Along with purely high temperature characteristics, other mechanical characteristics, which must also be determined under high temperatures, are also important in power plant technology. In addition to high temperature resistance, the modified operation mode of many power plants caused by a fluctuating supply from wind and solar power plants is a factor, placing special requirements on materials.
Many power plants must be able to be started up and shut down again in a flexible way, and in short intervals. This leads to material thermo-mechanical fatigue (TMF), where the material expands thermally with every start up and shut down. Most power plants of the 20th century were not designed for such stresses and must be recalculated and converted accordingly in retrospect.
Another issue for all steam power plants, but specifically for A-USC power plants operated at temperatures up to 760 °C and vapor pressures up to 380 bar, is material corrosion. The way in which the materials react (relaxation or retardation) is observed at a constant strain or stress over a longer period of time at elevated temperatures. This is also done cyclically (creep fatigue).