Diffusion of hydrogen in bcc tungsten studied with first principle calculations
Diffusion of hydrogen in bcc tungsten studied with first principle calculations
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DOI：
10.1063/1.3386515
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发表时间：
2010-06
影响因子：
3.2
通讯作者：
K. Heinola;T. Ahlgren
中科院分区：
文献类型：
--
作者：
K. Heinola;T. Ahlgren
采用第一性原理计算方法研究了体心立方钨中氢的迁移特性。氢在钨中具有低溶解度，并且占据四面体间隙位点，与八面体间隙位点相比具有0.38 eV的能量差。用调和过渡态理论计算了氢在铝合金中的扩散系数，在1500 K以上的温度下与实验结果符合较好。发现两个相邻四面体位置之间的迁移势垒的高度为0.21 eV，这低于在1100和2400 K之间的温度范围内从脱气测量获得的迁移势垒的值0.39 eV。在29 K时，对扩散速率的隧穿修正比从高温测量外推的实验D与实验结果更吻合。
First principle calculations were used to study the hydrogen migration properties in bulk bcc tungsten. Hydrogen has low solubility in tungsten and occupies the tetrahedral interstitial site with an energy difference of 0.38 eV compared to the octahedral interstitial site. The hydrogen diffusion coefficient was evaluated using the harmonic transition state theory and was found to agree with the experimental results at temperatures above 1500 K. The height of the migration barrier between two adjacent tetrahedral sites was found to be 0.21 eV, which is lower than the value 0.39 eV obtained for the migration barrier from degassing measurements in the temperature range between 1100 and 2400 K. The tunneling correction to the diffusion rate provides much better agreement with the experimental result at 29 K than the extrapolated experimental D from high temperature measurements.