Wrinkled Shrinkage on Surface Monophasic Structure of Floating Refractory Alloy Droplets Solidified in Space Environment

The surface-wrinkled shrinkage structure of spheres is very common and also quite intriguing to explore and reveal the analogous droplet solidification kinetics in the space environment. Here, a liquid-to-solid phase transition experiment of floating refractory alloy droplets is designed to study the surface wrinkled shrinkage structures aboard China Space Station with a 10⁻⁵ gravity level. The experimental Ti-Ni-V alloy droplets undergo an extremely high overheating temperature beyond 1800 K and then achieve a supercooling of 307 K, displaying a strong thermodynamic metastability. The spherical surface deformation structures of this alloy under microgravity coupled with extreme metastable solidification are explored. Moreover, through the active control of metastable rapid solidification, a surface monophasic structure and a B2 structure capable of stress-induced martensitic transformation are facilitated by wrinkled shrinkage dynamics under microgravity. Their findings shed further light on the surface deformation structures during the microgravity solidification process.