Competitive segregation to grain boundaries between Cr and Co in FeNiCrCo alloy

Alloying elements segregating to grain boundaries (GBs) is vital in determining structural stability and mechanical properties of alloys, especially in high-entropy alloys (HEAs) that consist of multiple elements. However, some details remain unclear, such as the process of varied atoms (Cr and Co) cosegregation to GBs in FeNiCrCo alloy. Therefore, the competition and cooperation between Fe, Ni, Cr, and Co atoms segregating to GBs of FeNiCrCo alloy were investigated via molecular dynamic (MD) simulation. Five [110] symmetric tilt GBs of FeNiCrCo were applied to study the relation between the tendency of atomic segregation especially Cr and Co and GB characters including GB energy and GB excess free volume (GB excess volume). A competitive segregation phenomenon between Cr and Co atoms was discovered, which could be dominated by GB excess volume and different atomic radii among components.