ผลของเทลลูเรียมต่อโครงสร้างจุลภาคและสมบัติทางกลของโลหะบัดกรี SAC105

Abstract

This research studied the synthesis of the SAC105 lead-free solder alloys with added Te contents of 0, 0.5, 1.0, 1.5, and 2.0 wt.% by the permanent mold casting process. The effects of Te on the microstructure, thermal behavior, mechanical properties, and wettability of SAC105 solder alloys were observed. The results showed that the microstructure of the SAC105 solder alloy consists of the β-Sn matrix phase and the Ag3Sn and Cu6Sn5 IMC phases. The small addition of Te formed a new SnTe IMC phase in the solder matrix and resulted in the coarsening of the IMC phases. The addition of Te slightly affected the melting temperature and pasty range but significantly increased the undercooling of SAC105 solder alloys. The ultimate tensile strength (UTS), yield strength (YS), and hardness of the solder alloy increased with the addition of Te due to the second phase strengthening effect; while adding Te more than 0.5 wt.%, the UTS and YS decreased due to coarsening of the microstructure. The fracture surface of the SAC105 solder alloy shows the ductile fracture mode while adding Te to the solder, resulting in the mixed ductile-brittle fracture mode. The addition of Te slightly affected the shear strength of the solder joint and tended to decrease as the amount of Te increased, caused by the thickness of the IMC layers between the solder and Cu substrate. Te increases the wettability of the solder alloy, increases the spreading area, and reduces the contact angle, but it doesn't significantly increase the thickness of IMC. From this research, the addition of 0.5 wt.% Te was the optimal amount to improve the microstructure, thermal behavior, mechanical properties, and wettability of the SAC105 solder alloy.