Fig. 6: Schematic diagram illustrating the oxygen redistribution dynamics in the CoCrNi-O MPEAs.

Upon plastic straining, Shockley partial dislocations in the alloy can slide along close-packed planes, while Frank partial dislocations can climb along coherent twin boundaries to accommodate the plastic deformation, resulting in the columnar grains transformed into globular grains. The SFs and NTs induced by partial dislocations, along with the (Cr, O)-rich clusters induced by oxygen in grain interiors, serve to hinder dislocation motion and promote accumulation and multiplication of dislocations, which enhance strain hardening during deformation. In the interaction between partial dislocations and the (Cr, O)-rich clusters, oxygen atoms are dragged to the GBs and gradually accumulate at these GBs, thereby increase the O-M bonds at the GBs, increasing the GB strength and stabilizing them.