A thermo-kinetic correlation for grain growth in nanocrystalline alloys

The thermo-kinetic stabilization that incorporates mixed effects of grain boundary (GB) energy and activation energy for GB migration has shown enormous advantages in describing thermal stability of nanocrystalline materials. However, its underlying physics is still unclear due to the lack of proofs that the two effects coexist and act together to impact on grain growth. In this work, a thermo-kinetic correlation is derived to bridge GB energy and activation energy in nanocrystalline alloys. Meanwhile, molecular dynamic simulations are performed to determine the two parameters in Al-based systems. The results shows that upon GB segregation, the GB energy is reduced in contrast with the increased activation energy. This analytically suggests a thermo-kinetic origin for stabilization due to GB segregation, other than pure thermodynamic or kinetic sources.