Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/75031
Type: Artigo de periódico
Title: The effect of cooling rate on the dendritic spacing and morphology of Ag3Sn intermetallic particles of a SnAg solder alloy
Author: Garcia, LR
Osorio, WR
Garcia, A
Abstract: The size and morphology of intermetallic compounds of Sn-Ag solder alloys can have a significant influence on the mechanical strength of solder joints. The aim of the present study is to characterize the as-cast microstructure of a Sn-2 wt.% Ag solder alloy, and to correlate the resulting scale of the dendritic matrix and the morphology of the Ag3Sn intermetallic compound (IMC) with the corresponding solidification cooling rate. Pre-heated low-carbon steel molds and a water-cooled solidification apparatus were used permitting a significant range of solidification cooling rates to be experimentally examined. It is shown that under very slow cooling conditions (0.02 degrees C/s) the microstructure of the sample is formed by a coarse dendritic matrix and a mixture of fiber and plate-like Ag3Sn IMC in the interdendritic region with the fibers located along the board line separating the matrix. For cooling rates from 0.15 to 1.15 degrees C/s a mixture of spheroid and fiber-like IMC and secondary dendrite arm spacings between 15 and 40 mu m, with the spheroids located in the center of the interdendritic region. At higher cooling rates, of about 8 degrees C/s only Ag3Sn spheroids (of about 0.5 mu m in diameter) prevail in the eutectic mixture. (C) 2010 Elsevier Ltd. All rights reserved.
Country: Inglaterra
Editor: Elsevier Sci Ltd
Rights: fechado
Identifier DOI: 10.1016/j.matdes.2010.12.046
Date Issue: 2011
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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