基于特殊准随机结构模型的顺磁性奥氏体相的第一性原理研究

First-principles study of paramagnetic austenite phase based on SQS model

利用特殊准随机结构(special quasi-random structure,SQS)模拟顺磁性奥氏体相,基于密度泛函理论的第一性原理,使用VASP软件计算了无磁性和顺磁性fcc Fe结构的磁矩、平衡晶格常数及空位形成能,并与前人的实验值和模拟计算值进行对比。结果显示,相较于传统的无磁性模拟方法而言,利用SQS模型模拟顺磁性奥氏体相不仅能体现出单个铁原子的磁性特点,并且计算得到的空位形成能和晶格常数与实验值有着更好的一致性,由此可见,利用SQS模型构建顺磁性奥氏体相是可行的。

In the paper,the special quasi-random structure(SQS)was applied to simulate the paramagnetic state of austenite phase.Aided by the density functional theory based on first-principles,the magnetic moment,equilibrium lattice constant and vacancy formation energy of non-magnetic and paramagnetic fcc Fe structures were calculated by using VASP software,and the results were compared with the previous experimental values and the calculated values by simulation.The results show that compared with the traditional non-magnetic simulation method,the use of the SQS model to simulate the paramagnetic austenite phase can not only reflect the magnetic characteristics of a single iron atom but also promise better consistency of the calculated vacancy formation energy and lattice constant with the previous experimental values.It is feasible to use the SQS model to construct the paramagnetic austenite phase.