Nondestructive evaluation of creep damage and life prediction of Ni-base superalloy used in advanced gas turbine blades by electrochemical technique

In order to develop a creep life assessment technique for directionally solidified Ni-base superalloy CM247LC, changes in electrochemical properties due to creep have been investigated. Experimental results on electrochemical polarization measurements revealed that the peak current density "Ip" and "Ipr" which appeared at a specific potential during potentiodynamic polarization reactivation measurements in dilute glyceregia solution linearly increased with a life fraction in early stage of the creep life and were uniquely correlated with Arrhenius type parameter "(t/tr)exp(-Qc/RT)". As a consequence, the creep life fraction can be estimated with high accuracy by the electrochemical technique.