Fractographic Study of Fatigue Crack Propagation

Fractographic studies were carried out on fatigue fracture of aluminum alloys and carbon steels. Special attention was given to the correlation between striation spacing and macroscopic crack growth rate and to the effect of stress change on the crack growth rate as determined by striation spacing measurements. Also the mechanism of formation of striations and tire tracks was examined by means of precisely matched electron fractographs of matching fracture surfaces. Some remarks are also made on the mechanisms of fatigue crack propagation.