SGER: A Study of a Ordered Body Centered Cubic Structure Superalloy Formed by Spinodal Decomposition

Dartmouth College, Hanover NH

Investigators

Abstract

In this SGER proposal, scientifically interesting features of a new quaternary alloy (Fe30Ni20Mn25Al25) will be examined to determine whether this particular alloy system would be useful as a structural material. This new alloy is a bcc equivalent of a nickel-based superalloy that has been used for high temperature structures. A major objective is to investigate in detail the kinetics of both the spinodal decomposition and the phase stability in bulk. In-situ high temperature transmission electron microscopy will be used to characterize phase coarsening and stability. Deformation behaviors will be characterized using both bulk and in-situ straining experiments in transmission electron microscope. The alloy will be considered in both as-cast and following different heat treatments to determine the optimum process conditions for sufficient ductility without sacrificing high-temperature strength. If successful, results from this work will have applicability to other alloy system since the spinodal decomposition, followed by ordering represents a new way of manipulating microstructures. The educational impacts include training a M.S. student and two undergraduates who will work on the project. They will acquire varying degrees of skill in materials characterization techniques and mechanical testing. In addition, a close collaboration with ORNL is planned wherein the materials will be processed at the national laboratory.