Infrared Brazing Ti50Ni50 and Ti-15-3 Alloys Using Two Ag-based Fillers

摘要

Microstructural evolution of infrared brazed Ti50Ni50 shape memory alloy and Ti-15-3 using BAg-8 and Ticusil active braze alloys is performed in the study. Only Ticusil active braze readily wets both Ti50Ni50 and Ti-15-3 substrates. The wettability of Ag-Cu braze on Ti50Ni50 substrate is improved by adding 4. 5wt% Ti into the braze alloy. The brazed Ti50Ni50/BAg-8/Ti-15-3 joint is mainly comprised of Ag-rich matrix and Cu-Ti intermetallics. The formation of interfacial Cu-(Ni)-Ti intermetallic phases is attributed to the wetting of both substrates. The brazed Ti50Ni50/ Ticusil/Ti-15-3 joint shows more vigorous reaction among filler metal and both substrates, resulting in forming huge amount of Cu-Ni-Ti intermetallic compounds in the joint.