Can Acoustic Emission (AE) Make Any Contribution to the Corrosion Research?
Paper reviews author's research results on the Acoustic Emission (AE) source wave analysis of delayed fracture and stress corrosion cracking (SCC), and discusses what contribution has the AE made to the corrosion research. Both the dynamics and progression of micro-fractures in hydrogen assisted fracture of high and low tension steels were quantitatively revealed by the source inversion or source wave analysis of AE signals. No theory or hypothesis proposed so far, however, appears to explain the extremely fast fracture and dilatation kinetics observed in hydrogen blistering of low strength steels. Transgranular SCC of austenitic stainless steel does not produce any AE, suggesting an anodic dissolution of metal along active paths, but intergranular SCC in solution and molten salts does produce AEs. In order to study the mechanism of environmental cracking, hybrid technique of AE and potential noise analyses is needed.