Sn addition on the tensile properties of high temperature Zn-4Al-3Mg solder alloys

The Zn-4Al-3Mg based solder alloy is a promising candidate to replace the conventional Pb-5Sn alloy in high-temperature electronic packaging. In this study, the tensile properties of Zn-4Al-3Mg-xSn alloys (x = 0, 6.8 and 13.2 wt.%) at high temperatures (e.g., 100 degrees C, and 200 degrees C) were investigated. It was found that the uniaxial tensile strength (UTS) of Zn-4Al-3Mg-xSn solder alloys all decrease monotonously with the increment of temperature. The elongation ratio at 100 degrees C is superior to that at room temperature whereas follows a significant drop at 200 degrees C. The microstructure observations show that a typical brittle fracture of Zn-4AI-3Mg alloy occurs at room temperature and 200 degrees C under normal tension, whereas a ductile fracture is found at 100 degrees C. The 6.8 wt.% Sn addition in Zn-4Al-3Mg alloy causes a dramatic decrease of yield strength, and a slight deterioration of the ductility. (C) 2011 Elsevier Ltd. All rights reserved.