Q. Expected service life of a component in high temperature environment?
The expected service life of a component in a high temperature environment is limited by either the materials' mechanical or metallurgical properties. Mechanical failure involves excessive creep of the material over time. Metallurgical failure involves the reaction of the material with its environment (e.g. oxidation, sulphidation, and other forms of high temperature corrosion) and the gradual modification of the microstructure in service.
In general, many cast alloys offer superior creep strength to their wrought counterparts above a certain temperature. However, other mechanical properties may be inferior. The reason for the superior creep strength is associated with both grain size and slight microstructural differences.