With the assumption that the sites of fracture nucleation are randomly distributed in the sample, we deduce out a set of enclosed equations for predicting the fragment number and size distribution.

The crack nucleation energy and the propagation energy were measured under impact and tensile testing. The fracture surface was examined by SEM.

The stress whitening can be clearly seen on the fatigue fracture surface and its region is the initiation and nucleation of fatigue crack which is the main part of total fatigue life.