On Prediction of Amorphous Phase Forming Compositions in the Iron-Rich Fe-Zr-B Ternary System and Their Synthesis

Abstract

A thermodynamic model parameter P H-S , which is a product of enthalpy of chemical mixing and mismatch entropy normalized by Boltzmann's constant, was used as a guiding tool to predict amorphous phase forming compositions in Fe-rich alloys of the Fe-Zr-B system. Attempts were made to evaluate the effect of Zr addition on the P H-S parameter and phase formation by mechanical alloying (MA) and rapid solidification processing (RSP). A systematic evaluation of the P H-S parameter of various binary compounds in the Fe-Zr-B system and ternary alloys indicated~-7 kJ/mol as a lower bound for the formation of amorphous phase. Model predictions were verified with phase formation in two random compositions in the Fe-rich end of the Fe-Zr-B system synthesized by MA and RSP.

Thermodynamic prediction of bulk metallic glass forming alloys in ternary Zr–Cu–X (X=Ag, Al, Ti, Ga) systems

“…Parameter P HS is the product of ΔH chem and ΔS σ /k B in specified range of 0.9-1.0 of ΔS config /R. P HS parameter has been shown earlier to predict closely the BMG forming composition in a few Zr based systems [16,17,12], Cu based system [18] and Fe based systems [19,20]. In the present paper similar attempt is made with an aim to find out minimum P HS values in Zr-Cu-Ag, Zr-Cu-Al, Zr-Cu-Ti and Zr-Cu-Ga systems so as to generalize the concept over a large number of systems.…”