Molecular dynamics study of grain boundary migration in Zr under temperature gradient
Directional annealing technology is widely used to enhance the comprehensive performance of high-temper-ature alloys by creating a temperature gradient environment to drive the directional migration of grain boundaries,resulting in the formation of superior columnar grain structures.However,significant differences in the migration a-bilities of different grain boundaries hinder the formation of columnar grain structures.In order to better control the directional annealing process,this study employed molecular dynamics simulations to investigate the migration be-havior of multiple grain boundaries in α-Zr under temperature gradients.The regularities between the energy change characteristics and migration behavior of different grain boundaries during the migration process were summarized,elucidating the mechanism of grain boundary migration influenced by factors such as excess energy and pre-melting temperature.The study found that higher atomic potential energy leads to lower migration activation enthalpy,and lower pre-melting temperature results in greater driving force,making grain boundary migration easier.This finding provides a theoretical basis for explaining the abnormal growth of grains and the cessation of grain boundary migra-tion under temperature gradient environments,and offers theoretical references for better controlling the micro-structure of such alloys and obtaining uniform columnar grains.
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