CALPHAD-assisted development of in-situ nanocrystallised melt-spun Co-Fe-B alloy with high Bs (1.57 T)

•Thermodynamic and topological parameters have been used to design an alloy with a tuned amorphisation capability.•Tuned parameters resulted in in-situ nanocrystallisation of Co7Fe3 with very-high Bs (1.57 T).•Based on Mössbauer spectrum, it is asserted that cobalt atoms form clusters, and boron atoms undergo short-range ordering.