Defect-induced Asymmetrical Mechanical Behavior in Shape Memory Zirconia: A Phase-Field Investigation
Defect-induced Asymmetrical Mechanical Behavior in Shape Memory Zirconia: A Phase-Field Investigation
复制标题
DOI：
10.1016/j.jeurceramsoc.2022.04.016
复制
发表时间：
2022-04
影响因子：
5.7
通讯作者：
Cheikh Cissé;M. A. Zaeem
中科院分区：
文献类型：
--
作者：
Cheikh Cissé;M. A. Zaeem
采用弹塑性相场模型研究了氧化钇稳定的四氧化锆在缺陷存在下的变形机制。一个显着的拉压不对称性检测。在压缩状态下比在拉伸状态下观察到更高的强度和更低的转变程度。此外，变形机制是不对称的，这取决于晶体取向。在某些情况下（另一些情况），拉伸（压缩）时没有相变，而压缩（拉伸）时既有相变又有塑性。这种张力-压缩不对称性归因于在张力与压缩中具有不同本征应变张量的不同单斜变体的激活。结果还揭示了更高程度的转变和塑性与较低的起始应力作为空隙尺寸的增加。椭圆形孔洞表现出方向性效应，当长半轴与加载方向成对角时，其最大应力强度因子为5.6 MPa m1/2，与实验结果吻合较好。
An elastoplastic phase-field model is used to investigate the deformation mechanisms of yttria stabilized tetragonal zirconia in presence of defects. A remarkable tension-compression asymmetry is detected. A higher strength and a lower degree of transformation are observed in compression than in tension. Also, deformation mechanism is asymmetric depending on the crystal orientation. For some cases (other cases), phase transformation is absent in tension (in compression), while both transformation and plasticity are present in compression (in tension). Such tension-compression asymmetry is attributed to activation of different monoclinic variants with different Eigen strain tensors in tension versus compression. Results also reveal a higher degree of transformation and plasticity with lower onset stresses as the void size increases. Elliptic voids exhibit a directional effect with a maximum stress intensity factor of 5.6 MPa m1/2when the long semi-axis is diagonally oriented with respect to the loading direction, and this prediction is comparable to experiments.