Abstract
For the purpose of studying the process to reach fracture in stress corrosion testing, X-ray diffraction patterns were analyzed and lattice faults were observed by transmission electron microscopy for the specimens during and after stress corrosion testing. From these experimental results, the half width ratio, the stored energy and the dislocation density were calculated. Then, the relation between the half width ratio and the dislocation density and the relation between the half width ratio and the life time were plotted. Both the half width ratio and the djslocation density against the logarithmic fracture time ratio were presented by one broken straight line. In addition, the stored energy was calculated from the analytical results of X-ray line profiles. The stored energy increased with the testing time and indicated the same value at the fracture time for the same kind of stainless steel.
It was also made clear that the relation between the stored energy and the dislocation density can be presented by a straight line, and that the stored energy arises from the lattice strain around the dislocation. Furthermore, we proposed a mechanism of stress corrosion cracking based upon the electron mcroscopic observation of the initial states of crack formation.
