CAREER: Twinning Induced Grain Boundary Engineering In Ultrafine Grain Materials: A Multidisciplinary Approach

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

CAREER: "Twinning Induced Grain Boundary Engineering In Ultrafine Grain Materials: A Multidisciplinary Approach" Ibrahim Karaman Department of Mechanical Engineering, Texas A&M University Abstract The manipulation of the interface content and structure of solids can be considered as one of the most important processes in the evolution of materials. This is particularly important for controlling the physical and mechanical properties of ultrafine grain materials (UFG) (grain size < 1 mm) because of the large volume fraction of interfaces. This CAREER program aims at developing new strategies for twinning induced grain boundary engineering (GBE), furthering the understanding of GBE in UFG materials, and developing predictive and control capabilities for the materials properties that are governed by grain boundaries and their interiors, utilizing an integrated research and education methodology. The RESEARCH PLAN focuses on three thrust areas: 1) processing: fabrication of UFG materials by severe plastic deformation processing followed by thermal treatments starting either from powder precursors or bulk precursors to vary the structure and fraction of the boundaries and the texture, 2) characterization: microstructural characterization of boundary character distribution, texture, and internal stress distribution utilizing unique experimental techniques such as orientation imaging microscopy and in-situ neutron diffraction, 3) modeling: developing a hierarchically structured materials modeling approach across length scales to predict the mechanical properties and microstructural evolution of UFG materials. Specific emphasis will be given to deformation and annealing twinning induced interfaces in low stacking fault energy, high strength steels. The research plan is SIGNIFICANT because, despite the importance of controlling the grain boundary character, there has never been a study combining GBE and bulk UFG materials and investigating the effect of twinning. The EDUCATION PLAN is to strengthen the faculty of materials engineering at Texas A&M University (TAMU) by developing a rigorous curriculum on metallic materials, and by motivating and preparing students who can contribute to UFG materials engineering on a long-term basis both as engineers and researchers. Since the micro materials world is a stranger to public, particularly the younger ones, in spite of all its fascinating developments, a significant effort will be put to bridge this gap. A pilot instructional unit will be developed, in collaboration with an area high school, to offer students a physical feel and hands-on experience with materials.