X2MnZ基Heusler合金磁和相稳定性及力学性能的理论研究

项目名称： X2MnZ基Heusler合金磁和相稳定性及力学性能的理论研究

项目编号： No.51301176

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 李春梅

作者单位： 中国科学院金属研究所

项目金额： 25万元

中文摘要： 合理设计的L21相X2MnZ基合金具有良好的磁形状记忆性能，是目前材料领域研究热点之一。随成分和制备工艺不同，合金磁有序方式可能发生改变，马氏体相变可能彻底消失，或同时伴随磁相变发生。了解合金化影响磁和相稳定性及力学性能的规律性并对其进行恰当控制，是实现X2MnZ基合金磁形状记忆性能优化的关键。众多X和Z合金原子及其组分很难用实验一一测量，且原子及其磁无序问题为第一原理计算造成极大困难。目前对合金化影响磁有序和马氏体相变及力学性能缺乏本质认识。本项目拟采用第一原理EMTO-CPA结合UppASD磁计算方法，系统研究X2MnZ基各合金奥氏体和马氏体相磁有序及转变温度、相稳定性、以及弹性力学性质；确定各组合金成分温度相图；探索合金化对磁和相稳定性及力学性能的影响规律及其物理机理；为解释L21相优异性能，并进一步合理控制合金化及组分，实现X2MnZ基合金磁和形状记忆性能的优化提供理论基础。

中文关键词： 第一性原理计算；马氏体相变；弹性模量；磁性质；形状记忆合金

英文摘要： L21-X2MnZ based alloys, under reasonable design, can possess good magnetic shape memory effect, which has become one of the hot fields of materials science research. Due to the different composition or preparation process, these alloys show different magnetic ordering, different phase stability, and they even occur the magnetic and structural phase transition at the same time. If we could have a good understanding and then reasonable control of the alloying effect on the magnetic and physical properties, as well as phase stability of X2MnZ based alloys, then we can realize the optimization of their magnetic shape memory performance. Since there are multitude choice of X and Z atoms and corresponding components, the experimental study of X2MnZ based alloys is very difficult. Moreover, both atomic and magnetic disordering situations make the first-principles calculation of these alloys to be impossible. Therefore, until now the true story of the alloying effect on the magnetic and physical properties and phase stability of X2MnZ based alloys still needs to be ascertained. In the present project, using the first-principles EMTO-CPA in combination with UppASD magnetic calculations, we will study systematically the magnetic ordering, crystal structure, elastic constants, and free energy including the vibrational and

英文关键词： First-principles calculation；Martensitic phase transformation；Elastic modulus；Magnetism；Shape memory alloys