Papers by Author: Yi Fan Fu

Abstract: A new method to evaluate the critical cooling rate, Rc of Fe-based metallic glass alloy was proposed and discussed. [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4 alloy particles were prepared with narrow size distribution and high sphericity by Pulsated Orifice Ejection Method in Ar, He and 50%Ar+50%He mixed atmosphere, respectively. Phase transition of a particle from amorphous to amorphous-crystalline and fully crystalline occurred with the increase of particle diameter. Rc of the formation of fully amorphous phase was estimated to be in the range of 700-1100 K/s, lower than that measured by time-temperature transformation diagram of bulk metallic alloy. No change of Rc occurred in Ar, He or 50%Ar+50%He mixed atmosphere, which proved it an effective method to evaluate the critical cooling rate of Fe-based metallic glass alloy.

Abstract: A simulation method was used to study the effects of physical parameters, including the contact angle between molten metal and material of orifice, surface tension and viscosity on particle formation of POEM. Droplets can be stably obtained only when the contact angel is at least 90° or larger, as well as the surface tension is adequate. Within a wide range, viscosity has little effect on droplet formation; as the viscosity increases, necking time is postponed and vibration time is shortened.