Yasuhiro Osafune

Influence of water embrittlement effect on mechanical properties of ADI

Water embrittlement in ADI has been studied experimentally for several loading conditions. The phenomenon has been explained on the basis of a hypothesis of hydrogen embrittlement. In addition to conventional tensile specimens, hole-edged CT specimens that can be used to measure the bending load were used. It was found that the latter were more susceptible to water embrittlement than the former, at the maximum tensile load. Some specimens were pre-strained in dry conditions before tensile testing in wet conditions. Specimens that had been pre-strained to values beyond the non-prestrained water rupture point exhibited very similar values in their rupture strain and rupture stress, regardless of the pre-strain value. A hydrogen embrittlement hypothesis is proposed to explain the experimental fact that the water embrittlement effect is observed for ADI but not in the case of a ferrite matrix.