Mechanical Stress Effects on 550 °C Hot Corrosion Propagation Rates in Precipitation Hardened Ni-Base Superalloys: CMSX-4, CM247LC DS and IN6203DS

Abstract Combinations of temperature, stress and hot corrosion may cause environmentally-assisted cracking in precipitation-hardened Ni-base superalloys, which is little understood. This research aims to increase current understanding by investigating the effects mechanical on propagation rate during corrosion-fatigue testing CMSX-4, CM247LC DS IN6203DS. The parameters used tests included a high R-ratio, frequency, temperature 550 °C. results showed CMSX-4 experienced predictable rate, also increased rates, but no obvious trend was apparent; whilst IN6203DS evidence an rate. These different behaviours appear be result interaction between microstructural features, include gamma-prime volume fractions both matrix eutectic regions, along with distribution structure. subsequently affected respective fatigue results, experiencing fracture significantly more scatter involved results. All specimens completed without cracking. It, therefore, appears that precipitation hardened are susceptible cracking, experience rates.