POWRE: Hysteresis, Domain Switching and Phase Transformations in Ferroelastic Perovskite Ceramics

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This project addresses mechanical performance of perovskite ceramics using a combination of methods such as bending techniques, micro- and nano-indentation tests coupled with X-ray phase analysis, Raman spectroscopy and electrical conductivity measurements. The project seeks fun-damental knowledge about relationships between hysteresis effects (domain reorientation, phase transformations, etc.) and mechanical behavior of perovskite ceramics, improved understanding of perovskite strength, hardness and fracture toughness and discovery of new toughening mecha-nisms. The approach involves the study of different first or second order phase transitions, such as nonmetal-metal transitions, martensitic transitions, order-disorder transitions, accompanied by volume changes, leading to toughening of perovskites during loading. A paramount goal is to determine the presence of domain reorientation or phase transformation during indentation and bending tests. Studies of reversible transitions that occur upon unloading of samples are also ex-pected to be feasible. New knowledge about domain reorientation, phase transformation, metalli-zation in perovskites will be gained. Key properties relevant to structural performance will be measured within a feedback loop to microstructural and phase composition optimization.%%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The project provides support at a critical time, helping the PI to re-establish her career after a brief interruption as she moved from Europe to the US, and will enhance the PI's ability to succeed in an area where women are underrepresented, allowing her to serve as a role model for other women in mechanical engineering. The proposed research will also have an educational impact, training students with a breadth of experience. The research is expected to contribute basic materials science knowledge at a fundamental level of special relevance to the behavior of ceramic materials, and to assist with the integration of re-search and education. The project is co-supported by the Division of Materials Research, and the MPS OMA(Office of Multidisciplinary Activities). ***