Crack Initiation in Austempered Ductile Iron Strained in Contact With Different Liquids

R.A. MARTÍNEZ, S.N. SIMISON AND R.E. BOERI

Beijing, China

Simposio; Eight International Symposium on the Science and Processing of Cast Iron; 2006

Tsinghua University

The mechanical behavior of austempered ductile iron shows an embrittlement phenomenon when the material is plastically strained in contact with different liquids. This effect has been discovered and studied in recent years. Nevertheless, it has not been completely clarified yet, to the best of our knowledge. Recent studies demonstrated that surface cracks generate on the tensile samples during the early stages of plastic deformation when tensile tests are carried out on ADI samples. The goal of this work is to identify the critical stress values for the initiation of cracks when tensile tests are carried out with the samples in contact with water and other liquids. The results show that cracks form at different stresses, depending on the nature of the fluid in contact with the sample surface. The sub critical cracks observed on the samples tested in air showed increasing length as local stress augments, which indicates the existence of a stable growth period.