Microstructure and morphology of Si crystals grown in pure Si and Al-Si melts

• Main Authors: Toropova, L. V., Alexandrov, D. V., Rettenmayr, M., Liu, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing Ltd 2022
• Subjects: DENDRITE; DENDRITE TIP; INTERFACE SHAPE; PHASE TRANSFORMATION; SILICON; ALUMINUM COMPOUNDS; CRYSTAL GROWTH; CRYSTALS; ELECTROMAGNETIC PROPULSION; MORPHOLOGY; UNDERCOOLING; ELECTROMAGNETIC LEVITATION; FEATHERY STRUCTURE; MELT UNDERCOOLING; PHASES TRANSFORMATION; PRIMARY SI; SI CRYSTALS; UNDERCOOLINGS; DML
• Online Access: http://elar.urfu.ru/handle/10995/132465; https://doi.org/10.1088/1361-648x/ac3792

Microstructure of Al-40 wt%Si samples solidified in electromagnetic levitation furnace is studied at high melt undercooling. Primary Si with feathery and dendritic structures is observed. As this takes place, single Si crystals either contain secondary dendrite arms or represent faceted structures. Our experiments show that at a certain undercooling, there exists the microstructural transition zone of faceted to non-faceted growth. Also, we analyze the shape of dendritic crystals solidifying from liquid Si as well as from hypereutectic Al-Si melts at high growth undercoolings. The shapes of dendrite tips grown at undercoolings >100 K along the surface of levitated Al-40 wt%Si droplets are compared with pure Si dendrite tips from the literature. The dendrite tips are digitized and superimposed with theoretical shape function recently derived by stitching the Ivantsov and Brener solutions. We show that experimental and theoretical dendrite tips are in good agreement for Si and Al-Si samples. © 2022 IOP Publishing Ltd. Deutsche Forschungsgemeinschaft, DFG, (Re1261/23) Russian Science Foundation, RSF, (21-79-10012) LVT gratefully acknowledges fruitful discussions about the theoretical results with Prof. Peter Galenko, and financial support from the Russian Science Foundation (Project No. 21-79-10012). MR and DML are grateful for financial support by Deutsche Forschungsgemeinschaft, Grant Re1261/23.