Search

The microstructural evolution of a cold drawn copper wire (reduction area of 38%) during primary recrystallization and grain growth was observed in situ by electron backscatter diffraction. Two thermal treatments were performed, and successive scans were acquired on samples undergoing heating from ambient temperature to a steady state of 200°C or 215°C. During a third in situ annealing, the temperature was continuously increased up to 600°C. Nuclei were observed to grow at the expense of the deformed microstructure. This growth was enhanced by the high stored energy difference between the nuclei and their neighbors (driving energy in recrystallization) and by the presence of high-angle grain boundaries of high mobility. In the early stages of growth, the nuclei twin and the newly created orientations continue to grow to the detriment of the strained copper. At high temperatures, the disappearance of some twins was evidenced by the migration of the incoherent twin boundaries. Thermal grooving of grain boundaries is observed at these high temperatures and affects the high mobile boundaries but tends to preserve the twin boundaries of lower energy. Thus, grooving may contribute to the twin vanishing.

The authors report three cases of jaundice which developed during pregnancy and which rapidly resulted in the death of the patients. One case was a fulminant case of cytomegalovirus hepatitis and the other two were cases of acute steatosis of pregnancy. The clinical features are marked by the rapid development of a neurological syndrome resulting in coma and the association of blood dyscrasias due to major hepato-cellular failure resulting in DIC. The rapid progression of the disease generally results in the death of the mother and the child. However, there are some reports of survival with total cure after rapid extraction of the foetus, which justify an active therapeutic attitude.