Microstructure and mechanical properties of Bi₂₇In₃₈Sn₃₅ foil produced by rapid solidification

Investigations into the microstructure of Bi₂₇In₃₈Sn₃₅ alloy have shown that an increase in the melt cooling rate from 10² to 10⁵ K/s leads to a change in the solidifi cation mechanism. At a melt cooling rate of 10² K/s, we observe consecutive solidifi cation of the dendrites of the Sn₄In phase, and then that of BiIn and BiIn₂ phases in the interdendritic space. Bi₂₇In₃₈Sn₃₅ foil produced by rapid solidifi cation consists of BiIn, BiIn2, and Sn4In phases forming a lace-like structure. The foil′s chemical composition determined by X-ray spectral analysis was constant in thickness. Alloy foil phase grains have a microcrystalline structure and texture. The aging of rapidly solidifi ed foil at room temperature causes size enlargement in phase and grain precipitations, which determines the change in its physical properties. Foil aging causes an increase in microhardness and affects tensile deformation: there is consolidation of rapidly solidifi ed alloy at the initial stage of deformation and a reduction in its plasticity
Investigations into the microstructure of Bi₂₇In₃₈Sn₃₅ alloy have shown that an increase in the melt cooling rate from 10² to 10⁵ K/s leads to a change in the solidifi cation mechanism. At a melt cooling rate of 10² K/s, we observe consecutive solidifi cation of the dendrites of the Sn₄In phase, and then that of BiIn and BiIn₂ phases in the interdendritic space. Bi₂₇In₃₈Sn₃₅ foil produced by rapid solidifi cation consists of BiIn, BiIn2, and Sn4In phases forming a lace-like structure. The foil′s chemical composition determined by X-ray spectral analysis was constant in thickness. Alloy foil phase grains have a microcrystalline structure and texture. The aging of rapidly solidifi ed foil at room temperature causes size enlargement in phase and grain precipitations, which determines the change in its physical properties. Foil aging causes an increase in microhardness and affects tensile deformation: there is consolidation of rapidly solidifi ed alloy at the initial stage of deformation and a reduction in its plasticity
Author:  S. V. Gusakova, V. G. Shepelevich,O. V. Gusakova
Keywords:  bismuth, indium, stannum (tin), lead-free solder, grain, texture, phase, microhardness, specifi c surface.
Page:  534-540