The Study of Infrared Brazing Ti50Ni50/CP-Ti and Ti50Ni50/Ti-15-3
Date Issued
2012
Date
2012
Author(s)
Chien, Kuang-Ting
Abstract
Wetting behavior、microstructural evolution and bonding strength of infrared brazed Ti50Ni50/CP-Ti using Cusil-ABA filler are studied. For brazing at 850℃, many interfacial layers are observed including α-Ti/Ti2Cu eutectoid, Ti2Cu, TiCu, Ti3Cu4, TiCu4, Ag-rich matrix and (CuxNi1-x)2Ti layers. Raising the brazing time and temperature let Cu atoms have enough time to diffuse into CP-Ti, so α-Ti/Ti2Cu eutectoid layer will become thicker. The shear tests indicate the brazed joint is mainly fractured along the Ti3Cu4 layer and central Ag-rich matrix in which the fracture surface exhibits ductile/brittle mixing mode. For brazing at 900℃, Ag-rich phase is expelled from braze and the brazed joint is full of intermetallic phases which change the fracture mode to brittle one. For using 40Ti-20Zr-20Cu-20Ni filler infrared bazed Ti-15-3 alloy and Ti50Ni50, Ti2Ni, β-Ti and residual filler are formed in the braze. During the shear tests, the crack forms in the Ti2Ni phase and then propagates until the sample is fractured. The higher the brazing temperature is or the longer the brazing time is, the more the continuous Ti2Ni will be. Therefore, the shear strength of the brazed joint decreases with increasing the brazing time or temperature. When using 70Ti-15Cu-15Ni filler brazed Ti-15-3/Ti50Ni50, Ti2Ni, β-Ti and dissolved Ti50Ni50 are formed in the braze. The shear tests show the crack is also formed in the Ti2Ni phase and the fracture surface exhibits brittle mode. The amount of Ti2Ni phase increases and that of β-Ti and dissolved Ti50Ni50 decreases with increasing the brazing time and temperature, and thus the shear strength of the brazed joint decreases simultaneously.
Subjects
Infrared brazing
Ti50Ni50
Ti-15-3 alloy
Cusil-ABA Ag-based filler
Ti-based filler
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R99522706-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):50a3e84ca7b09eed58a88314a7713eab