Influence of aluminide diffusion coating on low cycle fatigue properties of René 80

Low cycle fatigue is one of the most important phenomena affecting the lifetime of jet engine blades. In this paper, the effect of aluminide diffusion coating (CODEP-B) on low cycle fatigue properties of René 80 has been studied at temperature of 871 °C, R = 0 and strain rate of about 2 × 10−3 s−1. Experimental results show that the applied cyclic strain is lower than 0.8%, the presence of aforesaid coating increases the fatigue lifetime. In coated specimens, while the total cyclic strain is lower than 0.8%, the nucleation of the cracks occurs merely in substrate, but in cyclic strain more than 1%, as a result of simultaneous nucleation of cracks in the coating surface, diffusion layer and in the substrate, fatigue lifetime of the coated specimens is lower than that of uncoated specimens.