Multi-field Coupled Inverse Hall–Petch Relations for Ferroelectric Nanocrystals  

作　　者：Xiaodong Zhang Wei Yan Xuhui Lou Yujun Chen Zhihong Zhou Qingyuan Wang Lianhua Ma Xiaobao Tian 

机构地区：[1]Non-Destructive Testing Laboratory,School of Quality and Technical Supervision,Hebei University,Baoding 071002,China [2]AVIC Huiyang Aviation Propeller Co.,Ltd,Baoding 071051,China [3]Department of Mechanics and Engineering,Sichuan University,Chengdu 610065,China [4]Yibin Institute of Industrial Technology,Sichuan University Yibin Park,Yibin 644000,China [5]Research Institute of Interdisciplinary Sciences(RISE),Dongguan University of Technology,Dongguan 523808,China [6]School of Materials Science and Engineering,Dongguan University of Technology,Dongguan 523808,China

出　　处：《Acta Mechanica Solida Sinica》2024年第1期139-147,共9页固体力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.12172117,12372154);National Science and Technology Major Project(No.J2019-1II-0010-0054);National Numerical Windtunnel(No.NNW2019-JT01-023);High-Performance Computing Center of Hebei University。

摘　　要：Tailoring grain size can improve the strength of polycrystals by regulating the proportion of grains to grain boundaries and the interaction area.As the grain size decreases to the nanoscale,the deformation mechanism in polycrystals shifts from being primarily mediated by dislocations to deformation occurring within the grains and grain boundaries.However,the mechanism responsible for fine-grain strengthening in ferroelectric materials remains unclear,primarily due to the complex multi-field coupling effect arising from spontaneous polarization.Through molecular dynamics simulations,we investigate the strengthening mechanism of barium titanate(BaTiO3),with extremely fine-grain sizes.This material exhibits an inverse Hall–Petch relationship between grain size and strength,rooting in the inhomogeneous concentration of atomic strain and grain rotation.Furthermore,we present a theoretical model to predict the transition from the inverse Hall–Petch stage to the Hall–Petch stage based on strength variations with size,which aligns well with the simulation results.It has been found that the piezoelectric properties of the BaTiO3 are affected by polarization domain switching at various grain sizes.This study enhances our understanding of the atomic-scale mechanisms that contribute to the performance evolution of fine-grain nano-ferroelectric materials.It also provides valuable insights into the design of extremely small-scale ferroelectric components.

关 键 词：FERROELECTRICS Multi-field coupling Molecular dynamics Fine-grain reinforcement Inverse Hall-Petch effect 

分 类 号：O34[理学—固体力学]