Brazeability and mechanical properties of Ag–Cu–Sn brazing filler metals on copper-brazed joint

Abstract

This paper describes an investigation of cadmium-free silver brazing filler metals, the ternary Ag–Cu–Sn alloys. The influences of tin content on solidus and liquidus temperatures and gap filling ability of Ag–Cu–Sn alloys on copper were investigated. Microstructures of the joint and the shear strength were examined. Investigation on gap filling ability test procedure was performed according to ISO 5179-1983. The result from differential thermal analysis showed that the solidus and liquidus temperatures of the filler metals decreased with the increment of tin content in Ag–Cu–Sn. The results from the shear test showed that the brazed joint exhibited the highest strength at 10 wt-% tin content in the filler metal. The joint gaps of less than 0·10 mm were proposed when designing the brazed joint for Ag–Cu–Sn filler metals.