Influence of the Residual Stresses Induced by Shot-Peening on the Oxidation of Zr Plates

Abstract

The present study evaluates the influence of the residual stress on the oxidation rate of Zr at 650°C. It is shown that the oxidation rate can be substantially decreased by shot-peening. A systematic instigation of the various factors (such as the residual stress, the surface pollution and the chemical composition of the oxidation atmosphere) is realized to separate their influence on the oxidation. The influence of an annealing made after the shot-peening is also considered. One show that the pollution of the surface during the shot-peening process is not responsible for the oxidation rate decrease.

Effect of laser shock peening on the high temperature oxidation resistance of titanium

“…Indeed, large compressive stresses and surface hardening induced by mechanical treatments, such as shot-peening (SP) with WC balls, has been reported to play a positive role in the oxidation resistance of zirconium for instance [9][10]. A beneficial effect of SP treatments on the high fatigue performance of several titanium alloys has also been reported [11].…”

Influence of machining processes on rim zone properties and high temperature oxidation behavior of 42CrMo4

“…As compressive residual stresses were measured from the iron peak of the base material, they are considered to be present at the oxide scale substrate interface and thus could still be inhibitive regarding the inward diffusion of oxygen. Moreover, the slow oxidation rate of EDM samples during heating is in contrast to the investigations of Evans and Optanasu et al regarding the influence of residual stresses. A reason for the higher oxidation resistance of EDM surfaces could be the structure of the white layer of 42CrMo4 that was found to consist of a micro‐crack‐containing recast layer and a subjacent heat affected zone .…”

“…The oxidation resistance was linked to rim zone residual stresses as well as the residual stress profile dependent on the depth by Raceanu et al and Optanasu et al previously. Compressive residual stresses were found to increase the oxidation resistance of zirconium plates due to the integration of the stress tensor in Fick's law, inhibiting the diffusion of oxygen into the material, while tensile residual stresses increase the oxidation rate . During isothermal exposure, the oxidation rate is strongly dependent on diffusion in the oxide layer as indicated by the parabolic shape of the mass change (Figure ).…”

“…Anionic diffusion of oxygen into the metal lattice can be influenced by present stress gradients and thereby impact the oxidation process. In this case, the oxide growth rate was decreased due to present compressive residual stresses …”

“…Very recent publications on the oxidation behavior of commercially pure zirconium with consideration of targeted compressive residual stresses have demonstrated decreased oxidation rates . Anionic diffusion of oxygen into the metal lattice can be influenced by present stress gradients and thereby impact the oxidation process.…”