Newly-developed pseudo-high entropy amorphous alloys: Structure/ microstructure evolution, mechanical and corrosion properties

The influence of devitrification on microstructure, corrosion, and mechanical properties of two new FeCrMoNbB and FeCrMoNiB pseudo-high entropy (PHE) amorphous alloys have been investigated to be used as coatings. Amorphous ribbons produced by melt spinning were heat-treated to simulate crystallization. Amounts of amorphous phases were kept at high temperatures and crystallized in multi-principal element bcc or FCC phases and borides. A 500 mu m thick physically simulated coating of commercial-grade precursors using spray forming was produced to infer their viability. The Nb-PHE alloy's coating was nearly amorphous. Ribbons' hardness and elastic modulus evaluated by nanoindentation depended on annealing temperatures and were remarkably high. Potentiodynamic polarization curves in chlorine-rich solution at different pHs showed outstanding corrosion resistance in amorphous conditions. After devitrification, both compositions preserved excellent corrosion behavior up to similar to 700 degrees C. Pitting corrosion was absent. Resistance to corrosion and wear indicates that these materials are promising for coating applications.