Solidification of tin on quasicrystalline surfaces

Abstract

A two-phase alloy of β-Sn and Al₆₃Cu₂₅Fe₁₂ quasicrystal produced by melt-spinning was annealed and aged to form various microstructures of tin in a quasicrystalline (QC) or microcrystalline (MC) matrix. The morphology and structure of the interfaces was studied by scanning and transmission electron microscopy and was related to melting and solidification behavior of tin studied by differential scanning calorimetry. In a MC matrix the tin phase occurred as nanoparticles and solidified with an undercooling of about 35°C. In a QC matrix, tin formed intergranular layers on faceted matrix grains. Tin showed multiple solidification peaks in undercooling ranging from 8°C to 43°C, indicating several distinct nucleation sites which compete with each other and are selected kinetically. The interfacial energy (depending on the structural state of the matrix) had a more dominating effect on the solidification of tin than the size, shape and the distribution of the tin particles. It was also concluded that solidification of tin is easier on quasicrystalline surfaces than on aluminum.

Keywords:

• quasicrystal
• tin
• solidification
• transmission electron microscopy
• phase transformation

Acknowledgements

This work is supported by Japan Society for Promotion of Science under grant Kakenhi 19560671 (AS) and 19540382 and 21540330 (YM).