Impact toughness of LSP-treated materials in hydrogen

Determine how Laser Shock Peening and hydrogen exposure jointly affect the impact toughness of metallic materials, particularly high-strength steels used in cryogenic and high-pressure hydrogen service, and resolve the trade-off between strengthening, hydrogen trapping, and retained impact energy.

Background

Laser Shock Peening introduces compressive residual stresses that may inhibit hydrogen ingress while simultaneously producing grain refinement, high dislocation density, and other defects that can alter deformation and fracture. These competing effects may improve resistance to crack initiation yet reduce the ability of the material to absorb sudden impact energy.

The review states that systematic impact-toughness data for LSP-treated materials exposed to hydrogen are virtually absent. This unresolved strength–toughness trade-off is particularly important for pressure vessels and pipelines operating at reduced temperatures, where hydrogen can substantially reduce absorbed impact energy.