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

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 aceted 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.

Microstructural Transition of Poly(vinyl alcohol)-based Aerogels in the Present of Interpolymer Complexes

The interpolymer interactions play a vital role of determining the microstructure and the properties of polymer aerogels. In terms of Poly (vinyl alcohol) (PVA) aerogels, the conformation and behaviour of...

Simultaneous determination of interfacial molarities of an alcohol, bromide ion, and water during an alcohol induced microstructural transition: the difference between medium and long chain alcohols

Long-chain alcohol induced micelle-to-vesicle transition is accompanied with concurrent increase of interfacial water molarity and decrease of interfacial counterion molarity.