摘要
The creepfatigue properties of a nicklebased superalloy IN738LC with monomodal precipitates were investigated at elevated temperature. It was observed that the cyclic life (number of cycles to failure) decreases with increasing creep deformation. All specimens showed intergranular failure.The microscopical examination did not find the typical creep damage in form of cavitation along grain boundaries. Instead, carbide oxidation and grain boundary oxidation were frequently observed. All cracks initiated at the specimen surface and propagated along the grain boundaries. Therefore, the oxidation of grain boundaries under creep load is the possible creep damage. A damage mechanism has been discussed and the DanzerModel can be well used to explain it.
The creepfatigue properties of a nicklebased superalloy IN738LC with monomodal precipitates were investigated at elevated temperature. It was observed that the cyclic life (number of cycles to failure) decreases with increasing creep deformation. All specimens showed intergranular failure.The microscopical examination did not find the typical creep damage in form of cavitation along grain boundaries. Instead, carbide oxidation and grain boundary oxidation were frequently observed. All cracks initiated at the specimen surface and propagated along the grain boundaries. Therefore, the oxidation of grain boundaries under creep load is the possible creep damage. A damage mechanism has been discussed and the DanzerModel can be well used to explain it.
