Investigation of the features of the origin and the growth of the fatigue cracks in specimens from the granulated nickel alloy EP741NP

Abstract

The results of low-cycle fatigue testing and fracture studies of the tested cylindrical samples made of the granulated nickel alloy EP741NP are presented. Low-сycle fatigue tests were conducted under a rigid loading cycle, at various levels of deformation, temperature and cycle asymmetry. With the help of scanning electron microscopy (SEM), the place of origin of the fatigue crack was investigated, the dynamics of its development were determined, which made it possible to establish the conditions of origin and the duration of growth of the fatigue crack from internal defects or from the surface of the sample. A relationship has been established between the origin, duration of crack growth and overall durability. The results obtained will make it possible to predict what the origin of a fatigue crack in a material will be under the given conditions.