Besides, the microstructure
around the defect band became coarse and comprised large and
dendritic ESCs (Fig. 3). According to Eq. (1), the actual stress applied
on the defect band would be roughly equal to that on the
gas-shrinkage pore, and the fracture stress of the microstructure
around the defect band would also be roughly equal to that around
the gas-shrinkage pore. Accordingly, the crack would simultaneously
initiate at the defect band and gas-shrinkage pore in the
center of the specimen.