EAGER: Building Strong and Tough Multiphase Ceramics via Interface Tailoring

University Of Texas At Arlington, Arlington TX

Investigators

Abstract

Strength and toughness are two important properties of structural materials, but they are often times mutually exclusive, especially in ceramic materials. Materials with high strength can carry higher loads before they fail, and materials with high toughness can deform to a greater extent without breaking. This EArly-concept Grants for Exploratory Research (EAGER) award supports research focused on the formation of new types of ceramic materials by blending two different phases to simultaneously achieve high strength and high toughness. It is hypothesized that structural changes at the microscopic scale will occur across the interfaces of these phases when the materials deform, which will result in increased overall toughness in an already high strength material system. Ceramic materials with high toughness have potential use for the development of super-efficient power plants, high temperature gas sensors, thermal protection systems for space vehicles and many other engineering applications. As such, results from this will benefit the U.S. economy and society. In addition, this award will support enhancement of teaching, training and learning through mentoring of graduate and undergraduate students. The objective of this research is to explore the formation of new types of Zirconium (Zr) based multiphase ceramic materials by selectively choosing phases with thermodynamically compatible crystal structures but different lattice constants to form energy dissipating microstructures. Three types of multiphase ceramics will be manufactured, namely ZrC-ZrB2 nanocomposites, ZrC-ZrB2 multilayer laminates and ZrB2-HfB2 solid solutions. Both experimental characterization and atomistic computations will be conducted to determine relative densities, grain sizes, and phases present in the fabricated solid solutions, nanocomposites, and laminates. The strength, fracture toughness, microhardness, and elastic properties of ceramics, nanocomposites, and laminates will be measured experimentally and calculated computationally. Following mechanical testing, fracture surfaces of the specimens will be examined to identify the failure origins. Atomistic computations will be performed to reveal atomic scale toughening mechanisms.