Next Article in Journal
Fatigue Behaviors of Resistance Spot Welds for 980 MPa Grade TRIP Steel
Previous Article in Journal
Effects of Zr, Y on the Microstructure and Properties of As-Cast Cu-0.5Y-xZr (wt.%) Alloys
Open AccessArticle

Vacuum Brazing Ti–15–3 with a TiNiNb Braze Alloy

1
Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
2
Institute of Materials Engineering, National Taiwan Ocean University, Keelung 202, Taiwan
*
Author to whom correspondence should be addressed.
Metals 2019, 9(10), 1085; https://doi.org/10.3390/met9101085
Received: 14 September 2019 / Revised: 5 October 2019 / Accepted: 7 October 2019 / Published: 9 October 2019
Among all types of brazing fillers, Ti-based fillers show satisfactory joint strengths in brazing titanium alloys. However, the major concern in using such fillers is the formation of Cu/Ni/Ti intermetallic compound(s) in the joint. In this study, a Ti–15–3 alloy was vacuum brazed with a clad Ti–35Ni–25Nb foil. The brazed zone consisted of a Ti2Ni intermetallic compound in a (β-Ti,Nb)-rich matrix for specimen brazing at 1000 °C/600 s. Raising brazing temperature and time resulted in the Ti2Ni dissolving into the (β-Ti,Nb)-rich matrix. For the specimen brazing at 1100 °C/600s, Ti2Ni could only be observed at the grain boundaries of the (β-Ti,Nb)-rich matrix. After further raising it to 1200 °C/600 s, the Ti2Ni intermetallic compound was all dissolved into the (β-Ti,Nb)-rich phase. The average shear strength was significantly raised from 140 (1000 °C/600 s) to 620 MPa (1100 °C/3600 s). Crack initiation/propagation in the brittle Ti2Ni compound with the cleavage fractograph were changed into the Ti–15–3 base metal with a ductile dimple fractograph. The advantage of using Nb in the TiNiNb filler foil was its ability to stabilize β-Ti, and most of the Ni in the braze alloy was dissolved into the β-Ti matrix. The brazed joint could be free of any intermetallic phases with a proper brazing cycle applied, and the joint was suitable for a few harsh applications, e.g., repeated stresses and impact loadings. View Full-Text
Keywords: brazing; β titanium; electron backscatter diffraction; filler metal; dissolution; joint strength brazing; β titanium; electron backscatter diffraction; filler metal; dissolution; joint strength
Show Figures

Figure 1

MDPI and ACS Style

Kao, C.-S.; Tsay, L.-W.; Wang, S.-B.; Shiue, R.-K. Vacuum Brazing Ti–15–3 with a TiNiNb Braze Alloy. Metals 2019, 9, 1085.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop