While investigating the behavior of the dislocations which were emitted from O precipitates under thermal stresses, a new type of defect was found. This was an aggregate of dislocations which were distributed in a rhombic pattern. Such defects formed in the region where the O precipitation amounted to more than 3 x 1017/cm3 under large thermal stresses.

K.Minowa, S.Isomae, M.Kitano: Materials Science Forum, 1995, 196-201, 1829-34