Embrittlement of austempered ductile iron caused by contact with water andother liquids

Recent research has reported that austempered ductile irons (ADI) suffer a marked embrittlement when the material is tested in tension with its surfac e in contact with water. The objective of this investigation is to verify t hat embrittlement phenomenon, and to characterise the behaviour of several strength grades of ADI, The embrittlement effect of other wetting agents is also investigated. The results verified prior studies. A noticeable decrea se in UTS and elongation takes place when ADI samples of grades 2 to 4 are tested immersed in water. The embrittlement effect is not affected by the c oncentration of protons in water. Embrittlement of ADI was also found when testing in contact with isopropyl alcohol and SAE 30 lubricant oil. A very strong wetting agent (WD40(TM) oil) does not cause embrittlement. Pearlitic matrix ductile irons also suffer embrittlement in contact with water, whil e ferritic matrix ductile irons of the same chemical composition, do not su ffer embrittlement, The present study advances in the characterisation of t he embrittlement of ADI, and identifies new embrittling liquids, but does n ot provide a definite explanation for its causes.