Super Responses of Decomposed Two-Phase Nanodispersions to External Stimuli: Theory and Modeling

分解的两相纳米分散体对外部刺激的超响应：理论与建模

• 批准号: 1207122
• 负责人: Armen Khachaturyan
• 金额: $ 38.99万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207122&HistoricalAwards=false
• 关键词: Super; Responses; Decomposed; Two; Phase

TECHNICAL SUMMARYThis award supports theoretical and computational investigations of new functionalities in materials with a focus on giant low hysteretic recoverable strain response to applied stress, magnetic and electric fields. This effect is expected in traditional precipitation hardened alloys when they are two-phase nanodispersions consisting of precipitates of a low-symmetry phase embedded in a cubic matrix. The precipitates of a low-symmetry phase formed at the early stages of decomposition are single domain particles that have one of several symmetry-related orientation variants. The strain response is caused by coherent switching between different orientation variants of the precipitates. This is a new effect. The switching- generated macroscopic strain is giant in comparison with the intrinsic responses to the applied fields. If the applied field is stress, the material becomes superelastic; if it is a magnetic field, the material becomes an extrinsic super-magnetostrictor. This project will investigate conditions that could lead to a giant low hysteretic strain response of precipitation hardened alloys to the applied fields. The scientific goal of the project is to develop a blueprint for the search of alloy systems and the processing conditions that would provide exceptional functional properties of these systems. The goal of this project is to provide access to a new class of functional materials with unique combinations of mechanical and functional properties. Specific goals of this project include: 1. Developing theories and computer models that can explicitly take into considerations all physically significant energy contributions affecting the recoverable stress and/or magnetic field-induced switching of single-domain orientation variants and thus macroscopic strain response. 2. Clarifying mechanisms that control the formation of coherent two-phase material systems with flexible orientation variants of nanoprecipitates. In particular, the development of the understanding of the effects of elastic moduli, lattice mismatch, and magneto-structural coupling of the constituent phases, as well as the optimization of the effects of thermo-mechanical/ thermo-magnetic treatments. 3. Establishing correlations between the microstructure and dynamic strain responses to differently directed applied stress and/or magnetic fields. This award also provides support that will enable: (1) further collaboration with experimentalists in order to validate our findings and search for advanced functional materials of this kind, (ii) the education and training of the next generation of materials researchers.NON- TECHNICAL SUMMARYThis award supports an exploration of the practically uncharted territory of the functional behavior of decomposed nanostructured materials. Nanodispersive decomposed systems are technologically important structural materials that have been a subject of intensive research for decades. However, there are very important aspects of these materials that have been previously overlooked: under certain conditions, the precipitation hardened nanodispersions can acquire unique functional properties. The materials can have giant recoverable strain responses to the external stimuli, which can be interpreted as superelasticity, super magnetostriction, shape memory and ferromagnetic memory effects. The goal of this theoretical and computational research is to: (i) investigate the formation of these kinds of materials during decomposition and ways to optimize their properties, (ii) study the mechanisms and dynamics of their switching-induced strain responses, and (iii) develop a blueprint for engineering a new class of spontaneously formed inexpensive functional materials with desired super responses to applied stress, electric, and magnetic fields. The project has the potential to open a practically untapped source of super-responsive functional materials. In particular, its success would open a way to develop materials with dramatically enhanced magneto-mechanical properties, and to engineer inexpensive magnetostrictive alloys that are free from critical rare-earth elements that are difficult to obtain, but still have desired properties comparable or even exceeding those of rare-earth based compounds.This award also supports educational activities to educate and train a postdoctoral research associate and graduate students, preparing them for the challenges of materials research in the 21st century which will require an interdisciplinary approach and synergy between different branches of physics and engineering.

技术摘要这一奖项支持对材料中新功能的理论和计算调查，重点是巨大的低滞后可回收应变响应对施加的应力，磁场和电场。当传统的沉淀硬合金是两相纳米分散物中，这些效果是在它们由嵌入立方基质中的低对称相的沉淀物组成的。在分解早期阶段形成的低对称相的沉淀物是具有几种与对称相关方向变体之一的单个域颗粒。应变响应是由于沉淀物的不同方向变体之间的相干切换引起的。这是一个新效果。与对应用场的内在响应相比，开关生成的宏观应变是巨大的。如果施加的场是应力，则材料将变得超弹性。如果是磁场，则材料将变成外在的超级磁通剂。该项目将调查可能导致降水对应用领域的巨大的低滞后应力反应。该项目的科学目标是为搜索合金系统以及将为这些系统提供出色功能特性的处理条件开发蓝图。该项目的目的是提供具有机械和功能特性独特组合的新型功能材料。该项目的具体目标包括：1。开发理论和计算机模型，这些理论和计算机模型可以明确考虑所有具有物理上重要的能量贡献，这些能量贡献影响了可回收的应力和/或磁场诱导的单位方向变体的切换，从而宏观菌株响应。 2。澄清机制，以控制具有柔性方向变体的相干两相材料系统的形成。特别是，对组成阶段的弹性模量，格子不匹配和磁结构耦合的影响的理解以及对热机械/热磁性处理的影响的优化。 3。建立与不同定向的应力和/或磁场之间的微观结构与动态应变响应之间的相关性。该奖项还提供了支持：（1）与实验者进一步合作，以验证我们的发现并寻找此类高级功能材料，（ii）对下一代材料研究人员进行的教育和培训。《技术摘要》颁发了探索，这支持了探索实际不理领域的实用领域，该领域是分辨出了NAN构造材料的功能行为。 纳米分散性分解系统是技术上重要的结构材料，几十年来一直是一项密集研究的主题。但是，这些材料以前已经忽略了这些材料非常重要的方面：在某些条件下，降水硬化的纳米分散可以获得独特的功能特性。这些材料可以对外部刺激具有巨大的可回收应变反应，可以将其解释为超弹性，超磁结，形状记忆和铁磁记忆效应。 The goal of this theoretical and computational research is to: (i) investigate the formation of these kinds of materials during decomposition and ways to optimize their properties, (ii) study the mechanisms and dynamics of their switching-induced strain responses, and (iii) develop a blueprint for engineering a new class of spontaneously formed inexpensive functional materials with desired super responses to applied stress, electric, and magnetic fields. 该项目有可能打开实际上未开发的超响应功能材料的来源。特别是，它的成功将打开一种开发具有显着增强磁力机械特性的材料的方法，并向工程师廉价的磁性合金不含关键的稀有元素，这些元素无法获得，但仍难以获得所需的属性，但仍具有可比甚至超过稀有奖学的奖项，以支持稀有奖的学生，以教育和培训培训的教育和培训，并培训了培训的培训，并培训了培训的培训。 21世纪材料研究的挑战将需要跨学科的方法和物理和工程分支之间的协同作用。