Meeting materials needs in extreme naval corrosive and oxidative environments

Abstract

High temperature applications demand materials that have a variety of properties such as high strength, toughness, creep resistance, fatigue resistance, as well a resistance to degradation by interaction with the environment. All potential metallic materials become unstable in many high temperature environments without the presence of a stable, protective coating on the component surface. Reliable high temperature propulsion materials are critical for enabling improvements in engine efficiency, reducing fuel costs, and decreasing maintenance/total life cycle costs. Propulsion materials for both Naval aircraft and ship gas turbine engines are subjected to the corrosive marine, salt laden environment to differing degrees. Materials life is dependent on dynamic combinations of temperature, cyclic activities and mechanical stress with the marine environment. Research seeks to explore and understand the thermodynamics and kinetics of materials interactions and material stability in Naval environments and temperatures in order to develop models that lead to creating new materials or establishing life prediction of existing and novel materials. This research may discover new mechanisms and causes that lead to materials instabilities and degradation at high temperatures. The research and the models that follow need to address how these mechanisms are fundamentally influenced by mechanics, interdiffusion, coating or materials chemistry, temperature, environment and structure in order to establish fundamental scientific principles to mitigate such instabilities and degradation. This paper will dwell on some past results of materials testing and offer some views on future directions into materials research in high temperature materials in aggressive Naval environments which can be applicable to other services.