Fatigue failure predictions for steels in the very high cycle region – A review and recommendations

The nature and the mechanism of crack initiation and early growth for very-high-cycle fatigue of metallic materials – An overview

“…The advances of the research on VHCF have been summarized from different angles in several recent reviews, e.g. [17][18][19][20][21][22][23]. After the brief introduction to the origination of VHCF research, this overview will concentrate on the research progress in the characteristics of crack initiation and early growth for VHCF of metallic materials, and will focus on the cases of high-strength steels and titanium alloys.…”

Ultrasonic fatigue testing of cast steel G42CrMo4 at elevated temperatures

“…Specimens were then cooled in liquid nitrogen and broken. SEM investigations using SE contrast were performed on all fracture surfaces to determine the following parameters: (i) the diameter of the FiE (see (1) in Figure 3A), (ii) the shortest distance of the defect's edge from the surface (see (2) in Figure 3A) and (iii) the area of the defect (see ellipse and polygon, respectively, in Figure 3B). Two different methods of defect area determination were performed in this work: (i) drawing an ellipse around the defect (see (3) in Figure 3B) and (ii) drawing a polygon around the contour of the defect (see (4) in Figure 3B).…”

“…The application of fatigue experiments in the range of very high cycle fatigue (VHCF) using the ultrasonic testing technique has received much attention in recent years. [1][2][3][4] Due to the significance for components used at elevated temperatures such as pistons or turbine blades, fatigue testing at higher temperatures came into focus. However, only few publications about ultrasonic fatigue tests in the VHCF regime at elevated temperatures were published until now.…”

Analysis of temperature and fracture surface of AISI4140 steel in very high cycle fatigue regime

“…A shorter distance of the fisheye and a smaller fisheye size leads to a shorter fatigue life, as during the propagating phase, an interior fisheye grows up to reach the specimen surface until the failure occurs, requiring a longer time. Figure 18 shows the measurements of both fish-eye size and fish-eye distance to specimen surface as a function of fatigue life [31]. It is shown from that the fish-eye size are within a relatively small range between about 7 and 20 µm and the fish-eye distance to specimen surface are distributed in a large range between 26 and 419 µm.…”