Date of Award

January 2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Matthew N. Cavalli

Abstract

Superalloys for use in hydrogen-burning gas turbines must demonstrate long-term durability in environments that may be more corrosive than typical turbines due to the presence of impurities in the combusted syngas. This long-term durability implies high oxidation and spallation resistance to different types of corrosion attacks as well as a high strength to be able to withstand the residual stresses induced by the temperature gradients. The performance of these superalloys in these environments can only be realistically assessed if their design involves a good understanding of the types of microcontaminants present in the syngas as well as resulting stresses induced during high temperature operation. This work has two main goals: 1) Characterize the composition of typical syngas combustion flue gases and 2) Successfully fabricate bi-layer structures of iron- and nickel-based superalloys using evaporative metal bonding (EMB) and perform a finite element analysis to predict the stresses at the bonding surface at all temperatures.

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