Cyclic deformation of metals and alloys

Phenomena associated with rapid hardening or softening caused by cyclic straining in the early stages of fatigue life of metals and alloys are reviewed. The factors which control these phenomena are described and also the dislocation structures which are associated with them. In so far as the mechanisms of cyclic deformation are understood these too are described and a number of parallels between cyclic and unidirectional deformation are pointed out. A similar approach is then taken for materials which contain second phases for strength. Note that these studies apply to cycling at ambient temperatures or below. High-temperature cyclic deformation is beyond the scope of this review. An engineering method of predicting cyclic stress-strain response from tensile testing data is examined in the light of the fundamental knowledge described, and is shown to be severely limited. A method of improving such prediction by introducing additional microstructural information which is readily available is suggested. 117 references