Study on Microstructure and Properties of GTD111 Turbine Blade of E Class Gas Turbinein Service

Metallographic, hardness, SEM, EDS and XRD analysis test methods were applied to study the microstructure and properties of the first stage rotor blade GTD111 of E class gas turbine after service. The results show that the metallographic structure of the blade is typical dendrite morphology with obvious primary and secondary crystal characteristics. The main precipitates of the blade are γ’ phase, σ phase, MC carbide. γ’ is the main precipitation strengthening phase, the main component is Al Ni₃. γ’ has obvious coarsening and rafting on the root position. MC carbides mainly exist in the form of（Ti, Ta） C, which is formed by a large amount of solid solution of Ta element in Ti C. At high temperatures, stress concentration and microcracks are easy to occur at coarse MC carbides.