Creep-fatigue crack growth behaviour of a nickel-based powder metallurgy superalloy under high temperature

Creep-fatigue crack growth behaviour of a nickel-based powder metallurgy superalloy has been investigated. Experiments were conducted at 750 degrees C with various dwell times. Results show that dwell time induced creep damage is significant by transforming a transgranular dominating cracking mode into a completely intergranular one. The observed dependence of crack growth rate on the dwell time and Delta K is complex indicating that the interaction between creep and fatigue is significant. Therefore, a factor reflecting the degree of the interaction was proposed to help modelling the creep-fatigue crack growth rates. The results are encouraging. (C) 2011 Elsevier Ltd. All rights reserved.