Infrared brazing of high-strength titanium alloys by Ti-15Cu-15Ni and Ti-15Cu-25Ni filler foils
Journal
Materials Science and Engineering A
Journal Volume
420
Journal Issue
1-2
Pages
155-164
Date Issued
2006
Author(s)
Abstract
Microstructures and fracture behaviors of infrared heated, vacuum brazed Ti-6Al-4V and Ti-15-3 alloys using two Ti-Cu-Ni braze fillers have been characterized to establish the effects of brazing process parameter and chemical composition on the strength of brazed joints. The brazed joint initially contains two prominent phases; a Ti alloy matrix alloyed with V, Cr, Ni, Cu and Al and a Cu-Ni-rich Ti phase. Brazing temperature and soak time control the amount of Cu-Ni-rich Ti phase in the brazed joints. The fracture mode changes from brittle cleavage to quasi-cleavage to ductile dimple as the amount of Cu-Ni-rich Ti phase is reduced in the brazed joint. Both brazing temperature and soak time are critical to eliminate the Cu-Ni-rich Ti phase for optimal shear strength and ductile fracture of brazed joints. A post-brazing annealing at lower temperature is also shown to be an effective way to homogenize the microstructure of brazed joint for improved joint strength. © 2006 Elsevier B.V. All rights reserved.
Type
journal article