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  • Effect study and applicatio...
    Nie, Xiangfan; He, Weifeng; Zang, Shunlai; Wang, Xuede; Zhao, Jie

    Surface & coatings technology, 08/2014, Letnik: 253
    Journal Article

    Laser shock peening (LSP) is an effective surface treatment for improving fatigue resistance of metallic materials, in which high-amplitude beneficial residual stresses and structure changes can be produced. In aero-engines, the compressor blade made of TC11 titanium alloy was prone to result in high cycle fatigue (HCF) failure. The aim of this paper was to utilize LSP with befitting parameters to improve the HCF performance of TC11 titanium alloy. Firstly, the microstructure and mechanical properties of TC11 titanium alloy with different LSP impacts were observed and measured via transmission electron microscope (TEM), residual stress tester and microhardness tester. High-density dislocations and nanostructure were observed in the surface layer. High-amplitude compressive residual stresses were induced and microhardness was remarkably improved. According to the effects, a set of LSP parameters with three LSP impacts was confirmed and applied on standard vibration specimens. Vibration fatigue tests were conducted to validate the strengthening effect on HCF strength. The fracture mechanism was analyzed by fracture analysis. The strengthening mechanism of LSP was indicated by establishing the relationship between fatigue characteristics and effects on residual stress and microstructural changes. •High-density dislocations and nanostructure are generated after LSP processing.•With LSP impacts increased, nano-grains get smaller and more uniform.•The fatigue strength of TC11 titanium alloy is improved from 483.2MPa to 593.6MPa.•The strengthening mechanism was indicated by LSP effects for fatigue behavior.