Electron-irradiation-induced solid-state amorphization in supersaturated Ni–Zr solid solutions

Abstract

Electron-irradiation-induced solid-state amorphization (SSA) in supersaturated Ni–Zr solid solution models was investigated by molecular dynamics (MD) simulations, focusing on the threshold composition for the occurrence of SSA. The threshold composition for the MeV electron irradiation-induced SSA can be estimated to be around Ni 82Zr 18. A Ni 82Zr 18 solid solution shows SSA, while a Ni 83Zr 17 solid solution can maintain its original crystalline structure against irradiation. Thermal recovery of the lattice defects introduced during electron irradiation can be seen in both Ni 83Zr 17 and Ni 82Zr 18 solid solutions. There is a significant difference between Ni 83Zr 17 and Ni 82Zr 18 in terms of changes in the number of 12-faced volonoi polyhedrons, namely, the number of constituent atoms whose coordination number is 12. A change in the combination of various volonoi polyhedrons (a change in coordination number of constituent atoms) during the introduction of lattice defects and thermal recovery precedes SSA in the Ni–Zr solid solution model.