IN SITU TEM OBSERVATION OF DISLOCATION EMISSION, MOTION INDUCED BY ANODIC DISSOLUTION AND THE INITIATION OF SCC IN BRASS THIN FOIL
溶解促进位错发射,运动导致黄铜薄膜应力腐蚀的TEM原位观察

The in situ TEM observations of dislocation emission, motion and the initiation of nanocrack in brass in corrosive solution were carried out. Using a special constant displacement device, the dislocation configuration change ahead of a loaded crack tip before and after anodic dissolution in the deionized water and the initiation, propagation of nanometre scale stress corrosion cracks has been observed. The results showed that SCC in brass thin foil specimen could occur in water. The localized anodic dissolution of brass in water at room temperature facilitated dislocation emission, multiplication and motion. A nanocrack initiated in the DFZ or at the blunted crack tip in corrosion solution after dislocations emission, multiplication and motion reached a critical condition. Because of the influence of the corrosion solution, the nanocrack will propagate and form a cleavage or intergranular microcrack during stress corrosion instead of blunting in to a void as it does during a tension test without solution.