Effect of Intragranular Solute Atom Segregation on the Mechanical Properties of the Ni-Co Alloy

XF Lu and X Yang and W Zhang and X Guo and JQ Ren and HT Xue and FL Tang, JOURNAL OF PHYSICAL CHEMISTRY C, 127, 9717-9724 (2023).

DOI: 10.1021/acs.jpcc.3c01720

Inthe present contribution, a certain amount of Co atoms was addedto the grains (GI) of nano-polycrystalline Ni by a molecular dynamicsmethod to study the effect of solute atom content on the mechanicalproperties of the alloy. It was found that the tensile strength andyield strength of the alloy increased with the increase of Co atomiccontent. With the increase of Co content, the grain boundary atomicpotential energy decreased and the grain boundary became more stable.As the strain increased, the Co atoms in the grain migrated to thegrain boundary, the lattice distortion at the grain boundary increased,and the dislocation nucleation at the grain boundary increased, forminga stable dislocation network and hindering the grain boundary migration.The 1/6⟨112⟩ Shockley incomplete dislocation formedat the grain boundary became the stacking fault source, which wasalso the source of transformation from the internal stacking faultto the external stacking fault, finally transforming into deformationtwins. As the strain increased, the content of Shockley incomplete dislocations in the crystal increased, interacting with other dislocationsto dominate the deformation process.

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