Effects of In addition on microstructure and properties of SAC305 solder
Xiaolei Ren, Yunpeng Wang, Yanqing Lai, S.Y. Shi, Xiaoying Liu, Longjiang Zou, Ning Zhao
Abstract
In powderswith different contents (0.5−10 wt.%)were melted into the Sn−3.0Ag−0.5Cu (SAC305) solder to change the microstructure and thus improve the properties of the solder. The results showed that β -Sn(In), Ag 3 (Sn,In) and Cu 6 (Sn,In) 5 phases existed in all the In-added solders, and an additional phase of InSn 4 was found in the SAC305−10In solder. With increasing In addition amount, the β -Sn nucleation sites were increased and the nucleation model was changed from {101} to {301}, which refined the β -Sn grains and transformed the β -Sn morphology from large grains to interlaced grains and finally to multiple grains. As a result, a combined effect of fine grain strengthening and solid solution strengthening was achieved to increase the microhardness of the SAC305 −x In solders with increasing In addition amount.