Effects of Ti addition to Sn-Ag and Sn-Cu solders

Minor alloying addition to solders has been an important strategy to improve the integrity and reliability of Pb-free solder joints. In this study, a small amount of Ti was added to Sn-Cu and Sn-Ag solders, and their microstructures, solidification behaviors, mechanical properties, and high temperature aging characteristics were investigated. Thermal analysis confirmed Ti addition being very effective in reducing the undercooling. Correlations between cooling rates, microstructure, and microhardness were established. One pronounced feature of Ti addition was that Ti-added solders had microstructures very stable against extreme aging conditions. © 2011 Elsevier B.V. All rights reserved.