In-situ XRD study of actuation mechanisms in BiFeO3-K0.5Bi0.5TiO3-PbTiO3 ceramics
In-situ XRD study of actuation mechanisms in BiFeO3-K0.5Bi0.5TiO3-PbTiO3 ceramics
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DOI：
10.1016/j.actamat.2019.02.026
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发表时间：
2019-04-15
期刊：
影响因子：
9.4
通讯作者：
Hall, David A.
中科院分区：
文献类型：
--
作者：
Li, Yizhe;Chen, Ying;Hall, David A.
在本研究中，我们报道了一种适用于高温压电应用的非遍历弛豫铁电材料，0.57BiFeO（3）-0.21K（0.5）Bi（0.5）TiO（3）-0.22PbTiO（3），其表现出约420 ℃的T-m。通过结合原位同步辐射XRD和应变测量的结果，使用数字图像相关，一个伪立方非遍历弛豫菱面体铁电体的转变被确定，伴随着接近零的体积应变。提出了一种利用衍射应力分析中的不变交点确定无应变状态下菱面体铁电相的晶体学参数的方法。相变过程进行了分析相结合的方法峰形拟合和全图案细化：得到的结果说明了应变所产生的相变，以及本征/非本征贡献和各向异性的场致应变。该研究揭示了不寻常的微观应变行为，区别于正常的菱形铁电体，表现出遍历和正常的铁电材料的综合性能，并导致一个占主导地位的本征晶格应变连同较弱的非本征畴开关效应。不同晶粒族之间的弹性耦合也反映在它们相似的应变取向分布（SOD）函数中。(C)2019由Elsevier Ltd代表Acta Materialia Inc.发布。
In the present study, we report a nonergodic relaxor ferroelectric composition for high temperature piezoelectric applications, 0.57BiFeO(3)-0.21K(0.5)Bi(0.5)TiO(3)-0.22PbTiO(3), which exhibits T-m around 420 degrees C. By combining the results of in-situ synchrotron XRD and strain measurements using digital image correlation, a pseudocubic nonergodic relaxor to rhombohedral ferroelectric transformation is identified, accompanied by a volume strain close to zero. A methodology is developed to determine the crystallographic parameters of the transformed rhombohedral ferroelectric phase in a strain-free state, using the invariant intersection for diffraction stress analysis. The phase transformation process was analyzed by methods combining peak profile fitting and full pattern refinement: the results obtained illustrate the strain arising from the phase transformation, together with intrinsic/extrinsic contributions and anisotropy in the field-induced strain. The study reveals unusual microscopic strain behavior, distinguished from that of normal rhombohedral ferroelectrics, showing the combined properties of ergodic and normal ferroelectric materials and leading to a dominant intrinsic lattice strain together with a weaker extrinsic domain switching effect. The elastic coupling between different grain families is also reflected in their similar strain orientation distribution (SOD) functions. (C) 2019 Published by Elsevier Ltd on behalf of Acta Materialia Inc.