摘要：薄膜材料，特别是纳米尺度上的薄膜材料，在化工、军事、微电子领域得到了广泛的运用。在长期的实验过程中，人们一步一步从认识到发现材料的特性不仅仅会依赖薄膜材料的化学组成成分，同时还会与材料的微观粒子结构密切相关。为了清楚地认知并了解材料的微观结构和宏观性能间的内在关系，科学家们致力于在纳米程度甚至分子原子尺度乃至更为微小的尺度来研究分析物质的组分单元发生的微观过程和运动规律及其特性，本文采用分子动力学方法，以纯铁纳米薄膜为研究对象，研究温度变化所引发的薄膜内部的相变。对采用的Meyer-Entel势进行了测试，在得到该势可以正确定性描述相变的基础上，通过监控温度变化过程中材料内应力的变化确定相变点，并通过观察原子结构示意图研究相变机理。薄膜中所获得的结果与块状材料体系进行了对比。

关键词：分子动力学模拟；薄膜；相变；形核和长大

Molecular Dynamics Simulation of Thin Film Phase Transition

Abstract：Thin film materials, especially those on the nanometer scale, have been widely used in chemical, military, and microelectronics fields. In the course of long-term experiments, people step by step from the recognition that the characteristics of the discovered material not only depend on the chemical composition of the film material, but also closely related to the microstructure of the material. In order to clearly understand and understand the intrinsic relationship between the microstructure and macroscopic properties of materials, scientists have devoted themselves to studying the microscopic processes and movements of the constituent units of the analytical material at the nanoscale or even at the molecular atomic scale or even smaller scale. This thesis used molecular dynamics simulation method with pure-iron thin film as the study object, to study the phase transition in thin film induced by temperature changing. We firstly tested the Meyer-Entel potential to confirm if it can correctly describe the phase transition of iron. By checking the internal stress during the temperature increasing/decreasing cycle, we confirm the phase transition temperature. The transition mechanism was studied by observation the atomic snapshot. Finally,the results from thin film are compared with bulk material.

KeyWords: MD；thin film；phase transition；nucleation and growth 

目录

1  绪论 1

2  相变 1

2.1相变的概念 1

2.2铁元素的相变 2

2.3马氏体的相变 2

2.4薄膜材料的相关研究 3

3  分子动力学 3

3.1分子动力学概述 3

3.2初始条件 3

3.3分子动力学的基本原理 4

3.4 边界条件 4

3.4.1 周期性边界条件 4

3.4.2 自由边界条件 5

3.5系综 6

3.5.1 正则系统 6

3.5.2 微正则系统 6

3.5.3 等温等压系统 6

3.6近邻原子分析法 6

3.7原子间作用势 7

3.7.1原子间嵌入势 7

3.7.2 铁元素在原子间作用势 薄膜相变的分子动力学模拟:http://www.chuibin.com/wuli/lunwen_205859.html