Laser metal deposition as repair technology for Inconel 718

Abstract From an economic and sustainability point of view, repair is considered a promising alternative for high value-added aeronautical materials. In this study, laser metal deposition (LMD) was used for simulating the repair of damaged Inconel 718 (IN718) parts. Grooves were machined in IN718 substrates using abrasive water jet (AWJ) and filled with powdered IN718 alloy. Based on these results, a set of optimal LMD process parameters were selected for depositing material layers on milled substrates with various of roughness and texture levels induced by AWJ machining to evaluate the effect of surface preparation on repair quality. The substrate-deposit repair interfaces were characterized using microscopic analysis and multi-scale hardness tests. The results showed the influence of scan speed on the height of the weld bead, while increasing laser power and scan speed were both found to increase weld bead height. Dilution increased with a decrease in scan speed. Additionally, repair quality was found to be independent of the different surface conditions. Overall, the repairs exhibited excellent weldability, and were free of cracks and lack-of-fusion defects. Furthermore, microhardness measurements yielded higher values of hardness in the deposit area than in the substrate for all repairs.