Constraining Earth's Lower Mantle Point Defect Chemistry from the Charge Disproportionation of Iron

从铁的电荷歧化中限制地球下地幔点缺陷化学

• 批准号: 20K14580
• 负责人: RITTERBEX S
• 金额: $ 2.66万
• 依托单位: Ehime University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2020
• 资助国家: 日本
• 起止时间: 2020-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-20K14580/
• 关键词: Grain boundaries; Ferropericlase; Mechanical behavior; Earth's mantle; Super-Earth exoplanets; Iron partitioning; Ab initio simulations; Critical shear strength; Ferrous Iron; Spin transition; Plastic deformation; Earth's lower mantle; Ideal s

This project aimed investigating the relation between crystal chemistry, lattice defects and the mechanical behavior of ferropericlase. We carried out atomistic simulations based on the density functional theory, conducted on Type I and II subsystems of the Information Technology Center at Nagoya University.Results show iron to prefer specific grain boundary sites affecting the pressure-induced spin transition and grain boundary partitioning of iron. With those data, ideal shear strengths were determined. It has been shown that high-angle grain boundary motion is particularly accommodated by either shear-coupled migration or grain boundary sliding. The mechanical strengths were found to strongly vary with pressure resulting in grain boundary hardening and weakening across a broad pressure range. By considering the influence of iron spin state on grain boundary migration, we have shown that ferrous iron has a non-unique effect on the criticial shear strength of grain boundaries. In the mantle of super-Earth exoplanets, significant grain boundary weakening is observed to occur, providing a new mechanism of enhanced ductility with depth.

本计画旨在探讨铁方镁石的晶体化学、晶格缺陷与力学行为之间的关系。我们进行了原子模拟的基础上的密度泛函理论，在名古屋大学的信息技术中心的I型和II型子系统进行。结果表明，铁更喜欢特定的晶界网站影响的压力诱导自旋转变和晶界铁的分区。根据这些数据，确定了理想的剪切强度。它已被证明，高角度晶界运动是特别容纳的剪切耦合迁移或晶界滑动。的机械强度被发现强烈的变化与压力，导致在晶界硬化和削弱在一个广泛的压力范围。通过考虑铁的自旋状态对晶界迁移的影响，我们证明了亚铁对晶界临界剪切强度的影响是非唯一的。在超地球系外行星的地幔中，观察到发生了显着的晶界弱化，提供了一种新的机制，即随着深度的增加，韧性增强。

项目成果

Novel configurations of VN4 and VN4H defects in diamond platelets: Structure, Energetics and vibrational properties

金刚石片中 VN4 和 VN4H 缺陷的新颖配置：结构、能量学和振动特性

• DOI: 10.1016/j.diamond.2020.107957
• 发表时间: 2020
• 期刊: Diamond & Related Materials
• 影响因子: 4.1
• 作者: 小山 雪乃丞;ウォリス サイモン;永冶 方敬;T. Gu; S. Ritterbex; T. Tsuchiya; W. Wang
• 通讯作者: T. Gu; S. Ritterbex; T. Tsuchiya; W. Wang

First-principles study of the mechanical behavior of (Mg,Fe)O tilt grain boundaries in planetary mantles

行星地幔(Mg,Fe)O倾斜晶界力学行为的第一性原理研究

• 发表时间: 2021
• 作者: 大村訓史;下條冬樹;土屋卓久;T. Tsuchiya and K. Ito;S. Ritterbex and T. Tsuchiya
• 通讯作者: S. Ritterbex and T. Tsuchiya

Spin transition in (Mg,Fe)O tilt grain boundaries across the Earth's lower mantle

(Mg,Fe)O 中的自旋转变使地球下地幔的晶界倾斜

• 发表时间: 2020
• 作者: 盛合秀;折橋裕二;佐々木実;沼田翔伍;浅沼尚;平田岳史;淺原良浩;S. Ritterbex and T. Tsuchiya
• 通讯作者: S. Ritterbex and T. Tsuchiya

Viscosity of HCP iron and its implications for the dynamics of Earth’s inner core

HCP 铁的粘度及其对地球内核动力学的影响

• 发表时间: 2021
• 作者: Ohmura Satoshi;Shimojo Fuyuki;Tsuchiya Taku;S. Ritterbex and T. Tsuchiya
• 通讯作者: S. Ritterbex and T. Tsuchiya

Ab initio investigation of the intercrystalline mechanical behavior of ferropericlase at extreme pressures of planetary mantles

行星地幔极压下方镁石晶间力学行为的从头算研究

• 发表时间: 2022
• 作者: S. Ritterbex;T. Tsuchiya
• 通讯作者: T. Tsuchiya