Tailored Microstructures of SLM Inconel 718 Achieved through Process Parameter Control

Additive manufacturing (AM) gives users tremendous freedom in the production of parts. Geometries not attainable through traditional machining may be achieved, and tailored microstructures unique to specific applications can be designed in. This study focuses on achieving tailored microstructures of Inconel 718 by selective laser melting (SLM). It is shown that through varying specific process parameters—laser focal shift and scanning strategy—the microstructure can be adjusted to improve mechanical performance. Through the use of a defocused laser, large columnar grains are formed in the as-built condition that persist through post-processing treatments. Scanning with continuous laser tracks as opposed to the island scanning strategy also produces a variation in the microstructure. Observed mechanical properties were affected by the tailored microstructure, showing improvement in the intended areas. Hardware that may require different functionality at various locations within the same part can be achieved through microstructural tailoring based on laser focus shift and scanning strategy.