Novel predictive methodology of amorphisation of gas-atomised Fe-Si-B alloy powders

The present work is focused on developing amorphisation capability criteria to predict regions with high amorphous forming ability (AFA) in the Fe-Si-B phase diagram. First, the AFA of Fe-Si-B alloy powders was evaluated by conventional empirical glass forming parameters, which eventually did not guide to the best AFA alloy. Then, AFA analysis was extended to the ternary phase diagram, calculated using CALPHAD, along with superimposed mathematical model based on topological instability factor (λ), estimated critical cooling rate (R_C) and critical particle size (d_C), to confine the phase diagram regions with larger AFA. The alloy with the highest AFA shows optimum atomic size mismatch when λ = 0.204. Furthermore, the optimal region in the phase diagram to design alloys with high AFA is where Fe₂B is the first solid phase under equilibrium solidification. Within these two limits, the alloys with lower liquidus temperatures show the highest AFA for the gas-atomised powders.