Influence of laser shock peening on irradiation defects in austenitic stainless steels

Abstract

The laser shock peening process can generate a dislocation network, stacking faults, and deformation twins in the near surface of austenitic stainless steels by the interaction of laserdriven shock waves with metals. In-situ transmission electron microscopy (TEM) irradiation studies suggest that these dislocations and incoherent twin boundaries can serve as effective sinks for the annihilation of irradiation defects. As a result, the irradiation resistance is improved as the density of irradiation defects in laser-peened stainless steels is much lower than that in untreated steels. After heating to 300 °C, a portion of the dislocations and stacking faults are annealed out while the deformation twins remain stable, which still provides improved irradiation resistance. These findings have important implications on the role of laser shock peening on the lifetime extension of austenitic stainless steel components in nuclear reactor environments.

Effect of Laser Shock Peening on the Microstructures and Properties of Oxide‐Dispersion‐Strengthened Austenitic Steels

“…The improvement in mechanical and corrosion properties such as hardness, fatigue strength, stress corrosion cracking, and hydrogen embrittlement by LSP have been well documented in the literature . Recently, it is reported by our team that the microstructural changes by LSP are beneficial for improving the radiation resistance of austenitic stainless steels . The dislocations and incoherent twin boundaries can serve as high strength sinks for the annihilation of irradiation defects during 1 MeV Kr ion irradiation at room temperature.…”

Laser shock peening without coating induced residual stress distribution, wettability characteristics and enhanced pitting corrosion resistance of austenitic stainless steel

“…Especially in nuclear reactors, metals used in reactor cores need to perform optimally in at elevated temperature range of 300-350 °C as well as in aqueous environments. The conditions inside a nuclear reactor may lead to corrosion or stress corrosion cracking (SCC), radiation hardening [2], radiation defects and radiation embrittlement or helium embrittlement of the metals. Therefore it is essential and advisable to use materials which can withstand those conditions.…”

“…Sano et al [6] utilized the second harmonic laser for underwater nuclear power plant maintenance applications, and their research explained that LSPwC could induce compressive residual stress on the surface and prompts to the aversion of SCC start and enhancement of fatigue strength. Q. Lu et al [2] performed laser shock peening (LSP) on 304 austenitic stainless steel and unveiled that the dislocation sinks created due to LSP process help in improving radiation resistance and lowering the radiation defect densities at room temperature (25 °C) and as well as at 300 °C. Peyre et al [8] carried out LSP on 316L austenitic stainless steel and revealed the post beneficial effects of LSP on its pitting corrosion resistance.…”

Laser Shock Induced Deformation of Copper Foil on Diverse Molds and the Cross-Sectional Microstructure Changes

“…The images of the hexagonal structures in Figure 7 indicates the process of squeezing, bending, and extending the copper foil in laser shock forming. The plastic deformation of copper foil is equivalent to being rolled in an ultrashort time, which makes the copper work harden [19,20].…”