Microstructure evolution during indentation of Inconel-718 created by additive manufacturing

Finishing of components originating from additive manufacturing (AM) is critically important for providing them with adequate tolerances and fatigue life. These processes often rely on surface deformation for removal of roughness features and enhancing the underlying microstructures. Optimization of finishing processes is however challenging for AM components as their mechanics of deformation is complicated by microstructure/defect/roughness combinations present in as-received surfaces. In this work, the mechanics of surface deformation in additively manufactured IN718 is studied via indentation. Effects of graded surface microstructure, surface texture and porosity defects on microstructure evolution trajectories are delineated. Using these insights, a finite element based numerical framework of surface deformation of additively manufactured IN718 is created. Utility of this framework in analysis of surface deformation of various microstructure/defect/roughness combinations is demonstrated. Implications of these insights in the optimization of finishing processes of various additively created parts is discussed.