电子和原子层次材料行为的计算机模拟

COMPUTER SIMULATION OF THE MATERIALS BEHAVIOUR AT THE ELECTRONIC AND ATOMIC SCALE

先进的理论和计算技术以及结合计算机的威力，提供了在电子和原子层次上了解材料及其演化过程细节的可能性，具有无先例的准确性、使材料设计和性能预测成为可能本文首先慨括了理论计算方法的发展，扼要地介绍了能带结构计算、分子团簇计算、局域密度泛函理论、键序、原子间作用势、镶嵌原子势、N－体势、MonteCarlo法和分子动力学法、对分析技术、双体分布函数和键取向序等其次介绍了采用离散变分Xα方法和分子动力学计算方法获得的一些具体成果：如研究合金化改善Ni3Al塑性的电子结构机制；材料硬度的新计算方法；Co3Ti的环境脆性；S，P等对Ni／Ni3Al界面结合的影响；H，O，Mn和V对TiAl以及Nb对Ti3Al塑性的影响；合金元素在TiNi，TiAl和Ti3Al中的替代行为；抗热腐蚀镍基单晶合金的成分设计：实验条件很难实现的超高冷却速度和超高压下的相变行为；非晶形成的判据;Gibbs自由能等热力学参数的计算和金属填充碳纳米管的能力等。

Advanced theoretical-computational techniques combined with the power of computers provide an understanding of matter at the electronic and atomic scale with an unprecedented level of detail and accuracy, enabling the materials design and properties prediction to realize. Firstly in this review paper, the progress of the theoretical calculation methods has been summarized, briefly introducing band structure calculation, molecular cluster calculation, local density functional theory, bond order, interatomic potential, embedded atom potential, N-body potential, Monte Carlo method.molecular dynamics method, pair analysis, pair distribution function. bond orientational order etc. The second part of this review paper introduces some ex.mples of application and interesting results. BYusing discrete variational X. method and molecular dynamics calculation, a number of recent new materials have been selected to study typical problems, such as electronic structure mechanism of improving the ductility of Ni3Al by alloying, new calculation method to predict the material hardness, environmental embrittlement of Co3Ti; influence of S, P and other impurities on the interface cohesion of Ni/Ni3Al; influence of H, O, Mn and V on the ductility of TiAl as well as Nb on the ductility of Ti3Al; substitution behavior of alloying elements in TiNi, TiAl and Ti3Al; alloy design of a hotcorrosion-resistant single crystal Ni-base superalloy; phase transformation under extremely rapid cooling rate or super high pressure which are very difficult to be realized by experimental methods, criterion of amorphous formation; calculation of Gibbs free energy and other thermodynamics parameters, and filling ability of metals in carbon nanotubes, etc.