Experimental and simulated investigations of low cycle fatigue behavior in a nickel-based superalloy with different volume fractions of δ phase

The fatigue crack initiation life and damage mechanisms of three heat-treated nickel-based alloy with different volume fractions of delta phase have been investigated based on experiment and crystal plasticity simulation. With the help of fatigue indicator parameters (FIPs), the predicted fatigue lives are agreed well with experimental results, where energy dissipation based FIP shows more accurate life prediction than plastic slip based FIP does. Maximum fatigue damage sites shift from grain boundary to delta phase boundary by increasing delta phase and applied strain level. Furthermore, the existence of delta phase leads to the increase of plastic slip accumulation and decrease of localized stress level.