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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Cooling thermal parameters and microstructure features of directionally solidified ternary Sn-Bi-(Cu,Ag) solder alloys

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Silva, Bismarck L. [1] ; Garcia, Amauri [2] ; Spinelli, Jose E. [1]
Total Authors: 3
[1] Univ Fed Sao Carlos, UFSCar, Dept Mat Engn, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Estadual Campinas, UNICAMP, Dept Mfg & Mat Engn, BR-13083860 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: MATERIALS CHARACTERIZATION; v. 114, p. 30-42, APR 2016.
Web of Science Citations: 14

Low temperature soldering technology encompasses Sn-Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 degrees C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi-Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn-Bi-(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn-Bi-(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the micro structural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn-Bi-Cu and Sn-Bi-Ag alloys examined. (C) 2016 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 13/08259-3 - Microstructure and mechanical behavior of Sn-Bi-Cu and Sn-Bi-Ag lead-free solder alloys
Grantee:Bismarck Luiz Silva
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 13/13030-5 - Microstructure, thermal parameters, segregation and mechanical properties of lead-free Sn-based, Zn-based and Bi-based solder alloys
Grantee:José Eduardo Spinelli
Support type: Regular Research Grants