Phase field modeling of the tetragonal-to-monoclinic phase transformation in zirconia
Phase field modeling of the tetragonal-to-monoclinic phase transformation in zirconia
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DOI：
10.1016/j.actamat.2013.05.015
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发表时间：
2013-08-01
期刊：
影响因子：
9.4
通讯作者：
Chen, Long-Qing
中科院分区：
文献类型：
--
作者：
Mamivand, Mahmood;Zaeem, Mohsen Asle;Chen, Long-Qing
氧化锆从四方晶格到单斜双晶格的同素异形体相变是通过马氏体孪晶机制发生的，该机制与温度、应力和环境有复杂的关系。本文讨论了一个相场模型的建立，该模型解释了控制马氏体相变的主要冶金机制。利用代表不同相变路径的非守恒序参数，模拟了母相与产物相之间的对称约简和取向关系。考虑了非均匀性和各向异性弹性特性来确定合成弹性应力。在不同的初始条件和边界条件下，在有限元框架中求解了四边形到单斜曲面变换的控制方程。结果表明，施加不同的初始条件，如种子胚或随机，对松弛期后的孪生模式和亲本相和产物相的最终体积分数没有影响。另一方面，施加不同的边界条件会导致完全不同的孪晶模式和相体积分数。该模型既能预测孪晶的“V”形形貌，又能预测表面应力释放的“山墙顶”模式，通过透射电子显微镜和原子力显微镜观察到这是四方向单斜转变的特征。(C) 2013材料学报Elsevier Ltd.出版。版权所有。
The allotropic phase transformation in zirconia from the tetragonal to monoclinic double lattices is known to occur by a martensitic twinning mechanism which shows a complex dependence on temperature, stress and environment. This paper is concerned with the development of a phase field model which accounts for the main metallurgical mechanisms governing this martensitic transition. The symmetry reduction and orientation relationship between the parent and product phases were simulated using several non-conserved order parameters representing different transformation paths. Inhomogeneous and anisotropic elastic properties were considered to determine the resultant elastic stresses. Governing equations of the tetragonal-to-monoclinic transformation were solved in a finite element framework under a variety of initial and boundary conditions. It was shown that applying different initial conditions, such as seed embryo or random, did not change the twinning patterns or the final volume fractions of the parent and product phases after the relaxation period. On the other hand, enforcing different boundary conditions resulted in completely different twinning patterns and phase volume fractions. The model was able to predict both the "V" shape morphology of twinning and the surface stress relief with "gable roof" patterns, which were observed by transmission electron microscopy and atomic force microscopy to be characteristic of the tetragonal-to-monoclinic transition. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.