Study of transformation induced intergranular microcracking in tetragonal zirconia polycrystals with the phase field method
Study of transformation induced intergranular microcracking in tetragonal zirconia polycrystals with the phase field method
复制标题
相场法研究四方氧化锆多晶相变诱导晶间微裂纹
DOI：
10.1016/j.msea.2017.06.060
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发表时间：
2017-07
期刊：
影响因子：
6.4
通讯作者：
Jun Luo
中科院分区：
文献类型：
--
作者：
Jingming Zhu;Jun Luo
氧化钇稳定的四相氧化锆多晶体（TZPs）的上级断裂韧性来源于在扩展裂纹前缘周围的拉伸应力场中应力诱导的四相到单斜（t-m）相的转变。然而，当TZP暴露于潮湿环境中时，可发生自发相变，这伴随着晶间微裂纹，并导致机械性能的损失。这种现象，通常称为低温降解（LTD）或老化，被认为是TZP用于其临床应用（如股骨头和牙科植入物）的主要缺点。为了探索相变诱发晶间微裂纹的机理，本文建立了一个能同时模拟相变和晶间微裂纹的耦合相场模型。通过研究具有纯剪切本征应变的单个孪晶变体的微裂纹形核，验证了相场模型的有效性。用相场模型得到的形核微裂纹长度与理论预测吻合较好。讨论了双晶本征应变对微裂纹形核的影响以及单斜孪晶微裂纹形核的影响。在此基础上，利用相场模拟方法研究了t-m相变引起的多晶四相氧化锆陶瓷的晶间微裂纹。研究发现，马氏体变体的宽度及其与晶界的夹角对微裂纹形核有重要影响。讨论了马氏体孪晶的显微组织和沿晶微裂纹的分布。研究结果有助于理解TZP在水热老化后的降解机理。
The superior fracture toughness of yttria stabilized tetragonal zirconia polycrystals (TZPs) originates from the stress-induced tetragonal to monoclinic (t-m) phase transformation in the tensile stress field around a propagating crack front. However, spontaneous phase transformation can take place when TZPs are exposed to humid environments, which is accompanied by intergranular microcracking and results in the loss of mechanical properties. This phenomenon, usually called low temperature degradation (LTD) or aging, is considered as a main drawback of TZPs for their clinical applications such as femoral heads and dental implants. In order to explore the mechanisms behind transformation induced intergranular microcracking, a coupled phase field model is developed in this paper, which can simulate the t-m phase transformation and intergranular microcracking simultaneously. The phase field model is validated by studying the microcrack nucleation from a single twin variant with a pure shear eigenstrain. The length of the nucleated microcrack obtained with the phase field modelling matches well with the theoretical prediction. The influence of the dilatational eigenstrain on microcrack nucleation and microcrack nucleation from a monoclinic twin are fully discussed. After that, phase field simulations are conducted to study t-m transformation induced intergranular microcracking in polycrystalline tetragonal zirconia ceramics. It is found that the width of the martensitic variants and their incidence angles to the grain boundary have significant influences on microcrack nucleation. The microstructure of the martensitic twins and the distribution of the intergranular microcracks are fully discussed. The results are helpful to understand the degradation mechanisms of TZPs after the hydrothermal aging.
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影响因子：
15.1
作者：
A. G. Khachaturi︠a︡n
通讯作者：
A. G. Khachaturi︠a︡n
DOI：
10.1016/j.cma.2016.04.009
发表时间：
2016-12
影响因子：
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作者：
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作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
9.4
作者：
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通讯作者：
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