GOALI: Fundamentals of High Temperature Deformation in Polycrystalline Ni-Al-Nb Eutectic Alloys

Illinois Institute Of Technology, Chicago IL

Investigators

Abstract

TECHNICAL SUMMARY: Novel polycrystalline pseudo-ternary eutectic gamma-gamma'-delta alloys, based on the Ni-Al-Nb system, have been recently demonstrated to possess a promising set of high temperature properties that may permit radical changes in the design of modern gas turbine engines and lead to revolutionary improvements in performance and efficiency. This aim of this research program will be to establish a fundamental understanding of the mechanisms governing the high temperature strength of these alloys. This will be accomplished by selecting a series of near eutectic Ni-Al-Nb based alloys with the objectives of quantifying how alloying additions and the equilibrium volume fraction of delta phase affect the strength and creep resistance. Both bulk and novel small-scale mechanical testing methods will be used to systematically isolate contributions from chemical and microstructural strengthening at elevated temperatures. Detailed transmission electron microscopy studies will be used to elucidate the underlying deformation mechanisms governing the mechanical properties of the alloy system. Computational modeling of the deformation mechanics will be used to complement the experimental measurements and assist in the formulation of a physics-based constitutive model capable of accurately predicting the deformation characteristics of this novel alloy system at elevated temperatures. Results from the proposed program are expected to suggest new directions for the development of revolutionary new materials that have the potential to replace conventional Ni-base superalloys in high temperature structural applications. NON-TECHNICAL SUMMARY: Advances in high temperature structural materials have served as key enabling technologies that have been critical to the development of ultra-efficient gas turbines with reduced fuel consumption, and minimization of CO2 and NOX emissions. In addition to the economic and environmental benefits, there exists a strategic need for the U.S. to maintain technological leadership in this field due to the importance of advanced gas turbine technologies for power generation, space exploration, aerospace/marine propulsion and various other defense related applications. The aim of the proposal is to investigate the fundamental deformation behavior of a novel new class of high temperature structural materials by combining experimental measurements with physics-based constitutive models. With direct involvement of the Co-PI from Rolls-Royce North American Technologies, graduate and undergraduate students will have the opportunity to contribute significantly to technological advancements within a fast-paced industrial research setting and develop innovative solutions for industrially relevant problems. In conjunction with the proposed research, both the PI and the graduate students will be actively involved with promoting educational outreach activities aimed at local Chicago-area secondary school science teachers to enhance the middle/high school curricula and raise the students? awareness of materials science and engineering. This will include the provision of resources and support for both the ASM Materials Camp for high school students and the ASM Teacher's Camp for high school science teachers.