Corrosion and subsequent waterwall wastage has been a significant problem for coal-burning power companies since low NOx burner conditions have been implemented in their furnaces. In order to reduce the amount of waterwall corrosion, coatings for the boiler tubes, such as weld overlay claddings, are currently being pursued. Iron-aluminum based coatings are presently being studied as possible co...

A multi-year effort has been focused on optimizing the long-term oxidation performance of ingot-processed (IP) and oxide-dispersion strengthened (ODS) Fe3Al and iron aluminidebased coatings. Based on results from several composition iterations, a Hf-doped alloy (Fe28Al-2Cr-0.05at.%Hf) has been developed with significantly better high temperature oxidation resistance than other iron aluminides. ...

A detailed model of the role of asperities in crack closure has been initiated in Part 1 of this article. Crack opening stress is defined as the far-field stress required to overcome the asperity-induced contact stresses along the crack. In this Part 2, the magnitude of crack opening stress is established as a function of roughness (s0); asperity density (N); maximum stress level (Smax/Sy); sha...

The fractional concentration of Ni-vacancies in NiAl at high temperature has been determined for compositions between 50 and 53 at.% Ni from measurements using perturbed angular correlation of gamma rays (PAC). The vacancies were detected by quadrupole interactions induced at nearby In/Cd impurity probes present on the Al sublattice in high dilution. One set of measurements was made at high tem...

Nickel superalloys are the main materials used in manufacturing of turbine blades and vanes aero-space industry. They works is extremely high temperature a corrosive environment (oxidation, hot corrosion) undergo several different thermo-mechanical loads. Aluminide coatings method protection surface nickel against exhaust gasses jet en-gine. In presented article microstructural characterization...

Titanium Aluminide and TiAl matrix composites reinforced with alumina fibers (PRD166) were fabricated by powder metallurgy. During isothermal oxidation at 950 and 1070 OC, composites containing PRD166 fibers exhibited larger weight gains than monolithic TiAI; the composites showed evidence of oxidation along the perimeter of the fibers. A fiber reaction, which was observed after oxidation in ai...