Microstructural evolution and deformation features in gas turbine blades operated in-service

• DOI: 10.1016/j.jallcom.2014.08.246
• Publication Date: 2014-09-09T09:08:17Z
• Authors: Fei Sun; Jinyan Tong; Qiang Feng; Jianxin Zhang
• Keywords: Lüders band

Abstract The nickel based superalloy GH4037 is employed in gas turbine blades because of its high temperature strength and oxidation resistance. Microstructural evolution and deformation features in gas turbine blades after 1600 h service have been investigated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The microstructure of blade changes according to complex and comprehensive temperature and stress fields applied on it. Microstructural observations show that minor carbide precipitates dispersedly precipitate in the matrix. Two MC decomposition reactions occur: MC + γ → M 23 C 6 + γ′ and MC + γ → M 23 C 6 + η. Blocky, closely spaced M 23 C 6 particles continuously distribute along grain boundaries. The main deformation features, such as slip bands, APB-coupled dislocation pairs, stacking faults bound by partial dislocations and deformation twinning, have also been analyzed in terms of fundamental deformation mechanisms and environmental effects.