Twin engineering on crystal structures has been successfully employed to enhance physical properties in many materials. However, twin engineering for electroelastic moduli of ferroelectric materials has not been explored through both experimental and theoretical approaches. In this work, a self-consistent model is developed to predict the effective electroelastic moduli of twinned ferroelectric polycrystals, via treating the twinned ferroelectric grains as a polycrystalline compound consisting of two phases with equal volume fraction. The developed model has been utilized to investigate the effects of microstructural features, including grain shape and orientation distribution, on the macroscopic electroelastic properties of twinned BaTiO3 polycrystals. The results show that when the volume fraction of one phase is zero, the developed model can recover the expected results for untwinned BaTiO3 polycrystals, agreeing with the previously theoretical results on untwinned polycrystals. Comparing with untwinned ferroelectric polycrystals, twinned polycrystals possess superior effective longitudinal electroelastic performance, especially the elastic constant <InlineEquation ID="IEq1"> <EquationSource Format="TEX">${C}_{33}^{}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mi>C</mi> <mrow> <mn>33</mn> </mrow> <mrow> <mrow /> <mo>∗</mo> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>, dielectric constant <InlineEquation ID="IEq2"> <EquationSource Format="TEX">${\kappa }_{33}^{}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mi>κ</mi> <mrow> <mn>33</mn> </mrow> <mrow> <mrow /> <mo>∗</mo> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation> and piezoelectric coefficient <InlineEquation ID="IEq3"> <EquationSource Format="TEX">${e}_{33}^{*}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mi>e</mi> <mrow> <mn>33</mn> </mrow> <mrow> <mrow /> <mo>∗</mo> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>. For twinned ferroelectric polycrystals, the optimal grain shape and texture coefficient for effective electroelastic moduli are also determined. The results suggest that twin engineering can enhance the macroscopic electroelastic properties of ferroelectric polycrystals, offering a new strategy to improve the electroelastic properties of ferroelectrics.

Enhancing the effective electroelastic moduli of ferroelectric polycrystals via twinned structures

期刊论文
发表日期：

2025年10月13日

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Cuiping Li,
Ningbo He,
Chihou Lei,
Dongliang Shan,
Zhanpeng Zhang,
Kai Pan,
Gengsheng Yu,
Yunya Liu

摘要

Twin engineering on crystal structures has been successfully employed to enhance physical properties in many materials. However, twin engineering for electroelastic moduli of ferroelectric materials has not been explored through both experimental and theoretical approaches. In this work, a self-consistent model is developed to predict the effective electroelastic moduli of twinned ferroelectric polycrystals, via treating the twinned ferroelectric grains as a polycrystalline compound consisting of two phases with equal volume fraction. The developed model has been utilized to investigate the effects of microstructural features, including grain shape and orientation distribution, on the macroscopic electroelastic properties of twinned BaTiO₃ polycrystals. The results show that when the volume fraction of one phase is zero, the developed model can recover the expected results for untwinned BaTiO₃ polycrystals, agreeing with the previously theoretical results on untwinned polycrystals. Comparing with untwinned ferroelectric polycrystals, twinned polycrystals possess superior effective longitudinal electroelastic performance, especially the elastic constant ${C}_{33}^{*}$ $C_{33}^{*}$ , dielectric constant ${\kappa }_{33}^{*}$ $κ_{33}^{*}$ and piezoelectric coefficient ${e}_{33}^{*}$ $e_{33}^{*}$ . For twinned ferroelectric polycrystals, the optimal grain shape and texture coefficient for effective electroelastic moduli are also determined. The results suggest that twin engineering can enhance the macroscopic electroelastic properties of ferroelectric polycrystals, offering a new strategy to improve the electroelastic properties of ferroelectrics.