Shear strain-induced structure relaxation of Ni Sigma 17 110(223) grain boundary: A molecular dynamics simulation

HT Xue and XD Yu and X Zhou and FL Tang and XY Li and YZ Wu and JQ Ren and XF Lu, MODERN PHYSICS LETTERS B, 36, 2150401 (2022).

DOI: 10.1142/S0217984921504017

The stabilization of grain boundaries (GBs) is beneficial for improving the stability and mechanical properties of nanocrystalline (NC) metals. Molecular dynamics (MD) calculations were performed to investigate the shear response of Ni Sigma 17 110(223) symmetrical tilt GB. It was found that under the action of shear, the nucleation and evolution of the GB source Shockley partial dislocations ultimately result in the low-energy-state transformation of the GB structure units (SUs). However, the Ag atom contained in the GB increases the shear stress and strain required for the GB relaxation, and the strain range for the GB relaxation is expanded, indicating the inhibitory effect of the Ag atom on the structural relaxation of Ni Sigma 17 110(223) GB. As the temperature increases from 10 K to 250 K, the structural relaxation of Ni Sigma 17 110(223) GB becomes easier to proceed. In addition to segregation-induced GB stabilization, strain-induced GB relaxation and the roles of foreign atom and temperature clarified in this work could provide several new entry points for stabilizing high-energy GBs.

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