Calculated Elasticity of Al-Bearing Phase D
Calculated Elasticity of Al-Bearing Phase D
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DOI：
10.3390/min12080922
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发表时间：
2022-07
期刊：
影响因子：
2.5
通讯作者：
E. Thompson;A. Campbell;J. Tsuchiya
中科院分区：
文献类型：
--
作者：
E. Thompson;A. Campbell;J. Tsuchiya
使用第一性原理计算，本研究评估的结构，状态方程，和弹性的三个组成的D相高达75 GPa：（1）镁端元[MgSi 2 O 4（OH）2]，（2）铝端元[Al 2SiO 4（OH）2]，和（3）相D与50%的Al取代[AlMg0.5Si1.5O4（OH）2]。我们发现，Mg-端元经历氢键对称化，这种对称化与相D的体积模量增加22%有关，与以前的研究一致。Al 2SiO 4（OH）2也经历氢键对称化，但随之而来的体积模量的增加只有13%-一个显着偏离的Mg端成员的22%的增加。此外，Al-端元相D相对于其Mg-端元对应物更致密（2%-6%）、更不易压缩（6%-25%），并且具有更快的压缩速度（6%-12%）和剪切速度（12%-15%）。最后，我们研究了50%Al取代的D相[AlMg0.5Si1.5O4（OH）2]的性质，发现氢键对称性，状态方程参数和弹性常数的这种联络线组合物不能准确地建模通过插值的Mg和Al端元的属性。
Using first-principles calculations, this study evaluates the structure, equation of state, and elasticity of three compositions of phase D up to 75 GPa: (1) the magnesium endmember [MgSi2O4(OH)2], (2) the aluminum endmember [Al2SiO4(OH)2], and (3) phase D with 50% Al-substitution [AlMg0.5Si1.5O4(OH)2]. We find that the Mg-endmember undergoes hydrogen-bond symmetrization and that this symmetrization is linked to a 22% increase in the bulk modulus of phase D, in agreement with previous studies. Al2SiO4(OH)2 also undergoes hydrogen-bond symmetrization, but the concomitant increase in bulk modulus is only 13%—a a significant departure from the 22% increase of the Mg-end member. Additionally, Al-endmember phase D is denser (2%–6%), less compressible (6%–25%), and has faster compressional (6%–12%) and shear velocities (12%–15%) relative to its Mg-endmember counterpart. Finally, we investigated the properties of phase D with 50% Al-substitution [AlMg0.5Si1.5O4(OH)2], and found that the hydrogen-bond symmetrization, equation of state parameters, and elastic constants of this tie-line composition cannot be accurately modeled by interpolating the properties of the Mg- and Al-endmembers.