（1 National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China) (2 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China）
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DOI:
10.7502/j.issn.1674-3962.2012.12.03
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Abstract:
Turbine blades are one of the most important hot section components in gas turbine systems. They are subjected to complex combination of inhomogenous stresses and temperature distribution as well as high temperature corrosion and oxidation environment, resulting in failures caused by creep, low cycle fatigue and high temperature corrosion/oxidation. In order to understand failure mechanisms and develop proper rejuvenation heattreatment to extend the life time of turbine blades, it is of great necessity to study the relationship between microstructure and mechanical property degradation of turbine blades during service. This paper is to review the previous studies associated with service induced degradation of turbine blades. Various kinds of typical microstructural degradations are also classified, combined with the investigation of microstructural degradation of different types of turbine blades in aeroengines by our group (service time in air:1 200~20 000 h, respectively). The following microstructural degradation is included: surface coating degradation, precipitation of Topologically ClosePacked Phases (TCPs), formation of second reaction zone (SRZ), coarsening and rafting of γ′ phase, decomposition or precipitation of carbides, and initiation of creep cavities and cracks, etc. In addition, previous studies of mechanical property degradation and the rejuvenation heattreatment of turbine blades are also summarized. It is suggested that the investigation of the mechanism for the service induced degradation of hot section components is of great importance and economic significance for the life management and materials safety in gas turbines.