A review of mechanical and metallurgical aspects of damage in turbine blades made of nickel based superalloys

Today, global demand for energy has increased due to economic and population growth. Turbines play an important role in generating power in order to generate electricity. This industry is one of the important factors in the global economy and has experienced continuous growth from the early years. To achieve higher thermodynamic efficiency in turbines from higher inlet temperature and pressure, advanced aerodynamics, efficient blade cooling systems, advanced alloys with higher temperature tolerance, heat treatment and metal and thermal barrier ceramic coatings is used. Under turbine operating conditions, some damage may occur that will decrease its life. In present study, mechanical and metallurgical aspects of turbine blade destruction and the development of materials to overcome it have been analyzed. Failure mechanisms must be identified to estimate blade life. The combination of different variables causes stress and complex damage mechanisms such as creep and fatigue are created by changing mechanical and heat stresses. In addition to the above, the importance of coating on gas turbine blades is mentioned. After investigation of various aspects of damage to clarify the issue, some case studies of failure during operation are briefly described.