Effects of solidification thermal parameters on microstructure and mechanical properties of Sn-Bi solder alloys

Silva, Bismarck Luiz; Silva, Vítor Covre Evangelista da; Garcia, Amauri; Spinelli, José Eduardo

Effects of solidification thermal parameters on microstructure and mechanical properties of Sn-Bi solder alloys

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dc.contributor.author	Silva, Bismarck Luiz
dc.contributor.author	Silva, Vítor Covre Evangelista da
dc.contributor.author	Garcia, Amauri
dc.contributor.author	Spinelli, José Eduardo
dc.date.accessioned	2021-03-12T15:14:30Z
dc.date.available	2021-03-12T15:14:30Z
dc.date.issued	2017-01-10
dc.description.resumo	Samples extracted along the length of directionally solidified (DS) castings of three Sn-xBi alloys (x = 34 wt.%Bi, 52 wt.%Bi and 58 wt.%Bi) were first evaluated metallographically and then subjected to scanning electron microscopy and energy-dispersive x-ray spectroscopy analyses. The characteristic length scale of both eutectic and dendritic phases forming the microstructure were determined and correlated with solidification thermal parameters (growth rate V, and cooling rate Ṫ). Tensile and Vickers hardness tests were performed to allow strength and ductility to be discussed as a function of both microstructure features and alloy solute content. The tertiary dendrite arm spacings along the length of the DS Sn-52 wt.%Bi alloy casting are shown to be lower than those obtained for the Sn-34 wt.%Bi alloy casting. The results of mechanical tests show that, with the decrease in the alloy Bi content, both tensile strength and hardness are improved. This is shown to be mainly attributed to the higher density of Bi precipitates decorating the Sn-rich dendrites, which are finer than the equivalent phase developed for the Sn-52 wt.%Bi alloy. However, the ductility is shown to be significantly improved for specimens associated with regions of more refined microstructure of the Sn-52 wt.%Bi alloy DS casting. A microstructure combining much branched dendrites, fine Bi particles within the β-Sn dendritic matrix and an important proportion of very fine eutectic formed by alternate Bi-rich and Sn-rich phase, seems to be conducive to this higher ductility. In this case, the fracture surface is shown to be more finely broken with presence of dimples for this particular condition, i.e., characteristic of a ductile fracture mode	pt_BR
dc.identifier.citation	Bismarck, L.S.; SILVA, V. C. E.; Garcia, A. ; SPINELLI, J. E.. Effects of Solidification Thermal Parameters on Microstructure and Mechanical Properties of Sn-Bi Solder Alloys. Journal of Electronic Materials, v. 46, p. 1754-1769, 2017. Disponivel: https://link.springer.com/article/10.1007%2Fs11664-016-5225-7 Acesso em: 26 jan. 2021. https://doi.org/10.1007/s11664-016-5225-7	pt_BR
dc.identifier.doi	10.1007/s11664-016-5225-7
dc.identifier.issn	0361-5235
dc.identifier.issn	1543-186X
dc.identifier.uri	https://repositorio.ufrn.br/handle/123456789/31836
dc.language	en	pt_BR
dc.publisher	Springer	pt_BR
dc.rights	Attribution 3.0 Brazil	*
dc.rights.uri	http://creativecommons.org/licenses/by/3.0/br/	*
dc.subject	Sn-Bi alloys	pt_BR
dc.subject	Solidification	pt_BR
dc.subject	Microstructure	pt_BR
dc.subject	Bi precipitates	pt_BR
dc.subject	Tensile strength	pt_BR
dc.subject	Fracture surface	pt_BR
dc.title	Effects of solidification thermal parameters on microstructure and mechanical properties of Sn-Bi solder alloys	pt_BR
dc.type	article	pt_BR