Non-Destructive Evaluation of Creep Damage of Ni-Based Superalloy Using A Scanning Blue Laser Microscope
In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-based superalloys under creep and fatigue conditions quantitatively. The refractive index of the gamma-prime phase is found to be smaller than that of the gamma phase in the Ni-based superalloy, when the wavelength of an irradiated laser beam is shorter than 500 nm. Therefore, it is possible to evaluate the creep damage of this material quantitatively and non-destructively by observing the change of the micro texture in a grain (rafting) using a scanning laser microscope.
Yu Zhou, Shan-Tung Tu and Xishan Xie
K. Akahoshi et al., "Non-Destructive Evaluation of Creep Damage of Ni-Based Superalloy Using A Scanning Blue Laser Microscope", Key Engineering Materials, Vols. 353-358, pp. 2391-2394, 2007