Phase-Transition Dynamics of Forsterite from Glass to Liquid States
Phase-Transition Dynamics of Forsterite from Glass to Liquid States
复制标题
镁橄榄石从玻璃态到液态的相变动力学
DOI：
10.1021/acsearthspacechem.9b00238
复制
发表时间：
2020
影响因子：
2.8
通讯作者：
T. Ikeda
中科院分区：
文献类型：
--
作者：
J. Nishizawa;T. Ikeda
为了研究橄榄石从玻璃态到熔融态的转变机制，我们在10-3000 K的温度范围内进行了分子动力学计算。结果表明，从10k开始加热，在1567k附近的热膨胀系数发生了显著变化。这个温度是从玻璃态到液态的转变点。为了研究相变的机理，分析了原子的剪切黏度和自扩散过程。结果表明，在1300和1800 K左右，扩散系数随加热的增加速率发生了变化。这表明在过冷的液体状态下，扩散机制发生了变化。通过对原子运动轨迹的观察，发现原子在过冷液体基体中以不连续跳变的方式迁移。在低温条件下，Si密度高、Mg密度低的原子的跳变概率高于平均跳变概率。结果表明一个动态的…
To investigate the transition mechanisms of forsterite from a glassy to molten state, we performed molecular dynamics calculations in a temperature range of 10–3000 K. The results show that the thermal expansion coefficient changes remarkably at around 1567 K during heating from 10 K. This temperature is the transition point from glassy to liquid states. To investigate the mechanisms of the phase transition, shear viscosity and self-diffusion processes of atoms were analyzed. The result shows that the increasing rates of diffusion coefficients with heating change at around 1300 and 1800 K. This suggests that a diffusion mechanism changes in the supercooled liquid state. From the observation of the trajectories of atoms, it was found that atoms migrate through discontinuous hopping in the supercooled liquid matrices. The hopping probability of atoms, which is located in positions with higher Si and lower Mg densities, is higher than the average probability at low temperatures. The result indicates a dynami...