An investigation has been conducted to examine the morphological influ
ence on fatigue life of low carbon steel with dual phase microstructur
e. The results showed that dual-phase microstructure, composed by ferr
ite and martensite had superior symmetrical bending fatigue strength w
hen compared with ferrite-pearlite steel. Through those tests, evidenc
es of different mechanisms were verified (such as ferrite cyclic harde
ning, slip band formation and beginning of crack nucleation and propag
ation). Based on the fatigue tests results, various mechanisms stages
were discussed associated with different microstructure morphology. Co
pyright (C) 1996 Published by Elsevier Science Limited.