Alloying and microstructure modulation strategies enable superior corrosion and oxidation resistances for thermoplastic manufacture of Fe-B-Nb-Y-Cr-Al bulk metallic glasses

Cost-effective Fe-based bulk metallic glasses (BMGs) exhibit excellent structural-functional characteristics, yet their thermoplastic processing (TPP) of precise components is always constrained by the low thermal stability, high oxidation, and corrosion susceptibility as well as limited glass-forming ability (GFA). In this study, advanced Fe_69-x(B_22.8Nb_3.7Y_4.5)_1-y/31Cr_xAl_y (x = 0–8, y = 0–3) alloys were prepared with the specific alloying and microstructure modulation strategies to motivate multiple enhancement mechanisms. The positive mixing enthalpy of Y-Nb induces a liquid-liquid phase transition (LLPT), elevating the crystallization barrier height to enhance both GFA and thermal stability. Alloying with Cr and Al promotes the formation of denser oxide films, significantly improving corrosion resistance and high-temperature oxidation resistance. It was also found that the thermoplastic deformation can remarkably enhance the corrosion resistance by densifying the glassy structure, as well as lowering the energy state and residual stress. The correlation mechanisms among the GFA, structural stability, TPP process, oxidation, and corrosion resistances were also explored by atomic models. These findings should provide a new alloying paradigm for developing TPP BMGs and innovative strategies for enhancements of oxidation and corrosion resistance.