Environmentally induced cracking of austempered ductile iron by contact with water and other liquids

摘要

An unusual environmentally assisted embrittlement effect has been reported to affect austempered ductile iron when it is tested in tension with its surface in contact with water and other fluids. The occurrence of this effect has been verified by several laboratories, but the embrittlement mechanism has not been fully explained yet. This work gives an updated view of the current understanding of the environmentally assisted embrittlement of ADI. The influence of the environment (different liquids) and of different ADI grades is discussed. The features of the fracture surfaces are also detailed. Recent results of testing under applied potential are presented. Constant tensile tension with a localised point of contact with water allowed to determine the characteristics of the initiation of the fracture. Interrupted tensile test in air on polished and etched samples were performed in order to detect possible surface defects that could act as fracture initiators.