Microstructure evolution and tribological properties of rapidly solidified FeCoNiSi0.5 multi-principal component alloy

FeCoNiSi 0.5 multi-principal component alloy has been prepared under different liquid undercooling conditions by glass fluxing combined with cyclic superheating techniques. Its microstructure evolution and wear properties of this alloy were investigated in details. The results indicated that the solidified structure of alloys transformed from coarse dendrites to worm-like dendrites, demonstrating that increased liquid undercooling significantly promoted grain refinement. Phase constitution included both the face-centered cubic (FCC-FeCoNi) and Ni 31 Si 12 phases. Furthermore, an ordered FCC structure(L1 2 ) was observed in the interdendritic region. Nanoindentation tests indicated that alloy undercooling had a substantial impact on the nano-hardness of the FCC-FeCoNi phase. In terms of tribological properties, grain refinement and an elevated volume fraction of SiO 2 in wear debris were identified as crucial factors enhancing the wear resistance of FeCoNiSi 0.5 alloy. Moreover, a transition in the dominant wear mechanism from abrasive wear to oxidative wear was facilitated by increased undercooling. This positive correlation highlighted the potential of adjusting undercooling to achieve higher undercooling as an effective strategy for improving the wear-resistant properties of metallic materials.