Plastic deformation and twinning mechanisms in magnesian calcites: a non-equilibrium computer simulation study†,Physical Chemistry Chemical Physics

当前位置： X-MOL 学术 › Phys. Chem. Chem. Phys. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Plastic deformation and twinning mechanisms in magnesian calcites: a non-equilibrium computer simulation study†
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2017-12-19 00:00:00 , DOI: 10.1039/c7cp06924c
Sanha Lee _{1,

2,

3} , Gøran Brekke-Svaland _{1,

2,

3} , Fernando Bresme _{1,

2,

3}

Affiliation

Deformation twinning provides a mechanism for energy dissipation in crystalline structures, with important implications on the mechanical response of carbonate biogenic materials. Carbonate crystals can incorporate magnesium, e.g. in the sea, modifying their elastic response significantly. We present a full atom computational investigation of the dependence of the twinning response of calcite with magnesium content, covering compositions compatible with three main structures, calcite, dolomite and magnesite. We find, in agreement with experiments that the incorporation of magnesium disfavors twinning as a dissipation mechanism in ordered structures (dolomite, magnesite), however the response is strongly dependent on the arrangement of the magnesium ions in the crystal structure. We show that structures with a high content of magnesium (>33%) in a disordered arrangement, lead to plastic response before twinning or fracturing. We demonstrate that the position of the magnesium ions plays a key role in the determination of the crystal deformation mode. This observation is correlated with the formation of percolation clusters of magnesium in magnesian calcites.

中文翻译：

镁方解石的塑性变形和孪生机理：非平衡计算机模拟研究†

变形孪晶为晶体结构中的能量耗散提供了一种机制，这对碳酸盐生物成因材料的机械响应具有重要意义。碳酸盐晶体可以掺入镁，例如在海中，极大地改变了它们的弹性反应。我们对方解石与镁含量的孪生反应的依赖性进行了全原子计算研究，涵盖了与方解石，白云石和菱镁矿三个主要结构兼容的成分。我们发现，与实验相一致，镁的引入不利于孪晶作为有序结构（白云石，菱镁矿）中的耗散机制，但是响应强烈依赖于镁离子在晶体结构中的排列。我们显示，镁含量高（> 33％）的结构无序排列，导致孪晶或断裂之前的塑性响应。我们证明镁离子的位置在确定晶体变形模式中起关键作用。

更新日期：2017-12-19

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11