Principle of Engineering Graded Materials with Self-Assembling Microstructures

这项由材料研究部门颁发的奖项是为了开发理论原理和计算工具，以设计通过制造梯度介观结构来控制自组装微结构的材料。Roytburd和Bruck教授将应用这些原理来制造具有更强的变形响应、更高的频率响应和更高的可靠性的形状记忆薄膜材料。使用分级结构，可以通过成分、颗粒大小、织构和/或温度中的梯度施加的约束来控制自组装多域结构。工程化梯度介观结构和自组织微纳多域结构的结合为设计具有多种长度尺度的可控结构的新材料提供了广阔的机会。为了实现这些研究目标，将完成以下工作：(1)梯度自组装材料中非等温马氏体相变的理论和模型；(2)梯度自组装微结构的加工和表征；(3)梯度自组装膜中内应力分布的表征；(4)梯度自组装膜驱动特性的表征。要实现该项目的目标，需要结合三个科学研究领域：功能梯度材料、马氏体相变和热传递。该研究计划结合了A·罗伊特伯德博士和H·A·布鲁克博士的专业知识和能力。罗伊特伯德博士是一位专门研究马氏体相变的理论家，而布鲁克博士则是一位专门研究分级材料制造和表征的实验者。这项研究在两个方面做出了贡献：(1)发展了一种新的自洽的、经实验验证的梯度自组装膜中非等温马氏体相变模型；(2)表征了梯度自组装膜中的结构梯度和内应力分布。预计将在以下领域产生更广泛的影响：(1)开发具有优化驱动性能的微器件；(2)发展梯度自组装材料中的相变理论；(3)利用自洽的数学公式来描述涉及复杂热机械行为的问题的基础；(4)利用梯度自组装膜模拟生物材料的驱动行为；(5)通过使用最先进的研究和教育工具，加强学生的实践知识和经验，这些学生将成为未来功能材料和MEMS领域的研究人员；以及(6)通过代表人数不足的少数群体参与拟议的研究工作，加强机械和材料界的多样性。

This award by the Division of Materials Research is to develop theoretical principles and computational tools to design materials with self-assembled microstructures controlled through fabricating graded mesoscopic architectures. Professors Roytburd and Bruck will apply these principles to fabricate shape-memory film materials with enhanced deformation response, increased frequency response, and improved reliability. Using a graded architecture, the self-assembling polydomain structure can be controlled through the constraint imposed by a gradient in composition, grain size, texture, and/or temperature. The combination of engineered graded mesostructures and self-organized micro- and nano-polydomain structures presents broad opportunities to design new materials with well-controlled structures at multiple length scales. To achieve these research goals the following tasks will be accomplished: (1) Theory and modeling of non-isothermal martensitic transformations in graded self-assembled materials; (2) Processing and characterization of graded self-assembled microstructures; (3) Characterization of internal stress distributions in graded self-assembled films; and (4) Characterization of actuation properties of graded self-assembled films. Accomplishing the goals of the project requires a combination of three scientific research areas: Functionally Graded Materials, Martensitic Phase Transformations, and Heat Transfer. The research plan unites the expertise and capabilities of Dr. A. Roytburd, a theorist specializing in martensitic phase transformations, and Dr. H.A. Bruck, an experimentalist specializing in graded material fabrication and characterization. Intellectual contributions from this research are in two areas: (1) Development of a new self-consistent, experimentally verified model for nonisothermic martensite transformation in graded self-assembled films, and (2) Characterization of structural gradients and internal stress distributions within graded self-assembled films. Broader impacts are expected in the following areas: (1) development of microdevices with optimized actuation properties; (2) development of a theory for phase transformations in graded self-assembled materials; (3) a basis for formulating problems involving complex thermomechanical behavior using self-consistent mathematical formulations; (4) mimicry of the actuation behavior of biological materials using graded self-assembled films; (5) strengthening the practical knowledge and experience of students who will serve as future researchers in the functional materials and MEMS communities by using state-of-the-art research and education tools; and (6) enhanced diversity within the mechanics and materials community through the participation of underrepresented minorities in the proposed research efforts.