Microstructure and hot corrosion behavior of the Ni-based superalloy GH202 treated by laser shock processing

Journal Article · Wed Mar 15 04:00:00 EDT 2017 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2017.01.021· OSTI ID:22689726

Cao, Jiangdong ^[1]; Zhang, Junsong ^[1]; Hua, Yinqun ^[1]; Chen, Ruifang ^[2]; Li, Zhibao ^[1]; Ye, Yunxia ^[2]

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1. School of Material Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)

The effects of laser shock processing on microstructure, the residual stress, and hot corrosion behavior of the Ni-based superalloy GH202 were investigated. The microstructures of GH202 before and after laser shock processing (LSP) were characterized by electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). A large number of crystal defects (twins, dislocation arrays, and high dense tangles) were generated on the surface of GH202 treated with LSP. The cross-sectional compressive residual stress and micro-hardness of specimens treated by LSP were improved significantly. The corrosion kinetics of GH202 with or without LSP treatment at 800 °C and 900 °C were investigated. Analysis by X-ray diffraction (XRD) revealed that the corrosion products mainly consist of Cr{sub 2}O{sub 3}, TiO{sub 2}, Al{sub 2}O{sub 3}, NiO, CrS, Ni{sub 3}S{sub 2}, and Na{sub 2}CrO{sub 4}. The surface and cross-section morphologies were observed by scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS). The results confirmed that the crystal defects induced by LSP promotes the creation of diffusion paths for elements (Cr, Al, and Ti), allowing the formation of tiny homogeneous oxidation films in a very short time. Additionally, the spallation of oxidation film on the treated specimens was alleviated significantly. Overall, the hot corrosion resistance of Ni-based GH202 induced by LSP was improved in Na{sub 2}SO{sub 4} and NaCl molten salt from 800 °C to 900 °C. - Highlights: • Microstructure changes of GH202 before and after LSP were observed by EBSD and TEM. • The hardness and residual compressive stress after LSP were significantly increased. • The increased diffusion paths for elements helped to form oxidation films quickly. • Hot corrosion resistance of GH202 after LSP was significantly improved.

• OSTI ID: 22689726
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 125; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
BACKSCATTERING
CHROMIUM OXIDES
CORROSION
CORROSION PRODUCTS
CORROSION RESISTANCE
DISLOCATIONS
ELECTRON DIFFRACTION
HARDNESS
HEAT RESISTING ALLOYS
MICROSTRUCTURE
NICKEL BASE ALLOYS
NICKEL OXIDES
OXIDATION
RESIDUAL STRESSES
SCANNING ELECTRON MICROSCOPY
SODIUM CHLORIDES
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION