Role of tri-capped triangular prism (TTP) polyhedra in formation and destabilization of Fe–Y–B glassy alloys

•B-centered clusters appear mainly as TTP polyhedron in Fe–Y–B glasses.•Increasing cY and cB improves the GFA of Fe72Y4B20 glasses.•Increasing cY and cB triggers the formation of nanoscale network structure.•Increasing cY and cB strengthens B-centered TTP backbone.

Since the structural characterization of Fe-based disordered system is less than other metallic glasses, we investigate the Fe76 − 2xY4 + xB20 + x (x = 0 and 2) glasses and melts via the variation of tri-capped triangular prism (TTP) polyhedron with changing the composition. B-centered clusters mainly appear in the manner of TTP polyhedron in both alloys, which is strengthened by increasing yttrium and boron contents (cY and cB) and considered as the network/backbone in the Fe-based glassy alloys. Increasing cY and cB improves the onset temperature of the first crystallization event with decreasing its activation energy, deteriorates the corrosion resistance of present alloys in NaCl and H2SO4 solutions, and triggers the formation of nanoscale network structure. These experimental results can be ascribed to the strengthened network/backbone in the alloys.