Microstructure and Mechanical Properties of a SiO{sub 2} Ceramic and TC4 Alloy Joint Brazed with a Nanocomposite Filler

Journal Article · Mon Jul 15 00:00:00 EDT 2019 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-019-04147-3· OSTI ID:22970679

Bian, Hong ^[1]; Zhang, Qi ^[2]; Song, Yanyu ^[1]; Liu, Duo ^[3]; Liu, Jinghe ^[2]; Song, Xiaoguo ^[3]

---

1. Harbin Institute of Technology, School of Materials Science and Engineering (China)
2. Harbin Institute of Technology at Weihai, Shandong Provincial Key Lab of Special Welding Technology (China)
3. Harbin Institute of Technology, State Key Laboratory of Advanced Welding and Joining (China)

Vacuum brazing of TC4 alloy and SiO{sub 2} ceramic was achieved using a nano-AgCuNi braze alloy. The melting temperature of nano-AgCu powders was analyzed by differential scanning calorimeter. Furthermore, the effects of the Ni content on the microstructure and mechanical properties of the joints were studied. The results showed that the melting temperature of the nano-AgCu filler was 774 °C. A decrease in the melting temperature of 6 °C was observed, compared with the general AgCu filler, and this decrease enabled the interfacial reaction of the joint to begin earlier. The typical interfacial microstructure of the TC4/nano-AgCuNi/SiO{sub 2} ceramic joint brazed at 950 °C for 10 min was TC4/α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectoid structure/Ti{sub 2}(Cu,Ni) compound with α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectic structure/Ti{sub 4}O{sub 7} + TiSi{sub 2}/SiO{sub 2} ceramics. The homogeneous microstructure of α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectoid structure primarily existed in the diffusion layer. Additionally, the refined α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectic structure created via a eutectic reaction and Ti{sub 2}(Cu,Ni) compound was distributed in the brazing seam. The Ni content could influence the formation of Ti-Cu-Ni ternary intermetallic compounds (IMCs). An increase in Ni led to an increase in the α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectic structure in the brazing seam. The shear strength of the brazed joints first increased and then decreased with the increase in the nano-Ni content, and the optimal shear strength of 30.1 MPa was achieved at 10 wt.% Ni. The increase in the α-Ti + Ti{sub 2}(Cu,Ni) + Ti{sub 2}(Ni,Cu) hypereutectic structure and the decrease in brittle compounds enhanced the shear strength of the joint. Fracture analysis of the joints brazed at 950 °C for 10 min indicated that the cracks mainly occurred in SiO{sub 2} ceramic.

• OSTI ID: 22970679
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 7 Vol. 28; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BRAZED JOINTS
BRAZING ALLOYS
CERAMICS
COPPER
FILLERS
INTERMETALLIC COMPOUNDS
MELTING POINTS
MICROSTRUCTURE
SHEAR PROPERTIES
SILICA
SILICON OXIDES
TITANIUM SILICIDES