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.
