THE INFLUENCE OF MICROSTRUCTURE ON THE GROWTH OF SMALL FATIGUE CRACKS

— Recent experimental work on the growth of small fatigue cracks is surveyed and critically analyzed. It is shown that microcracks grow at anomalous rapid rates relative to large ones only when certain criteria, involving crack size, plastic zone size, and micro-structural element size, are met. Retardation and arrest of microcracks is found to correlate with microstructural element size, hence with crystallographic influence.