A REVIEW OF FAILURE MECHANISMS OF ULTRA-HIGH CYCLE FATIGUE IN ENGINEERING MATERIALS

摘要

Fatigue behavior of engineering materials has been extensively studied. However, most published research does not extend past around 10~7 cycles. Because plots of the stress versus number of cycles to failure (S-N curves) of ferrous alloys and some other materials apparently reach a horizontal asymptote, it was assumed that specimens tested at stresses below the asymptote, called fatigue limit, would have infinite lives. However, research over the recent years has discovered fatigue failures at stresses below the fatigue limit and lives above 10~7 cycles, termed ultra-high cycle fatigue (UHCF). This paper reviews several failure mechanisms and models for UHCF, including slip mechanism, hydrogen-embrittlement mechanism, area~1/2 parameter model, and fatigue-crack initiation at porosities and inhomogeneities.