Inconel 718 produced by laser powder bed fusion: an overview of the influence of processing parameters on microstructural and mechanical properties

Abstract

The substantial growth of laser powder bed fusion (LPBF) technology has partly been driven by its opportunity to provide high-performance complex design solutions with outstanding benefits for the aerospace industry. The key opportunities for metal additive manufacturing in aerospace applications include significant cost and lead-time reductions in addition to the possibility of highly efficient complex and lightweight designs. Inconel 718 (IN718) alloy is one of the most common materials usually employed in rocket engines, turbine blades, and turbocharges. The high geometrical complexity of the type of components demanded a detailed exploration of the LPBF of IN718 parts in the last years. As-built and post-processed IN718 LPBFed parts are covered both in terms of the processing parameters as for the metallurgical and physical properties and the mechanical properties (tensile, hardness, and fatigue properties). These complex inter-relations are presented in such a manner (graphs and tables) that can act as engineering tools for helping engineers and designers to obtain near-net-shape parts made of IN718 with the desired properties. This comprehensive overview of the influence of LPBF processing parameters on the final properties of IN718 alloy allows understanding that there is no straightforward relation between energy density and final properties of LPBFed IN718 parts. Thus, the combination of different parameters must be considered and studied individually based on the requirements of each final application. Based on these observations, challenges and future opportunities are also highlighted for the LPBF production of multi-functional IN718 aerospace parts.