Dynamic Localization Effect of Dendritic and Eutectic Growth Patterns Stimulated by Space Fluid Flow.

Area of Science:

• Materials Science
• Solidification Physics
• Space Science

Background:

• Conventional solidification theory predicts fixed eutectic morphologies and parabolic dendritic tips under negligible volume effects.
• Terrestrial gravity-induced convection disrupts ordered phase separation during solidification.
• Microgravity offers a unique environment to study fundamental solidification processes.

Purpose of the Study:

• To investigate the influence of space fluid flow on eutectic and dendritic growth patterns.
• To understand the mechanisms driving transitions in solidification morphologies under microgravity.
• To explore applications in space manufacturing and controlled crystal growth.

Main Methods:

• Experiments conducted aboard the China Space Station.
• Observation of eutectic and dendritic growth dynamics under microgravity.
• Analysis of solute-thermal coupling and Marangoni convection effects.

Main Results:

• Space fluid flow localized solute-thermal coupling, inducing transitions among worm-like, lamellar, and faceted eutectic growth patterns.
• Marangoni convection at large undercoolings resulted in non-parabolic dendritic tip morphologies (dome-like, finger-like, needle-like).
• Ordered separation of eutectic and dendritic zones was observed, governed by localized temperature and concentration fields, unlike in terrestrial gravity.

Conclusions:

• Microgravity conditions, driven by space fluid flow, significantly alter solidification dynamics, leading to novel growth patterns.
• The findings challenge conventional solidification theories and highlight the importance of fluid flow in phase transitions.
• This research has implications for in-situ resource utilization and advanced material manufacturing in space.