Effects of laser shock processing on the microstructure evolution and the oxidation behavior of TP347H austenitic steel in supercritical water environment

• Published in: Materials chemistry and physics 2024-09, Vol.323, p.129629, Article 129629
• Main Authors: Zhang, Tianyi, Zhu, Zhongliang, Zhang, Naiqiang
• Format: Article
• Language: English
• Subjects: Austenitic steel; Laser shock processing; Oxidation; Plastic deformation layer; Supercritical water
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2024.129629

The effects of laser shock processing (LSP) treatment on TP347H austenitic steel were investigated through exploring the residual stress distribution, the evolutions of microstructure and the oxidation behavior in supercritical water (SCW, 640 °C/27 MPa). Results show that the plastic deformation layer (PDL) and the compressive residual stress (about −550 MPa maximum value) were detected on TP347H after LSP, and the fine grain layer existed in PDL. Due to the compressive residual stress in PDL, TP347H after LSP presented an excellent oxidation resistance in SCW, presenting oxidation rate of 0.5–0.8 times compared with TP347H. This was mainly attributed to the increased molar volume of Cr in PDL, leading to the existence of the stress-dependent chemical potential (μs) of Cr. μs promoted the formation of Cr2O3 and FeCr2O4, and improved the diffusion flux of Cr during oxidation. •The plastic deformation layer (PDL) and the gradient residual compressive stress were detected on TP347H after laser shock processing (LSP).•The oxidation behavior of TP347H after LSP was improved, presenting a low oxidation rate and a high Cr containing substance in oxidation layer.•The evolution of the molar volume of Cr induced by the stress-dependent chemical potential in PDL was discussed in detail.