Characterization of Crack Tip Electrochemistry Using a Simulated Crack

Abstract

Abstract A major problem confronting attempts to model environmentally assisted crack growth is the uncertainty present in the rates of electrode reactions within a crack. This results partially from the lack of definition of the solution chemistry and electrode potential at a crack tip. This paper addresses the question of how the environment within the occluded region of a crack differs from that of the bulk environment, and more specifically, identifies the important role of dynamic strain on the chemistry of the crack tip environment. Since it has been concluded that much of the desired information cannot be obtained from actual cracks, the experimental approach uses a simulated crack which has the flexibility to examine the influence of the critical geometrical, mechanical, and electrochemical variables. Results obtained on AISI 304 stainless steel (SS) in 0.1 M Na2SO4 demonstrate that dynamic strain has a marked effect on crack tip chemistry. The application of dynamic strain is shown to shift the c...