CHARACTERISATION OF CRACK GROWTH AT ELEVATED TEMPERATURE IN A NEW NICKEL-BASED SUPERALLOY

摘要

Crack growth at elevated temperature has been examined in a new nickel-based superalloy for four loading waveforms at 650 and 725°C.An Arrehenius relationship has been developed to characterize the crack growth behaviour. Mechanical variables including load waveform, temperature, stress intensity factor and an oxidation sensitive time are explicitly accounted for. The formulation is developed considering a predominantly oxidation-driven crack growth mechanism, an assumption made based on the experimental observations.