Application of T33-Stress to Predict the Lower Bound Fracture Toughness for Increasing the Test Specimen Thickness in the Transition Temperature Region

• Main Authors: Kai Lu, Toshiyuki Meshii
• Format: Article
• Language: English
• Published: Hindawi Limited 2014-01-01
• Series: Advances in Materials Science and Engineering
• Online Access: http://dx.doi.org/10.1155/2014/269137

This work was motivated by the fact that although fracture toughness of a material in the ductile-to-brittle transition temperature region Jc exhibits the test specimen thickness (TST) effect on Jc, frequently described as Jc∝(TST)-1/2, experiences a contradiction that is deduced from this empirical formulation; that is, Jc = 0 for large TST. On the other hand, our previous works have showed that the TST effect on Jc could be explained as a difference in the out-of-plane constraint and correlated with the out-of-plane T33-stress. Thus, in this work, the TST effect on Jc for the decommissioned Shoreham reactor vessel steel A533B was demonstrated from the standpoint of out-of-plane constraint. The results validated that T33 was effective for describing the Jc decreasing tendency. Because the Shoreham data included a lower bound Jc for increasing TST, a new finding was made that T33 successfully predicted the lower bound of Jc with increasing TST. This lower bound Jc prediction with T33 conquered the contradiction that the empirical Jc∝(TST)-1/2 predicts Jc = 0 for large TST.