David N Seidman

Development of High-Temperature Cobalt-Based Superalloys

The goal of this research effort is to develop new high-temperatures cobalt-based superalloys, with the aim of supplanting nickel-based superalloys with gamma(f.c.c.) plus gamma-prime(L12 structure) microstructures, for use as turbine blades in commercial and millitary aircraft and land-based natural-gas fired turbines for producing electricity. The driving force for this research is that the maximum operating temperature of nickel-based superalloys is reaching a plateau and hence their thermodynamic efficiency is also on a plateau. These alloys are studied using atom-probe tomography, scanning electron microscopy, microhardness and creep measurements, and three-dimensional dislocation dynamics (In cooperation with Prof. David C. Dunand).

Five-Dimensional Correlative Studies of the Temporal Evolution of Nickel-Aluminum Alloys on a Nano- to Subnanoscale

The focus of this research is on temporal evolution of the nucleation, growth and coarsening gamma-prime (L12 structure) precipitates in Ni-Al alloys utilizing three-dimensional atom-probe tomography, scanning and transmission electron microscopies, monovacancy mediated lattice-kinetics Monte Carlo simulations. Phase separation in multicomponent alloys is basic to understanding and predicting microstructures of all high-temperature alloys.

HIgh-Temperature Aluminum Alloys

The aim of this research project is to increase the maximum operating temperature aluminum alloys. The highest operating temperature of commercial Al alloys in about 463 K. We have developed Al alloys that can operate at temperatures as high as 698 K for extended periods of time. Our alloys can be used to replace the front brake rotors in vehicles, thereby decreasing their weight and helping to make them more fuel efficient. (In cooperation with Prof. David C. Dunand).

A High Strength and High Toughness Steel

We are working on a high-strength and high-toughness steels for Naval applications. This is a low-ccarbon 10 wt.% Ni steel, which is subjected to QLT (quench, lamellarization, temperature) treatment that yields a steel with about 18 % austenite, which is strong, tough, projectile resistant and weldable.