Prediction of Material Damages Based on a High-Cycle Fatigue Model and Non-destructive Testing Data

In this paper, the results of the investigation of the process of fatigue fracture of the carbon steels, low-alloy steels, Ni-based, as well as Ti-based alloy specimens are presented. Samples were studied in a state of normalization of the material structure, as well as after strengthening treatment by surface plastic deformation. During the fatigue tests, the count rate of acoustic emission (AE) signals was recorded simultaneously in three frequency bands. The fatigue test results were processed in accordance with the hypothesis of a pole in the fatigue curves of materials of the same class with different technological heredity. For this purpose, the coordinates of the fatigue curve poles for the investigated materials were determined. It has been established that the ordinates of the poles of the fatigue curves correspond to the activation energy of destruction of the volume of one mole of the metal that forms the basis of the alloy. The abscissas of the poles for different classes of steel were determined by searching for optimal values of the main statistical parameters (the maximum correlation coefficient with minimum standard deviation). An explicit connection between the abscissa of the pole and the mechanical and physical properties of the alloys under study has not been established.