Observation of Bi Coarsening and Dissolution Behaviors in Melting Al–Bi Immiscible Alloy

Using synchrotron radiography,a melting process of the Al-10 wt%Bi immiscible alloy was fully observed,and Bi solute coarsening and dissolution behaviors as well as their effect on the microstructural evolution were also investigated.We found that two different steps including coarsening and dissolution processes can be used to describe the structure evolution in melting Al-10 wt%Bi immiscible alloy.And diffusion coalescence controlled the coalescence of Bi droplets at the early stage of the melting Al-10 wt%Bi immiscible alloy,while the coagulation during movement did at later stage.Also,the larger the droplet,the larger the distance of the steady-state concentration distribution around the droplet.