形状记忆合金时效效应的微观机理及调控方法

项目名称： 形状记忆合金时效效应的微观机理及调控方法

项目编号： No.51471126

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 邓俊楷

作者单位： 西安交通大学

项目金额： 80万元

中文摘要： 形状记忆合金（SMAs）作为一种新型功能材料受到人们广泛关注，但是其普遍存在的时效效应严重限制了基于SMAs的物理器件的实际应用。SMAs时效效应的物理起源长期以来存在争议，直到点缺陷短程对称一致性（SC-SRO）模型的提出（Nature，1997），才为时效效应提供了统一的微观解释。申请人前期工作也从原子尺度验证了SC-SRO模型的合理性及其对时效效应的影响（PRB 2010a，b；APL，2010）。然而，SC-SRO模型本身的物理起源，即点缺陷为何遵循SC-SRO模型，尚存疑未解。本项目拟利用原子模拟方法对该模型的物理起源进行研究，揭示SMAs时效效应的微观机理，并提出调控时效效应的理论方法；进而利用第一性原理计算，通过调制成分或缺陷掺杂对SMAs时效效应进行调控；最后进行实验验证。本项目不仅对理解SMAs时效现象的物理起源具有重要理论意义，也可以为开发高可靠性SMAs提供理论指导。

中文关键词： 形状记忆合金；马氏体相变；时效效应；点缺陷；原子模拟

英文摘要： As new functional materials, shape memory alloys (SMAs) have received considerable attention so far. However, only a few of SMAs can be used in commercial applications. This is because the majority of SMAs suffer from the aging effects which can cause the instability of physical properties of SMAs devices. As common physical behaviors in SMAs, the aging effects have puzzled materials scientists and their origin has remained controversial during the past decades. In 1997, a postulation named symmetry-conforming short-range order (SC-SRO) model was proposed to provide a unified microscopic explanation for aging effects in SMAs (Nature,1997). Using atomistic simulations, our previous works have demonstrated the validity of SC-SRO model (PRB, 2010a, b; APL,2010). However, the origin of SC-SRO, i.e., the underlying reason why point defects follow the SC-SRO model is still unclear. In the present project, the origin of SC-SRO model and the microscopic mechanism of aging effects in SMAs will be systematically investigated using atomistic simulations. Given the fundamental understanding of microscopic mechanism, the approaches to controlling (even avoiding) aging effects will be proposed. Employing frist-principles calculations, the SMAs with tunable aging effects will be designed through composition variation or point defect engineering. Such promising SMAs are expected to be examined by experiments. We believe our project will not only offer the deep understanding of aging effects in SMAs but also enable the development of new highly reliable shape memory alloys.

英文关键词： shape memory alloys;martensite phase transfromation;aging effects;point defects;atomistic simulations