Extrusions and intrusions in fatigued metals. Part 1. State of the art and history

Current state and historical progress in experimental and theoretical studies Of surface relief appertaining to persistent slip hands (PSBs) and leading to fatigue crack initiation in cyclically deformed metals is presented as a thorough critical overview. A comprehensive inventory of microscopic techniques for this Study is tabulated chronologically with emphasis to their applicability to polycrystals. The most relevant experimental characteristics concerning surface relief evolution, namely the form Of extrusions and intrusions ill single- and polycrystalline materials, are Surveyed. Theoretical models and computational simulations of extrusion and intrusion formation and fatigue crack initiation are critically reviewed.