Characterization of Additive Manufactured Objects

Hybrid Layered Manufacturing (HLM) combines the benefits of both subtractive and Additive Manufacturing (AM). In this paper authors did characterization of AM components by using Kernel Average Misorientation (KAM), Electron Backscatter Diffraction (EBSD) and hardness tester. The main focus is on matrix integrity during Gas Metal Arc Welding (GMAW) deposition and surface quality during machining. The primary process parameters that control the resulting mechanical properties, residual stress, microstructures, texture and misorientation have been studied under various process parameters. The effect of these process parameters on texture misorientation was studied at the three different regions of the sample using EBSD. EBSD shows the microstructure is different in the top, middle and bottom regions. It was observed that the average KAM was increased as the welding current and stepover increments are increased. The microstructure showed a distinct variation along the layer thickness due to the difference in thermal cycle and cooling sequence of each layer. The effect of welding current and stepover increment on residual stress were studied. A maximum of 117 MPa compressive residual stress was found for maximum value of welding current and stepover. Nanoindentation measurement for hardness test showed a promising result of uniform hardness at the top and bottom layers for specific processing parameters. Based on the experimental results from different combination of process parameters, the optimum process parameters for HLM process are recommended.