Processing a Fe67Mo4.5Cr2.3Al2Si3C7P8.7B5.5 metallic glass: Experimental and computed TTT and CCT curves

Abstract

For metallic glass synthesis and processing the possible formation of crystals should be described by CCT curves. Motivated by results of the synthesis of wires of the Fe67Mo4.5Cr2.3Al2Si3C7P8.7B5.5 alloy by melt extraction, a methodology is proposed to compute TTT and CCT curves based on the classical nucleation and growth theory. The thermophysical parameters needed for the calculation are entirely derived from DSC experiments, including those expressing the Vogel-Fulcher-Tammann equation for viscosity. The critical cooling rate for amorphous wires is estimated and matched with the CCT curve. Then, the corresponding computed TTT curve is shown to reproduce well the experimental results of isothermal crystallization of the ribbons.