激光诱导信息材料超快相变的热力效应及其作用机理研究

项目名称： 激光诱导信息材料超快相变的热力效应及其作用机理研究

项目编号： No.51271006

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 刘富荣

作者单位： 北京工业大学

项目金额： 80万元

中文摘要： 光致相变技术是利用激光作用下物质相在晶态/非晶态之间的转变来实现信息快速存储的一种技术，如何阐明激光诱导信息材料超快相变的机理是当前本领域尚未解决而又亟待解决的根本问题。不同于热致相变过程，光致相变的突出特点是超快的加热和冷却速度使得相变过程同时受温度和应力的驱动。本项目首先在理论上发展激光诱导非平衡相变的动力学理论并建立光致相变材料的本构关系，在此基础上，建立温度场/应力场耦合的数值模型（FEM），阐明激光诱导相变过程中温度场、应力场的变化规律。根据设计的实验方案，研究激光诱导相变区组织和性能的分布特征，建立温度-应力-显微组织的关系。最后，构建有限元与第一原理分子动力学耦合模型（FEM/MD(AIMD)），研究温度、应力作用下微结构和性能的起源及变化规律，解释激光诱导相变的超快性和可循环性,揭示激光诱导相变机理。项目的开展，不仅具有重要的理论意义，也具有深远的工程应用背景。

中文关键词： 相变材料；激光辐照；晶化行为；第一性原理分析；三维有限元模拟

英文摘要： Laser induced phase transition is a technology to achieve the information storing by the ultrafast transition between the crystalline and amorphous states of the phase change materials (PCMs). How to explain the mechanism of the ultrafast transformation has become one of the key problems to be settled in this field. Different from the thermal equilibrium phase transition, the characteristics of laser induced transformation are regarded as the ultrafast heating and cooling by laser irradiations, therefore, the transition between the crystalline and amorphous states is affected by both the temperature and stress.Firstly, the theory of nonequilibrium phase transition for laser processing and the thermo-elastic-plastic constitutive relation for the PCMs are built up respectively. Based on the theoretical model, a temperature/stress coupled numerical model (FEM) is then built up to simulate the variation of the temperature and stress fields during the process of laser induced transformation. Then the microstrcuture and properties of the laser irradiation zone are studied following the new scheme of the experiment. The relation among the temperature, stress and microstructure is further elucidated based on the experimental and simulated results.Finally,a finite element and ab initio molecular dynamics coupled model (

英文关键词： Phase change material；laser irradiation；crystallization behavior；first-principles analysis；three - dimensional finite element simulation