Postdoctoral Research Associateship in CS&E

为了确定临界位错运动参数，对几种不同材料的原子阵列进行了一系列分子动力学模拟。它们是Peierls应力(启动位错运动所需的应力)和温度相关的阻尼系数(由位错速度作为外加应力和温度的函数获得)。这些量很难直接测量，也很难用理论方法估计，但它们对于预测和理解材料的塑性响应和断裂行为具有相当重要的意义。计算机模拟是非常合适的，因为可以通过嵌入原子方法为选定的金属系统构建可靠的原子间相互作用。该计划将是首次认真尝试通过计算机模拟方法确定特定金属的这些数量。//

A series of Molecular Dynamics simulations on atomic arrays of several different materials of up to one million atoms in order to determine critical dislocation mobility parameters is proposed. These are the Peierls stress (the stress required to initiate dislocation motion), and the temperature dependent damping coefficient (obtained from the dislocation velocity as a function of applied stress and temperature). These quantities are extremely difficult to measure directly, or estimate by theoretical means, yet they are of considerable importance in predicting and understanding the plastic response and fracture behavior of materials. Computer simulation are ideally suited, now that reliable interatomic interactions can be constructed for selected metal systems by means of the Embedded Atom Method. This program would be the first serious attempt to determine these quantities for specific metals by computer simulation methods.//