Simulation of very high temperature overheating during isothermal creep of single crystal Ni-base superalloy

A study was conducted to demonstrate the simulation of very high temperature overheating during isothermal creep of single crystal nickel (Ni)-base superalloy. An experimental set-up was developed and used for the simulation of overheating under load (OEI). The experimental set-up represented the One Engine Inoperative events, which were expected to be encountered during in-service operation of turboshaft engines for helicopters. The study provided better results, in comparison to classical testing equipment that were used for the non-isothermal testing conditions. It was also found that faster the heating, or cooling during the overheating process, the longer the non-isothermal creep life. It was observed that the strain was promoted by significant reduction of the volume fraction of the reinforcing phase in the heating and cooling stage, during the simulation of the OEI.