Open AccessColumnar-to-equiaxed transition in a laser scan for metal additive manufacturing
Author(s) -
Lang Yuan,
Adrian S. Sabau,
Gui Wang,
Arvind Prasad,
P D Lee
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/861/1/012007
Subject(s) - equiaxed crystals , materials science , microstructure , nucleation , laser power scaling , selective laser melting , laser , temperature gradient , thermal , fusion , fabrication , composite material , metallurgy , optics , thermodynamics , medicine , linguistics , physics , philosophy , alternative medicine , pathology , quantum mechanics
In laser powder bed fusion additive manufacturing (LPBFAM), different solidification conditions, e.g., thermal gradient and cooling rate, can be achieved by controlling the process parameters, such as laser power and laser speed. Tailoring the behaviour of the columnar to equiaxed transition (CET) of the printed alloy during fabrication can facilitate the production of highly customized microstructures. In this study, effective analytical solutions for both thermal conduction and solidification are employed to model solidifying melt pools. Microstructure textures and solidification conditions are evaluated for numerous combinations of laser power and laser speed under bead-on-plate conditions. This analytical-based high-throughput tool was demonstrated to select specific process parameters that lead to desired microstructures. Two selected process conditions were examined in detail by a highly parallelized microstructural solidification model to reveal both nucleation and grain growth. Both numerical solutions agree well with experiments that are performed based on bead-on-plate conditions, indicating that these numerical models aid evaluation of the nucleation parameters, providing insights for controlling CET during the LPBFAM processing.