Microstructure Evolution in Immiscible AlSiBi Alloys Under Reduced Gravity Conditions

摘要: Strip cast Al−Si−Bi alloys were directionally melted and solidified in the Isothermal Heating Facility (IHF) of Werkstofflabor on board Spacelab mission D2. The main objective experiment was to investigate microstructure evolution during melting solidification exhibiting a miscibility gap liquid state. rearranges from an evenly distributed dispersion soild Bismuth particles solid AlSi matrix due thermocapillary motion Bi-rich droplets microgravity. strip casting process provides material with well-defined particle dispersion. Two runs performed successfully. Samples Bi-content 7 wt.% two different rates solidified. Their as-solidified microstructures clearly show that Bi moved by as anticipated. mean size increased factor droplet distribution exhibits maximum very big droplets, revealing coalescence drops contributed coarsening results are analyzed numerical modell for such alloys: Discrete Multi-Particle Approach (DMPA) is presented some detail applied results.