应变玻璃合金中随机场起源的原子模拟与实验验证

项目名称： 应变玻璃合金中随机场起源的原子模拟与实验验证

项目编号： No.51501141

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 宗洪祥

作者单位： 西安交通大学

项目金额： 21万元

中文摘要： 应变玻璃合金作为一类重要的智能材料具有很好的力学响应特性，其微观形成机制也引起了广泛的关注。文献和前期的理论研究认为，点缺陷诱发的随机场（Random field）是产生应变玻璃化转变的核心原因。但是迄今为止人们对点缺陷导致随机场产生的微观机制仍不清楚。本申请项目拟通过分析广义的玻璃态材料的物理图像的共性特点，从原子尺度提出应变玻璃合金中随机场的物理起源假说：应变玻璃中的随机场来源于以点缺陷为核心的应变网络，而不是单个点缺陷应力场的简单叠加。本项目拟运用基于半经验势函数的原子模拟方法，首先研究材料中应变网络的形成机制和存在的普遍性；进而研究应变网络对应变玻璃态转变行为的影响，并分析应变网络与体系中随机场之间的联系；最后本项目将通过实验手段来进一步验证上述理论假说与模拟结果。本项目将从原子尺度揭示应变玻璃中随机场的微观起源，可以为设计和开发新的应变玻璃合金材料提供理论指导。

中文关键词： 应变玻璃合金；随机场；马氏体相变；玻璃态转变；原子模拟

英文摘要： As a key member of the family of smart materials, strain glass alloys have attracted wide attention. It is found that strain glass alloys exhibit remarkable functional properties, such as shape memory effect and superelasticity. An open question related to this class of alloys is the formation mechanism of strain glassy state. It is theorized that quenched random field can change the stability of martensite, and further lead to the formation of strain glass, i.e., frozen disordered local strain states. However, it is still not clear how this randomness invoked. .. A comparable level of understanding has been studied on other glassy materials. In structural glasses, a mechanically stiff, percolating network of atoms with icosahedral local packing forms when approaching the glass transition. Recent studies on relaxor ferroelectrics also indicate that a hydrogen-bond-like network of dipoles is formed during the relaxor transition. Inspired from the above understanding, we propose that point defects induced strain network plays a dominate role in the generation of random field in strain glass materials... The project is organized as follows. Firstly, with the help of molecular dynamics methods, the applicant intends to investigate the formation mechanism of strain networks, and then to check the generality of strain networks within this class of materials. Secondly, the relationship between random field and strain networks will be clarified by using a combination of molecular dynamics and Monte Carlo simulations. Finally, the hypothesis and simulation results will be verified experimentally... The present project not only try to uncover the microscopic origin of random filed from atomic scale and enrich our understanding of glassy behavior in this class of materials, but also provides theoretic guidance in developing new strain glass alloys.

英文关键词： Strain glass alloys;Random field;Martensitic transformation;glass transition;Atomic simulation