysis of the obtained particles was carried out by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscope (TEM). The results show that the phase transitions of particles from the fully crystalline phase to the mixed phase which is consisted of the glassy phase and the crystalline phase to the fully glassy phase occurs as the particle diameter decreases. The particles obtained in the fully glassy phase have a diameter of less than 515 mu m. Critical cooling rate for fully glassy phase is estimated to be in the range of 800 similar to 1100 K/s. No changes of the critical cooling rate occur in argon or helium atmosphere. Critical cooling rate measured in this method is definitely lower than that measured by time-temperature transformation diagram of bulk metallic alloy.