Abstract
The substructure formation around fatigue cracks in α-brass, copper and aluminium was studied by means of X-ray microbeam technique, in order to make clear the relation between substructure and fatigue crack propagation.
The results obtained were as follows: (1) There exist plastic zones in the vicinity of fatigue cracks in all the cases. (2) In α-brass subgrains were formed only with in the plastic zone, whereas in copper and aluminium grains were divided into smaller subgrains in the zone than in the matrix. (3) The substructure became pronounced as the stacking fault energy increased. (4) In aluminium, fatigue cracks propagated more quickly in the specimen with a more developed substructure.
From the experimental results, it is concluded that the substructure formation is not only an incidental phenomenon but plays an important role in the mechanism of fatigue crack propagation.
