Fabrication of micro-nano multi-scale hierarchical porous structure on the surface of Inconel718 nickel-base superalloy by one-step method

Abstract

A new high-efficiency composite process consisting of laser machining and abrasive belt grinding was proposed to prepare multi-scale graded microstructures on the surface of Inconel718 nickel-base superalloy for aviation. The scheme is based on the machining characteristics of abrasive belt grinding, low damage molding and high-efficiency grinding and polishing, the effective combination of ultrashort pulse laser-induced surface microstructure growth, and the thermal effect in the process of high-energy beam machining, so as to realize the efficient preparation of hierarchical microstructure. In the one-step forming process, the accuracy of the material surface is ensured by abrasive belt grinding. The porous microstructure on the surface is catalyzed by the thermal effect produced by the high-energy beam laser. The scale of the porous structure is 3 µm–6 µm, the pore surface will generate nanoparticles, the size is below 100 nm, and dense nanoparticles will be generated on the surface. The porous structure can be super hydrophilic and adsorbed to form a liquid membrane. The formation of rib-like microstructures on the surface induced by ultrashort pulse laser makes the liquid film have directional spreading properties. Rib-like microstructure height is 50 µm–150 µm and it can be adjusted by setting the scanning line width. The one-step method for preparing hierarchical microstructures proposed in this study can efficiently process large-area microstructure surfaces with different wetting properties. • The porous structure, nanoparticles, and rib-like bulges can be efficiently fabricated. • The microstructure can be easily regulated.