Understanding of grain growth and texture formation of Inconel 718 processed by single-track laser scanning

The advantageous weldability of Inconel 718 proves highly beneficial for metal additive manufacturing. The grain structure and texture of Inconel fabricated by selective laser melting (SLM) are interesting due to their impact on corresponding mechanical properties. The grain growth generally follows <001> direction, but the understanding of texture formation along printing and scanning directions, affected by the thermal history of melting and cooling, is still challenging, which limits the texture design. As Laser Powder Bed Fusion (LPBF) has many variables from laser-powder interaction and the overlap of different molten layers, this talk will use SLM single track to reduce the variables and facilitate the understanding of the development of grain and texture in Inconel 718. Three different laser scanning rates were selected to transition from conduction mode to keyhole mode, and the thermal histories from the melting and cooling processes were collected by an in situ thermal camera with a frame rate up to 1800 frames/s. A relationship between scanning rate, thermal history, melt pool geometry, texture formation will be discussed.