Influence of bismuth on the solidification of Sn-0.7Cu-0.05Ni-xBi/Cu joints
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
The improvement of solder joint mechanical performance due to bismuth additions is of ongoing interest. This paper investigates the influence of 0–14 wt% Bi on microstructure formation in Sn-0.7 wt%Cu-0.05 wt%Ni-xBi solder balls on Cu substrates. It is shown that Bi additions reduce the Ni content of (Cu,Ni)6Sn5, increase the size of primary (Cu,Ni)6Sn5 rods and reduce the thickness of the Cu6Sn5 reaction layer, although these effects are subtle until the Bi content reaches ∼5 wt%Bi and Bi additions of ≤5 wt% did not significantly affect the positive effects of Ni. Higher Bi additions (≥8 wt% Bi) caused a transition of the tin growth texture from columnar grains with a <110> fibre texture towards a single grain with subgrains. Bi additions increased the non-equilibrium freezing range and caused a nonequilibrium ternary eutectic reaction in joints containing ≥2 wt% Bi. Bi contents less than 2 wt% are required to prevent (Bi) phase formation during solidification.
Date Issued
2016-12-31
Date Acceptance
2016-12-29
Citation
JOURNAL OF ALLOYS AND COMPOUNDS, 2016, 701, pp.321-334
ISSN
0925-8388
Publisher
ELSEVIER
Start Page
321
End Page
334
Journal / Book Title
JOURNAL OF ALLOYS AND COMPOUNDS
Volume
701
Copyright Statement
© 2017 Elsevier B.V. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Nihon Superior Co Ltd
Engineering & Physical Science Research Council (EPSRC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000395839100042&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
N/A
EP/M002241/1
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Materials Science, Multidisciplinary
Metallurgy & Metallurgical Engineering
Chemistry
Materials Science
Intermetallics
Microstructure
Phase diagrams
Thermal analysis
Lead-free solder
LEAD-FREE SOLDER
SN-AG-CU
INTERMETALLIC COMPOUND LAYERS
CRACK-GROWTH-BEHAVIOR
NI SOLDER
MECHANICAL-PROPERTIES
INTERFACIAL REACTION
GRAIN-ORIENTATION
FLUIDITY LENGTH
THERMAL FATIGUE
Materials
0912 Materials Engineering
0914 Resources Engineering And Extractive Metallurgy
0204 Condensed Matter Physics
Publication Status
Published