Author/Authors :
Chapetti، نويسنده , , M.D and Miyata، نويسنده , , H and Tagawa، نويسنده , , T and Miyata، نويسنده , , T and Fujioka، نويسنده , , M، نويسنده ,
Abstract :
Fatigue strength of two ultra-fine grained steels (grain sizes 0.8 and 1 μm) was investigated. A coarse grained (grain size 12.5 μm) SM490 steel with a similar chemical composition was also analysed for comparison purpose. An important improvement on smooth fatigue strength was observed in ultra-fine grained steels and results obey the Hall-Petch relation usually observed between smooth fatigue limit and grain size. High fatigue notch sensitivity was observed and no improvement in fatigue limit of sharp notches is expected.
