Abstract
In order to improve fatigue life of GH3039 superalloy, GH3039 superalloy sheets were treated by laser shock peening (LSP). The microstructure of GH3039 superalloy before and after LSP was characterized using an optical microscope, transmission electron microscope (TEM), and X-ray diffractometer. The fatigue life of the samples with and without LSP was investigated by fatigue experiments. Moreover, surface profile and residual stress were also examined. Experimental results indicated that the grains in the surface layer of the LSP sample were remarkably refined and reached the nanometer scale. The average surface roughness increased from 0.024 μm to 0.19 μm after LSP. The average fatigue life of the laser treated samples was 2.01 times larger than that of the untreated specimens. Additionally, mathematical statistical analysis confirms that LSP has a significant influence on the fatigue life of GH3039 superalloy. The improvement of fatigue life for the laser processed GH3039 superalloy was mainly attributed to compressive residual stress and grain refinement generated by LSP.
Highlights
As a solid solution strengthened austenitic alloy, the nickel-based superalloy GH3039 has been widely used for critical parts of aeroengines due to its excellent mechanical properties, good anti-oxidation, and high corrosion resistance [1,2,3]
Zhou et al [10] indicated that the fatigue life of the laser treated TC4 specimens increased by 107.86% relative to the original specimens
The objective of this paper is to provide a technological and theoretical basis for laser shock peening (LSP) technology application in aeroengine
Summary
As a solid solution strengthened austenitic alloy, the nickel-based superalloy GH3039 has been widely used for critical parts of aeroengines due to its excellent mechanical properties, good anti-oxidation, and high corrosion resistance [1,2,3]. In order to decrease damage of parts under extreme working conditions, surface treatment technologies, such as shot peening [4], cavitation peening [5], deep cold rolling [6], and laser shock peening (LSP) [7], are utilized to improve the service life of key parts. Comparing with other surface treatment methods, LSP, as an innovative surface processing technology, can significantly improve fatigue resistance of metallic materials by introducing deeper residual compressive stress layer and ultrahigh strain rate plastic deformation [8]. Zhou et al [10] indicated that the fatigue life of the laser treated TC4 specimens increased by 107.86% relative to the original specimens. LSP was employed to realize the microstructure change in the surface layer of the metallic materials. Ren et al [11]
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