Mechanical and chemical post-treatments for enhancement in tribological performance of laser powder directed energy deposited Inconel 625

Abstract

Laser powder-directed energy deposition (LP-DED) technique has shown tremendous potential to fabricate high-performance superalloy parts for real engineering applications. However, certain disadvantages like poor surface quality and incompetent mechanical and wear properties limit its practical usage. Hence, the current work investigates the effect of different post-processing techniques, including laser shock peening (single shot) (LSP1), laser shock peening (three shots) (LSP2), shot peening (high pressure) (SP1), shot peening (low pressure) (SP2), glass bead blasting (GB), sand blasting (SB), and electroless coating (EC) on the surface quality, hardness, and wear resistance of Inconel 625 (IN625) samples fabricated by LP-DED technique. EC sample resulted in the least surface roughness value (0.09 µm), whereas LSP2 sample exhibited the highest increase of 32.4 % in hardness compared to the as-polished (AP) sample. This can be attributed to grain refinement and the plastic deformation in the samples. Further, the wear test confirmed that LSP2 sample resulted in the lowest coefficient of friction (0.6) and wear rate (0.58 × 10-4 mm3/N.m) among the post-processed samples. © 2025 Elsevier B.V.