Onset of Curved Dendrite Growth in an Al-Cu Welding Pool: A Phase Field Study
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A phase field model is developed to predict curved dendrite growth in the gas tungsten arc (GTA) welding pool of an Al-Cu alloy. The equations of temperature gradient, pulling velocity and dendrite growth orientation are proposed to consider the transient solidification process during welding. Solidification microstructures and solute diffusion along the fusion boundary in the welding pool are predicted by using the phase field model coupled with transient solidification conditions. Predicted primary dendrites are curved and point toward the welding direction. Welding experiments are carried out to observe solidification microstructures of the weld. Comparisons of simulation results with experimental measurements are conducted. Predicted dendritic morphology, dendrite growth orientation, primary dendrite arm spacing and initial cell spacing give a good agreement with experimental measurements.
This research is supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and financial support from the Fundamental Research Funds for the Central Universities NP2016204. The author Wang is supported by the China Scholarship Council as a visiting graduate student at Purdue University (No. 201706830042).