Laser-irradiation-induced dynamically recrystallized microstructure and properties of supersonic-particle-deposited Ni-Fe-Cr-Nb-Ti-Al high-entropy alloy coating

Abstract

A recrystallization-refined Ni-Fe-Cr-Nb-Ti-Al high-entropy alloy coating was prepared by supersonic particle deposition followed by laser irradiation. The surface-interface morphology, microstructure, grain orientation, and phase were examined by scanning electron microscopy, energy-dispersive spectrometry, electron backscatter diffraction, and X-ray diffraction analyses, respectively. The inverse pole figure of the coating showed that a large number of ultrafine grains and even nanograins filled the entire microscopic image. In addition, the refined grains did not show obvious preferred orientations and indicated isotropic features. Further, the fatigue limit of the recrystallized coating was 252 MPa, and the ability to realize uniform plastic deformation and stable deformation was enhanced owing to the high tensile strength and elongation ratio, which were 3000 MPa and 14%, respectively. The coating had a friction coefficient of 0.189, residual stress of −14.3 ± 6 MPa, and microhardness of 720 kgf/mm 2 . The capacitance radius of the Nyquist plot indicated that passivation formation improved the shielding performance of the coating. • A recrystallization refining coating was prepared by LR on Al-alloy after SPD. • The UFGs and NGs showed diversified preferred orientation and isotropic feature. • The ability of uniform plastic deformation and stable deformation were enhanced. • The Nyquist showed the passivation improved coating shielding performance. • The friction coefficient was negatively correlated with the hardness.