Fatigue crack growth measurement in a superalloy at elevated temperature

Crack growth experiments at elevated temperature were performed in a nickel-based powder metallurgy (PM) superalloy. The crack propagation procedure was monitored by travelling microscope, high temperature extensometer and beachmarking technique. The appropriate creep crack growth relating parameter for the present alloy was discussed. The crack growth behaviours in standard compact tension specimens and side-grooved compact tension specimens were compared. Several crack length measurement techniques including beachmarking, linear correction and compliance measurement were discussed and the results were compared.