Effects of laser peening on tensile properties and martensitic transformation of AISI 316L stainless steel in a hydrogen-rich environment

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 788; p. 139543
• Main Authors: Huang, Shu, Ma, Donghui, Sheng, Jie, Agyenim-Boateng, Emmanuel, Zhao, Jiaxi, Zhou, Jianzhong
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 24.06.2020; Elsevier BV
• Subjects: AISI 316L stainless Steel; Austenitic stainless steels; Chemical reactions; Compressive properties; Dislocation density; Elongation; Fracture morphologies; Grain boundaries; Grain refinement; Hydrogen; Hydrogen embrittlement; Hydrogen penetration; Laser peening (LP); Laser shock processing; Lasers; Martensite; Martensite transformation; Martensitic transformations; Peening; Residual stress; Slow strain rate; Stainless steel; Stretch in a hydrogen-rich environment; Surface layers; Tensile properties; Tensile tests; Ultimate tensile strength; Laser peening (LP); AISI 316L stainless Steel; Martensite transformation; Stretch in a hydrogen-rich environment; Tensile properties; Fracture morphologies
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2020.139543

Slow strain rate tensile test in a hydrogen-rich environment was performed to study the effects of laser peening (LP) on the tensile properties and martensitic transformation of AISI 316L stainless steel. Underlying physio-chemical processes involved in hydrogen embrittlement of 316L steel in the hydrogen-rich environment has been proposed. Results show that the grain refinement, mechanical twins and high-density dislocations were found in the laser peened specimens. The movement of hydrogen-carrying dislocations and martensite transformation were prevented by complex grain boundaries and high-density dislocations during tensile process. The ultimate tensile strength of the laser peened specimen were increased by 7.73% and 8.45% in air and hydrogen-rich environment respectively compared with that of non-laser peened specimen. What's more, the elongation loss of laser peened sample was far less than that of non-LP sample in a hydrogen-rich environment. LP induced compressive residual stress (CRS), grain refinement, high-density dislocations and a dense surface layer on the treated surface are beneficial for suppressing hydrogen penetration. •Tensile properties of 316L steel were improved by LP in the hydrogen-rich environment.•LP was effective for preventing martensitic transformation in 316L steel.•A dynamic hydrogen charging device was developed for tensile test in the hydrogen-rich environment.•Underlying physio-chemical processes involved in HE of 316L steel in the hydrogen-rich environment has been proposed.