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.

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.

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.

Microstructural characterization of biobased carbon foam by means of X-ray microtomography and compared to conventional techniques

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 96057-96064 ◽  
Author(s):  
Juliette Merle ◽  
Pascale Sénéchal ◽  
Fabrice Guerton ◽  
Peter Moonen ◽  
Pierre Trinsoutrot ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mercury Intrusion Porosimetry ◽  
Microstructural Characterization ◽  
Carbon Foam ◽  
X Ray ◽  
Mercury Intrusion ◽  
Scanning Electron

The objective of this work is to compare three techniques for characterizing the morphology of porous bio-based carbon foam, namely mercury intrusion porosimetry, scanning electron microscopy and X-ray microtomography.

Microstructural Characterization of Glass-to-Metal Brazed Joint

2012 ◽  
Vol 616-618 ◽  
pp. 1732-1735 ◽  
Author(s):  
Xi Hai Shen ◽  
Yu Gang Zheng ◽  
Liang Chang ◽  
Jin Jia Guo ◽  
Song Bin Ye ◽  
...  
Keyword(s):  
Thermal Power ◽  
Microstructural Characterization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solar Thermal Power ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Scanning Electron

Aiming at the glass-to-metal seals serving in the Solar Thermal Power (STP), glass-to-metal vacuum brazed joints were studied. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed to examine the microstructure and element contents of interface seam on the glass-to-metal vacuum brazed joints. Also, the compositional concentration of the interface seam was measured by using energy dispersive spectroscopy (EDS).

Microstructural characterization of silica aerogels using scanning electron microscopy

1996 ◽  
Vol 31 (21) ◽  
pp. 5683-5689 ◽  
Author(s):  
G. M. Pajonk ◽  
A. Venkateswara Rao ◽  
N. N. Parvathy ◽  
E. Elaloui
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microstructural Characterization ◽  
Silica Aerogels ◽  
Scanning Electron

scholarly journals Microstructural characterization of ice cores

2005 ◽  
Vol 42 ◽  
pp. 441-444 ◽  
Author(s):  
Ian Baker ◽  
Daniel Iliescu ◽  
Rachel Obbard ◽  
Hui Chang ◽  
Benjamin Bostick ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscopy ◽  
Ice Core ◽  
Ice Cores ◽  
Microstructural Characterization ◽  
Electron Backscatter ◽  
Scanning Electron

AbstractIn this paper, we outline the use of Raman spectroscopy coupled with scanning confocal optical microscopy for determining the microstructural location of impurities in ice-core specimens. We also demonstrate how the orientations of grains and the misorientations across grain boundaries can be determined to high precision for ice polycrystals using either selected area channeling patterns or electron backscatter patterns in a scanning electron microscope.

scholarly journals Nanostructured Energetic Materials with Sol-gel Methods

2003 ◽  
Vol 800 ◽  
Author(s):  
Alexander E. Gash ◽  
Joe H. Satcher ◽  
Randall L. Simpson ◽  
Brady J. Clapsaddle
Keyword(s):  
Thermal Properties ◽  
Energetic Materials ◽  
Energetic Material ◽  
Sol Gel ◽  
Small Scale ◽  
Fine Grained ◽  
Electron Microscopies ◽  
Burn Rate ◽  
Scanning Electron

AbstractThe utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe2O3/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed on the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH4ClO4) oxidizer present.

Influence of Welding Process on the Microstructure of Carbon Steel and Stainless Steel Heterogeneous Welded Joints

2016 ◽  
Vol 1138 ◽  
pp. 31-36
Author(s):  
Maria Cristina Dijmarescu ◽  
Dumitru Titi Cicic ◽  
Corneliu Rontescu ◽  
Gheorhe Solomon
Keyword(s):  
Chemical Composition ◽  
Carbon Steel ◽  
Structural Characterization ◽  
Base Material ◽  
Welding Process ◽  
Cored Wire ◽  
Base Materials ◽  
Flux Cored Arc Welding ◽  
Welded Seam

The reactions of the base material, during the welding process, consist in chemical composition, volume, structure and granulation changes. There are multiple problems which can occur by welding two steels with totally different chemical composition, i.e. carbon steel S235JR + AR and austenitic stainless X2CrNiMo17-12-2. The process used for making the heterogeneous joint was flux cored arc welding (FCAW), numerically coded 136. The paper presents the effects of welding through heat input, on the structural characterization of welded seam and heat affected zone. It also focuses on the structural characterization of the welded joint obtained using the flux cored wire T 23 12 L P C/M 1, and determining how the base materials participate at the formation of the welding joint.

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