Creep crack growth of GH3535 alloy at elevated temperatures

Highlights: • Creep crack growth behavior of GH3535 allov used as structural material of TMSR at different temperatures was investigated. • The relationships between crack gowth rate crack initiation time and C* parameter are independent of temperature. • The propagation mechanism of GH3535 at different temperatures was found by observing the fracture and crack tip morphology. • Oxidation promotes the crack growth and the interaction between crack growth and oxidation is described. The behavior and micromechanism of creep crack growth (CCG) of GH3535 alloy at 650 to 750 °C have been investigated experimentally. The relationships among the effective stress intensity factor, fracture parameter C^⁎, and CCG rate were obtained and the effect of temperature on the crack initiation time were analyzed. The results show that it is suitable to use the fracture parameter C^⁎ to correlate the CCG rate at different temperatures and that the CCG rate and fracture parameter C^⁎ have a good linear relationship in a narrow band in the log-log scale. This linear relationship does not depend on temperature when using the fracture parameter C^⁎ to correlate the crack initiation time. During crack propagation, intergranular propagation and dimple transgranular fracture occurred successively. The crack growth is found to be accompanied by oxidation.