Absence of toughening behavior in 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 relaxor ceramic
Absence of toughening behavior in 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 relaxor ceramic
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DOI：
10.1016/j.scriptamat.2017.04.023
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发表时间：
2017-07-15
影响因子：
6
通讯作者：
Roedel, J.
中科院分区：
文献类型：
--
作者：
Voegler, M.;Daniels, J. E.;Roedel, J.
研究了未极化的0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3弛豫铁电体的断裂行为。前人的研究表明，机械应力可以引起亚稳态铁电长程有序，导致裂纹尖端过程区，增加裂纹扩展过程中的裂纹阻力。紧凑拉伸试件中的裂纹扩展产生了恒定的抗裂性，它是裂纹长度的函数。这与非原位X射线衍射实验是一致的，在断口表面没有检测到剩余的诱导过程区。我们认为，通过宏观应力-应变测量确定的非常高的相变应力是导致没有韧化的原因。(C)2017 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
The fracture behavior of the unpoled 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO(3) relaxor ferroelectric was investigated. Previous studies indicated that a metastable ferroelectric long-range order can be induced by mechanical stresses, which could lead to a crack tip process zone and increasing crack resistance during crack growth. Crack propagation in compact tension samples yielded a constant crack resistance as function of crack length. This is consistent with ex situ x-ray diffraction experiments, where a remanent induced process zone on the fracture surface could not be detected. We suggest the very high transformation stress, determined via macroscopic stress-strain measurements, is responsible for the absence of toughening. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.