Joining of TiAl Alloy Using Novel Ag–Cu Sputtered Coated Ti Brazing Filler

2018 ◽  
Vol 25 (1) ◽  
pp. 192-195 ◽  
Author(s):  
Sónia Simões ◽  
Ana Soares ◽  
Carlos José Tavares ◽  
Aníbal Guedes
Keyword(s):  
Tial Alloy ◽  
Base Material ◽  
Microstructural Characterization ◽  
Thin Layers ◽  
Copper Films ◽  
Tial Alloys ◽  
Brazing Fillers ◽  
Cu Films ◽  
Potential Use

AbstractThe aim of this study is to evaluate the potential use of titanium foil coated with sputtered silver and copper films as a novel brazing filler for joining TiAl alloys. For this purpose, a detailed microstructural characterization of the resulting brazing interfaces was carried out. The development of brazing fillers that allow the joining of TiAl alloys without compromising the service temperature is a fruitful prospect. Brazing experiments were performed in a vacuum at 900, 950, and 980°C, with a dwell time of 30 min. Microstructural characterization reveals that brazing joints can be obtained successfully at 950 and 980°C. The interface consists of a large central region of α-Ti with an amount of Al and Ti–Ag compound and thin layers, mainly composed of intermetallic compounds, formed close to the base material. A novel brazing filler consisting of Ti foil coated with sputtered Ag and Cu films inhibits the extensive formation of soft (Ag) zones or coarse brittle Ti–Al–(Cu,Ni) particles. Hence, the need for post-brazing heat treatments for the joining of TiAl alloys was avoided.

scholarly journals Microstructural Characterization of Dissimilar Titanium Alloys Joints Using Ni/Al Nanolayers

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 715 ◽  
Author(s):  
Sónia Simões ◽  
Filomena Viana ◽  
Ana Ramos ◽  
M. Vieira ◽  
Manuel Vieira
Keyword(s):  
Titanium Alloys ◽  
Diffusion Bonding ◽  
Base Material ◽  
Microstructural Characterization ◽  
Thin Layers ◽  
Electron Microscopies ◽  
Base Materials ◽  
Material Surfaces ◽  
Scanning Electron

This study demonstrates the potential of the use of Ni/Al nanolayers for joining dissimilar titanium alloys. For this purpose, a detailed microstructural characterization of the diffusion bonding interfaces of TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V was carried out. The nanolayers (alternated aluminum and nickel (Ni-7V wt.%) layers) were deposited onto the base material surfaces. Diffusion bonding was performed at 700 and 800 °C under pressures ranging from 5 to 40 MPa and at dwell times between 60 and 180 min. Microstructural characterization was performed using high resolution transmission and scanning electron microscopies. The results revealed that dissimilar titanium joints (TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V) assisted by Ni/Al nanolayers can be obtained successfully at 800 °C for 60 min using a pressure of 20 MPa. The bond interfaces are thin (less than 10 µm) and mainly composed of NiAl grains with a few nanometric grains of Al8V5. Thin layers of Al-Ni-Ti intermetallic compounds were formed adjacent to the base materials due to their reaction with the nanolayers.

Microstructural Characterization of α2 + γ Titanium Aluminides

1997 ◽  
Vol 3 (S2) ◽  
pp. 701-702
Author(s):  
D. J. Larson ◽  
M. K. Miller
Keyword(s):  
Titanium Aluminides ◽  
Base Alloy ◽  
Significant Proportion ◽  
Weight Ratio ◽  
High Strength ◽  
Microstructural Characterization ◽  
Two Phase ◽  
Tial Alloys ◽  
Boron Doped

Two-phase α2+γ TiAl alloys with microalloying additions, Fig. 1, are of interest due to the high strength-to-weight ratio they can provide in automotive and aircraft applications. In boron-doped α2+γTiAl containing Cr, Nb, and W, the B levels were found to be significantly depleted below the nominal alloy content in both the α2 andγ phases. The boron solubilities in the γ and α2 phases were 0.011 ± 0.005 at. % B and 0.003 ± 0.005 at. % B, respectively in Ti-47% Al-2% Cr-1.8% Nb-0.2% W-0.15 % B that was aged for 2 h at 900°C (base alloy). The majority of the B was in a variety of borides including TiB, TiB2 and a Cr-enriched (Ti,Cr)2B precipitate. With the exception of the smaller (< 50 nm thick) Cr-enriched (Ti,Cr)2B precipitates, Fig. 2, most of the borides were larger than ∼100 nm. A significant proportion of the microalloying additions is in these borides, Table 1.

scholarly journals Joining Alumina to Titanium Alloys Using Ag-Cu Sputter-Coated Ti Brazing Filler

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4802
Author(s):  
Omid Emadinia ◽  
Aníbal Guedes ◽  
Carlos José Tavares ◽  
Sónia Simões
Keyword(s):  
Microstructural Characterization ◽  
Interface Bonding ◽  
Soft Or ◽  
Tial Alloys ◽  
X Ray ◽  
Distribution Maps ◽  
Ti Oxides ◽  
Ti Alloys ◽  
Central Regions

