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

技术概要：基于Ni-Al-Nb系统的新型多晶伪三元共晶γ-γ '-δ合金最近已被证明具有一组有希望的高温性能，这可能允许现代燃气涡轮机发动机的设计发生根本性变化，并导致性能和效率的革命性改进。本研究计划的目的是建立对这些合金高温强度机制的基本理解。这将通过选择一系列近共晶Ni-Al-Nb基合金来实现，其目的是量化合金添加剂和δ相的平衡体积分数如何影响强度和抗蠕变性。散装和新的小规模的机械测试方法将被用来系统地隔离在高温下的化学和微观结构强化的贡献。详细的透射电子显微镜研究将被用来阐明基本的变形机制的合金系统的机械性能。变形力学的计算建模将被用来补充实验测量，并协助制定一个基于物理的本构模型，能够准确地预测这种新型合金系统在高温下的变形特性。预计该计划的结果将为革命性新材料的开发提供新的方向，这些新材料有可能在高温结构应用中取代传统的镍基高温合金。高温结构材料的进步已经成为关键的使能技术，这些技术对于开发具有降低的燃料消耗的超高效燃气轮机至关重要，以及最小化CO2和NOX排放。除了经济和环境效益之外，由于先进的燃气涡轮机技术对于发电、空间探索、航空航天/船舶推进和各种其他国防相关应用的重要性，美国还存在保持该领域技术领先地位的战略需求。该提案的目的是通过将实验测量与基于物理的本构模型相结合，研究新型高温结构材料的基本变形行为。通过劳斯莱斯北美技术公司的Co-PI的直接参与，研究生和本科生将有机会在快节奏的工业研究环境中为技术进步做出重大贡献，并为工业相关问题开发创新解决方案。结合拟议的研究，PI和研究生将积极参与促进教育推广活动，旨在当地芝加哥地区的中学科学教师，以加强初中/高中课程，提高学生？材料科学和工程的认识。这将包括为高中学生的ASM材料营和高中科学教师的ASM教师营提供资源和支持。

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.