Fractographic Analysis of Fatigue Failures

Although fractography is usually applied to basic research, it can also be used in studies of machine components which have failed in service or in testing. This paper discusses fractographic methods which can be used to obtain information about the stress state, environmental factors, initiating cause, and crack growth characteristics of fatigue failures. The macroscopic and microscopic fracture surface features of fatigue failures are illustrated with photomacrographs and scanning electron microscope (SEM) fractographs, and the use of SEM fractography in crack growth studies is described.