The joining of alumina (Al2O3) to γ-TiAl and Ti6Al4V alloys, using Ag-Cu sputter-coated Ti brazing filler foil, was investigated. Brazing experiments were performed at 980 °C for 30 min in vacuum. The microstructure and chemical composition of the brazed interfaces were analyzed by scanning electron microscopy and by energy dispersive X-ray spectroscopy, respectively. A microstructural characterization of joints revealed that sound multilayered interfaces were produced using this novel brazing filler. Both interfaces are composed mainly of α-Ti, along with Ti2(Ag,Cu) and TiAg intermetallics. In the case of the brazing of γ-TiAl alloys, α2-Ti3Al and γ-TiAl intermetallics are also detected at the interface. Bonding to Al2O3 is promoted by the formation of a quite hard Ti-rich layer, which may reach a hardness up to 1872 HV 0.01 and is possibly composed of a mixture of α-Ti and Ti oxides. Hardness distribution maps indicate that no segregation of either soft or brittle phases occurs at the central regions of the interfaces or near the base Ti alloys. In addition, a smooth hardness transition was established between the interface of Al2O3 to either γ-TiAl or Ti6Al4V alloys.

Physical and Microstructural Characterization of Cathode, Composite Cathode and Electrolyte Ceramics to ITSOFC

2014 ◽  
Vol 775-776 ◽  
pp. 52-56
Author(s):  
Reinaldo Azevedo Vargas ◽  
Everton Bonturim ◽  
Marco Andreoli ◽  
Rubens Chiba ◽  
Emília Satoshi Miyamaru Seo
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Microstructural Characterization ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Spraying ◽  
Potential Use

The (La0.60Sr0.40)(Co0.20Fe0.80)O3-δ - LSCF, (Ce0.90Gd0.10)O1.95 - CGO composites and LSCF were deposited by wet powder spraying deposition method for the purpose of investigating their potential use in Intermediate Temperature Solid Oxide Fuel Cells. The interlayers are necessary between CGO electrolytes and LSCF cathodes in order to improve the performance of these materials. LSCF powders synthesized by citrate technique were calcined at 900 °C for 4 h and, their LSCFCGO composites and LSCF suspensions deposited on CGO substrate and, sintered in 1100 °C for 1 h, were formed pseudo-perovskite. The ceramics materials were analyzed by X-ray diffraction (XRD) and chemical composition of different half-cells layers by scanning electron microscope with energy dispersive (SEM-EDS). The results are in agreement with the literature and indicate that route studied is adequate for crystal structures formation compatible with films the 35 μm thick total for study of conductivity between the cathode and the electrolyte.

scholarly journals Diffusion Bonding of Ti6Al4V to Al2O3 Using Ni/Ti Reactive Multilayers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 655
Author(s):  
Marcionilo Silva ◽  
Ana S. Ramos ◽  
M. Teresa Vieira ◽  
Sónia Simões
Keyword(s):  
Thin Films ◽  
Diffusion Bonding ◽  
Mechanical Characterization ◽  
Base Material ◽  
Microstructural Characterization ◽  
Multilayer Thin Films ◽  
X Ray ◽  
Distribution Maps ◽  
Base Materials

This paper aims to investigate the diffusion bonding of Ti6Al4V to Al2O3. The potential of the use of reactive nanolayered thin films will also be investigated. For this purpose, Ni/Ti multilayer thin films with a 50 nm modulation period were deposited by magnetron sputtering onto the base materials. Diffusion bonding experiments were performed at 800 °C, under 50 MPa and a dwell time of 60 min, with and without interlayers. Microstructural characterization of the interface was conducted through scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The joints experiments without interlayer were unsuccessful. The interface is characterized by the presence of a crack close to the Al2O3 base material. The results revealed that the Ni/Ti reactive multilayers improved the diffusion bonding process, allowing for sound joints to be obtained at 800 °C for 60 min. The interface produced is characterized by a thin thickness and is mainly composed of NiTi and NiTi2 reaction layers. Mechanical characterization of the joint was assessed by hardness and reduced Young’s modulus distribution maps that enhance the different phases composing the interface. The hardness maps showed that the interface exhibits a hardness distribution similar to the Al2O3, which can be advantageous to the mechanical behavior of the joints.

scholarly journals Microstructural Characterization of Electroplated Copper Films on Copper-Alloy Seed Layer

2007 ◽  
Vol 56 (6) ◽  
pp. 465-470
Author(s):  
Yukinori HIROSE ◽  
Kazuhito HONDA ◽  
Kazuyoshi MAEKAWA ◽  
Hiroshi MIYAZAKI ◽  
Akira UEDONO ◽  
...  
Keyword(s):  
Copper Alloy ◽  
Seed Layer ◽  
Microstructural Characterization ◽  
Copper Films ◽  
Electroplated Copper
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