Abstract
During the laser based manufacturing process such as metal additive manufacturing (AM) and laser cladding, enhancing or inhibiting liquid metal flow within the laser-induced melt pool provides a promising approach to tune material microstructure and the resulting mechanical properties. However, the effect of convection flow, specifically the dominant Marangoni convection flow in the melt pool, on the as-solidified material microstructure is still vague. This study aims to reveal convection-modified grain evolution in the laser melting process, e.g., the selective laser melting AM. We use a process-microstructure model and systematically design comparative simulation cases (with and without convection flow) to identify the effects of convection flow on melt pool geometry, solidification conditions, and as-solidified grain structure formation. The model is validated by secondary electron images and electron backscatter diffraction of the laser melted IN625 alloy provided by NIST Additive Manufacturing Benchmark Test Series. It is found that the strong Marangoni convection flow can widen the melt pool and notably affect the solidified microstructure in terms of grain growth directions and bulk nucleation events. This study provides a quantitative basis for controlling the as-solidified microstructure by manipulating the convection flow in the laser-induced melt pool.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.