Abstract 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.

中文翻译：

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高强度对比双相桥锰矿/方镁石中的变形不均匀性和晶内晶格取向错误

摘要 由于桥锰矿/方镁石聚集体在地球下地幔中的普遍存在及其对理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，已知相之间的强度对比和单晶弹塑性各向异性都会影响晶粒内取向错误的发展和晶体织构的演变。在这项研究中，使用有限元求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斜方相（桥锰矿，MgSiO3）和相对较弱的立方相（方镁石，MgO）的聚集体. 相位的相对强度被参数化以阐明强度对比对纹理演化的影响，并执行单相模拟以进行比较。总体而言，结果表明两相之间的相对强度影响塑性的发展和整体纹理演变。根据与聚集体中塑性和取向差的演变相关的趋势，以及它们对相之间的强度对比以及晶粒和相的空间分布的依赖性，对结果进行了讨论。