2009 Volume 50 Issue 7 Pages 1902-1904
The solidification behavior and structure of Bi-Ag alloys with low Ag content (0 mass%∼11 mass%) which are now being applied as high temperature Pb-free solders were investigated. The results show that Bi-Ag alloys exhibited a nonequilibrium eutectic solidification feature and a considerably large undercooling. A longer cooling period to reach eutectic temperature enhanced the faceting of primary Ag crystals. The large value of the entropy of solution for Ag near the eutectic point should account for this.