Surface Integrity of Additively Manufactured Workpieces after Machine Hammer Peening

Additively manufactured workpieces often exhibit issues such as porosity, roughness, and induced tensile residual stresses. The surface characteristics of such workpieces can be modified by post-processing techniques like Machine Hammer Peening (MHP). However, the influence of MHP on surface characteristics of additively manufactured workpieces has not been comprehensively studied. Thus, this study investigates the influence of MHP on surface integrity of workpieces created using wire-based Laser Metal Deposition (LMD-w) with Inconel 718 wire. The effect of secondary temperature on surface integrity is first evaluated. Following this, the impact of MHP process parameters on surface integrity is systematically investigated. The quantification of surface integrity is achieved by measuring its key aspects such as topography and surface layer characteristics, including surface roughness, waviness, hardness, recrystallization, and residual stresses. Microstructural analysis of the selected samples is conducted employing Scanning Electron Microscope (SEM) and optical microscopy. The obtained results provide valuable insights into the effectiveness of MHP on the surface integrity of LMD-w workpieces, along with practical guidelines for its optimization. Extending its impact, the study enhances the broader understanding of surface treatment in additive manufacturing.