Evaluation of Microstructure, Residual Stress, and Mechanical Properties in Different Planes of Wire + Arc Additive Manufactured Nickel-Based Superalloy

The present study investigates microstructure, mechanical characteristics, and residual stresses of alloy C-276 thick wall component manufactured by wire arc additive manufacturing technique. The microstructure of the fabricated thick wall part has been analysed in various regions. The microstructure at the top, intermediate, and bottom regions result in equiaxed, cellular, and columnar dendrites. Microsegregation was evaluated in the interdendritic regions of the top, intermediate, and bottom surfaces and in travel and build directions. Further in electron backscatter diffraction investigates the texture and microstructure of materials by utilising the inverse pole figure and grain boundary maps in travel and build directions. Also, as compared to low angle grain boundaries, the fraction of high angle grain boundaries is higher in build direction than travel direction. Further, residual stress analysis exhibits the tensile residual stress in the travel direction compared to build direction and compressive stresses were induced in the top region of the deposited part in the build direction. Also, no substantial deviations of microhardness values were in multiple as-deposited regions. Typically, the tensile properties of the material vary significantly across various direction such as horizontal, vertical and inclined. The higher tensile strength observed in the horizontal direction (745 ± 6.2 MPa) compared to vertical and inclined directions. This study provides better insights into the additively manufactured nickel-based superalloy's microstructure, residual stress and mechanical properties.