Development of an interatomic potential for the simulation of defects, plasticity, and phase transformations in titanium.
Development of an interatomic potential for the simulation of defects, plasticity, and phase transformations in titanium.
复制标题
DOI：
10.1063/1.4964654
复制
发表时间：
2016-10
期刊：
影响因子：
--
通讯作者：
Mikhail I Mendelev;Tom L. Underwood;Graeme Ackland
中科院分区：
文献类型：
--
作者：
Mikhail I Mendelev;Tom L. Underwood;Graeme Ackland
提出了描述钛的缺陷、塑性和高温相变的新的原子间势。拟合马氏体相变温度需要一种高效、准确的方法来确定。我们应用了基于竞争固相熔化温度的分子动力学方法、Gibbs-Helmholtz积分和晶格开关蒙特卡罗方法：这些方法都将hcp-bcc的转变温度控制在2K以内。我们能够开发出嵌入原子势，它对低或高温数据都有很好的拟合，但不是两者都能。第一个发展势(Ti1)再现了hcp-bcc转变和熔化温度，适用于相变和体心立方钛的模拟。另外两个势(Ti2和Ti3)正确地描述了缺陷的性质，可以用来模拟hcp钛的塑性或辐射损伤。单个嵌入原子方法势不能同时描述低温和高温相，这可能归因于忽略了电子自由度，特别是bcc具有更高的电子熵。从电势Ti1和Ti2的组合获得的温变电势可以用来模拟在任何温度下的钛特性。
New interatomic potentials describing defects, plasticity, and high temperature phase transitions for Ti are presented. Fitting the martensitic hcp-bcc phase transformation temperature requires an efficient and accurate method to determine it. We apply a molecular dynamics method based on determination of the melting temperature of competing solid phases, and Gibbs-Helmholtz integration, and a lattice-switch Monte Carlo method: these agree on the hcp-bcc transformation temperatures to within 2 K. We were able to develop embedded atom potentials which give a good fit to either low or high temperature data, but not both. The first developed potential (Ti1) reproduces the hcp-bcc transformation and melting temperatures and is suitable for the simulation of phase transitions and bcc Ti. Two other potentials (Ti2 and Ti3) correctly describe defect properties and can be used to simulate plasticity or radiation damage in hcp Ti. The fact that a single embedded atom method potential cannot describe both low and high temperature phases may be attributed to neglect of electronic degrees of freedom, notably bcc has a much higher electronic entropy. A temperature-dependent potential obtained from the combination of potentials Ti1 and Ti2 may be used to simulate Ti properties at any temperature.