3rd TAGRA

This study the effect of post-heat-treatment routes on the microstructure, mechanical properties, and tribological behaviour of Wire-Laser Metal Deposition (Wire-LMD) fabricated Inconel 718. Initially, the Inconel 718 wire was additively manufactured with a Meltio M450 system for fabricating large and dense metallic components with minimal material wastage. The fabricated Inconel 718 was subjected to Direct Aging (DA), Solution Treatment and Aging (STA), and Homogenization plus Solution Treatment and Aging (HSTA). The microstructural evolution was examined using optical microscopy, Field Emission Scanning Electron Microscope (FESEM), and Energy Dispersive Spectroscopy (EDS) analysis to assess phase distribution and elemental homogeneity. Vickers microhardness measurements were conducted to evaluate the strengthening response due to heat treatment. Dry reciprocating wear tests were performed used ball on disc tribometer under varying normal loads to study wear behaviour, supported by 3D profilometry and worn surface morphology analysis. The as-deposited sample exhibited columnar dendrites, elemental segregation, and Nb-rich Laves phases, resulting in lower hardness and inferior wear resistance. Heat treatment significantly modified the microstructure by promoting precipitation and dissolving deleterious Laves phases. Among the investigated conditions, the HSTA treatment resulted in the highest hardness and lowest wear rate due to improved microstructural homogeneity. The study establishes a clear correlation between heat treatment, microstructure, hardness, and wear mechanisms, highlighting the effectiveness of HSTA for enhancing the tribological performance of Wire-LMD Inconel 718.