Deformation heterogeneity and intragrain lattice misorientation in high strength contrast, dual-phase bridgmanite/periclase
Deformation heterogeneity and intragrain lattice misorientation in high strength contrast, dual-phase bridgmanite/periclase
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DOI：
10.1016/j.actamat.2020.02.061
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发表时间：
2020-05-01
期刊：
影响因子：
9.4
通讯作者：
Wenk, Hans-Rudolf
中科院分区：
文献类型：
--
作者：
Kasemer, Matthew;Zepeda-Alarcon, Eloisa;Wenk, Hans-Rudolf
由于桥镁橄榄石/方镁石集合体在地球下地幔中的普遍存在及其对了解地球动力学过程的重要性，因此对其进行了研究。在双相多晶聚集体中，相间强度差和单晶的弹塑性各向异性都会影响晶内取向不良的发展和晶体织构的演化。在这项研究中，用有限元解方法进行了全场晶体塑性模拟，并将其应用于具有钙钛矿结构的机械强度较强的正交相(布里奇曼石，MgSiO_3)和相对较弱的立方相(方镁石，MgO)的集合体。为了阐明强度对比度对织构演化的影响，对各相的相对强度进行了参数化，并进行了单相模拟比较。结果表明，两相之间的相对强度影响塑性的发展，从而影响织构的整体演化。根据集料中塑性和取向偏差的演变趋势，以及它们对相之间的强度对比以及颗粒和相的空间分布的依赖性，对结果进行了讨论。(C)2020 Acta Materialia Inc.由爱思唯尔有限公司出版。版权所有。
A bridgmanite/periclase aggregate is investigated due to its prevalence in the Earth's lower mantle and its importance for understanding geodynamic processes. In dual-phase polycrystalline aggregates, both strength contrast between phases and single crystal elastic and plastic anisotropy are known to influence the development of intragrain misorientation, and the evolution of crystallographic texture. In this study, full-field crystal plasticity simulations are performed with a finite element solution method, and applied to an aggregate of a mechanically strong orthorhombic phase with perovskite structure (bridgmanite, MgSiO3), and a relatively weaker cubic phase (periclase, MgO). The relative strengths of the phases are parameterized to elucidate the effect that strength contrast has on texture evolution and single-phase simulations are performed for comparison. Overall, results indicate that the relative strength between the two phases influences the development of plasticity, and the overall texture evolution. Results are discussed in light of trends related to the evolution of plasticity and misorientation in the aggregate, and their dependence on both the strength contrast between phases as well as the spatial distribution of grains and phases. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.