Enhanced nanocrystalline stability of BCC iron via copper segregation

FY Wang and LS Dong and HH Wu and PH Bai and SZ Wang and GL Wu and JH Gao and JM Zhu and XY Zhou and XP Mao, PROGRESS IN NATURAL SCIENCE- MATERIALS INTERNATIONAL, 33, 185-192 (2023).

DOI: 10.1016/j.pnsc.2023.05.001

Nanocrystalline alloys are known for their high density of grain boundaries (GBs), which results in low thermal stability and a tendency for coarsening. In this work, we investigated Fe-Cu alloys to explore the effects of Cu concentration on the thermal stability of nanocrystalline samples. Using hybrid molecular dynamics (MD) and Monte Carlo (MC) simulations, annealing treatments of nanocrystalline samples with varied Cu concentrations were conducted. The simulation results revealed that Cu atoms tended to accumulate at GBs. Subsequently, the model with Cu segregation was subjected to mechanical creep loading at various temperatures. Through the analysis of atomic structure evolution during creep deformation, it was found that Cu segregation efficiently stabilizes GBs and restricts their movement. The present findings highlight that the thermal stability of nanocrystalline Fe-Cu alloys can be effectively improved by introducing suitable Cu segregation at GBs.

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