Improvement of hydrogen embrittlement resistance of 2205 duplex stainless steel by laser peening

The hydrogen embrittlement (HE) resistance of 2205 duplex stainless steel (DSS) treated with laser peening (LP) with different laser power densities was studied. The results show that LP changes the morphologies and distribution of ferrite phase and austenitic phase, thus changes the path of hydrogen transportation and diffusing. LP-induced grain refinement provides more tortuous grain boundaries that increases the difficulty of hydrogen atoms to penetrate them. The beneficial LP-induced microstructures interacts (e.g. dislocation entanglements, dislocation walls, mechanical twins) and helps to trap the hydrogen atoms, reducing their mobility ability. The hydrogen determination test provides direct evidence that LP reduced the amount of hydrogen penetration into the material. In addition, the tensile fracture exhibits that the average depth of the brittle region was inversely proportional to the laser power density, suggesting that an increase in laser power density can reduce the HE sensitivity of 2205 DSS.