Abstract
A novel Ni30Cr25Al15Co15Mo5Ti5Y5 high-entropy alloy(HEA)coating was irradiated to optimize its inter-nal structure via laser after supersonic particle deposition(SPD).Owing to the high energy density of the laser and large temperature gradient,the crystallization process of the molecules and atoms in the coat-ing was restrained and supercooling occurred.Experimental results showed that a considerable number of nano-crystal grains precipitated and amorphous structures were formed because of the random ori-entation of the crystals.The baseline of differential scanning calorimetry scans obtained for the coating started to shift at the Tg of 939.37℃and a step was observed.Multiple dispersion peaks and lattice fringes indicated that the nucleation of the irradiated laser-induced topology optimized(LTO)coating was incomplete.The laser-induced topology optimizing treatment led to quasi-isotropy in the SPD coat-ing.Furthermore,the LTO coating exhibited a residual stress of 18.4 MPa,stress-strain response,and fatigue limit of 265 MPa.Hence,the LTO coating exhibited higher performance than the unirradiated SPD coating.The Nyquist and Bode electrochemical impedance spectra of the LTO coating,including two re-laxation processes,indicated that the corrosion process steadily recovered to the equilibrium state.This implies that the uniform oxidation passivation layer on the surface of the LTO coating insulated the ma-terial from the corrosive medium,protecting the substrate from further corrosion,thus enhancing the structural security of the material for use in super-intense laser facility applications.
基金项目
a grant from the Natural Sci-ence Foundation of Jiangsu Province(BK20191036)
Foundation of Research Project of China(JCKY61420051911)
NETL
NSTL
万方数据