Investigation of triple-coalescence behaviors for comprehensively understanding the structural evolution of coalesced TiAl droplets from an atomic-level view

摘要

Although great progress has been made in the study of binary-coalescence dynamics, the coalescence behavior of multiple droplets remains to be further investigated as it plays a pivotal role in many industrial processes and advanced technologies. Here, the triple-coalescence dynamics of three metallic droplets are studied by employing molecular dynamics (MD) simulation. Firstly, simulation results give visible evidence that the coalescing process would be favorable when droplets are closely arranged or more liquid bridges are formed. Then, the triple-coalescence behaviors of one Al and two Ti droplets are explored by considering two strategies. When the Al droplet is initially located on the side position, a nonsynchronous coalescing behavior caused by the combination effect of preferential coalescing between two adjacent Ti droplets and "swallowing" coalescing of the Al droplet is observed, leading to some distinct transient segregation microstructures of the coalesced TiAl droplets that are highly sensitive to the arrangement mode during the structural evolution, which prolongs the formation of a homogeneous TiAl droplet. In another strategy involving one center Al droplet, however, the coalescing behavior changes to be synchronous, inducing a "sandwich-like" configuration of the TiAl droplet, which is beneficial to rapidly obtain a homogeneous microstructure of the coalesced TiAl droplet. (C) 2020 Elsevier B.V. All rights reserved.