The fundamentals associated with acoustic emission monitoring of fatigue crack initiation and propagation of Ti-6AI-4V were studied. Acoustic emission can detect and locate incipient fatigue crack extensions of approximately 1 0 gm. The technique therefore can serve as a sensitive warning to material failure. There are three distinct stages during which acoustic emission is generated. These sta...

Abstract Rolling contact fatigue tests were performed on specimens containing spheroidal inclusions to clarify the effect of orientation inclusions, and results compared with those stringer‐shaped inclusions. For all types inclusion, cracks first formed rolling surface then propagated in depth direction, an internal crack parallel from deepest point vertical crack, which led flaking. The flakin...

The modulus and internal friction of Armco iron rere continuously measured during cathodic charging rith hydtogen to investigate crack initiation and grorth. The observed modulus decrease ras attributed to crack initiation and grorth. The internal friction increase doring cathodic charging ras atfributed to plastic deformation accompanying the crack formation. Both the modulos and internal fric...

This paper explores the fracture process based on finite element simulation. Both probabilistic and deterministic methods are employed to model crack initiation, and several commonly used criteria are utilized to predict crack growth. It is concluded that the criteria of maximum tensile stress, maximum normal stress, and maximum Mises stress, as well as the Coulomb-Mohr criterion are able to pr...

The effect of an electroless Ni-Cu-P coating on the fatigue behavior of quenched and tempered CK45 steel has been investigated. The fatigue tests under rotating bending conditions have been conducted in three different conditions of uncoated, as-deposited and shot peened prior to the coating deposition. The results indicate that plating of the base steel leads to a fatigue life reduction. The d...

the effect of an electroless ni-cu-p coating on the fatigue behavior of quenched and tempered ck45 steel has been investigated. the fatigue tests under rotating bending conditions have been conducted in three different conditions of uncoated, as-deposited and shot peened prior to the coating deposition. the results indicate that plating of the base steel leads to a fatigue life reduction. the d...

The very high cycle fatigue behavior (10-10 cycles) of Ti-6246 has been investigated using ultrasonic fatigue techniques. In this regime of fatigue (0.4-0.6σYS), only certain microstructural regions are susceptible to fatigue damage accumulation, and lifetimes are related to the distribution of fatigue critical microstructural neighborhoods. Three distinct categories of crystallographic crack i...

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. ...