Atomistic insight into dendrite growth orientation transition in Al-Cu alloy

A Swamy and D Dolce and P Choudhury, MATERIALS TODAY COMMUNICATIONS, 37, 107404 (2023).

DOI: 10.1016/j.mtcomm.2023.107404

In this study, we investigate the impact of solid-melt interfacial energy anisotropy on the microstructure of components. Our focus is on the Al-Cu system's Al-rich side, where we compute the solid-melt interfacial free energy and its anisotropy using Molecular Dynamics (MD) simulations. Our findings reveal that, as the Cu concentration in the melt increases, the preferred dendrite growth orientation shifts from <100> to <110>. Furthermore, atomic density profile analysis shows an improvement in ordering in the (110) plane at higher Cu concentrations. Our results suggest that the transition in dendrite growth orientation is a consequence of the weakened anisotropy between (100) and (110) interfacial energies at higher Cu concentrations and undercooling temperatures. We also observe displaced atomic density profiles between Al and Cu atoms in proximity to the interface. We propose that a displaced atomic density profile between solute and solvent atoms could be a characteristic feature of systems undergoing a dendrite orientation transition.

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