The Process Parameters Extended Criterion for Laser Engineered Net Shaping of Inconel 738

Laser engineered net shaping processing has been an efficient technique for the rapidly manufacturing high-temperature superalloy parts in recent years. While, for the high crack susceptibility superalloy such as Inconel 738 alloy, the current flawless processing window is very narrow and resultantly limits the application of laser engineered net shaping processing in the area of turbine engines due to discreteness and complexed mutual correlation of the process parameters. In this work, experiments were conducted to study the effect of processing parameters such as laser power and scanning speed on the formability, especially the crack formation and distribution, of laser manufactured Inconel 738 alloy. The results indicate that the element Ti segregation and low-meting point \( \upgamma/\upgamma^{{\prime }} \) eutectic generation at the high-angle grain boundary lead to continuous liquid film form during the heating process and then generates cracks under the induction of inclusions such as carbides during the cooling of periodic depositing process. Reducing the element, Ti segregation by optimizing processing parameters and suppression of the remolten of \( \upgamma/\upgamma^{{\prime }} \) eutectic during the periodic depositing process can efficiently expand the flawless window for the directly manufacturing Inconel 738 alloy by laser engineered net shaping process.