马氏体-奥氏体界面电子态以及它们在马氏体相变过程中的作用

作者的“Laser模型”基于如下假设:马氏体相变可看作一种以电子气为工质的量子热机。本文研究界面电子态在此过程中的作用。本文考虑的模型由简单六方晶体结构(马氏体)和简单立方晶体结构(奥氏体)组成。界面两边都是s电子,以紧束缚Hamitonian算符近似描绘。由解Dyson方程可从解析的半无限介质的Green函数导得界面Green函数,从而解得各层电子态密度。本研究结果显示出相变过程中电子跃迁特征:电子自三维的母相带态进入二维(界面)的反键轨道,再进入三维的马氏体相的带态,以驱动相变。

THE EIECTRONIC STATES AT PARENT-MARTENSITE INTERFACE AND THEIR ROLE IN MARTENSITIC TRANSFORMATIONS

The author's "Laser model" for martensitic transformations (MATs) is based on the assumption that MATs can be taken as a kind of quantum heat engine using electrons as working substance. The prensent paper is a study of the role of interface electronic states in the electronic cycle in MATs. A model austenite-martensite interface with austenite having a simple cubic structure and martensite a simple hexagonal structure is presented. The method used to investigate the interface is the Green's function technique. Both sides are described by s-type tight-binding Hamiltonians which allow us to use the analytical results for the Green's functions for a bulk material to derive the interface Green's functions by solving the appropriate Dyson's equations. The densities of states (DOS) on the various atomic planes of the model interface have been numerically calculated. These results have clearly shown how the electronic transition actually occurs through the processes: from the three dimensional band states of parent phase, to the two dimensional antibonding band states (interface states), and then to the three dimensional band states of martensitic phase, to bring about the crystal transformation.