Thermal manipulation of containerless processing for eutectic Zr-V refractory alloy under microgravity

： Containerless processing under microgravity provides a suitable platform for solidification of refractory alloys. However, there exit great challenges to investigate the complete thermal history of refractory alloys, from laser heating and melting to radiative cooling and undercooling. Based on the space thermal features of solidification experiments, a computational multiphysics model was proposed that integrates heat transfer, the Navier-Stokes equations, and the apparent heat capacity method to design different thermal manipulation strategies. The calculated thermal history reproduced the measured heating, melting, and cooling trends, supporting the use of the model for analyzing temperature evolution during these stages. The parametric research results of thermal manipulation revealed that laser power and sample size significantly influence the melting process by regulating the heating rate. Numerical parametric analyses further indicated that the cooling rate and accessible undercooling range can be regulated by sample size and laser heating, thereby providing an operating window for tailoring eutectic solidification in microgravity experiments. It was discovered that the directional trunk and branching eutectic features were formed as unique eutectic skeletons such as feather-like and trident structures, owing to nucleation and growth from multiple directions and the difference in growth velocity between the two eutectic phases. These results provide further insight to explore the effects of thermal manipulation strategy on rapid eutectic solidification under microgravity.